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Commit 61b7efdd authored by Linus Torvalds's avatar Linus Torvalds
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Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/spi-2.6

parents 3e2b32b6 2e10c84b
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Documentation/spi/butterfly 0 → 100644
View file @ 61b7efdd
spi_butterfly - parport-to-butterfly adapter driver
===================================================
This is a hardware and software project that includes building and using
a parallel port adapter cable, together with an "AVR Butterfly" to run
firmware for user interfacing and/or sensors. A Butterfly is a $US20
battery powered card with an AVR microcontroller and lots of goodies:
sensors, LCD, flash, toggle stick, and more. You can use AVR-GCC to
develop firmware for this, and flash it using this adapter cable.
You can make this adapter from an old printer cable and solder things
directly to the Butterfly. Or (if you have the parts and skills) you
can come up with something fancier, providing ciruit protection to the
Butterfly and the printer port, or with a better power supply than two
signal pins from the printer port.
The first cable connections will hook Linux up to one SPI bus, with the
AVR and a DataFlash chip; and to the AVR reset line. This is all you
need to reflash the firmware, and the pins are the standard Atmel "ISP"
connector pins (used also on non-Butterfly AVR boards).
Signal Butterfly Parport (DB-25)
------ --------- ---------------
SCK = J403.PB1/SCK = pin 2/D0
RESET = J403.nRST = pin 3/D1
VCC = J403.VCC_EXT = pin 8/D6
MOSI = J403.PB2/MOSI = pin 9/D7
MISO = J403.PB3/MISO = pin 11/S7,nBUSY
GND = J403.GND = pin 23/GND
Then to let Linux master that bus to talk to the DataFlash chip, you must
(a) flash new firmware that disables SPI (set PRR.2, and disable pullups
by clearing PORTB.[0-3]); (b) configure the mtd_dataflash driver; and
(c) cable in the chipselect.
Signal Butterfly Parport (DB-25)
------ --------- ---------------
VCC = J400.VCC_EXT = pin 7/D5
SELECT = J400.PB0/nSS = pin 17/C3,nSELECT
GND = J400.GND = pin 24/GND
The "USI" controller, using J405, can be used for a second SPI bus. That
would let you talk to the AVR over SPI, running firmware that makes it act
as an SPI slave, while letting either Linux or the AVR use the DataFlash.
There are plenty of spare parport pins to wire this one up, such as:
Signal Butterfly Parport (DB-25)
------ --------- ---------------
SCK = J403.PE4/USCK = pin 5/D3
MOSI = J403.PE5/DI = pin 6/D4
MISO = J403.PE6/DO = pin 12/S5,nPAPEROUT
GND = J403.GND = pin 22/GND
IRQ = J402.PF4 = pin 10/S6,ACK
GND = J402.GND(P2) = pin 25/GND
Documentation/spi/spi-summary 0 → 100644
View file @ 61b7efdd
Overview of Linux kernel SPI support
====================================
02-Dec-2005
What is SPI?
------------
The "Serial Peripheral Interface" (SPI) is a synchronous four wire serial
link used to connect microcontrollers to sensors, memory, and peripherals.
The three signal wires hold a clock (SCLK, often on the order of 10 MHz),
and parallel data lines with "Master Out, Slave In" (MOSI) or "Master In,
Slave Out" (MISO) signals. (Other names are also used.) There are four
clocking modes through which data is exchanged; mode-0 and mode-3 are most
commonly used. Each clock cycle shifts data out and data in; the clock
doesn't cycle except when there is data to shift.
SPI masters may use a "chip select" line to activate a given SPI slave
device, so those three signal wires may be connected to several chips
in parallel. All SPI slaves support chipselects. Some devices have
other signals, often including an interrupt to the master.
Unlike serial busses like USB or SMBUS, even low level protocols for
SPI slave functions are usually not interoperable between vendors
(except for cases like SPI memory chips).
- SPI may be used for request/response style device protocols, as with
touchscreen sensors and memory chips.
- It may also be used to stream data in either direction (half duplex),
or both of them at the same time (full duplex).
- Some devices may use eight bit words. Others may different word
lengths, such as streams of 12-bit or 20-bit digital samples.
In the same way, SPI slaves will only rarely support any kind of automatic
discovery/enumeration protocol. The tree of slave devices accessible from
a given SPI master will normally be set up manually, with configuration
tables.
SPI is only one of the names used by such four-wire protocols, and
most controllers have no problem handling "MicroWire" (think of it as
half-duplex SPI, for request/response protocols), SSP ("Synchronous
Serial Protocol"), PSP ("Programmable Serial Protocol"), and other
related protocols.
Microcontrollers often support both master and slave sides of the SPI
protocol. This document (and Linux) currently only supports the master
side of SPI interactions.
Who uses it? On what kinds of systems?
---------------------------------------
Linux developers using SPI are probably writing device drivers for embedded
systems boards. SPI is used to control external chips, and it is also a
protocol supported by every MMC or SD memory card. (The older "DataFlash"
cards, predating MMC cards but using the same connectors and card shape,
support only SPI.) Some PC hardware uses SPI flash for BIOS code.
SPI slave chips range from digital/analog converters used for analog
sensors and codecs, to memory, to peripherals like USB controllers
or Ethernet adapters; and more.
Most systems using SPI will integrate a few devices on a mainboard.
Some provide SPI links on expansion connectors; in cases where no
dedicated SPI controller exists, GPIO pins can be used to create a
low speed "bitbanging" adapter. Very few systems will "hotplug" an SPI
controller; the reasons to use SPI focus on low cost and simple operation,
and if dynamic reconfiguration is important, USB will often be a more
appropriate low-pincount peripheral bus.
Many microcontrollers that can run Linux integrate one or more I/O
interfaces with SPI modes. Given SPI support, they could use MMC or SD
cards without needing a special purpose MMC/SD/SDIO controller.
How do these driver programming interfaces work?
------------------------------------------------
The <linux/spi/spi.h> header file includes kerneldoc, as does the
main source code, and you should certainly read that. This is just
an overview, so you get the big picture before the details.
SPI requests always go into I/O queues. Requests for a given SPI device
are always executed in FIFO order, and complete asynchronously through
completion callbacks. There are also some simple synchronous wrappers
for those calls, including ones for common transaction types like writing
a command and then reading its response.
There are two types of SPI driver, here called:
Controller drivers ... these are often built in to System-On-Chip
processors, and often support both Master and Slave roles.
These drivers touch hardware registers and may use DMA.
Or they can be PIO bitbangers, needing just GPIO pins.
Protocol drivers ... these pass messages through the controller
driver to communicate with a Slave or Master device on the
other side of an SPI link.
So for example one protocol driver might talk to the MTD layer to export
data to filesystems stored on SPI flash like DataFlash; and others might
control audio interfaces, present touchscreen sensors as input interfaces,
or monitor temperature and voltage levels during industrial processing.
And those might all be sharing the same controller driver.
A "struct spi_device" encapsulates the master-side interface between
those two types of driver. At this writing, Linux has no slave side
programming interface.
There is a minimal core of SPI programming interfaces, focussing on
using driver model to connect controller and protocol drivers using
device tables provided by board specific initialization code. SPI
shows up in sysfs in several locations:
/sys/devices/.../CTLR/spiB.C ... spi_device for on bus "B",
chipselect C, accessed through CTLR.
/sys/devices/.../CTLR/spiB.C/modalias ... identifies the driver
that should be used with this device (for hotplug/coldplug)
/sys/bus/spi/devices/spiB.C ... symlink to the physical
spiB-C device
/sys/bus/spi/drivers/D ... driver for one or more spi*.* devices
/sys/class/spi_master/spiB ... class device for the controller
managing bus "B". All the spiB.* devices share the same
physical SPI bus segment, with SCLK, MOSI, and MISO.
How does board-specific init code declare SPI devices?
------------------------------------------------------
Linux needs several kinds of information to properly configure SPI devices.
That information is normally provided by board-specific code, even for
chips that do support some of automated discovery/enumeration.
DECLARE CONTROLLERS
The first kind of information is a list of what SPI controllers exist.
For System-on-Chip (SOC) based boards, these will usually be platform
devices, and the controller may need some platform_data in order to
operate properly. The "struct platform_device" will include resources
like the physical address of the controller's first register and its IRQ.
Platforms will often abstract the "register SPI controller" operation,
maybe coupling it with code to initialize pin configurations, so that
the arch/.../mach-*/board-*.c files for several boards can all share the
same basic controller setup code. This is because most SOCs have several
SPI-capable controllers, and only the ones actually usable on a given
board should normally be set up and registered.
So for example arch/.../mach-*/board-*.c files might have code like:
#include <asm/arch/spi.h> /* for mysoc_spi_data */
/* if your mach-* infrastructure doesn't support kernels that can
* run on multiple boards, pdata wouldn't benefit from "__init".
*/
static struct mysoc_spi_data __init pdata = { ... };
static __init board_init(void)
{
...
/* this board only uses SPI controller #2 */
mysoc_register_spi(2, &pdata);
...
}
And SOC-specific utility code might look something like:
#include <asm/arch/spi.h>
static struct platform_device spi2 = { ... };
void mysoc_register_spi(unsigned n, struct mysoc_spi_data *pdata)
{
struct mysoc_spi_data *pdata2;
pdata2 = kmalloc(sizeof *pdata2, GFP_KERNEL);
*pdata2 = pdata;
...
if (n == 2) {
spi2->dev.platform_data = pdata2;
register_platform_device(&spi2);
/* also: set up pin modes so the spi2 signals are
* visible on the relevant pins ... bootloaders on
* production boards may already have done this, but
* developer boards will often need Linux to do it.
*/
}
...
}
Notice how the platform_data for boards may be different, even if the
same SOC controller is used. For example, on one board SPI might use
an external clock, where another derives the SPI clock from current
settings of some master clock.
DECLARE SLAVE DEVICES
The second kind of information is a list of what SPI slave devices exist
on the target board, often with some board-specific data needed for the
driver to work correctly.
Normally your arch/.../mach-*/board-*.c files would provide a small table
listing the SPI devices on each board. (This would typically be only a
small handful.) That might look like:
static struct ads7846_platform_data ads_info = {
.vref_delay_usecs = 100,
.x_plate_ohms = 580,
.y_plate_ohms = 410,
};
static struct spi_board_info spi_board_info[] __initdata = {
{
.modalias = "ads7846",
.platform_data = &ads_info,
.mode = SPI_MODE_0,
.irq = GPIO_IRQ(31),
.max_speed_hz = 120000 /* max sample rate at 3V */ * 16,
.bus_num = 1,
.chip_select = 0,
},
};
Again, notice how board-specific information is provided; each chip may need
several types. This example shows generic constraints like the fastest SPI
clock to allow (a function of board voltage in this case) or how an IRQ pin
is wired, plus chip-specific constraints like an important delay that's
changed by the capacitance at one pin.
(There's also "controller_data", information that may be useful to the
controller driver. An example would be peripheral-specific DMA tuning
data or chipselect callbacks. This is stored in spi_device later.)
The board_info should provide enough information to let the system work
without the chip's driver being loaded. The most troublesome aspect of
that is likely the SPI_CS_HIGH bit in the spi_device.mode field, since
sharing a bus with a device that interprets chipselect "backwards" is
not possible.
Then your board initialization code would register that table with the SPI
infrastructure, so that it's available later when the SPI master controller
driver is registered:
spi_register_board_info(spi_board_info, ARRAY_SIZE(spi_board_info));
Like with other static board-specific setup, you won't unregister those.
The widely used "card" style computers bundle memory, cpu, and little else
onto a card that's maybe just thirty square centimeters. On such systems,
your arch/.../mach-.../board-*.c file would primarily provide information
about the devices on the mainboard into which such a card is plugged. That
certainly includes SPI devices hooked up through the card connectors!
NON-STATIC CONFIGURATIONS
Developer boards often play by different rules than product boards, and one
example is the potential need to hotplug SPI devices and/or controllers.
For those cases you might need to use use spi_busnum_to_master() to look
up the spi bus master, and will likely need spi_new_device() to provide the
board info based on the board that was hotplugged. Of course, you'd later
call at least spi_unregister_device() when that board is removed.
When Linux includes support for MMC/SD/SDIO/DataFlash cards through SPI, those
configurations will also be dynamic. Fortunately, those devices all support
basic device identification probes, so that support should hotplug normally.
How do I write an "SPI Protocol Driver"?
----------------------------------------
All SPI drivers are currently kernel drivers. A userspace driver API
would just be another kernel driver, probably offering some lowlevel
access through aio_read(), aio_write(), and ioctl() calls and using the
standard userspace sysfs mechanisms to bind to a given SPI device.
SPI protocol drivers somewhat resemble platform device drivers:
static struct spi_driver CHIP_driver = {
.driver = {
.name = "CHIP",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = CHIP_probe,
.remove = __devexit_p(CHIP_remove),
.suspend = CHIP_suspend,
.resume = CHIP_resume,
};
The driver core will autmatically attempt to bind this driver to any SPI
device whose board_info gave a modalias of "CHIP". Your probe() code
might look like this unless you're creating a class_device:
static int __devinit CHIP_probe(struct spi_device *spi)
{
struct CHIP *chip;
struct CHIP_platform_data *pdata;
/* assuming the driver requires board-specific data: */
pdata = &spi->dev.platform_data;
if (!pdata)
return -ENODEV;
/* get memory for driver's per-chip state */
chip = kzalloc(sizeof *chip, GFP_KERNEL);
if (!chip)
return -ENOMEM;
dev_set_drvdata(&spi->dev, chip);
... etc
return 0;
}
As soon as it enters probe(), the driver may issue I/O requests to
the SPI device using "struct spi_message". When remove() returns,
the driver guarantees that it won't submit any more such messages.
- An spi_message is a sequence of of protocol operations, executed
as one atomic sequence. SPI driver controls include:
+ when bidirectional reads and writes start ... by how its
sequence of spi_transfer requests is arranged;
+ optionally defining short delays after transfers ... using
the spi_transfer.delay_usecs setting;
+ whether the chipselect becomes inactive after a transfer and
any delay ... by using the spi_transfer.cs_change flag;
+ hinting whether the next message is likely to go to this same
device ... using the spi_transfer.cs_change flag on the last
transfer in that atomic group, and potentially saving costs
for chip deselect and select operations.
- Follow standard kernel rules, and provide DMA-safe buffers in
your messages. That way controller drivers using DMA aren't forced
to make extra copies unless the hardware requires it (e.g. working
around hardware errata that force the use of bounce buffering).
If standard dma_map_single() handling of these buffers is inappropriate,
you can use spi_message.is_dma_mapped to tell the controller driver
that you've already provided the relevant DMA addresses.
- The basic I/O primitive is spi_async(). Async requests may be
issued in any context (irq handler, task, etc) and completion
is reported using a callback provided with the message.
After any detected error, the chip is deselected and processing
of that spi_message is aborted.
- There are also synchronous wrappers like spi_sync(), and wrappers
like spi_read(), spi_write(), and spi_write_then_read(). These
may be issued only in contexts that may sleep, and they're all
clean (and small, and "optional") layers over spi_async().
- The spi_write_then_read() call, and convenience wrappers around
it, should only be used with small amounts of data where the
cost of an extra copy may be ignored. It's designed to support
common RPC-style requests, such as writing an eight bit command
and reading a sixteen bit response -- spi_w8r16() being one its
wrappers, doing exactly that.
Some drivers may need to modify spi_device characteristics like the
transfer mode, wordsize, or clock rate. This is done with spi_setup(),
which would normally be called from probe() before the first I/O is
done to the device.
While "spi_device" would be the bottom boundary of the driver, the
upper boundaries might include sysfs (especially for sensor readings),
the input layer, ALSA, networking, MTD, the character device framework,
or other Linux subsystems.
Note that there are two types of memory your driver must manage as part
of interacting with SPI devices.
- I/O buffers use the usual Linux rules, and must be DMA-safe.
You'd normally allocate them from the heap or free page pool.
Don't use the stack, or anything that's declared "static".
- The spi_message and spi_transfer metadata used to glue those
I/O buffers into a group of protocol transactions. These can
be allocated anywhere it's convenient, including as part of
other allocate-once driver data structures. Zero-init these.
If you like, spi_message_alloc() and spi_message_free() convenience
routines are available to allocate and zero-initialize an spi_message
with several transfers.
How do I write an "SPI Master Controller Driver"?
-------------------------------------------------
An SPI controller will probably be registered on the platform_bus; write
a driver to bind to the device, whichever bus is involved.
The main task of this type of driver is to provide an "spi_master".
Use spi_alloc_master() to allocate the master, and class_get_devdata()
to get the driver-private data allocated for that device.
struct spi_master *master;
struct CONTROLLER *c;
master = spi_alloc_master(dev, sizeof *c);
if (!master)
return -ENODEV;
c = class_get_devdata(&master->cdev);
The driver will initialize the fields of that spi_master, including the
bus number (maybe the same as the platform device ID) and three methods
used to interact with the SPI core and SPI protocol drivers. It will
also initialize its own internal state.
master->setup(struct spi_device *spi)
This sets up the device clock rate, SPI mode, and word sizes.
Drivers may change the defaults provided by board_info, and then
call spi_setup(spi) to invoke this routine. It may sleep.
master->transfer(struct spi_device *spi, struct spi_message *message)
This must not sleep. Its responsibility is arrange that the
transfer happens and its complete() callback is issued; the two
will normally happen later, after other transfers complete.
master->cleanup(struct spi_device *spi)
Your controller driver may use spi_device.controller_state to hold
state it dynamically associates with that device. If you do that,
be sure to provide the cleanup() method to free that state.
The bulk of the driver will be managing the I/O queue fed by transfer().
That queue could be purely conceptual. For example, a driver used only
for low-frequency sensor acess might be fine using synchronous PIO.
