[PATCH] I2C: algorithm and bus driver for PCA9564

Attached is a driver for the PCA9564 "Parallel to I2C" chip, it is
similar in principle to the PCF8584 which is supported by the
i2c-algo-pcf and i2c-elektor code, however it's not code compatible in
any way: http://www.semiconductors.philips.com/pip/PCA9564PW.html

The patch contains the PCA algorithm driver and a bus driver for an ISA
card. It only supports master send and receive but I'm not sure that the
Linux i2c stack supports client side operation anyhow, and I have no
hardware to test on.

It was tested on a PC104 card containing the PCA chip and an Atmel TPM
device and also on a separate PC104 card with a DS1307 RTC hotwired onto
it for testing purposes.

The driver is against a 2.6 BK tree pulled on Friday. I also have a
fairly trivial 2.4 backport if that is of interest.

From: Ian Campbell <icampbell@arcom.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/i2c/algos/Kconfig

@@ -27,6 +27,17 @@ config I2C_ALGOPCF
 	  This support is also available as a module.  If so, the module 
 	  will be called i2c-algo-pcf.
 
+config I2C_ALGOPCA
+	tristate "I2C PCA 9564 interfaces"
+	depends on I2C
+	help
+	  This allows you to use a range of I2C adapters called PCA adapters.
+	  Say Y if you own an I2C adapter belonging to this class and then say
+	  Y to the specific driver for you adapter below.
+
+	  This support is also available as a module.  If so, the module 
+	  will be called i2c-algo-pca.
+
 config I2C_ALGOITE
 	tristate "ITE I2C Algorithm"
 	depends on MIPS_ITE8172 && I2C

drivers/i2c/algos/Makefile

@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_I2C_ALGOBIT)	+= i2c-algo-bit.o
 obj-$(CONFIG_I2C_ALGOPCF)	+= i2c-algo-pcf.o
+obj-$(CONFIG_I2C_ALGOPCA)	+= i2c-algo-pca.o
 obj-$(CONFIG_I2C_ALGOITE)	+= i2c-algo-ite.o
 
 ifeq ($(CONFIG_I2C_DEBUG_ALGO),y)

drivers/i2c/algos/i2c-algo-pca.h

+#ifndef I2C_PCA9564_H
+#define I2C_PCA9564_H 1
+
+#define I2C_PCA_STA		0x00 /* STATUS  Read Only  */
+#define I2C_PCA_TO		0x00 /* TIMEOUT Write Only */
+#define I2C_PCA_DAT		0x01 /* DATA    Read/Write */
+#define I2C_PCA_ADR		0x02 /* OWN ADR Read/Write */
+#define I2C_PCA_CON		0x03 /* CONTROL Read/Write */
+
+#define I2C_PCA_CON_AA		0x80 /* Assert Acknowledge */
+#define I2C_PCA_CON_ENSIO	0x40 /* Enable */
+#define I2C_PCA_CON_STA		0x20 /* Start */
+#define I2C_PCA_CON_STO		0x10 /* Stop */
+#define I2C_PCA_CON_SI		0x08 /* Serial Interrupt */
+#define I2C_PCA_CON_CR		0x07 /* Clock Rate (MASK) */
+
+#define I2C_PCA_CON_330kHz	0x00
+#define I2C_PCA_CON_288kHz	0x01
+#define I2C_PCA_CON_217kHz	0x02
+#define I2C_PCA_CON_146kHz	0x03
+#define I2C_PCA_CON_88kHz	0x04
+#define I2C_PCA_CON_59kHz	0x05
+#define I2C_PCA_CON_44kHz	0x06
+#define I2C_PCA_CON_36kHz	0x07
+
+#endif /* I2C_PCA9564_H */

drivers/i2c/busses/Kconfig

@@ -419,4 +419,15 @@ config I2C_VOODOO3
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-voodoo3.
 
+config I2C_PCA_ISA
+	tristate "PCA9564 on an ISA bus"
+	depends on I2C
+	select I2C_ALGOPCA
+	help
+	  This driver supports ISA boards using the Philips PCA 9564
+	  Parallel bus to I2C bus controller
+	  
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-pca-isa.
+
 endmenu

drivers/i2c/busses/Makefile

@@ -22,6 +22,7 @@ obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o
 obj-$(CONFIG_I2C_NFORCE2)	+= i2c-nforce2.o
 obj-$(CONFIG_I2C_PARPORT)	+= i2c-parport.o
 obj-$(CONFIG_I2C_PARPORT_LIGHT)	+= i2c-parport-light.o
+obj-$(CONFIG_I2C_PCA_ISA)	+= i2c-pca-isa.o
 obj-$(CONFIG_I2C_PIIX4)		+= i2c-piix4.o
 obj-$(CONFIG_I2C_PROSAVAGE)	+= i2c-prosavage.o
 obj-$(CONFIG_I2C_RPXLITE)	+= i2c-rpx.o

