Commit 011f23a3 authored by Mika Westerberg's avatar Mika Westerberg Committed by Grant Likely

spi/ep93xx: implemented driver for Cirrus EP93xx SPI controller

This patch adds an SPI master driver for the Cirrus EP93xx SPI controller found
in EP93xx chips.
Signed-off-by: default avatarMika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 1dcf57ce
Cirrus EP93xx SPI controller driver HOWTO
=========================================
ep93xx_spi driver brings SPI master support for EP93xx SPI controller. Chip
selects are implemented with GPIO lines.
NOTE: If possible, don't use SFRMOUT (SFRM1) signal as a chip select. It will
not work correctly (it cannot be controlled by software). Use GPIO lines
instead.
Sample configuration
====================
Typically driver configuration is done in platform board files (the files under
arch/arm/mach-ep93xx/*.c). In this example we configure MMC over SPI through
this driver on TS-7260 board. You can adapt the code to suit your needs.
This example uses EGPIO9 as SD/MMC card chip select (this is wired in DIO1
header on the board).
You need to select CONFIG_MMC_SPI to use mmc_spi driver.
arch/arm/mach-ep93xx/ts72xx.c:
...
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <mach/ep93xx_spi.h>
/* this is our GPIO line used for chip select */
#define MMC_CHIP_SELECT_GPIO EP93XX_GPIO_LINE_EGPIO9
static int ts72xx_mmc_spi_setup(struct spi_device *spi)
{
int err;
err = gpio_request(MMC_CHIP_SELECT_GPIO, spi->modalias);
if (err)
return err;
gpio_direction_output(MMC_CHIP_SELECT_GPIO, 1);
return 0;
}
static void ts72xx_mmc_spi_cleanup(struct spi_device *spi)
{
gpio_set_value(MMC_CHIP_SELECT_GPIO, 1);
gpio_direction_input(MMC_CHIP_SELECT_GPIO);
gpio_free(MMC_CHIP_SELECT_GPIO);
}
static void ts72xx_mmc_spi_cs_control(struct spi_device *spi, int value)
{
gpio_set_value(MMC_CHIP_SELECT_GPIO, value);
}
static struct ep93xx_spi_chip_ops ts72xx_mmc_spi_ops = {
.setup = ts72xx_mmc_spi_setup,
.cleanup = ts72xx_mmc_spi_cleanup,
.cs_control = ts72xx_mmc_spi_cs_control,
};
static struct spi_board_info ts72xx_spi_devices[] __initdata = {
{
.modalias = "mmc_spi",
.controller_data = &ts72xx_mmc_spi_ops,
/*
* We use 10 MHz even though the maximum is 7.4 MHz. The driver
* will limit it automatically to max. frequency.
*/
.max_speed_hz = 10 * 1000 * 1000,
.bus_num = 0,
.chip_select = 0,
.mode = SPI_MODE_0,
},
};
static struct ep93xx_spi_info ts72xx_spi_info = {
.num_chipselect = ARRAY_SIZE(ts72xx_spi_devices),
};
static void __init ts72xx_init_machine(void)
{
...
ep93xx_register_spi(&ts72xx_spi_info, ts72xx_spi_devices,
ARRAY_SIZE(ts72xx_spi_devices));
}
Thanks to
=========
Martin Guy, H. Hartley Sweeten and others who helped me during development of
the driver. Simplemachines.it donated me a Sim.One board which I used testing
the driver on EP9307.
#ifndef __ASM_MACH_EP93XX_SPI_H
#define __ASM_MACH_EP93XX_SPI_H
struct spi_device;
/**
* struct ep93xx_spi_info - EP93xx specific SPI descriptor
* @num_chipselect: number of chip selects on this board, must be
* at least one
*/
struct ep93xx_spi_info {
int num_chipselect;
};
/**
* struct ep93xx_spi_chip_ops - operation callbacks for SPI slave device
* @setup: setup the chip select mechanism
* @cleanup: cleanup the chip select mechanism
* @cs_control: control the device chip select
*/
struct ep93xx_spi_chip_ops {
int (*setup)(struct spi_device *spi);
void (*cleanup)(struct spi_device *spi);
void (*cs_control)(struct spi_device *spi, int value);
};
#endif /* __ASM_MACH_EP93XX_SPI_H */
......@@ -117,6 +117,16 @@ config SPI_DAVINCI
help
SPI master controller for DaVinci and DA8xx SPI modules.
config SPI_EP93XX
tristate "Cirrus Logic EP93xx SPI controller"
depends on ARCH_EP93XX
help
This enables using the Cirrus EP93xx SPI controller in master
mode.
To compile this driver as a module, choose M here. The module will be
called ep93xx_spi.
config SPI_GPIO
tristate "GPIO-based bitbanging SPI Master"
depends on GENERIC_GPIO
......
......@@ -21,6 +21,7 @@ obj-$(CONFIG_SPI_DAVINCI) += davinci_spi.o
obj-$(CONFIG_SPI_DESIGNWARE) += dw_spi.o
obj-$(CONFIG_SPI_DW_PCI) += dw_spi_pci.o
obj-$(CONFIG_SPI_DW_MMIO) += dw_spi_mmio.o
obj-$(CONFIG_SPI_EP93XX) += ep93xx_spi.o
obj-$(CONFIG_SPI_GPIO) += spi_gpio.o
obj-$(CONFIG_SPI_IMX) += spi_imx.o
obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o
......
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