But the queue will probably be very real, using message->queue, PIO,
often DMA (especially if the root filesystem is in SPI flash), and
execution contexts like IRQ handlers, tasklets, or workqueues (such
as keventd). Your driver can be as fancy, or as simple, as you need.
THANKS TO
---------
Contributors to Linux-SPI discussions include (in alphabetical order,
by last name):
David Brownell
Russell King
Dmitry Pervushin
Stephen Street
Mark Underwood
Andrew Victor
Vitaly Wool
arch/arm/Kconfig
View file @ 61b7efdd
......@@ -729,6 +729,8 @@ source "drivers/char/Kconfig"
source "drivers/i2c/Kconfig"
source "drivers/spi/Kconfig"
source "drivers/hwmon/Kconfig"
#source "drivers/l3/Kconfig"
......
drivers/Kconfig
View file @ 61b7efdd
......@@ -44,6 +44,8 @@ source "drivers/char/Kconfig"
source "drivers/i2c/Kconfig"
source "drivers/spi/Kconfig"
source "drivers/w1/Kconfig"
source "drivers/hwmon/Kconfig"
......
drivers/Makefile
View file @ 61b7efdd
......@@ -41,6 +41,7 @@ obj-$(CONFIG_FUSION) += message/
obj-$(CONFIG_IEEE1394) += ieee1394/
obj-y += cdrom/
obj-$(CONFIG_MTD) += mtd/
obj-$(CONFIG_SPI) += spi/
obj-$(CONFIG_PCCARD) += pcmcia/
obj-$(CONFIG_DIO) += dio/
obj-$(CONFIG_SBUS) += sbus/
......
drivers/input/touchscreen/Kconfig
View file @ 61b7efdd
......@@ -11,6 +11,19 @@ menuconfig INPUT_TOUCHSCREEN
if INPUT_TOUCHSCREEN
config TOUCHSCREEN_ADS7846
tristate "ADS 7846 based touchscreens"
depends on SPI_MASTER
help
Say Y here if you have a touchscreen interface using the
ADS7846 controller, and your board-specific initialization
code includes that in its table of SPI devices.
If unsure, say N (but it's safe to say "Y").
To compile this driver as a module, choose M here: the
module will be called ads7846.
config TOUCHSCREEN_BITSY
tristate "Compaq iPAQ H3600 (Bitsy) touchscreen"
depends on SA1100_BITSY
......
drivers/input/touchscreen/Makefile
View file @ 61b7efdd
......@@ -4,6 +4,7 @@
# Each configuration option enables a list of files.
obj-$(CONFIG_TOUCHSCREEN_ADS7846) += ads7846.o
obj-$(CONFIG_TOUCHSCREEN_BITSY) += h3600_ts_input.o
obj-$(CONFIG_TOUCHSCREEN_CORGI) += corgi_ts.o
obj-$(CONFIG_TOUCHSCREEN_GUNZE) += gunze.o
......
drivers/input/touchscreen/ads7846.c 0 → 100644
View file @ 61b7efdd
/*
* ADS7846 based touchscreen and sensor driver
*
* Copyright (c) 2005 David Brownell
*
* Using code from:
* - corgi_ts.c
* Copyright (C) 2004-2005 Richard Purdie
* - omap_ts.[hc], ads7846.h, ts_osk.c
* Copyright (C) 2002 MontaVista Software
* Copyright (C) 2004 Texas Instruments
* Copyright (C) 2005 Dirk Behme
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/device.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/ads7846.h>
#ifdef CONFIG_ARM
#include <asm/mach-types.h>
#ifdef CONFIG_ARCH_OMAP
#include <asm/arch/gpio.h>
#endif
#else
#define set_irq_type(irq,type) do{}while(0)
#endif
/*
* This code has been lightly tested on an ads7846.
* Support for ads7843 and ads7845 has only been stubbed in.
*
* Not yet done: investigate the values reported. Are x/y/pressure
* event values sane enough for X11? How accurate are the temperature
* and voltage readings? (System-specific calibration should support
* accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)
*
* app note sbaa036 talks in more detail about accurate sampling...
* that ought to help in situations like LCDs inducing noise (which
* can also be helped by using synch signals) and more generally.
*/
#define TS_POLL_PERIOD msecs_to_jiffies(10)
struct ts_event {
/* For portability, we can't read 12 bit values using SPI (which
* would make the controller deliver them as native byteorder u16
* with msbs zeroed). Instead, we read them as two 8-byte values,
* which need byteswapping then range adjustment.
*/
__be16 x;
__be16 y;
__be16 z1, z2;
};
struct ads7846 {
struct input_dev input;
char phys[32];
struct spi_device *spi;
u16 model;
u16 vref_delay_usecs;
u16 x_plate_ohms;
struct ts_event tc;
struct spi_transfer xfer[8];
struct spi_message msg;
spinlock_t lock;
struct timer_list timer; /* P: lock */
unsigned pendown:1; /* P: lock */
unsigned pending:1; /* P: lock */
// FIXME remove "irq_disabled"
unsigned irq_disabled:1; /* P: lock */
};
/* leave chip selected when we're done, for quicker re-select? */
#if 0
#define CS_CHANGE(xfer) ((xfer).cs_change = 1)
#else
#define CS_CHANGE(xfer) ((xfer).cs_change = 0)
#endif
/*--------------------------------------------------------------------------*/
/* The ADS7846 has touchscreen and other sensors.
* Earlier ads784x chips are somewhat compatible.
*/
#define ADS_START (1 << 7)
#define ADS_A2A1A0_d_y (1 << 4) /* differential */
#define ADS_A2A1A0_d_z1 (3 << 4) /* differential */
#define ADS_A2A1A0_d_z2 (4 << 4) /* differential */
#define ADS_A2A1A0_d_x (5 << 4) /* differential */
#define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */
#define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */
#define ADS_A2A1A0_vaux (6 << 4) /* non-differential */
#define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */
#define ADS_8_BIT (1 << 3)
#define ADS_12_BIT (0 << 3)
#define ADS_SER (1 << 2) /* non-differential */
#define ADS_DFR (0 << 2) /* differential */
#define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */
#define ADS_PD10_ADC_ON (1 << 0) /* ADC on */
#define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */
#define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */
#define MAX_12BIT ((1<<12)-1)
/* leave ADC powered up (disables penirq) between differential samples */
#define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
| ADS_12_BIT | ADS_DFR)
static const u8 read_y = READ_12BIT_DFR(y) | ADS_PD10_ADC_ON;
static const u8 read_z1 = READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON;
static const u8 read_z2 = READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON;
static const u8 read_x = READ_12BIT_DFR(x) | ADS_PD10_PDOWN; /* LAST */
/* single-ended samples need to first power up reference voltage;
* we leave both ADC and VREF powered
*/
#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
| ADS_12_BIT | ADS_SER)
static const u8 ref_on = READ_12BIT_DFR(x) | ADS_PD10_ALL_ON;
static const u8 ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
/*--------------------------------------------------------------------------*/
/*
* Non-touchscreen sensors only use single-ended conversions.
*/
struct ser_req {
u8 command;
u16 scratch;
__be16 sample;
struct spi_message msg;
struct spi_transfer xfer[6];
};
static int ads7846_read12_ser(struct device *dev, unsigned command)
{
struct spi_device *spi = to_spi_device(dev);
struct ads7846 *ts = dev_get_drvdata(dev);
struct ser_req *req = kzalloc(sizeof *req, SLAB_KERNEL);
int status;
int sample;
int i;
if (!req)
return -ENOMEM;
INIT_LIST_HEAD(&req->msg.transfers);
/* activate reference, so it has time to settle; */
req->xfer[0].tx_buf = &ref_on;
req->xfer[0].len = 1;
req->xfer[1].rx_buf = &req->scratch;
req->xfer[1].len = 2;
/*
* for external VREF, 0 usec (and assume it's always on);
* for 1uF, use 800 usec;
* no cap, 100 usec.
*/
req->xfer[1].delay_usecs = ts->vref_delay_usecs;
/* take sample */
req->command = (u8) command;
req->xfer[2].tx_buf = &req->command;
req->xfer[2].len = 1;
req->xfer[3].rx_buf = &req->sample;
req->xfer[3].len = 2;
/* REVISIT: take a few more samples, and compare ... */
/* turn off reference */
req->xfer[4].tx_buf = &ref_off;
req->xfer[4].len = 1;
req->xfer[5].rx_buf = &req->scratch;
req->xfer[5].len = 2;
CS_CHANGE(req->xfer[5]);
/* group all the transfers together, so we can't interfere with
* reading touchscreen state; disable penirq while sampling
*/
for (i = 0; i < 6; i++)
spi_message_add_tail(&req->xfer[i], &req->msg);
disable_irq(spi->irq);
status = spi_sync(spi, &req->msg);
enable_irq(spi->irq);
if (req->msg.status)
status = req->msg.status;
sample = be16_to_cpu(req->sample);
sample = sample >> 4;
kfree(req);
return status ? status : sample;
}
#define SHOW(name) static ssize_t \
name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
ssize_t v = ads7846_read12_ser(dev, \
READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
if (v < 0) \
return v; \
return sprintf(buf, "%u\n", (unsigned) v); \
} \
static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
SHOW(temp0)
SHOW(temp1)
SHOW(vaux)
SHOW(vbatt)
/*--------------------------------------------------------------------------*/
/*
* PENIRQ only kicks the timer. The timer only reissues the SPI transfer,
* to retrieve touchscreen status.
*
* The SPI transfer completion callback does the real work. It reports
* touchscreen events and reactivates the timer (or IRQ) as appropriate.
*/
static void ads7846_rx(void *ads)
{
struct ads7846 *ts = ads;
unsigned Rt;
unsigned sync = 0;
u16 x, y, z1, z2;
unsigned long flags;
/* adjust: 12 bit samples (left aligned), built from
* two 8 bit values writen msb-first.
*/
x = be16_to_cpu(ts->tc.x) >> 4;
y = be16_to_cpu(ts->tc.y) >> 4;
z1 = be16_to_cpu(ts->tc.z1) >> 4;
z2 = be16_to_cpu(ts->tc.z2) >> 4;
/* range filtering */
if (x == MAX_12BIT)
x = 0;
if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
/* compute touch pressure resistance using equation #2 */
Rt = z2;
Rt -= z1;
Rt *= x;
Rt *= ts->x_plate_ohms;
Rt /= z1;
Rt = (Rt + 2047) >> 12;
} else
Rt = 0;
/* NOTE: "pendown" is inferred from pressure; we don't rely on
* being able to check nPENIRQ status, or "friendly" trigger modes
* (both-edges is much better than just-falling or low-level).
*
* REVISIT: some boards may require reading nPENIRQ; it's
* needed on 7843. and 7845 reads pressure differently...
*
* REVISIT: the touchscreen might not be connected; this code
* won't notice that, even if nPENIRQ never fires ...
*/
if (!ts->pendown && Rt != 0) {
input_report_key(&ts->input, BTN_TOUCH, 1);
sync = 1;
} else if (ts->pendown && Rt == 0) {
input_report_key(&ts->input, BTN_TOUCH, 0);
sync = 1;
}
if (Rt) {
input_report_abs(&ts->input, ABS_X, x);
input_report_abs(&ts->input, ABS_Y, y);
input_report_abs(&ts->input, ABS_PRESSURE, Rt);
sync = 1;
}
if (sync)
input_sync(&ts->input);
#ifdef VERBOSE
if (Rt || ts->pendown)
pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
x, y, Rt, Rt ? "" : " UP");
#endif
/* don't retrigger while we're suspended */
spin_lock_irqsave(&ts->lock, flags);
ts->pendown = (Rt != 0);
ts->pending = 0;
if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
if (ts->pendown)
mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
else if (ts->irq_disabled) {
ts->irq_disabled = 0;
enable_irq(ts->spi->irq);
}
}
spin_unlock_irqrestore(&ts->lock, flags);
}
static void ads7846_timer(unsigned long handle)
{
struct ads7846 *ts = (void *)handle;
int status = 0;
unsigned long flags;
spin_lock_irqsave(&ts->lock, flags);
if (!ts->pending) {
ts->pending = 1;
if (!ts->irq_disabled) {
ts->irq_disabled = 1;
disable_irq(ts->spi->irq);
}
status = spi_async(ts->spi, &ts->msg);
if (status)
dev_err(&ts->spi->dev, "spi_async --> %d\n",
status);
}
spin_unlock_irqrestore(&ts->lock, flags);
}
static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
{
ads7846_timer((unsigned long) handle);
return IRQ_HANDLED;
}
/*--------------------------------------------------------------------------*/
static int
ads7846_suspend(struct spi_device *spi, pm_message_t message)
{
struct ads7846 *ts = dev_get_drvdata(&spi->dev);
unsigned long flags;
spin_lock_irqsave(&ts->lock, flags);
spi->dev.power.power_state = message;
/* are we waiting for IRQ, or polling? */
if (!ts->pendown) {
if (!ts->irq_disabled) {
ts->irq_disabled = 1;
disable_irq(ts->spi->irq);
}
} else {
/* polling; force a final SPI completion;
* that will clean things up neatly
*/
if (!ts->pending)
mod_timer(&ts->timer, jiffies);
while (ts->pendown || ts->pending) {
spin_unlock_irqrestore(&ts->lock, flags);
udelay(10);
spin_lock_irqsave(&ts->lock, flags);
}
}
/* we know the chip's in lowpower mode since we always
* leave it that way after every request
*/
spin_unlock_irqrestore(&ts->lock, flags);
return 0;
}
static int ads7846_resume(struct spi_device *spi)
{
struct ads7846 *ts = dev_get_drvdata(&spi->dev);
ts->irq_disabled = 0;
enable_irq(ts->spi->irq);
spi->dev.power.power_state = PMSG_ON;
return 0;
}
static int __devinit ads7846_probe(struct spi_device *spi)
{
struct ads7846 *ts;
struct ads7846_platform_data *pdata = spi->dev.platform_data;
struct spi_transfer *x;
int i;
if (!spi->irq) {
dev_dbg(&spi->dev, "no IRQ?\n");
return -ENODEV;
}
if (!pdata) {
dev_dbg(&spi->dev, "no platform data?\n");
return -ENODEV;
}
/* don't exceed max specified sample rate */
if (spi->max_speed_hz > (125000 * 16)) {
dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
(spi->max_speed_hz/16)/1000);
return -EINVAL;
}
/* We'd set the wordsize to 12 bits ... except that some controllers
* will then treat the 8 bit command words as 12 bits (and drop the
* four MSBs of the 12 bit result). Result: inputs must be shifted
* to discard the four garbage LSBs.
*/
if (!(ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL)))
return -ENOMEM;
dev_set_drvdata(&spi->dev, ts);
ts->spi = spi;
spi->dev.power.power_state = PMSG_ON;
init_timer(&ts->timer);
ts->timer.data = (unsigned long) ts;
ts->timer.function = ads7846_timer;
ts->model = pdata->model ? : 7846;
ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
init_input_dev(&ts->input);
ts->input.dev = &spi->dev;
ts->input.name = "ADS784x Touchscreen";
snprintf(ts->phys, sizeof ts->phys, "%s/input0", spi->dev.bus_id);
ts->input.phys = ts->phys;
ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
input_set_abs_params(&ts->input, ABS_X,
pdata->x_min ? : 0,
pdata->x_max ? : MAX_12BIT,
0, 0);
input_set_abs_params(&ts->input, ABS_Y,
pdata->y_min ? : 0,
pdata->y_max ? : MAX_12BIT,
0, 0);
input_set_abs_params(&ts->input, ABS_PRESSURE,
pdata->pressure_min, pdata->pressure_max, 0, 0);
input_register_device(&ts->input);
/* set up the transfers to read touchscreen state; this assumes we
* use formula #2 for pressure, not #3.
*/
x = ts->xfer;
/* y- still on; turn on only y+ (and ADC) */
x->tx_buf = &read_y;
x->len = 1;
x++;
x->rx_buf = &ts->tc.y;
x->len = 2;
x++;
/* turn y+ off, x- on; we'll use formula #2 */
if (ts->model == 7846) {
x->tx_buf = &read_z1;
x->len = 1;
x++;
x->rx_buf = &ts->tc.z1;
x->len = 2;
x++;
x->tx_buf = &read_z2;
x->len = 1;
x++;
x->rx_buf = &ts->tc.z2;
x->len = 2;
x++;
}
/* turn y- off, x+ on, then leave in lowpower */
x->tx_buf = &read_x;
x->len = 1;
x++;
x->rx_buf = &ts->tc.x;
x->len = 2;
x++;
CS_CHANGE(x[-1]);
for (i = 0; i < x - ts->xfer; i++)
spi_message_add_tail(&ts->xfer[i], &ts->msg);
ts->msg.complete = ads7846_rx;
ts->msg.context = ts;
if (request_irq(spi->irq, ads7846_irq, SA_SAMPLE_RANDOM,
spi->dev.bus_id, ts)) {
dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
input_unregister_device(&ts->input);
kfree(ts);
return -EBUSY;
}
set_irq_type(spi->irq, IRQT_FALLING);
dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
/* take a first sample, leaving nPENIRQ active; avoid
* the touchscreen, in case it's not connected.