drivers/i2c/busses/i2c-pca-isa.c

+/*
+ *  i2c-pca-isa.c driver for PCA9564 on ISA boards
+ *    Copyright (C) 2004 Arcom Control Systems
+ *
+ *  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/ioport.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/wait.h>
+
+#include <linux/i2c.h>
+#include <linux/i2c-algo-pca.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include "../algos/i2c-algo-pca.h"
+
+#define IO_SIZE 4
+
+#undef DEBUG_IO
+//#define DEBUG_IO
+
+static unsigned long base   = 0x330;
+static int irq 	  = 10;
+
+/* Data sheet recommends 59kHz for 100kHz operation due to variation
+ * in the actual clock rate */
+static int clock  = I2C_PCA_CON_59kHz;
+
+static int own    = 0x55;
+
+static wait_queue_head_t pca_wait;
+
+static int pca_isa_getown(struct i2c_algo_pca_data *adap)
+{
+	return (own);
+}
+
+static int pca_isa_getclock(struct i2c_algo_pca_data *adap)
+{
+	return (clock);
+}
+
+static void
+pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
+{
+#ifdef DEBUG_IO
+	static char *names[] = { "T/O", "DAT", "ADR", "CON" };
+	printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val);
+#endif
+	outb(val, base+reg);
+}
+
+static int
+pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
+{
+	int res = inb(base+reg);
+#ifdef DEBUG_IO
+	{
+		static char *names[] = { "STA", "DAT", "ADR", "CON" };	
+		printk("*** read  %s => %#04x\n", names[reg], res);
+	}
+#endif
+	return res;
+}
+
+static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap)
+{
+	int ret = 0;
+
+	if (irq > -1) {
+		ret = wait_event_interruptible(pca_wait,
+					       pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI);
+	} else {
+		while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0) 
+			udelay(100);
+	}
+	return ret;
+}
+
+static irqreturn_t pca_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
+	wake_up_interruptible(&pca_wait);
+	return IRQ_HANDLED;
+}
+
+static struct i2c_algo_pca_data pca_isa_data = {
+	.get_own		= pca_isa_getown,
+	.get_clock		= pca_isa_getclock,
+	.write_byte		= pca_isa_writebyte,
+	.read_byte		= pca_isa_readbyte,
+	.wait_for_interrupt	= pca_isa_waitforinterrupt,
+};
+
+static struct i2c_adapter pca_isa_ops = {
+	.owner          = THIS_MODULE,
+	.id		= I2C_HW_A_ISA,
+	.algo_data	= &pca_isa_data,
+	.name		= "PCA9564 ISA Adapter",
+};
+
+static int __init pca_isa_init(void)
+{
+
+	init_waitqueue_head(&pca_wait);
+
+	printk(KERN_INFO "i2c-pca-isa: i/o base %#08lx. irq %d\n", base, irq);
+
+	if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
+		printk(KERN_ERR "i2c-pca-isa: I/O address %#08lx is in use.\n", base);
+		goto out;
+	}
+
+	if (irq > -1) {
+		if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
+			printk(KERN_ERR "i2c-pca-isa: Request irq%d failed\n", irq);
+			goto out_region;
+		}
+	}
+
+	if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
+		printk(KERN_ERR "i2c-pca-isa: Failed to add i2c bus\n");
+		goto out_irq;
+	}
+
+	return 0;
+
+ out_irq:
+	if (irq > -1)
+		free_irq(irq, &pca_isa_ops);
+ out_region:
+	release_region(base, IO_SIZE);
+ out:
+	return -ENODEV;
+}
+
+static void pca_isa_exit(void)
+{
+	i2c_pca_del_bus(&pca_isa_ops);
+
+	if (irq > 0) {
+		disable_irq(irq);
+		free_irq(irq, &pca_isa_ops);
+	}
+	release_region(base, IO_SIZE);
+}
+
+MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
+MODULE_DESCRIPTION("ISA base PCA9564 driver");
+MODULE_LICENSE("GPL");
+
+module_param(base, ulong, 0);
+MODULE_PARM_DESC(base, "I/O base address");
+
+module_param(irq, int, 0);
+MODULE_PARM_DESC(irq, "IRQ");
+module_param(clock, int, 0);
+MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
+
+module_param(own, int, 0); /* the driver can't do slave mode, so there's no real point in this */
+
+module_init(pca_isa_init);
+module_exit(pca_isa_exit);

include/linux/i2c-algo-pca.h

+#ifndef _LINUX_I2C_ALGO_PCA_H
+#define _LINUX_I2C_ALGO_PCA_H
+
+struct i2c_algo_pca_data {
+	int  (*get_own)			(struct i2c_algo_pca_data *adap); /* Obtain own address */
+	int  (*get_clock)		(struct i2c_algo_pca_data *adap);
+	void (*write_byte)		(struct i2c_algo_pca_data *adap, int reg, int val);
+	int  (*read_byte)		(struct i2c_algo_pca_data *adap, int reg);
+	int  (*wait_for_interrupt)	(struct i2c_algo_pca_data *adap);
+};
+
+#define I2C_PCA_ADAP_MAX	16
+
+int i2c_pca_add_bus(struct i2c_adapter *);
+int i2c_pca_del_bus(struct i2c_adapter *);
+
+#endif /* _LINUX_I2C_ALGO_PCA_H */

include/linux/i2c-id.h

@@ -194,6 +194,7 @@
 #define I2C_ALGO_OCP    0x120000	/* IBM or otherwise On-chip I2C algorithm */
 #define I2C_ALGO_BITHS	0x130000	/* enhanced bit style adapters	*/
 #define I2C_ALGO_OCP_IOP3XX  0x140000	/* XSCALE IOP3XX On-chip I2C alg */
+#define I2C_ALGO_PCA	0x150000	/* PCA 9564 style adapters	*/
 
 #define I2C_ALGO_EXP	0x800000	/* experimental			*/
 
@@ -239,6 +240,9 @@
 #define I2C_HW_P_ISA	0x01	/* generic ISA Bus inteface card	*/
 #define I2C_HW_P_ELEK	0x02	/* Elektor ISA Bus inteface card	*/
 
+/* --- PCA 9564 based algorithms */
+#define I2C_HW_A_ISA	0x00	/* generic ISA Bus interface card	*/
+
 /* --- ACPI Embedded controller algorithms                              */
 #define I2C_HW_ACPI_EC          0x00