*/
(void) ads7846_read12_ser(&spi->dev,
READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
/* ads7843/7845 don't have temperature sensors, and
* use the other sensors a bit differently too
*/
if (ts->model == 7846) {
device_create_file(&spi->dev, &dev_attr_temp0);
device_create_file(&spi->dev, &dev_attr_temp1);
}
if (ts->model != 7845)
device_create_file(&spi->dev, &dev_attr_vbatt);
device_create_file(&spi->dev, &dev_attr_vaux);
return 0;
}
static int __devexit ads7846_remove(struct spi_device *spi)
{
struct ads7846 *ts = dev_get_drvdata(&spi->dev);
ads7846_suspend(spi, PMSG_SUSPEND);
free_irq(ts->spi->irq, ts);
if (ts->irq_disabled)
enable_irq(ts->spi->irq);
if (ts->model == 7846) {
device_remove_file(&spi->dev, &dev_attr_temp0);
device_remove_file(&spi->dev, &dev_attr_temp1);
}
if (ts->model != 7845)
device_remove_file(&spi->dev, &dev_attr_vbatt);
device_remove_file(&spi->dev, &dev_attr_vaux);
input_unregister_device(&ts->input);
kfree(ts);
dev_dbg(&spi->dev, "unregistered touchscreen\n");
return 0;
}
static struct spi_driver ads7846_driver = {
.driver = {
.name = "ads7846",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = ads7846_probe,
.remove = __devexit_p(ads7846_remove),
.suspend = ads7846_suspend,
.resume = ads7846_resume,
};
static int __init ads7846_init(void)
{
/* grr, board-specific init should stay out of drivers!! */
#ifdef CONFIG_ARCH_OMAP
if (machine_is_omap_osk()) {
/* GPIO4 = PENIRQ; GPIO6 = BUSY */
omap_request_gpio(4);
omap_set_gpio_direction(4, 1);
omap_request_gpio(6);
omap_set_gpio_direction(6, 1);
}
// also TI 1510 Innovator, bitbanging through FPGA
// also Nokia 770
// also Palm Tungsten T2
#endif
// PXA:
// also Dell Axim X50
// also HP iPaq H191x/H192x/H415x/H435x
// also Intel Lubbock (additional to UCB1400; as temperature sensor)
// also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky)
// Atmel at91sam9261-EK uses ads7843
// also various AMD Au1x00 devel boards
return spi_register_driver(&ads7846_driver);
}
module_init(ads7846_init);
static void __exit ads7846_exit(void)
{
spi_unregister_driver(&ads7846_driver);
#ifdef CONFIG_ARCH_OMAP
if (machine_is_omap_osk()) {
omap_free_gpio(4);
omap_free_gpio(6);
}
#endif
}
module_exit(ads7846_exit);
MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
MODULE_LICENSE("GPL");
drivers/mtd/devices/Kconfig
View file @ 61b7efdd
......@@ -47,6 +47,22 @@ config MTD_MS02NV
accelerator. Say Y here if you have a DECstation 5000/2x0 or a
DECsystem 5900 equipped with such a module.
config MTD_DATAFLASH
tristate "Support for AT45xxx DataFlash"
depends on MTD && SPI_MASTER && EXPERIMENTAL
help
This enables access to AT45xxx DataFlash chips, using SPI.
Sometimes DataFlash chips are packaged inside MMC-format
cards; at this writing, the MMC stack won't handle those.
config MTD_M25P80
tristate "Support for M25 SPI Flash"
depends on MTD && SPI_MASTER && EXPERIMENTAL
help
This enables access to ST M25P80 and similar SPI flash chips,
used for program and data storage. Set up your spi devices
with the right board-specific platform data.
config MTD_SLRAM
tristate "Uncached system RAM"
depends on MTD
......
drivers/mtd/devices/Makefile
View file @ 61b7efdd
......@@ -23,3 +23,5 @@ obj-$(CONFIG_MTD_MTDRAM) += mtdram.o
obj-$(CONFIG_MTD_LART) += lart.o
obj-$(CONFIG_MTD_BLKMTD) += blkmtd.o
obj-$(CONFIG_MTD_BLOCK2MTD) += block2mtd.o
obj-$(CONFIG_MTD_DATAFLASH) += mtd_dataflash.o
obj-$(CONFIG_MTD_M25P80) += m25p80.o
drivers/mtd/devices/m25p80.c 0 → 100644
View file @ 61b7efdd
/*
* MTD SPI driver for ST M25Pxx flash chips
*
* Author: Mike Lavender, mike@steroidmicros.com
*
* Copyright (c) 2005, Intec Automation Inc.
*
* Some parts are based on lart.c by Abraham Van Der Merwe
*
* Cleaned up and generalized based on mtd_dataflash.c
*
* This code is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/interrupt.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/spi/spi.h>
#include <linux/spi/flash.h>
#include <asm/semaphore.h>
/* NOTE: AT 25F and SST 25LF series are very similar,
* but commands for sector erase and chip id differ...
*/
#define FLASH_PAGESIZE 256
/* Flash opcodes. */
#define OPCODE_WREN 6 /* Write enable */
#define OPCODE_RDSR 5 /* Read status register */
#define OPCODE_READ 3 /* Read data bytes */
#define OPCODE_PP 2 /* Page program */
#define OPCODE_SE 0xd8 /* Sector erase */
#define OPCODE_RES 0xab /* Read Electronic Signature */
#define OPCODE_RDID 0x9f /* Read JEDEC ID */
/* Status Register bits. */
#define SR_WIP 1 /* Write in progress */
#define SR_WEL 2 /* Write enable latch */
#define SR_BP0 4 /* Block protect 0 */
#define SR_BP1 8 /* Block protect 1 */
#define SR_BP2 0x10 /* Block protect 2 */
#define SR_SRWD 0x80 /* SR write protect */
/* Define max times to check status register before we give up. */
#define MAX_READY_WAIT_COUNT 100000
#ifdef CONFIG_MTD_PARTITIONS
#define mtd_has_partitions() (1)
#else
#define mtd_has_partitions() (0)
#endif
/****************************************************************************/
struct m25p {
struct spi_device *spi;
struct semaphore lock;
struct mtd_info mtd;
unsigned partitioned;
u8 command[4];
};
static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
{
return container_of(mtd, struct m25p, mtd);
}
/****************************************************************************/
/*
* Internal helper functions
*/
/*
* Read the status register, returning its value in the location
* Return the status register value.
* Returns negative if error occurred.
*/
static int read_sr(struct m25p *flash)
{
ssize_t retval;
u8 code = OPCODE_RDSR;
u8 val;
retval = spi_write_then_read(flash->spi, &code, 1, &val, 1);
if (retval < 0) {
dev_err(&flash->spi->dev, "error %d reading SR\n",
(int) retval);
return retval;
}
return val;
}
/*
* Set write enable latch with Write Enable command.
* Returns negative if error occurred.
*/
static inline int write_enable(struct m25p *flash)
{
u8 code = OPCODE_WREN;
return spi_write_then_read(flash->spi, &code, 1, NULL, 0);
}
/*
* Service routine to read status register until ready, or timeout occurs.
* Returns non-zero if error.
*/
static int wait_till_ready(struct m25p *flash)
{
int count;
int sr;
/* one chip guarantees max 5 msec wait here after page writes,
* but potentially three seconds (!) after page erase.
*/
for (count = 0; count < MAX_READY_WAIT_COUNT; count++) {
if ((sr = read_sr(flash)) < 0)
break;
else if (!(sr & SR_WIP))
return 0;
/* REVISIT sometimes sleeping would be best */
}
return 1;
}
/*
* Erase one sector of flash memory at offset ``offset'' which is any
* address within the sector which should be erased.
*
* Returns 0 if successful, non-zero otherwise.
*/
static int erase_sector(struct m25p *flash, u32 offset)
{
DEBUG(MTD_DEBUG_LEVEL3, "%s: %s at 0x%08x\n", flash->spi->dev.bus_id,
__FUNCTION__, offset);
/* Wait until finished previous write command. */
if (wait_till_ready(flash))
return 1;
/* Send write enable, then erase commands. */
write_enable(flash);
/* Set up command buffer. */
flash->command[0] = OPCODE_SE;
flash->command[1] = offset >> 16;
flash->command[2] = offset >> 8;
flash->command[3] = offset;
spi_write(flash->spi, flash->command, sizeof(flash->command));
return 0;
}
/****************************************************************************/
/*
* MTD implementation
*/
/*
* Erase an address range on the flash chip. The address range may extend
* one or more erase sectors. Return an error is there is a problem erasing.
*/
static int m25p80_erase(struct mtd_info *mtd, struct erase_info *instr)
{
struct m25p *flash = mtd_to_m25p(mtd);
u32 addr,len;
DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
flash->spi->dev.bus_id, __FUNCTION__, "at",
(u32)instr->addr, instr->len);
/* sanity checks */
if (instr->addr + instr->len > flash->mtd.size)
return -EINVAL;
if ((instr->addr % mtd->erasesize) != 0
|| (instr->len % mtd->erasesize) != 0) {
return -EINVAL;
}
addr = instr->addr;
len = instr->len;
down(&flash->lock);
/* now erase those sectors */
while (len) {
if (erase_sector(flash, addr)) {
instr->state = MTD_ERASE_FAILED;
up(&flash->lock);
return -EIO;
}
addr += mtd->erasesize;
len -= mtd->erasesize;
}
up(&flash->lock);
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return 0;
}
/*
* Read an address range from the flash chip. The address range
* may be any size provided it is within the physical boundaries.
*/
static int m25p80_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct m25p *flash = mtd_to_m25p(mtd);
struct spi_transfer t[2];
struct spi_message m;
DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
flash->spi->dev.bus_id, __FUNCTION__, "from",
(u32)from, len);
/* sanity checks */
if (!len)
return 0;
if (from + len > flash->mtd.size)
return -EINVAL;
spi_message_init(&m);
memset(t, 0, (sizeof t));
t[0].tx_buf = flash->command;
t[0].len = sizeof(flash->command);
spi_message_add_tail(&t[0], &m);
t[1].rx_buf = buf;
t[1].len = len;
spi_message_add_tail(&t[1], &m);
/* Byte count starts at zero. */
if (retlen)
*retlen = 0;
down(&flash->lock);
/* Wait till previous write/erase is done. */
if (wait_till_ready(flash)) {
/* REVISIT status return?? */
up(&flash->lock);
return 1;
}
/* NOTE: OPCODE_FAST_READ (if available) is faster... */
/* Set up the write data buffer. */
flash->command[0] = OPCODE_READ;
flash->command[1] = from >> 16;
flash->command[2] = from >> 8;
flash->command[3] = from;
spi_sync(flash->spi, &m);
*retlen = m.actual_length - sizeof(flash->command);
up(&flash->lock);
return 0;
}
/*
* Write an address range to the flash chip. Data must be written in
* FLASH_PAGESIZE chunks. The address range may be any size provided
* it is within the physical boundaries.
*/
static int m25p80_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
struct m25p *flash = mtd_to_m25p(mtd);
u32 page_offset, page_size;
struct spi_transfer t[2];
struct spi_message m;
DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
flash->spi->dev.bus_id, __FUNCTION__, "to",
(u32)to, len);
if (retlen)
*retlen = 0;
/* sanity checks */
if (!len)
return(0);
if (to + len > flash->mtd.size)
return -EINVAL;
spi_message_init(&m);
memset(t, 0, (sizeof t));
t[0].tx_buf = flash->command;
t[0].len = sizeof(flash->command);
spi_message_add_tail(&t[0], &m);
t[1].tx_buf = buf;
spi_message_add_tail(&t[1], &m);
down(&flash->lock);
/* Wait until finished previous write command. */
if (wait_till_ready(flash))
return 1;
write_enable(flash);
/* Set up the opcode in the write buffer. */
flash->command[0] = OPCODE_PP;
flash->command[1] = to >> 16;
flash->command[2] = to >> 8;
flash->command[3] = to;
/* what page do we start with? */
page_offset = to % FLASH_PAGESIZE;
/* do all the bytes fit onto one page? */
if (page_offset + len <= FLASH_PAGESIZE) {
t[1].len = len;
spi_sync(flash->spi, &m);
*retlen = m.actual_length - sizeof(flash->command);
} else {
u32 i;
/* the size of data remaining on the first page */
page_size = FLASH_PAGESIZE - page_offset;
t[1].len = page_size;
spi_sync(flash->spi, &m);
*retlen = m.actual_length - sizeof(flash->command);
/* write everything in PAGESIZE chunks */
for (i = page_size; i < len; i += page_size) {
page_size = len - i;
if (page_size > FLASH_PAGESIZE)
page_size = FLASH_PAGESIZE;
/* write the next page to flash */
flash->command[1] = (to + i) >> 16;
flash->command[2] = (to + i) >> 8;
flash->command[3] = (to + i);
t[1].tx_buf = buf + i;
t[1].len = page_size;
wait_till_ready(flash);
write_enable(flash);
spi_sync(flash->spi, &m);
if (retlen)
*retlen += m.actual_length
- sizeof(flash->command);
}
}
up(&flash->lock);
return 0;
}
/****************************************************************************/
/*
* SPI device driver setup and teardown
*/
struct flash_info {
char *name;
u8 id;
u16 jedec_id;
unsigned sector_size;
unsigned n_sectors;
};
static struct flash_info __devinitdata m25p_data [] = {
/* REVISIT: fill in JEDEC ids, for parts that have them */
{ "m25p05", 0x05, 0x0000, 32 * 1024, 2 },
{ "m25p10", 0x10, 0x0000, 32 * 1024, 4 },
{ "m25p20", 0x11, 0x0000, 64 * 1024, 4 },
{ "m25p40", 0x12, 0x0000, 64 * 1024, 8 },
{ "m25p80", 0x13, 0x0000, 64 * 1024, 16 },
{ "m25p16", 0x14, 0x0000, 64 * 1024, 32 },
{ "m25p32", 0x15, 0x0000, 64 * 1024, 64 },
{ "m25p64", 0x16, 0x2017, 64 * 1024, 128 },
};
/*
* board specific setup should have ensured the SPI clock used here
* matches what the READ command supports, at least until this driver
* understands FAST_READ (for clocks over 25 MHz).
*/
static int __devinit m25p_probe(struct spi_device *spi)
{
struct flash_platform_data *data;
struct m25p *flash;
struct flash_info *info;
unsigned i;
/* Platform data helps sort out which chip type we have, as
* well as how this board partitions it.
*/
data = spi->dev.platform_data;
if (!data || !data->type) {
/* FIXME some chips can identify themselves with RES
* or JEDEC get-id commands. Try them ...
*/
DEBUG(MTD_DEBUG_LEVEL1, "%s: no chip id\n",
flash->spi->dev.bus_id);
return -ENODEV;
}
for (i = 0, info = m25p_data; i < ARRAY_SIZE(m25p_data); i++, info++) {
if (strcmp(data->type, info->name) == 0)
break;
}
if (i == ARRAY_SIZE(m25p_data)) {
DEBUG(MTD_DEBUG_LEVEL1, "%s: unrecognized id %s\n",
flash->spi->dev.bus_id, data->type);
return -ENODEV;
}
flash = kzalloc(sizeof *flash, SLAB_KERNEL);
if (!flash)
return -ENOMEM;
flash->spi = spi;
init_MUTEX(&flash->lock);
dev_set_drvdata(&spi->dev, flash);
if (data->name)
flash->mtd.name = data->name;
else
flash->mtd.name = spi->dev.bus_id;
flash->mtd.type = MTD_NORFLASH;
flash->mtd.flags = MTD_CAP_NORFLASH;
flash->mtd.size = info->sector_size * info->n_sectors;
flash->mtd.erasesize = info->sector_size;
flash->mtd.erase = m25p80_erase;
flash->mtd.read = m25p80_read;
flash->mtd.write = m25p80_write;
dev_info(&spi->dev, "%s (%d Kbytes)\n", info->name,
flash->mtd.size / 1024);
DEBUG(MTD_DEBUG_LEVEL2,
"mtd .name = %s, .size = 0x%.8x (%uM) "
".erasesize = 0x%.8x (%uK) .numeraseregions = %d\n",
flash->mtd.name,
flash->mtd.size, flash->mtd.size / (1024*1024),
flash->mtd.erasesize, flash->mtd.erasesize / 1024,
flash->mtd.numeraseregions);
if (flash->mtd.numeraseregions)
for (i = 0; i < flash->mtd.numeraseregions; i++)
DEBUG(MTD_DEBUG_LEVEL2,
"mtd.eraseregions[%d] = { .offset = 0x%.8x, "
".erasesize = 0x%.8x (%uK), "
".numblocks = %d }\n",
i, flash->mtd.eraseregions[i].offset,
flash->mtd.eraseregions[i].erasesize,
flash->mtd.eraseregions[i].erasesize / 1024,
flash->mtd.eraseregions[i].numblocks);
/* partitions should match sector boundaries; and it may be good to
* use readonly partitions for writeprotected sectors (BP2..BP0).
*/
if (mtd_has_partitions()) {
struct mtd_partition *parts = NULL;
int nr_parts = 0;
#ifdef CONFIG_MTD_CMDLINE_PARTS
static const char *part_probes[] = { "cmdlinepart", NULL, };
nr_parts = parse_mtd_partitions(&flash->mtd,
part_probes, &parts, 0);
#endif
if (nr_parts <= 0 && data && data->parts) {
parts = data->parts;
nr_parts = data->nr_parts;
}
if (nr_parts > 0) {
for (i = 0; i < data->nr_parts; i++) {
DEBUG(MTD_DEBUG_LEVEL2, "partitions[%d] = "
"{.name = %s, .offset = 0x%.8x, "
".size = 0x%.8x (%uK) }\n",
i, data->parts[i].name,
data->parts[i].offset,
data->parts[i].size,
data->parts[i].size / 1024);
}
flash->partitioned = 1;
return add_mtd_partitions(&flash->mtd, parts, nr_parts);
}
} else if (data->nr_parts)
dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
data->nr_parts, data->name);
return add_mtd_device(&flash->mtd) == 1 ? -ENODEV : 0;
}
static int __devexit m25p_remove(struct spi_device *spi)
{
struct m25p *flash = dev_get_drvdata(&spi->dev);
int status;
/* Clean up MTD stuff. */
if (mtd_has_partitions() && flash->partitioned)
status = del_mtd_partitions(&flash->mtd);
else
status = del_mtd_device(&flash->mtd);
if (status == 0)
kfree(flash);
return 0;
}
static struct spi_driver m25p80_driver = {
.driver = {
.name = "m25p80",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = m25p_probe,
.remove = __devexit_p(m25p_remove),
};
static int m25p80_init(void)
{
return spi_register_driver(&m25p80_driver);
}
static void m25p80_exit(void)
{
spi_unregister_driver(&m25p80_driver);
}
module_init(m25p80_init);
module_exit(m25p80_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mike Lavender");
MODULE_DESCRIPTION("MTD SPI driver for ST M25Pxx flash chips");
drivers/mtd/devices/mtd_dataflash.c 0 → 100644
View file @ 61b7efdd
/*
* Atmel AT45xxx DataFlash MTD driver for lightweight SPI framework
*
* Largely derived from at91_dataflash.c:
* Copyright (C) 2003-2005 SAN People (Pty) Ltd
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/spi/spi.h>
#include <linux/spi/flash.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
/*
* DataFlash is a kind of SPI flash. Most AT45 chips have two buffers in
* each chip, which may be used for double buffered I/O; but this driver
* doesn't (yet) use these for any kind of i/o overlap or prefetching.
*
* Sometimes DataFlash is packaged in MMC-format cards, although the
* MMC stack can't use SPI (yet), or distinguish between MMC and DataFlash
* protocols during enumeration.
*/
#define CONFIG_DATAFLASH_WRITE_VERIFY
/* reads can bypass the buffers */
#define OP_READ_CONTINUOUS 0xE8
#define OP_READ_PAGE 0xD2
/* group B requests can run even while status reports "busy" */
#define OP_READ_STATUS 0xD7 /* group B */
/* move data between host and buffer */
#define OP_READ_BUFFER1 0xD4 /* group B */
#define OP_READ_BUFFER2 0xD6 /* group B */
#define OP_WRITE_BUFFER1 0x84 /* group B */
#define OP_WRITE_BUFFER2 0x87 /* group B */
/* erasing flash */
#define OP_ERASE_PAGE 0x81
#define OP_ERASE_BLOCK 0x50
/* move data between buffer and flash */
#define OP_TRANSFER_BUF1 0x53
#define OP_TRANSFER_BUF2 0x55
#define OP_MREAD_BUFFER1 0xD4
#define OP_MREAD_BUFFER2 0xD6
#define OP_MWERASE_BUFFER1 0x83
#define OP_MWERASE_BUFFER2 0x86
#define OP_MWRITE_BUFFER1 0x88 /* sector must be pre-erased */
#define OP_MWRITE_BUFFER2 0x89 /* sector must be pre-erased */
/* write to buffer, then write-erase to flash */
#define OP_PROGRAM_VIA_BUF1 0x82
#define OP_PROGRAM_VIA_BUF2 0x85
/* compare buffer to flash */
#define OP_COMPARE_BUF1 0x60
#define OP_COMPARE_BUF2 0x61
/* read flash to buffer, then write-erase to flash */
#define OP_REWRITE_VIA_BUF1 0x58
#define OP_REWRITE_VIA_BUF2 0x59
/* newer chips report JEDEC manufacturer and device IDs; chip
* serial number and OTP bits; and per-sector writeprotect.
*/
#define OP_READ_ID 0x9F
#define OP_READ_SECURITY 0x77
#define OP_WRITE_SECURITY 0x9A /* OTP bits */
struct dataflash {
u8 command[4];
char name[24];
unsigned partitioned:1;
unsigned short page_offset; /* offset in flash address */
unsigned int page_size; /* of bytes per page */
struct semaphore lock;
struct spi_device *spi;
struct mtd_info mtd;
};
#ifdef CONFIG_MTD_PARTITIONS
#define mtd_has_partitions() (1)
#else
#define mtd_has_partitions() (0)
#endif
/* ......................................................................... */
/*
* Return the status of the DataFlash device.
*/
static inline int dataflash_status(struct spi_device *spi)
{
/* NOTE: at45db321c over 25 MHz wants to write
* a dummy byte after the opcode...
*/
return spi_w8r8(spi, OP_READ_STATUS);
}
/*
* Poll the DataFlash device until it is READY.
* This usually takes 5-20 msec or so; more for sector erase.
*/
static int dataflash_waitready(struct spi_device *spi)
{
int status;
for (;;) {
status = dataflash_status(spi);
if (status < 0) {
DEBUG(MTD_DEBUG_LEVEL1, "%s: status %d?\n",
spi->dev.bus_id, status);
status = 0;
}
if (status & (1 << 7)) /* RDY/nBSY */
return status;
msleep(3);
}
}
/* ......................................................................... */
/*
* Erase pages of flash.
*/
static int dataflash_erase(struct mtd_info *mtd, struct erase_info *instr)
{
struct dataflash *priv = (struct dataflash *)mtd->priv;
struct spi_device *spi = priv->spi;
struct spi_transfer x = { .tx_dma = 0, };
struct spi_message msg;
unsigned blocksize = priv->page_size << 3;
u8 *command;
DEBUG(MTD_DEBUG_LEVEL2, "%s: erase addr=0x%x len 0x%x\n",
spi->dev.bus_id,
instr->addr, instr->len);
/* Sanity checks */
if ((instr->addr + instr->len) > mtd->size
|| (instr->len % priv->page_size) != 0
|| (instr->addr % priv->page_size) != 0)
return -EINVAL;
spi_message_init(&msg);
x.tx_buf = command = priv->command;
x.len = 4;
spi_message_add_tail(&x, &msg);
down(&priv->lock);
while (instr->len > 0) {
unsigned int pageaddr;
int status;
int do_block;
/* Calculate flash page address; use block erase (for speed) if
* we're at a block boundary and need to erase the whole block.
*/
pageaddr = instr->addr / priv->page_size;
do_block = (pageaddr & 0x7) == 0 && instr->len <= blocksize;
pageaddr = pageaddr << priv->page_offset;
command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;
command[1] = (u8)(pageaddr >> 16);
command[2] = (u8)(pageaddr >> 8);
command[3] = 0;
DEBUG(MTD_DEBUG_LEVEL3, "ERASE %s: (%x) %x %x %x [%i]\n",
do_block ? "block" : "page",
command[0], command[1], command[2], command[3],
pageaddr);
status = spi_sync(spi, &msg);
(void) dataflash_waitready(spi);
if (status < 0) {
printk(KERN_ERR "%s: erase %x, err %d\n",
spi->dev.bus_id, pageaddr, status);
/* REVISIT: can retry instr->retries times; or
* giveup and instr->fail_addr = instr->addr;
*/
continue;
}
if (do_block) {
instr->addr += blocksize;
instr->len -= blocksize;
} else {
instr->addr += priv->page_size;
instr->len -= priv->page_size;
}
}
up(&priv->lock);
/* Inform MTD subsystem that erase is complete */
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return 0;
}
/*
* Read from the DataFlash device.
* from : Start offset in flash device
* len : Amount to read
* retlen : About of data actually read
* buf : Buffer containing the data
*/
static int dataflash_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
struct dataflash *priv = (struct dataflash *)mtd->priv;
struct spi_transfer x[2] = { { .tx_dma = 0, }, };
struct spi_message msg;
unsigned int addr;
u8 *command;
int status;
DEBUG(MTD_DEBUG_LEVEL2, "%s: read 0x%x..0x%x\n",
priv->spi->dev.bus_id, (unsigned)from, (unsigned)(from + len));
*retlen = 0;
/* Sanity checks */
if (!len)
return 0;
if (from + len > mtd->size)
return -EINVAL;
/* Calculate flash page/byte address */
addr = (((unsigned)from / priv->page_size) << priv->page_offset)
+ ((unsigned)from % priv->page_size);
command = priv->command;
DEBUG(MTD_DEBUG_LEVEL3, "READ: (%x) %x %x %x\n",
command[0], command[1], command[2], command[3]);
spi_message_init(&msg);
x[0].tx_buf = command;
x[0].len = 8;
spi_message_add_tail(&x[0], &msg);
x[1].rx_buf = buf;
x[1].len = len;
spi_message_add_tail(&x[1], &msg);
down(&priv->lock);
/* Continuous read, max clock = f(car) which may be less than
* the peak rate available. Some chips support commands with
* fewer "don't care" bytes. Both buffers stay unchanged.
*/
command[0] = OP_READ_CONTINUOUS;
command[1] = (u8)(addr >> 16);
command[2] = (u8)(addr >> 8);
command[3] = (u8)(addr >> 0);
/* plus 4 "don't care" bytes */
status = spi_sync(priv->spi, &msg);
up(&priv->lock);
if (status >= 0) {
*retlen = msg.actual_length - 8;
status = 0;
} else
DEBUG(MTD_DEBUG_LEVEL1, "%s: read %x..%x --> %d\n",
priv->spi->dev.bus_id,
(unsigned)from, (unsigned)(from + len),
status);
return status;
}
/*
* Write to the DataFlash device.
* to : Start offset in flash device
* len : Amount to write
* retlen : Amount of data actually written
* buf : Buffer containing the data
*/
static int dataflash_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t * retlen, const u_char * buf)
{
struct dataflash *priv = (struct dataflash *)mtd->priv;
struct spi_device *spi = priv->spi;
struct spi_transfer x[2] = { { .tx_dma = 0, }, };
struct spi_message msg;
unsigned int pageaddr, addr, offset, writelen;
size_t remaining = len;
u_char *writebuf = (u_char *) buf;
int status = -EINVAL;
u8 *command;
DEBUG(MTD_DEBUG_LEVEL2, "%s: write 0x%x..0x%x\n",
spi->dev.bus_id, (unsigned)to, (unsigned)(to + len));
*retlen = 0;
/* Sanity checks */
if (!len)
return 0;
if ((to + len) > mtd->size)
return -EINVAL;
spi_message_init(&msg);
x[0].tx_buf = command = priv->command;
x[0].len = 4;
spi_message_add_tail(&x[0], &msg);
pageaddr = ((unsigned)to / priv->page_size);
offset = ((unsigned)to % priv->page_size);
if (offset + len > priv->page_size)
writelen = priv->page_size - offset;
else
writelen = len;
down(&priv->lock);
while (remaining > 0) {
DEBUG(MTD_DEBUG_LEVEL3, "write @ %i:%i len=%i\n",
pageaddr, offset, writelen);
/* REVISIT:
* (a) each page in a sector must be rewritten at least
* once every 10K sibling erase/program operations.
* (b) for pages that are already erased, we could
* use WRITE+MWRITE not PROGRAM for ~30% speedup.
* (c) WRITE to buffer could be done while waiting for
* a previous MWRITE/MWERASE to complete ...
* (d) error handling here seems to be mostly missing.
*
* Two persistent bits per page, plus a per-sector counter,
* could support (a) and (b) ... we might consider using
* the second half of sector zero, which is just one block,
* to track that state. (On AT91, that sector should also
* support boot-from-DataFlash.)
*/
addr = pageaddr << priv->page_offset;
/* (1) Maybe transfer partial page to Buffer1 */
if (writelen != priv->page_size) {
command[0] = OP_TRANSFER_BUF1;
command[1] = (addr & 0x00FF0000) >> 16;
command[2] = (addr & 0x0000FF00) >> 8;
command[3] = 0;
DEBUG(MTD_DEBUG_LEVEL3, "TRANSFER: (%x) %x %x %x\n",
command[0], command[1], command[2], command[3]);
status = spi_sync(spi, &msg);
if (status < 0)
DEBUG(MTD_DEBUG_LEVEL1, "%s: xfer %u -> %d \n",
spi->dev.bus_id, addr, status);
(void) dataflash_waitready(priv->spi);
}
/* (2) Program full page via Buffer1 */
addr += offset;
command[0] = OP_PROGRAM_VIA_BUF1;
command[1] = (addr & 0x00FF0000) >> 16;
command[2] = (addr & 0x0000FF00) >> 8;
command[3] = (addr & 0x000000FF);
DEBUG(MTD_DEBUG_LEVEL3, "PROGRAM: (%x) %x %x %x\n",
command[0], command[1], command[2], command[3]);
x[1].tx_buf = writebuf;
x[1].len = writelen;
spi_message_add_tail(x + 1, &msg);
status = spi_sync(spi, &msg);
spi_transfer_del(x + 1);
if (status < 0)
DEBUG(MTD_DEBUG_LEVEL1, "%s: pgm %u/%u -> %d \n",
spi->dev.bus_id, addr, writelen, status);
(void) dataflash_waitready(priv->spi);
#ifdef CONFIG_DATAFLASH_WRITE_VERIFY
/* (3) Compare to Buffer1 */
addr = pageaddr << priv->page_offset;
command[0] = OP_COMPARE_BUF1;
command[1] = (addr & 0x00FF0000) >> 16;
command[2] = (addr & 0x0000FF00) >> 8;
command[3] = 0;
DEBUG(MTD_DEBUG_LEVEL3, "COMPARE: (%x) %x %x %x\n",
command[0], command[1], command[2], command[3]);
status = spi_sync(spi, &msg);
if (status < 0)
DEBUG(MTD_DEBUG_LEVEL1, "%s: compare %u -> %d \n",
spi->dev.bus_id, addr, status);
status = dataflash_waitready(priv->spi);
/* Check result of the compare operation */
if ((status & (1 << 6)) == 1) {
printk(KERN_ERR "%s: compare page %u, err %d\n",
spi->dev.bus_id, pageaddr, status);
remaining = 0;
status = -EIO;
break;
} else
status = 0;
#endif /* CONFIG_DATAFLASH_WRITE_VERIFY */
remaining = remaining - writelen;
pageaddr++;
offset = 0;
writebuf += writelen;
*retlen += writelen;
if (remaining > priv->page_size)
writelen = priv->page_size;
else
writelen = remaining;
}
up(&priv->lock);
return status;
}
/* ......................................................................... */
/*
* Register DataFlash device with MTD subsystem.
*/
static int __devinit
add_dataflash(struct spi_device *spi, char *name,
int nr_pages, int pagesize, int pageoffset)
{
struct dataflash *priv;
struct mtd_info *device;
struct flash_platform_data *pdata = spi->dev.platform_data;
priv = (struct dataflash *) kzalloc(sizeof *priv, GFP_KERNEL);
if (!priv)
return -ENOMEM;
init_MUTEX(&priv->lock);
priv->spi = spi;
priv->page_size = pagesize;
priv->page_offset = pageoffset;
/* name must be usable with cmdlinepart */
sprintf(priv->name, "spi%d.%d-%s",
spi->master->bus_num, spi->chip_select,
name);
device = &priv->mtd;
device->name = (pdata && pdata->name) ? pdata->name : priv->name;
device->size = nr_pages * pagesize;
device->erasesize = pagesize;
device->owner = THIS_MODULE;
device->type = MTD_DATAFLASH;
device->flags = MTD_CAP_NORFLASH;
device->erase = dataflash_erase;
device->read = dataflash_read;
device->write = dataflash_write;
device->priv = priv;
dev_info(&spi->dev, "%s (%d KBytes)\n", name, device->size/1024);
dev_set_drvdata(&spi->dev, priv);
if (mtd_has_partitions()) {
struct mtd_partition *parts;
int nr_parts = 0;
#ifdef CONFIG_MTD_CMDLINE_PARTS
static const char *part_probes[] = { "cmdlinepart", NULL, };
nr_parts = parse_mtd_partitions(device, part_probes, &parts, 0);
#endif
if (nr_parts <= 0 && pdata && pdata->parts) {
parts = pdata->parts;
nr_parts = pdata->nr_parts;
}
if (nr_parts > 0) {
priv->partitioned = 1;
return add_mtd_partitions(device, parts, nr_parts);
}
} else if (pdata && pdata->nr_parts)
dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
pdata->nr_parts, device->name);
return add_mtd_device(device) == 1 ? -ENODEV : 0;
}
/*
* Detect and initialize DataFlash device:
*
* Device Density ID code #Pages PageSize Offset
* AT45DB011B 1Mbit (128K) xx0011xx (0x0c) 512 264 9
* AT45DB021B 2Mbit (256K) xx0101xx (0x14) 1025 264 9
* AT45DB041B 4Mbit (512K) xx0111xx (0x1c) 2048 264 9
* AT45DB081B 8Mbit (1M) xx1001xx (0x24) 4096 264 9
* AT45DB0161B 16Mbit (2M) xx1011xx (0x2c) 4096 528 10
* AT45DB0321B 32Mbit (4M) xx1101xx (0x34) 8192 528 10
* AT45DB0642 64Mbit (8M) xx111xxx (0x3c) 8192 1056 11
* AT45DB1282 128Mbit (16M) xx0100xx (0x10) 16384 1056 11
*/
static int __devinit dataflash_probe(struct spi_device *spi)
{
int status;
status = dataflash_status(spi);
if (status <= 0 || status == 0xff) {
DEBUG(MTD_DEBUG_LEVEL1, "%s: status error %d\n",
spi->dev.bus_id, status);
if (status == 0xff)
status = -ENODEV;
return status;
}
/* if there's a device there, assume it's dataflash.
* board setup should have set spi->max_speed_max to
* match f(car) for continuous reads, mode 0 or 3.
*/
switch (status & 0x3c) {
case 0x0c: /* 0 0 1 1 x x */
status = add_dataflash(spi, "AT45DB011B", 512, 264, 9);
break;
case 0x14: /* 0 1 0 1 x x */
status = add_dataflash(spi, "AT45DB021B", 1025, 264, 9);
break;
case 0x1c: /* 0 1 1 1 x x */
status = add_dataflash(spi, "AT45DB041x", 2048, 264, 9);
break;
case 0x24: /* 1 0 0 1 x x */
status = add_dataflash(spi, "AT45DB081B", 4096, 264, 9);
break;
case 0x2c: /* 1 0 1 1 x x */
status = add_dataflash(spi, "AT45DB161x", 4096, 528, 10);
break;
case 0x34: /* 1 1 0 1 x x */
status = add_dataflash(spi, "AT45DB321x", 8192, 528, 10);
break;
case 0x38: /* 1 1 1 x x x */
case 0x3c:
status = add_dataflash(spi, "AT45DB642x", 8192, 1056, 11);
break;
/* obsolete AT45DB1282 not (yet?) supported */
default:
DEBUG(MTD_DEBUG_LEVEL1, "%s: unsupported device (%x)\n",
spi->dev.bus_id, status & 0x3c);
status = -ENODEV;
}
if (status < 0)
DEBUG(MTD_DEBUG_LEVEL1, "%s: add_dataflash --> %d\n",
spi->dev.bus_id, status);
return status;
}
static int __devexit dataflash_remove(struct spi_device *spi)
{
struct dataflash *flash = dev_get_drvdata(&spi->dev);
int status;
DEBUG(MTD_DEBUG_LEVEL1, "%s: remove\n", spi->dev.bus_id);
if (mtd_has_partitions() && flash->partitioned)
status = del_mtd_partitions(&flash->mtd);
else
status = del_mtd_device(&flash->mtd);
if (status == 0)
kfree(flash);
return status;
}
static struct spi_driver dataflash_driver = {
.driver = {
.name = "mtd_dataflash",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
},
.probe = dataflash_probe,
.remove = __devexit_p(dataflash_remove),
/* FIXME: investigate suspend and resume... */
};
static int __init dataflash_init(void)
{
return spi_register_driver(&dataflash_driver);
}
module_init(dataflash_init);
static void __exit dataflash_exit(void)
{
spi_unregister_driver(&dataflash_driver);
}
module_exit(dataflash_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Andrew Victor, David Brownell");
MODULE_DESCRIPTION("MTD DataFlash driver");
drivers/spi/Kconfig 0 → 100644
View file @ 61b7efdd
#
# SPI driver configuration
#
# NOTE: the reason this doesn't show SPI slave support is mostly that
# nobody's needed a slave side API yet. The master-role API is not
# fully appropriate there, so it'd need some thought to do well.
#
menu "SPI support"
config SPI
bool "SPI support"
help
The "Serial Peripheral Interface" is a low level synchronous
protocol. Chips that support SPI can have data transfer rates
up to several tens of Mbit/sec. Chips are addressed with a
controller and a chipselect. Most SPI slaves don't support
dynamic device discovery; some are even write-only or read-only.
SPI is widely used by microcontollers to talk with sensors,
eeprom and flash memory, codecs and various other controller
chips, analog to digital (and d-to-a) converters, and more.
MMC and SD cards can be accessed using SPI protocol; and for
DataFlash cards used in MMC sockets, SPI must always be used.
SPI is one of a family of similar protocols using a four wire
interface (select, clock, data in, data out) including Microwire
(half duplex), SSP, SSI, and PSP. This driver framework should
work with most such devices and controllers.
config SPI_DEBUG
boolean "Debug support for SPI drivers"
depends on SPI && DEBUG_KERNEL
help
Say "yes" to enable debug messaging (like dev_dbg and pr_debug),
sysfs, and debugfs support in SPI controller and protocol drivers.
#
# MASTER side ... talking to discrete SPI slave chips including microcontrollers
#
config SPI_MASTER
# boolean "SPI Master Support"
boolean
default SPI
help
If your system has an master-capable SPI controller (which
provides the clock and chipselect), you can enable that
controller and the protocol drivers for the SPI slave chips
that are connected.
comment "SPI Master Controller Drivers"
depends on SPI_MASTER
config SPI_BITBANG
tristate "Bitbanging SPI master"
depends on SPI_MASTER && EXPERIMENTAL
help
With a few GPIO pins, your system can bitbang the SPI protocol.
Select this to get SPI support through I/O pins (GPIO, parallel
port, etc). Or, some systems' SPI master controller drivers use
this code to manage the per-word or per-transfer accesses to the
hardware shift registers.
This is library code, and is automatically selected by drivers that
need it. You only need to select this explicitly to support driver
modules that aren't part of this kernel tree.
config SPI_BUTTERFLY
tristate "Parallel port adapter for AVR Butterfly (DEVELOPMENT)"
depends on SPI_MASTER && PARPORT && EXPERIMENTAL
select SPI_BITBANG
help
This uses a custom parallel port cable to connect to an AVR
Butterfly <http://www.atmel.com/products/avr/butterfly>, an
inexpensive battery powered microcontroller evaluation board.
This same cable can be used to flash new firmware.
config SPI_BUTTERFLY
tristate "Parallel port adapter for AVR Butterfly (DEVELOPMENT)"
depends on SPI_MASTER && PARPORT && EXPERIMENTAL
select SPI_BITBANG
help
This uses a custom parallel port cable to connect to an AVR
Butterfly <http://www.atmel.com/products/avr/butterfly>, an
inexpensive battery powered microcontroller evaluation board.
This same cable can be used to flash new firmware.
#
# Add new SPI master controllers in alphabetical order above this line
#
#
# There are lots of SPI device types, with sensors and memory
# being probably the most widely used ones.
#
comment "SPI Protocol Masters"
depends on SPI_MASTER
#
# Add new SPI protocol masters in alphabetical order above this line
#
# (slave support would go here)
endmenu # "SPI support"
drivers/spi/Makefile 0 → 100644
View file @ 61b7efdd
#
# Makefile for kernel SPI drivers.
#
ifeq ($(CONFIG_SPI_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
endif
# small core, mostly translating board-specific
# config declarations into driver model code
obj-$(CONFIG_SPI_MASTER) += spi.o
# SPI master controller drivers (bus)
obj-$(CONFIG_SPI_BITBANG) += spi_bitbang.o
obj-$(CONFIG_SPI_BUTTERFLY) += spi_butterfly.o
# ... add above this line ...
# SPI protocol drivers (device/link on bus)
# ... add above this line ...
# SPI slave controller drivers (upstream link)
# ... add above this line ...
# SPI slave drivers (protocol for that link)
# ... add above this line ...
drivers/spi/spi.c 0 → 100644
View file @ 61b7efdd
/*
* spi.c - SPI init/core code
*
* Copyright (C) 2005 David Brownell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/autoconf.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
#include <linux/spi/spi.h>
/* SPI bustype and spi_master class are registered after board init code
* provides the SPI device tables, ensuring that both are present by the
* time controller driver registration causes spi_devices to "enumerate".
*/
static void spidev_release(struct device *dev)
{
const struct spi_device *spi = to_spi_device(dev);
/* spi masters may cleanup for released devices */
if (spi->master->cleanup)
spi->master->cleanup(spi);
spi_master_put(spi->master);
kfree(dev);
}
static ssize_t
modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
const struct spi_device *spi = to_spi_device(dev);
return snprintf(buf, BUS_ID_SIZE + 1, "%s\n", spi->modalias);
}
static struct device_attribute spi_dev_attrs[] = {
__ATTR_RO(modalias),
__ATTR_NULL,
};
/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
* and the sysfs version makes coldplug work too.
*/
static int spi_match_device(struct device *dev, struct device_driver *drv)
{
const struct spi_device *spi = to_spi_device(dev);
return strncmp(spi->modalias, drv->name, BUS_ID_SIZE) == 0;
}
static int spi_uevent(struct device *dev, char **envp, int num_envp,
char *buffer, int buffer_size)
{
const struct spi_device *spi = to_spi_device(dev);
envp[0] = buffer;
snprintf(buffer, buffer_size, "MODALIAS=%s", spi->modalias);
envp[1] = NULL;
return 0;
}
#ifdef CONFIG_PM
/*
* NOTE: the suspend() method for an spi_master controller driver
* should verify that all its child devices are marked as suspended;
* suspend requests delivered through sysfs power/state files don't
* enforce such constraints.
*/
static int spi_suspend(struct device *dev, pm_message_t message)
{
int value;
struct spi_driver *drv = to_spi_driver(dev->driver);
if (!drv->suspend)
return 0;
/* suspend will stop irqs and dma; no more i/o */
value = drv->suspend(to_spi_device(dev), message);
if (value == 0)
dev->power.power_state = message;
return value;
}
static int spi_resume(struct device *dev)
{
int value;
struct spi_driver *drv = to_spi_driver(dev->driver);
if (!drv->resume)
return 0;
/* resume may restart the i/o queue */
value = drv->resume(to_spi_device(dev));
if (value == 0)
dev->power.power_state = PMSG_ON;
return value;
}
#else
#define spi_suspend NULL
#define spi_resume NULL
#endif
struct bus_type spi_bus_type = {
.name = "spi",
.dev_attrs = spi_dev_attrs,
.match = spi_match_device,
.uevent = spi_uevent,
.suspend = spi_suspend,
.resume = spi_resume,
};
EXPORT_SYMBOL_GPL(spi_bus_type);
static int spi_drv_probe(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
return sdrv->probe(to_spi_device(dev));
}
static int spi_drv_remove(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
return sdrv->remove(to_spi_device(dev));
}
static void spi_drv_shutdown(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
sdrv->shutdown(to_spi_device(dev));
}
int spi_register_driver(struct spi_driver *sdrv)
{
sdrv->driver.bus = &spi_bus_type;
if (sdrv->probe)
sdrv->driver.probe = spi_drv_probe;
if (sdrv->remove)
sdrv->driver.remove = spi_drv_remove;
if (sdrv->shutdown)
sdrv->driver.shutdown = spi_drv_shutdown;
return driver_register(&sdrv->driver);
}
EXPORT_SYMBOL_GPL(spi_register_driver);
/*-------------------------------------------------------------------------*/
/* SPI devices should normally not be created by SPI device drivers; that
* would make them board-specific. Similarly with SPI master drivers.
* Device registration normally goes into like arch/.../mach.../board-YYY.c
* with other readonly (flashable) information about mainboard devices.
*/
struct boardinfo {
struct list_head list;
unsigned n_board_info;
struct spi_board_info board_info[0];
};
static LIST_HEAD(board_list);
static DECLARE_MUTEX(board_lock);
/* On typical mainboards, this is purely internal; and it's not needed
* after board init creates the hard-wired devices. Some development
* platforms may not be able to use spi_register_board_info though, and
* this is exported so that for example a USB or parport based adapter
* driver could add devices (which it would learn about out-of-band).
*/
struct spi_device *__init_or_module
spi_new_device(struct spi_master *master, struct spi_board_info *chip)
{
struct spi_device *proxy;
struct device *dev = master->cdev.dev;
int status;
/* NOTE: caller did any chip->bus_num checks necessary */
if (!spi_master_get(master))
return NULL;
proxy = kzalloc(sizeof *proxy, GFP_KERNEL);
if (!proxy) {
dev_err(dev, "can't alloc dev for cs%d\n",
chip->chip_select);
goto fail;
}
proxy->master = master;
proxy->chip_select = chip->chip_select;
proxy->max_speed_hz = chip->max_speed_hz;
proxy->irq = chip->irq;
proxy->modalias = chip->modalias;
snprintf(proxy->dev.bus_id, sizeof proxy->dev.bus_id,
"%s.%u", master->cdev.class_id,
chip->chip_select);
proxy->dev.parent = dev;
proxy->dev.bus = &spi_bus_type;
proxy->dev.platform_data = (void *) chip->platform_data;
proxy->controller_data = chip->controller_data;
proxy->controller_state = NULL;
proxy->dev.release = spidev_release;
/* drivers may modify this default i/o setup */
status = master->setup(proxy);
if (status < 0) {
dev_dbg(dev, "can't %s %s, status %d\n",
"setup", proxy->dev.bus_id, status);
goto fail;
}
/* driver core catches callers that misbehave by defining
* devices that already exist.
*/
status = device_register(&proxy->dev);
if (status < 0) {
dev_dbg(dev, "can't %s %s, status %d\n",
"add", proxy->dev.bus_id, status);
goto fail;
}
dev_dbg(dev, "registered child %s\n", proxy->dev.bus_id);
return proxy;
fail:
spi_master_put(master);
kfree(proxy);
return NULL;
}
EXPORT_SYMBOL_GPL(spi_new_device);
/*
* Board-specific early init code calls this (probably during arch_initcall)
* with segments of the SPI device table. Any device nodes are created later,
* after the relevant parent SPI controller (bus_num) is defined. We keep
* this table of devices forever, so that reloading a controller driver will
* not make Linux forget about these hard-wired devices.
*
* Other code can also call this, e.g. a particular add-on board might provide
* SPI devices through its expansion connector, so code initializing that board
* would naturally declare its SPI devices.
*
* The board info passed can safely be __initdata ... but be careful of
* any embedded pointers (platform_data, etc), they're copied as-is.
*/
int __init
spi_register_board_info(struct spi_board_info const *info, unsigned n)
{
struct boardinfo *bi;
bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL);
if (!bi)
return -ENOMEM;
bi->n_board_info = n;
memcpy(bi->board_info, info, n * sizeof *info);
down(&board_lock);
list_add_tail(&bi->list, &board_list);
up(&board_lock);
return 0;
}
EXPORT_SYMBOL_GPL(spi_register_board_info);
/* FIXME someone should add support for a __setup("spi", ...) that
* creates board info from kernel command lines
*/
static void __init_or_module
scan_boardinfo(struct spi_master *master)
{
struct boardinfo *bi;
struct device *dev = master->cdev.dev;
down(&board_lock);
list_for_each_entry(bi, &board_list, list) {
struct spi_board_info *chip = bi->board_info;
unsigned n;
for (n = bi->n_board_info; n > 0; n--, chip++) {
if (chip->bus_num != master->bus_num)
continue;
/* some controllers only have one chip, so they
* might not use chipselects. otherwise, the
* chipselects are numbered 0..max.
*/
if (chip->chip_select >= master->num_chipselect
&& master->num_chipselect) {
dev_dbg(dev, "cs%d > max %d\n",
chip->chip_select,
master->num_chipselect);
continue;
}
(void) spi_new_device(master, chip);
}
}
up(&board_lock);
}
/*-------------------------------------------------------------------------*/
static void spi_master_release(struct class_device *cdev)
{
struct spi_master *master;
master = container_of(cdev, struct spi_master, cdev);
kfree(master);
}
static struct class spi_master_class = {
.name = "spi_master",
.owner = THIS_MODULE,
.release = spi_master_release,
};
/**
* spi_alloc_master - allocate SPI master controller
* @dev: the controller, possibly using the platform_bus
* @size: how much driver-private data to preallocate; the pointer to this
* memory is in the class_data field of the returned class_device,
* accessible with spi_master_get_devdata().
*
* This call is used only by SPI master controller drivers, which are the
* only ones directly touching chip registers. It's how they allocate
* an spi_master structure, prior to calling spi_add_master().
*
* This must be called from context that can sleep. It returns the SPI
* master structure on success, else NULL.
*
* The caller is responsible for assigning the bus number and initializing
* the master's methods before calling spi_add_master(); and (after errors
* adding the device) calling spi_master_put() to prevent a memory leak.
*/
struct spi_master * __init_or_module
spi_alloc_master(struct device *dev, unsigned size)
{
struct spi_master *master;
if (!dev)
return NULL;
master = kzalloc(size + sizeof *master, SLAB_KERNEL);
if (!master)
return NULL;
class_device_initialize(&master->cdev);
master->cdev.class = &spi_master_class;
master->cdev.dev = get_device(dev);
spi_master_set_devdata(master, &master[1]);
return master;
}
EXPORT_SYMBOL_GPL(spi_alloc_master);
/**
* spi_register_master - register SPI master controller
* @master: initialized master, originally from spi_alloc_master()
*
* SPI master controllers connect to their drivers using some non-SPI bus,
* such as the platform bus. The final stage of probe() in that code
* includes calling spi_register_master() to hook up to this SPI bus glue.
*
* SPI controllers use board specific (often SOC specific) bus numbers,
* and board-specific addressing for SPI devices combines those numbers
* with chip select numbers. Since SPI does not directly support dynamic
* device identification, boards need configuration tables telling which
* chip is at which address.
*
* This must be called from context that can sleep. It returns zero on
* success, else a negative error code (dropping the master's refcount).
* After a successful return, the caller is responsible for calling
* spi_unregister_master().
*/
int __init_or_module
spi_register_master(struct spi_master *master)
{
static atomic_t dyn_bus_id = ATOMIC_INIT(0);
struct device *dev = master->cdev.dev;
int status = -ENODEV;
int dynamic = 0;
if (!dev)
return -ENODEV;
/* convention: dynamically assigned bus IDs count down from the max */
if (master->bus_num == 0) {
master->bus_num = atomic_dec_return(&dyn_bus_id);
dynamic = 1;
}
/* register the device, then userspace will see it.
* registration fails if the bus ID is in use.
*/
snprintf(master->cdev.class_id, sizeof master->cdev.class_id,
"spi%u", master->bus_num);
status = class_device_add(&master->cdev);
if (status < 0)
goto done;
dev_dbg(dev, "registered master %s%s\n", master->cdev.class_id,
dynamic ? " (dynamic)" : "");
/* populate children from any spi device tables */
scan_boardinfo(master);
status = 0;
done:
return status;
}
EXPORT_SYMBOL_GPL(spi_register_master);
static int __unregister(struct device *dev, void *unused)
{
/* note: before about 2.6.14-rc1 this would corrupt memory: */
spi_unregister_device(to_spi_device(dev));
return 0;
}
/**
* spi_unregister_master - unregister SPI master controller
* @master: the master being unregistered
*
* This call is used only by SPI master controller drivers, which are the
* only ones directly touching chip registers.
*
* This must be called from context that can sleep.
*/
void spi_unregister_master(struct spi_master *master)
{
(void) device_for_each_child(master->cdev.dev, NULL, __unregister);
class_device_unregister(&master->cdev);
master->cdev.dev = NULL;
}
EXPORT_SYMBOL_GPL(spi_unregister_master);
/**
* spi_busnum_to_master - look up master associated with bus_num
* @bus_num: the master's bus number
*
* This call may be used with devices that are registered after
* arch init time. It returns a refcounted pointer to the relevant
* spi_master (which the caller must release), or NULL if there is
* no such master registered.
*/
struct spi_master *spi_busnum_to_master(u16 bus_num)
{
if (bus_num) {
char name[8];
struct kobject *bus;
snprintf(name, sizeof name, "spi%u", bus_num);
bus = kset_find_obj(&spi_master_class.subsys.kset, name);
if (bus)
return container_of(bus, struct spi_master, cdev.kobj);
}
return NULL;
}
EXPORT_SYMBOL_GPL(spi_busnum_to_master);
/*-------------------------------------------------------------------------*/
static void spi_complete(void *arg)
{
complete(arg);
}
/**
* spi_sync - blocking/synchronous SPI data transfers
* @spi: device with which data will be exchanged
* @message: describes the data transfers
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout. Low-overhead controller
* drivers may DMA directly into and out of the message buffers.
*
* Note that the SPI device's chip select is active during the message,
* and then is normally disabled between messages. Drivers for some
* frequently-used devices may want to minimize costs of selecting a chip,
* by leaving it selected in anticipation that the next message will go
* to the same chip. (That may increase power usage.)
*
* Also, the caller is guaranteeing that the memory associated with the
* message will not be freed before this call returns.
*
* The return value is a negative error code if the message could not be
* submitted, else zero. When the value is zero, then message->status is
* also defined: it's the completion code for the transfer, either zero
* or a negative error code from the controller driver.
*/
int spi_sync(struct spi_device *spi, struct spi_message *message)
{
DECLARE_COMPLETION(done);
int status;
message->complete = spi_complete;
message->context = &done;
status = spi_async(spi, message);
if (status == 0)
wait_for_completion(&done);
message->context = NULL;
return status;
}
EXPORT_SYMBOL_GPL(spi_sync);
#define SPI_BUFSIZ (SMP_CACHE_BYTES)
static u8 *buf;
/**
* spi_write_then_read - SPI synchronous write followed by read
* @spi: device with which data will be exchanged
* @txbuf: data to be written (need not be dma-safe)
* @n_tx: size of txbuf, in bytes
* @rxbuf: buffer into which data will be read
* @n_rx: size of rxbuf, in bytes (need not be dma-safe)
*
* This performs a half duplex MicroWire style transaction with the
* device, sending txbuf and then reading rxbuf. The return value
* is zero for success, else a negative errno status code.
* This call may only be used from a context that may sleep.
*
* Parameters to this routine are always copied using a small buffer;
* performance-sensitive or bulk transfer code should instead use
* spi_{async,sync}() calls with dma-safe buffers.
*/
int spi_write_then_read(struct spi_device *spi,
const u8 *txbuf, unsigned n_tx,
u8 *rxbuf, unsigned n_rx)
{
static DECLARE_MUTEX(lock);
int status;
struct spi_message message;
struct spi_transfer x[2];
u8 *local_buf;
/* Use preallocated DMA-safe buffer. We can't avoid copying here,
* (as a pure convenience thing), but we can keep heap costs
* out of the hot path ...
*/
if ((n_tx + n_rx) > SPI_BUFSIZ)
return -EINVAL;
spi_message_init(&message);
memset(x, 0, sizeof x);
if (n_tx) {
x[0].len = n_tx;
spi_message_add_tail(&x[0], &message);
}
if (n_rx) {
x[1].len = n_rx;
spi_message_add_tail(&x[1], &message);
}
/* ... unless someone else is using the pre-allocated buffer */
if (down_trylock(&lock)) {
local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
if (!local_buf)
return -ENOMEM;
} else
local_buf = buf;
memcpy(local_buf, txbuf, n_tx);
x[0].tx_buf = local_buf;
x[1].rx_buf = local_buf + n_tx;
/* do the i/o */
status = spi_sync(spi, &message);
if (status == 0) {
memcpy(rxbuf, x[1].rx_buf, n_rx);
status = message.status;
}
if (x[0].tx_buf == buf)
up(&lock);
else
kfree(local_buf);
return status;
}
EXPORT_SYMBOL_GPL(spi_write_then_read);
/*-------------------------------------------------------------------------*/
static int __init spi_init(void)
{
int status;
buf = kmalloc(SPI_BUFSIZ, SLAB_KERNEL);
if (!buf) {
status = -ENOMEM;
goto err0;
}
status = bus_register(&spi_bus_type);
if (status < 0)
goto err1;
status = class_register(&spi_master_class);
if (status < 0)
goto err2;
return 0;
err2:
bus_unregister(&spi_bus_type);
err1:
kfree(buf);
buf = NULL;
err0:
return status;
}
/* board_info is normally registered in arch_initcall(),
* but even essential drivers wait till later
*
* REVISIT only boardinfo really needs static linking. the rest (device and
* driver registration) _could_ be dynamically linked (modular) ... costs
* include needing to have boardinfo data structures be much more public.
*/
subsys_initcall(spi_init);
drivers/spi/spi_bitbang.c 0 → 100644
View file @ 61b7efdd
/*
* spi_bitbang.c - polling/bitbanging SPI master controller driver utilities
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/config.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
/*----------------------------------------------------------------------*/
/*
* FIRST PART (OPTIONAL): word-at-a-time spi_transfer support.
* Use this for GPIO or shift-register level hardware APIs.
*
* spi_bitbang_cs is in spi_device->controller_state, which is unavailable
* to glue code. These bitbang setup() and cleanup() routines are always
* used, though maybe they're called from controller-aware code.
*
* chipselect() and friends may use use spi_device->controller_data and
* controller registers as appropriate.
*
*
* NOTE: SPI controller pins can often be used as GPIO pins instead,
* which means you could use a bitbang driver either to get hardware
* working quickly, or testing for differences that aren't speed related.
*/
struct spi_bitbang_cs {
unsigned nsecs; /* (clock cycle time)/2 */
u32 (*txrx_word)(struct spi_device *spi, unsigned nsecs,
u32 word, u8 bits);
unsigned (*txrx_bufs)(struct spi_device *,
u32 (*txrx_word)(
struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits),
unsigned, struct spi_transfer *);
};
static unsigned bitbang_txrx_8(
struct spi_device *spi,
u32 (*txrx_word)(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits),
unsigned ns,
struct spi_transfer *t
) {
unsigned bits = spi->bits_per_word;
unsigned count = t->len;
const u8 *tx = t->tx_buf;
u8 *rx = t->rx_buf;
while (likely(count > 0)) {
u8 word = 0;
if (tx)
word = *tx++;
word = txrx_word(spi, ns, word, bits);
if (rx)
*rx++ = word;
count -= 1;
}
return t->len - count;
}
static unsigned bitbang_txrx_16(
struct spi_device *spi,
u32 (*txrx_word)(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits),
unsigned ns,
struct spi_transfer *t
) {
unsigned bits = spi->bits_per_word;
unsigned count = t->len;
const u16 *tx = t->tx_buf;
u16 *rx = t->rx_buf;
while (likely(count > 1)) {
u16 word = 0;
if (tx)
word = *tx++;
word = txrx_word(spi, ns, word, bits);
if (rx)
*rx++ = word;
count -= 2;
}
return t->len - count;
}
static unsigned bitbang_txrx_32(
struct spi_device *spi,
u32 (*txrx_word)(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits),
unsigned ns,
struct spi_transfer *t
) {
unsigned bits = spi->bits_per_word;
unsigned count = t->len;
const u32 *tx = t->tx_buf;
u32 *rx = t->rx_buf;
while (likely(count > 3)) {
u32 word = 0;
if (tx)
word = *tx++;
word = txrx_word(spi, ns, word, bits);
if (rx)
*rx++ = word;
count -= 4;
}
return t->len - count;
}
/**
* spi_bitbang_setup - default setup for per-word I/O loops
*/
int spi_bitbang_setup(struct spi_device *spi)
{
struct spi_bitbang_cs *cs = spi->controller_state;
struct spi_bitbang *bitbang;
if (!spi->max_speed_hz)
return -EINVAL;
if (!cs) {
cs = kzalloc(sizeof *cs, SLAB_KERNEL);
if (!cs)
return -ENOMEM;
spi->controller_state = cs;
}
bitbang = spi_master_get_devdata(spi->master);
if (!spi->bits_per_word)
spi->bits_per_word = 8;
/* spi_transfer level calls that work per-word */
if (spi->bits_per_word <= 8)
cs->txrx_bufs = bitbang_txrx_8;
else if (spi->bits_per_word <= 16)
cs->txrx_bufs = bitbang_txrx_16;
else if (spi->bits_per_word <= 32)
cs->txrx_bufs = bitbang_txrx_32;
else
return -EINVAL;
/* per-word shift register access, in hardware or bitbanging */
cs->txrx_word = bitbang->txrx_word[spi->mode & (SPI_CPOL|SPI_CPHA)];
if (!cs->txrx_word)
return -EINVAL;
/* nsecs = (clock period)/2 */
cs->nsecs = (1000000000/2) / (spi->max_speed_hz);
if (cs->nsecs > MAX_UDELAY_MS * 1000)
return -EINVAL;
dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n",
__FUNCTION__, spi->mode & (SPI_CPOL | SPI_CPHA),
spi->bits_per_word, 2 * cs->nsecs);
/* NOTE we _need_ to call chipselect() early, ideally with adapter
* setup, unless the hardware defaults cooperate to avoid confusion
* between normal (active low) and inverted chipselects.
*/
/* deselect chip (low or high) */
spin_lock(&bitbang->lock);
if (!bitbang->busy) {
bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(cs->nsecs);
}
spin_unlock(&bitbang->lock);
return 0;
}
EXPORT_SYMBOL_GPL(spi_bitbang_setup);
/**
* spi_bitbang_cleanup - default cleanup for per-word I/O loops
*/
void spi_bitbang_cleanup(const struct spi_device *spi)
{
kfree(spi->controller_state);
}
EXPORT_SYMBOL_GPL(spi_bitbang_cleanup);
static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct spi_bitbang_cs *cs = spi->controller_state;
unsigned nsecs = cs->nsecs;
return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t);
}
/*----------------------------------------------------------------------*/
/*
* SECOND PART ... simple transfer queue runner.
*
* This costs a task context per controller, running the queue by
* performing each transfer in sequence. Smarter hardware can queue
* several DMA transfers at once, and process several controller queues
* in parallel; this driver doesn't match such hardware very well.
*
* Drivers can provide word-at-a-time i/o primitives, or provide
* transfer-at-a-time ones to leverage dma or fifo hardware.
*/
static void bitbang_work(void *_bitbang)
{
struct spi_bitbang *bitbang = _bitbang;
unsigned long flags;
spin_lock_irqsave(&bitbang->lock, flags);
bitbang->busy = 1;
while (!list_empty(&bitbang->queue)) {
struct spi_message *m;
struct spi_device *spi;
unsigned nsecs;
struct spi_transfer *t = NULL;
unsigned tmp;
unsigned cs_change;
int status;
m = container_of(bitbang->queue.next, struct spi_message,
queue);
list_del_init(&m->queue);
spin_unlock_irqrestore(&bitbang->lock, flags);
/* FIXME this is made-up ... the correct value is known to
* word-at-a-time bitbang code, and presumably chipselect()
* should enforce these requirements too?
*/
nsecs = 100;
spi = m->spi;
tmp = 0;
cs_change = 1;
status = 0;
list_for_each_entry (t, &m->transfers, transfer_list) {
if (bitbang->shutdown) {
status = -ESHUTDOWN;
break;
}
/* set up default clock polarity, and activate chip;
* this implicitly updates clock and spi modes as
* previously recorded for this device via setup().
* (and also deselects any other chip that might be
* selected ...)
*/
if (cs_change) {
bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
ndelay(nsecs);
}
cs_change = t->cs_change;
if (!t->tx_buf && !t->rx_buf && t->len) {
status = -EINVAL;
break;
}
/* transfer data. the lower level code handles any
* new dma mappings it needs. our caller always gave
* us dma-safe buffers.
*/
if (t->len) {
/* REVISIT dma API still needs a designated
* DMA_ADDR_INVALID; ~0 might be better.
*/
if (!m->is_dma_mapped)
t->rx_dma = t->tx_dma = 0;
status = bitbang->txrx_bufs(spi, t);
}
if (status != t->len) {
if (status > 0)
status = -EMSGSIZE;
break;
}
m->actual_length += status;
status = 0;
/* protocol tweaks before next transfer */
if (t->delay_usecs)
udelay(t->delay_usecs);
if (!cs_change)
continue;
if (t->transfer_list.next == &m->transfers)
break;
/* sometimes a short mid-message deselect of the chip
* may be needed to terminate a mode or command
*/
ndelay(nsecs);
bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(nsecs);
}
m->status = status;
m->complete(m->context);
/* normally deactivate chipselect ... unless no error and
* cs_change has hinted that the next message will probably
* be for this chip too.
*/
if (!(status == 0 && cs_change)) {
ndelay(nsecs);
bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(nsecs);
}
spin_lock_irqsave(&bitbang->lock, flags);
}
bitbang->busy = 0;
spin_unlock_irqrestore(&bitbang->lock, flags);
}
/**
* spi_bitbang_transfer - default submit to transfer queue
*/
int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m)
{
struct spi_bitbang *bitbang;
unsigned long flags;
m->actual_length = 0;
m->status = -EINPROGRESS;
bitbang = spi_master_get_devdata(spi->master);
if (bitbang->shutdown)
return -ESHUTDOWN;
spin_lock_irqsave(&bitbang->lock, flags);
list_add_tail(&m->queue, &bitbang->queue);
queue_work(bitbang->workqueue, &bitbang->work);
spin_unlock_irqrestore(&bitbang->lock, flags);
return 0;
}
EXPORT_SYMBOL_GPL(spi_bitbang_transfer);
/*----------------------------------------------------------------------*/
/**
* spi_bitbang_start - start up a polled/bitbanging SPI master driver
* @bitbang: driver handle
*
* Caller should have zero-initialized all parts of the structure, and then
* provided callbacks for chip selection and I/O loops. If the master has
* a transfer method, its final step should call spi_bitbang_transfer; or,
* that's the default if the transfer routine is not initialized. It should
* also set up the bus number and number of chipselects.
*
* For i/o loops, provide callbacks either per-word (for bitbanging, or for
* hardware that basically exposes a shift register) or per-spi_transfer
* (which takes better advantage of hardware like fifos or DMA engines).
*
* Drivers using per-word I/O loops should use (or call) spi_bitbang_setup and
* spi_bitbang_cleanup to handle those spi master methods. Those methods are
* the defaults if the bitbang->txrx_bufs routine isn't initialized.
*
* This routine registers the spi_master, which will process requests in a
* dedicated task, keeping IRQs unblocked most of the time. To stop
* processing those requests, call spi_bitbang_stop().
*/
int spi_bitbang_start(struct spi_bitbang *bitbang)
{
int status;
if (!bitbang->master || !bitbang->chipselect)
return -EINVAL;
INIT_WORK(&bitbang->work, bitbang_work, bitbang);
spin_lock_init(&bitbang->lock);
INIT_LIST_HEAD(&bitbang->queue);
if (!bitbang->master->transfer)
bitbang->master->transfer = spi_bitbang_transfer;
if (!bitbang->txrx_bufs) {
bitbang->use_dma = 0;
bitbang->txrx_bufs = spi_bitbang_bufs;
if (!bitbang->master->setup) {
bitbang->master->setup = spi_bitbang_setup;
bitbang->master->cleanup = spi_bitbang_cleanup;
}
} else if (!bitbang->master->setup)
return -EINVAL;
/* this task is the only thing to touch the SPI bits */
bitbang->busy = 0;
bitbang->workqueue = create_singlethread_workqueue(
bitbang->master->cdev.dev->bus_id);
if (bitbang->workqueue == NULL) {
status = -EBUSY;
goto err1;
}
/* driver may get busy before register() returns, especially
* if someone registered boardinfo for devices
*/
status = spi_register_master(bitbang->master);
if (status < 0)
goto err2;
return status;
err2:
destroy_workqueue(bitbang->workqueue);
err1:
return status;
}
EXPORT_SYMBOL_GPL(spi_bitbang_start);
/**
* spi_bitbang_stop - stops the task providing spi communication
*/
int spi_bitbang_stop(struct spi_bitbang *bitbang)
{
unsigned limit = 500;
spin_lock_irq(&bitbang->lock);
bitbang->shutdown = 0;
while (!list_empty(&bitbang->queue) && limit--) {
spin_unlock_irq(&bitbang->lock);
dev_dbg(bitbang->master->cdev.dev, "wait for queue\n");
msleep(10);
spin_lock_irq(&bitbang->lock);
}
spin_unlock_irq(&bitbang->lock);
if (!list_empty(&bitbang->queue)) {
dev_err(bitbang->master->cdev.dev, "queue didn't empty\n");
return -EBUSY;
}
destroy_workqueue(bitbang->workqueue);
spi_unregister_master(bitbang->master);
return 0;
}
EXPORT_SYMBOL_GPL(spi_bitbang_stop);
MODULE_LICENSE("GPL");
drivers/spi/spi_butterfly.c 0 → 100644
View file @ 61b7efdd
/*
* spi_butterfly.c - parport-to-butterfly adapter
*
* Copyright (C) 2005 David Brownell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/parport.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/spi/flash.h>
#include <linux/mtd/partitions.h>
/*
* This uses SPI to talk with an "AVR Butterfly", which is a $US20 card
* with a battery powered AVR microcontroller and lots of goodies. You
* can use GCC to develop firmware for this.
*
* See Documentation/spi/butterfly for information about how to build
* and use this custom parallel port cable.
*/
#undef HAVE_USI /* nyet */
/* DATA output bits (pins 2..9 == D0..D7) */
#define butterfly_nreset (1 << 1) /* pin 3 */
#define spi_sck_bit (1 << 0) /* pin 2 */
#define spi_mosi_bit (1 << 7) /* pin 9 */
#define usi_sck_bit (1 << 3) /* pin 5 */
#define usi_mosi_bit (1 << 4) /* pin 6 */
#define vcc_bits ((1 << 6) | (1 << 5)) /* pins 7, 8 */
/* STATUS input bits */
#define spi_miso_bit PARPORT_STATUS_BUSY /* pin 11 */
#define usi_miso_bit PARPORT_STATUS_PAPEROUT /* pin 12 */
/* CONTROL output bits */
#define spi_cs_bit PARPORT_CONTROL_SELECT /* pin 17 */
/* USI uses no chipselect */
static inline struct butterfly *spidev_to_pp(struct spi_device *spi)
{
return spi->controller_data;
}
static inline int is_usidev(struct spi_device *spi)
{
#ifdef HAVE_USI
return spi->chip_select != 1;
#else
return 0;
#endif
}
struct butterfly {
/* REVISIT ... for now, this must be first */
struct spi_bitbang bitbang;
struct parport *port;
struct pardevice *pd;
u8 lastbyte;
struct spi_device *dataflash;
struct spi_device *butterfly;
struct spi_board_info info[2];
};
/*----------------------------------------------------------------------*/
/*
* these routines may be slower than necessary because they're hiding
* the fact that there are two different SPI busses on this cable: one
* to the DataFlash chip (or AVR SPI controller), the other to the
* AVR USI controller.
*/
static inline void
setsck(struct spi_device *spi, int is_on)
{
struct butterfly *pp = spidev_to_pp(spi);
u8 bit, byte = pp->lastbyte;
if (is_usidev(spi))
bit = usi_sck_bit;
else
bit = spi_sck_bit;
if (is_on)
byte |= bit;
else
byte &= ~bit;
parport_write_data(pp->port, byte);
pp->lastbyte = byte;
}
static inline void
setmosi(struct spi_device *spi, int is_on)
{
struct butterfly *pp = spidev_to_pp(spi);
u8 bit, byte = pp->lastbyte;
if (is_usidev(spi))
bit = usi_mosi_bit;
else
bit = spi_mosi_bit;
if (is_on)
byte |= bit;
else
byte &= ~bit;
parport_write_data(pp->port, byte);
pp->lastbyte = byte;
}
static inline int getmiso(struct spi_device *spi)
{
struct butterfly *pp = spidev_to_pp(spi);
int value;
u8 bit;
if (is_usidev(spi))
bit = usi_miso_bit;
else
bit = spi_miso_bit;
/* only STATUS_BUSY is NOT negated */
value = !(parport_read_status(pp->port) & bit);
return (bit == PARPORT_STATUS_BUSY) ? value : !value;
}
static void butterfly_chipselect(struct spi_device *spi, int value)
{
struct butterfly *pp = spidev_to_pp(spi);
/* set default clock polarity */
if (value)
setsck(spi, spi->mode & SPI_CPOL);
/* no chipselect on this USI link config */
if (is_usidev(spi))
return;
/* here, value == "activate or not" */
/* most PARPORT_CONTROL_* bits are negated */
if (spi_cs_bit == PARPORT_CONTROL_INIT)
value = !value;
/* here, value == "bit value to write in control register" */
parport_frob_control(pp->port, spi_cs_bit, value ? spi_cs_bit : 0);
}
/* we only needed to implement one mode here, and choose SPI_MODE_0 */
#define spidelay(X) do{}while(0)
//#define spidelay ndelay
#define EXPAND_BITBANG_TXRX
#include <linux/spi/spi_bitbang.h>
static u32
butterfly_txrx_word_mode0(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
}
/*----------------------------------------------------------------------*/
/* override default partitioning with cmdlinepart */
static struct mtd_partition partitions[] = { {
/* JFFS2 wants partitions of 4*N blocks for this device ... */
/* sector 0 = 8 pages * 264 bytes/page (1 block)
* sector 1 = 248 pages * 264 bytes/page
*/
.name = "bookkeeping", // 66 KB
.offset = 0,
.size = (8 + 248) * 264,
// .mask_flags = MTD_WRITEABLE,
}, {
/* sector 2 = 256 pages * 264 bytes/page
* sectors 3-5 = 512 pages * 264 bytes/page
*/
.name = "filesystem", // 462 KB
.offset = MTDPART_OFS_APPEND,
.size = MTDPART_SIZ_FULL,
} };
static struct flash_platform_data flash = {
.name = "butterflash",
.parts = partitions,
.nr_parts = ARRAY_SIZE(partitions),
};
/* REVISIT remove this ugly global and its "only one" limitation */
static struct butterfly *butterfly;
static void butterfly_attach(struct parport *p)
{
struct pardevice *pd;
int status;
struct butterfly *pp;
struct spi_master *master;
struct platform_device *pdev;
if (butterfly)
return;
/* REVISIT: this just _assumes_ a butterfly is there ... no probe,
* and no way to be selective about what it binds to.
*/
/* FIXME where should master->cdev.dev come from?
* e.g. /sys/bus/pnp0/00:0b, some PCI thing, etc
* setting up a platform device like this is an ugly kluge...
*/
pdev = platform_device_register_simple("butterfly", -1, NULL, 0);
master = spi_alloc_master(&pdev->dev, sizeof *pp);
if (!master) {
status = -ENOMEM;
goto done;
}
pp = spi_master_get_devdata(master);
/*
* SPI and bitbang hookup
*
* use default setup(), cleanup(), and transfer() methods; and
* only bother implementing mode 0. Start it later.
*/
master->bus_num = 42;
master->num_chipselect = 2;
pp->bitbang.master = spi_master_get(master);
pp->bitbang.chipselect = butterfly_chipselect;
pp->bitbang.txrx_word[SPI_MODE_0] = butterfly_txrx_word_mode0;
/*
* parport hookup
*/
pp->port = p;
pd = parport_register_device(p, "spi_butterfly",
NULL, NULL, NULL,
0 /* FLAGS */, pp);
if (!pd) {
status = -ENOMEM;
goto clean0;
}
pp->pd = pd;
status = parport_claim(pd);
if (status < 0)
goto clean1;
/*
* Butterfly reset, powerup, run firmware
*/
pr_debug("%s: powerup/reset Butterfly\n", p->name);
/* nCS for dataflash (this bit is inverted on output) */
parport_frob_control(pp->port, spi_cs_bit, 0);
/* stabilize power with chip in reset (nRESET), and
* both spi_sck_bit and usi_sck_bit clear (CPOL=0)
*/
pp->lastbyte |= vcc_bits;
parport_write_data(pp->port, pp->lastbyte);
msleep(5);
/* take it out of reset; assume long reset delay */
pp->lastbyte |= butterfly_nreset;
parport_write_data(pp->port, pp->lastbyte);
msleep(100);
/*
* Start SPI ... for now, hide that we're two physical busses.
*/
status = spi_bitbang_start(&pp->bitbang);
if (status < 0)
goto clean2;
/* Bus 1 lets us talk to at45db041b (firmware disables AVR)
* or AVR (firmware resets at45, acts as spi slave)
*/
pp->info[0].max_speed_hz = 15 * 1000 * 1000;
strcpy(pp->info[0].modalias, "mtd_dataflash");
pp->info[0].platform_data = &flash;
pp->info[0].chip_select = 1;
pp->info[0].controller_data = pp;
pp->dataflash = spi_new_device(pp->bitbang.master, &pp->info[0]);
if (pp->dataflash)
pr_debug("%s: dataflash at %s\n", p->name,
pp->dataflash->dev.bus_id);
#ifdef HAVE_USI
/* even more custom AVR firmware */
pp->info[1].max_speed_hz = 10 /* ?? */ * 1000 * 1000;
strcpy(pp->info[1].modalias, "butterfly");
// pp->info[1].platform_data = ... TBD ... ;
pp->info[1].chip_select = 2,
pp->info[1].controller_data = pp;
pp->butterfly = spi_new_device(pp->bitbang.master, &pp->info[1]);
if (pp->butterfly)
pr_debug("%s: butterfly at %s\n", p->name,
pp->butterfly->dev.bus_id);
/* FIXME setup ACK for the IRQ line ... */
#endif
// dev_info(_what?_, ...)
pr_info("%s: AVR Butterfly\n", p->name);
butterfly = pp;
return;
clean2:
/* turn off VCC */
parport_write_data(pp->port, 0);
parport_release(pp->pd);
clean1:
parport_unregister_device(pd);
clean0:
(void) spi_master_put(pp->bitbang.master);
done:
platform_device_unregister(pdev);
pr_debug("%s: butterfly probe, fail %d\n", p->name, status);
}
static void butterfly_detach(struct parport *p)
{
struct butterfly *pp;
struct platform_device *pdev;
int status;
/* FIXME this global is ugly ... but, how to quickly get from
* the parport to the "struct butterfly" associated with it?
* "old school" driver-internal device lists?
*/
if (!butterfly || butterfly->port != p)
return;
pp = butterfly;
butterfly = NULL;
#ifdef HAVE_USI
spi_unregister_device(pp->butterfly);
pp->butterfly = NULL;
#endif
spi_unregister_device(pp->dataflash);
pp->dataflash = NULL;
status = spi_bitbang_stop(&pp->bitbang);
/* turn off VCC */
parport_write_data(pp->port, 0);
msleep(10);
parport_release(pp->pd);
parport_unregister_device(pp->pd);
pdev = to_platform_device(pp->bitbang.master->cdev.dev);
(void) spi_master_put(pp->bitbang.master);
platform_device_unregister(pdev);
}
static struct parport_driver butterfly_driver = {
.name = "spi_butterfly",
.attach = butterfly_attach,
.detach = butterfly_detach,
};
static int __init butterfly_init(void)
{
return parport_register_driver(&butterfly_driver);
}
device_initcall(butterfly_init);
static void __exit butterfly_exit(void)
{
parport_unregister_driver(&butterfly_driver);
}
module_exit(butterfly_exit);
MODULE_LICENSE("GPL");
include/linux/spi/ads7846.h 0 → 100644
View file @ 61b7efdd
/* linux/spi/ads7846.h */
/* Touchscreen characteristics vary between boards and models. The
* platform_data for the device's "struct device" holds this information.
*
* It's OK if the min/max values are zero.
*/
struct ads7846_platform_data {
u16 model; /* 7843, 7845, 7846. */
u16 vref_delay_usecs; /* 0 for external vref; etc */
u16 x_plate_ohms;
u16 y_plate_ohms;
u16 x_min, x_max;
u16 y_min, y_max;
u16 pressure_min, pressure_max;
};
include/linux/spi/flash.h 0 → 100644
View file @ 61b7efdd
#ifndef LINUX_SPI_FLASH_H
#define LINUX_SPI_FLASH_H
struct mtd_partition;
/**
* struct flash_platform_data: board-specific flash data
* @name: optional flash device name (eg, as used with mtdparts=)
* @parts: optional array of mtd_partitions for static partitioning
* @nr_parts: number of mtd_partitions for static partitoning
* @type: optional flash device type (e.g. m25p80 vs m25p64), for use
* with chips that can't be queried for JEDEC or other IDs
*
* Board init code (in arch/.../mach-xxx/board-yyy.c files) can
* provide information about SPI flash parts (such as DataFlash) to
* help set up the device and its appropriate default partitioning.
*
* Note that for DataFlash, sizes for pages, blocks, and sectors are
* rarely powers of two; and partitions should be sector-aligned.
*/
struct flash_platform_data {
char *name;
struct mtd_partition *parts;
unsigned int nr_parts;
char *type;
/* we'll likely add more ... use JEDEC IDs, etc */
};
#endif
include/linux/spi/spi.h 0 → 100644
View file @ 61b7efdd
/*
* Copyright (C) 2005 David Brownell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __LINUX_SPI_H
#define __LINUX_SPI_H
/*
* INTERFACES between SPI master-side drivers and SPI infrastructure.
* (There's no SPI slave support for Linux yet...)
*/
extern struct bus_type spi_bus_type;
/**
* struct spi_device - Master side proxy for an SPI slave device
* @dev: Driver model representation of the device.
* @master: SPI controller used with the device.
* @max_speed_hz: Maximum clock rate to be used with this chip
* (on this board); may be changed by the device's driver.
* @chip-select: Chipselect, distinguishing chips handled by "master".
* @mode: The spi mode defines how data is clocked out and in.
* This may be changed by the device's driver.
* @bits_per_word: Data transfers involve one or more words; word sizes
* like eight or 12 bits are common. In-memory wordsizes are
* powers of two bytes (e.g. 20 bit samples use 32 bits).
* This may be changed by the device's driver.
* @irq: Negative, or the number passed to request_irq() to receive
* interrupts from this device.
* @controller_state: Controller's runtime state
* @controller_data: Board-specific definitions for controller, such as
* FIFO initialization parameters; from board_info.controller_data
*
* An spi_device is used to interchange data between an SPI slave
* (usually a discrete chip) and CPU memory.
*
* In "dev", the platform_data is used to hold information about this
* device that's meaningful to the device's protocol driver, but not
* to its controller. One example might be an identifier for a chip
* variant with slightly different functionality.
*/
struct spi_device {
struct device dev;
struct spi_master *master;
u32 max_speed_hz;
u8 chip_select;
u8 mode;
#define SPI_CPHA 0x01 /* clock phase */
#define SPI_CPOL 0x02 /* clock polarity */
#define SPI_MODE_0 (0|0) /* (original MicroWire) */
#define SPI_MODE_1 (0|SPI_CPHA)
#define SPI_MODE_2 (SPI_CPOL|0)
#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
#define SPI_CS_HIGH 0x04 /* chipselect active high? */
u8 bits_per_word;
int irq;
void *controller_state;
void *controller_data;
const char *modalias;
// likely need more hooks for more protocol options affecting how
// the controller talks to each chip, like:
// - bit order (default is wordwise msb-first)
// - memory packing (12 bit samples into low bits, others zeroed)
// - priority
// - drop chipselect after each word
// - chipselect delays
// - ...
};
static inline struct spi_device *to_spi_device(struct device *dev)
{
return dev ? container_of(dev, struct spi_device, dev) : NULL;
}
/* most drivers won't need to care about device refcounting */
static inline struct spi_device *spi_dev_get(struct spi_device *spi)
{
return (spi && get_device(&spi->dev)) ? spi : NULL;
}
static inline void spi_dev_put(struct spi_device *spi)
{
if (spi)
put_device(&spi->dev);
}
/* ctldata is for the bus_master driver's runtime state */
static inline void *spi_get_ctldata(struct spi_device *spi)
{
return spi->controller_state;
}
static inline void spi_set_ctldata(struct spi_device *spi, void *state)
{
spi->controller_state = state;
}
struct spi_message;
struct spi_driver {
int (*probe)(struct spi_device *spi);
int (*remove)(struct spi_device *spi);
void (*shutdown)(struct spi_device *spi);
int (*suspend)(struct spi_device *spi, pm_message_t mesg);
int (*resume)(struct spi_device *spi);
struct device_driver driver;
};
static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
{
return drv ? container_of(drv, struct spi_driver, driver) : NULL;
}
extern int spi_register_driver(struct spi_driver *sdrv);
static inline void spi_unregister_driver(struct spi_driver *sdrv)
{
if (!sdrv)
return;
driver_unregister(&sdrv->driver);
}
/**
* struct spi_master - interface to SPI master controller
* @cdev: class interface to this driver
* @bus_num: board-specific (and often SOC-specific) identifier for a
* given SPI controller.
* @num_chipselect: chipselects are used to distinguish individual
* SPI slaves, and are numbered from zero to num_chipselects.
* each slave has a chipselect signal, but it's common that not
* every chipselect is connected to a slave.
* @setup: updates the device mode and clocking records used by a
* device's SPI controller; protocol code may call this.
* @transfer: adds a message to the controller's transfer queue.
* @cleanup: frees controller-specific state
*
* Each SPI master controller can communicate with one or more spi_device
* children. These make a small bus, sharing MOSI, MISO and SCK signals
* but not chip select signals. Each device may be configured to use a
* different clock rate, since those shared signals are ignored unless
* the chip is selected.
*
* The driver for an SPI controller manages access to those devices through
* a queue of spi_message transactions, copyin data between CPU memory and
* an SPI slave device). For each such message it queues, it calls the
* message's completion function when the transaction completes.
*/
struct spi_master {
struct class_device cdev;
/* other than zero (== assign one dynamically), bus_num is fully
* board-specific. usually that simplifies to being SOC-specific.
* example: one SOC has three SPI controllers, numbered 1..3,
* and one board's schematics might show it using SPI-2. software
* would normally use bus_num=2 for that controller.
*/
u16 bus_num;
/* chipselects will be integral to many controllers; some others
* might use board-specific GPIOs.
*/
u16 num_chipselect;
/* setup mode and clock, etc (spi driver may call many times) */
int (*setup)(struct spi_device *spi);
/* bidirectional bulk transfers
*
* + The transfer() method may not sleep; its main role is
* just to add the message to the queue.
* + For now there's no remove-from-queue operation, or
* any other request management
* + To a given spi_device, message queueing is pure fifo
*
* + The master's main job is to process its message queue,
* selecting a chip then transferring data
* + If there are multiple spi_device children, the i/o queue
* arbitration algorithm is unspecified (round robin, fifo,
* priority, reservations, preemption, etc)
*
* + Chipselect stays active during the entire message
* (unless modified by spi_transfer.cs_change != 0).
* + The message transfers use clock and SPI mode parameters
* previously established by setup() for this device
*/
int (*transfer)(struct spi_device *spi,
struct spi_message *mesg);
/* called on release() to free memory provided by spi_master */
void (*cleanup)(const struct spi_device *spi);
};
static inline void *spi_master_get_devdata(struct spi_master *master)
{
return class_get_devdata(&master->cdev);
}
static inline void spi_master_set_devdata(struct spi_master *master, void *data)
{
class_set_devdata(&master->cdev, data);
}
static inline struct spi_master *spi_master_get(struct spi_master *master)
{
if (!master || !class_device_get(&master->cdev))
return NULL;
return master;
}
static inline void spi_master_put(struct spi_master *master)
{
if (master)
class_device_put(&master->cdev);
}
/* the spi driver core manages memory for the spi_master classdev */
extern struct spi_master *
spi_alloc_master(struct device *host, unsigned size);
extern int spi_register_master(struct spi_master *master);
extern void spi_unregister_master(struct spi_master *master);
extern struct spi_master *spi_busnum_to_master(u16 busnum);
/*---------------------------------------------------------------------------*/
/*
* I/O INTERFACE between SPI controller and protocol drivers
*
* Protocol drivers use a queue of spi_messages, each transferring data
* between the controller and memory buffers.
*
* The spi_messages themselves consist of a series of read+write transfer
* segments. Those segments always read the same number of bits as they
* write; but one or the other is easily ignored by passing a null buffer
* pointer. (This is unlike most types of I/O API, because SPI hardware
* is full duplex.)
*
* NOTE: Allocation of spi_transfer and spi_message memory is entirely
* up to the protocol driver, which guarantees the integrity of both (as
* well as the data buffers) for as long as the message is queued.
*/
/**
* struct spi_transfer - a read/write buffer pair
* @tx_buf: data to be written (dma-safe memory), or NULL
* @rx_buf: data to be read (dma-safe memory), or NULL
* @tx_dma: DMA address of tx_buf, if spi_message.is_dma_mapped
* @rx_dma: DMA address of rx_buf, if spi_message.is_dma_mapped
* @len: size of rx and tx buffers (in bytes)
* @cs_change: affects chipselect after this transfer completes
* @delay_usecs: microseconds to delay after this transfer before
* (optionally) changing the chipselect status, then starting
* the next transfer or completing this spi_message.
* @transfer_list: transfers are sequenced through spi_message.transfers
*
* SPI transfers always write the same number of bytes as they read.
* Protocol drivers should always provide rx_buf and/or tx_buf.
* In some cases, they may also want to provide DMA addresses for
* the data being transferred; that may reduce overhead, when the
* underlying driver uses dma.
*
* If the transmit buffer is null, undefined data will be shifted out
* while filling rx_buf. If the receive buffer is null, the data
* shifted in will be discarded. Only "len" bytes shift out (or in).
* It's an error to try to shift out a partial word. (For example, by
* shifting out three bytes with word size of sixteen or twenty bits;
* the former uses two bytes per word, the latter uses four bytes.)
*
* All SPI transfers start with the relevant chipselect active. Normally
* it stays selected until after the last transfer in a message. Drivers
* can affect the chipselect signal using cs_change:
*
* (i) If the transfer isn't the last one in the message, this flag is
* used to make the chipselect briefly go inactive in the middle of the
* message. Toggling chipselect in this way may be needed to terminate
* a chip command, letting a single spi_message perform all of group of
* chip transactions together.
*
* (ii) When the transfer is the last one in the message, the chip may
* stay selected until the next transfer. This is purely a performance
* hint; the controller driver may need to select a different device
* for the next message.
*
* The code that submits an spi_message (and its spi_transfers)
* to the lower layers is responsible for managing its memory.
* Zero-initialize every field you don't set up explicitly, to
* insulate against future API updates. After you submit a message
* and its transfers, ignore them until its completion callback.
*/
struct spi_transfer {
/* it's ok if tx_buf == rx_buf (right?)
* for MicroWire, one buffer must be null
* buffers must work with dma_*map_single() calls, unless
* spi_message.is_dma_mapped reports a pre-existing mapping
*/
const void *tx_buf;
void *rx_buf;
unsigned len;
dma_addr_t tx_dma;
dma_addr_t rx_dma;
unsigned cs_change:1;
u16 delay_usecs;
struct list_head transfer_list;
};
/**
* struct spi_message - one multi-segment SPI transaction
* @transfers: list of transfer segments in this transaction
* @spi: SPI device to which the transaction is queued
* @is_dma_mapped: if true, the caller provided both dma and cpu virtual
* addresses for each transfer buffer
* @complete: called to report transaction completions
* @context: the argument to complete() when it's called
* @actual_length: the total number of bytes that were transferred in all
* successful segments
* @status: zero for success, else negative errno
* @queue: for use by whichever driver currently owns the message
* @state: for use by whichever driver currently owns the message
*
* An spi_message is used to execute an atomic sequence of data transfers,
* each represented by a struct spi_transfer. The sequence is "atomic"
* in the sense that no other spi_message may use that SPI bus until that
* sequence completes. On some systems, many such sequences can execute as
* as single programmed DMA transfer. On all systems, these messages are
* queued, and might complete after transactions to other devices. Messages
* sent to a given spi_device are alway executed in FIFO order.
*
* The code that submits an spi_message (and its spi_transfers)
* to the lower layers is responsible for managing its memory.
* Zero-initialize every field you don't set up explicitly, to
* insulate against future API updates. After you submit a message
* and its transfers, ignore them until its completion callback.
*/
struct spi_message {
struct list_head transfers;
struct spi_device *spi;
unsigned is_dma_mapped:1;
/* REVISIT: we might want a flag affecting the behavior of the
* last transfer ... allowing things like "read 16 bit length L"
* immediately followed by "read L bytes". Basically imposing
* a specific message scheduling algorithm.
*
* Some controller drivers (message-at-a-time queue processing)
* could provide that as their default scheduling algorithm. But
* others (with multi-message pipelines) could need a flag to
* tell them about such special cases.
*/
/* completion is reported through a callback */
void (*complete)(void *context);
void *context;
unsigned actual_length;
int status;
/* for optional use by whatever driver currently owns the
* spi_message ... between calls to spi_async and then later
* complete(), that's the spi_master controller driver.
*/
struct list_head queue;
void *state;
};
static inline void spi_message_init(struct spi_message *m)
{
memset(m, 0, sizeof *m);
INIT_LIST_HEAD(&m->transfers);
}
static inline void
spi_message_add_tail(struct spi_transfer *t, struct spi_message *m)
{
list_add_tail(&t->transfer_list, &m->transfers);
}
static inline void
spi_transfer_del(struct spi_transfer *t)
{
list_del(&t->transfer_list);
}
/* It's fine to embed message and transaction structures in other data
* structures so long as you don't free them while they're in use.
*/
static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags)
{
struct spi_message *m;
m = kzalloc(sizeof(struct spi_message)
+ ntrans * sizeof(struct spi_transfer),
flags);
if (m) {
int i;
struct spi_transfer *t = (struct spi_transfer *)(m + 1);
INIT_LIST_HEAD(&m->transfers);
for (i = 0; i < ntrans; i++, t++)
spi_message_add_tail(t, m);
}
return m;
}
static inline void spi_message_free(struct spi_message *m)
{
kfree(m);
}
/**
* spi_setup -- setup SPI mode and clock rate
* @spi: the device whose settings are being modified
*
* SPI protocol drivers may need to update the transfer mode if the
* device doesn't work with the mode 0 default. They may likewise need
* to update clock rates or word sizes from initial values. This function
* changes those settings, and must be called from a context that can sleep.
* The changes take effect the next time the device is selected and data
* is transferred to or from it.
*/
static inline int
spi_setup(struct spi_device *spi)
{
return spi->master->setup(spi);
}
/**
* spi_async -- asynchronous SPI transfer
* @spi: device with which data will be exchanged
* @message: describes the data transfers, including completion callback
*
* This call may be used in_irq and other contexts which can't sleep,
* as well as from task contexts which can sleep.
*
* The completion callback is invoked in a context which can't sleep.
* Before that invocation, the value of message->status is undefined.
* When the callback is issued, message->status holds either zero (to
* indicate complete success) or a negative error code. After that
* callback returns, the driver which issued the transfer request may
* deallocate the associated memory; it's no longer in use by any SPI
* core or controller driver code.
*
* Note that although all messages to a spi_device are handled in
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
*
* On detection of any fault during the transfer, processing of
* the entire message is aborted, and the device is deselected.
* Until returning from the associated message completion callback,
* no other spi_message queued to that device will be processed.
* (This rule applies equally to all the synchronous transfer calls,
* which are wrappers around this core asynchronous primitive.)
*/
static inline int
spi_async(struct spi_device *spi, struct spi_message *message)
{
message->spi = spi;
return spi->master->transfer(spi, message);
}
/*---------------------------------------------------------------------------*/
/* All these synchronous SPI transfer routines are utilities layered
* over the core async transfer primitive. Here, "synchronous" means
* they will sleep uninterruptibly until the async transfer completes.
*/
extern int spi_sync(struct spi_device *spi, struct spi_message *message);
/**
* spi_write - SPI synchronous write
* @spi: device to which data will be written
* @buf: data buffer
* @len: data buffer size
*
* This writes the buffer and returns zero or a negative error code.
* Callable only from contexts that can sleep.
*/
static inline int
spi_write(struct spi_device *spi, const u8 *buf, size_t len)
{
struct spi_transfer t = {
.tx_buf = buf,
.len = len,
};
struct spi_message m;
spi_message_init(&m);
spi_message_add_tail(&t, &m);
return spi_sync(spi, &m);
}
/**
* spi_read - SPI synchronous read
* @spi: device from which data will be read
* @buf: data buffer
* @len: data buffer size
*
* This writes the buffer and returns zero or a negative error code.
* Callable only from contexts that can sleep.
*/
static inline int
spi_read(struct spi_device *spi, u8 *buf, size_t len)
{
struct spi_transfer t = {
.rx_buf = buf,
.len = len,
};
struct spi_message m;
spi_message_init(&m);
spi_message_add_tail(&t, &m);
return spi_sync(spi, &m);
}
/* this copies txbuf and rxbuf data; for small transfers only! */
extern int spi_write_then_read(struct spi_device *spi,
const u8 *txbuf, unsigned n_tx,
u8 *rxbuf, unsigned n_rx);
/**
* spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
* @spi: device with which data will be exchanged
* @cmd: command to be written before data is read back
*
* This returns the (unsigned) eight bit number returned by the
* device, or else a negative error code. Callable only from
* contexts that can sleep.
*/
static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd)
{
ssize_t status;
u8 result;
status = spi_write_then_read(spi, &cmd, 1, &result, 1);
/* return negative errno or unsigned value */
return (status < 0) ? status : result;
}
/**
* spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read
* @spi: device with which data will be exchanged
* @cmd: command to be written before data is read back
*
* This returns the (unsigned) sixteen bit number returned by the
* device, or else a negative error code. Callable only from
* contexts that can sleep.
*
* The number is returned in wire-order, which is at least sometimes
* big-endian.
*/
static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd)
{
ssize_t status;
u16 result;
status = spi_write_then_read(spi, &cmd, 1, (u8 *) &result, 2);
/* return negative errno or unsigned value */
return (status < 0) ? status : result;
}
/*---------------------------------------------------------------------------*/
/*
* INTERFACE between board init code and SPI infrastructure.
*
* No SPI driver ever sees these SPI device table segments, but
* it's how the SPI core (or adapters that get hotplugged) grows
* the driver model tree.
*
* As a rule, SPI devices can't be probed. Instead, board init code
* provides a table listing the devices which are present, with enough
* information to bind and set up the device's driver. There's basic
* support for nonstatic configurations too; enough to handle adding
* parport adapters, or microcontrollers acting as USB-to-SPI bridges.
*/
/* board-specific information about each SPI device */
struct spi_board_info {
/* the device name and module name are coupled, like platform_bus;
* "modalias" is normally the driver name.
*
* platform_data goes to spi_device.dev.platform_data,
* controller_data goes to spi_device.controller_data,
* irq is copied too
*/
char modalias[KOBJ_NAME_LEN];
const void *platform_data;
void *controller_data;
int irq;
/* slower signaling on noisy or low voltage boards */
u32 max_speed_hz;
/* bus_num is board specific and matches the bus_num of some
* spi_master that will probably be registered later.
*
* chip_select reflects how this chip is wired to that master;
* it's less than num_chipselect.
*/
u16 bus_num;
u16 chip_select;
/* ... may need additional spi_device chip config data here.
* avoid stuff protocol drivers can set; but include stuff
* needed to behave without being bound to a driver:
* - chipselect polarity
* - quirks like clock rate mattering when not selected
*/
};
#ifdef CONFIG_SPI
extern int
spi_register_board_info(struct spi_board_info const *info, unsigned n);
#else
/* board init code may ignore whether SPI is configured or not */
static inline int
spi_register_board_info(struct spi_board_info const *info, unsigned n)
{ return 0; }
#endif
/* If you're hotplugging an adapter with devices (parport, usb, etc)
* use spi_new_device() to describe each device. You can also call
* spi_unregister_device() to start making that device vanish, but
* normally that would be handled by spi_unregister_master().
*/
extern struct spi_device *
spi_new_device(struct spi_master *, struct spi_board_info *);
static inline void
spi_unregister_device(struct spi_device *spi)
{
if (spi)
device_unregister(&spi->dev);
}
#endif /* __LINUX_SPI_H */
include/linux/spi/spi_bitbang.h 0 → 100644
View file @ 61b7efdd
#ifndef __SPI_BITBANG_H
#define __SPI_BITBANG_H
/*
* Mix this utility code with some glue code to get one of several types of
* simple SPI master driver. Two do polled word-at-a-time I/O:
*
* - GPIO/parport bitbangers. Provide chipselect() and txrx_word[](),
* expanding the per-word routines from the inline templates below.
*
* - Drivers for controllers resembling bare shift registers. Provide
* chipselect() and txrx_word[](), with custom setup()/cleanup() methods
* that use your controller's clock and chipselect registers.
*
* Some hardware works well with requests at spi_transfer scope:
*
* - Drivers leveraging smarter hardware, with fifos or DMA; or for half
* duplex (MicroWire) controllers. Provide chipslect() and txrx_bufs(),
* and custom setup()/cleanup() methods.
*/
struct spi_bitbang {
struct workqueue_struct *workqueue;
struct work_struct work;
spinlock_t lock;
struct list_head queue;
u8 busy;
u8 shutdown;
u8 use_dma;
struct spi_master *master;
void (*chipselect)(struct spi_device *spi, int is_on);
#define BITBANG_CS_ACTIVE 1 /* normally nCS, active low */
#define BITBANG_CS_INACTIVE 0
/* txrx_bufs() may handle dma mapping for transfers that don't
* already have one (transfer.{tx,rx}_dma is zero), or use PIO
*/
int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
/* txrx_word[SPI_MODE_*]() just looks like a shift register */
u32 (*txrx_word[4])(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits);
};
/* you can call these default bitbang->master methods from your custom
* methods, if you like.
*/
extern int spi_bitbang_setup(struct spi_device *spi);
extern void spi_bitbang_cleanup(const struct spi_device *spi);
extern int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m);
/* start or stop queue processing */
extern int spi_bitbang_start(struct spi_bitbang *spi);
extern int spi_bitbang_stop(struct spi_bitbang *spi);
#endif /* __SPI_BITBANG_H */
/*-------------------------------------------------------------------------*/
#ifdef EXPAND_BITBANG_TXRX
/*
* The code that knows what GPIO pins do what should have declared four
* functions, ideally as inlines, before #defining EXPAND_BITBANG_TXRX
* and including this header:
*
* void setsck(struct spi_device *, int is_on);
* void setmosi(struct spi_device *, int is_on);
* int getmiso(struct spi_device *);
* void spidelay(unsigned);
*
* A non-inlined routine would call bitbang_txrx_*() routines. The
* main loop could easily compile down to a handful of instructions,
* especially if the delay is a NOP (to run at peak speed).
*
* Since this is software, the timings may not be exactly what your board's
* chips need ... there may be several reasons you'd need to tweak timings
* in these routines, not just make to make it faster or slower to match a
* particular CPU clock rate.
*/
static inline u32
bitbang_txrx_be_cpha0(struct spi_device *spi,
unsigned nsecs, unsigned cpol,
u32 word, u8 bits)
{
/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
/* clock starts at inactive polarity */
for (word <<= (32 - bits); likely(bits); bits--) {
/* setup MSB (to slave) on trailing edge */
setmosi(spi, word & (1 << 31));
spidelay(nsecs); /* T(setup) */
setsck(spi, !cpol);
spidelay(nsecs);
/* sample MSB (from slave) on leading edge */
word <<= 1;
word |= getmiso(spi);
setsck(spi, cpol);
}
return word;
}
static inline u32
bitbang_txrx_be_cpha1(struct spi_device *spi,
unsigned nsecs, unsigned cpol,
u32 word, u8 bits)
{
/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
/* clock starts at inactive polarity */
for (word <<= (32 - bits); likely(bits); bits--) {
/* setup MSB (to slave) on leading edge */
setsck(spi, !cpol);
setmosi(spi, word & (1 << 31));
spidelay(nsecs); /* T(setup) */
setsck(spi, cpol);
spidelay(nsecs);
/* sample MSB (from slave) on trailing edge */
word <<= 1;
word |= getmiso(spi);
}
return word;
}
#endif /* EXPAND_BITBANG_TXRX */
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