/*
* i2c-pca-isa.c driver for PCA9564 on ISA boards
* Copyright (C) 2004 Arcom Control Systems
* Copyright (C) 2008 Pengutronix
*
* 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/kernel.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/isa.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-pca.h>
#include <asm/io.h>
#include <asm/irq.h>
#define DRIVER "i2c-pca-isa"
#define IO_SIZE 4
static unsigned long base;
static int irq = -1;
/* Data sheet recommends 59kHz for 100kHz operation due to variation
* in the actual clock rate */
static int clock = I2C_PCA_CON_59kHz;
static wait_queue_head_t pca_wait;
static void pca_isa_writebyte(void *pd, 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(void *pd, 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_waitforcompletion(void *pd)
{
int ret = 0;
if (irq > -1) {
ret = wait_event_interruptible(pca_wait,
pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
} else {
while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
udelay(100);
}
return ret;
}
static void pca_isa_resetchip(void *pd)
{
/* apparently only an external reset will do it. not a lot can be done */
printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
}
static irqreturn_t pca_handler(int this_irq, void *dev_id) {
wake_up_interruptible(&pca_wait);
return IRQ_HANDLED;
}
static struct i2c_algo_pca_data pca_isa_data = {
/* .data intentionally left NULL, not needed with ISA */
.write_byte = pca_isa_writebyte,
.read_byte = pca_isa_readbyte,
.wait_for_completion = pca_isa_waitforcompletion,
.reset_chip = pca_isa_resetchip,
};
static struct i2c_adapter pca_isa_ops = {
.owner = THIS_MODULE,
.algo_data = &pca_isa_data,
.name = "PCA9564 ISA Adapter",
.timeout = 100,
};
static int __devinit pca_isa_match(struct device *dev, unsigned int id)
{
int match = base != 0;
if (match) {
if (irq <= -1)
dev_warn(dev, "Using polling mode (specify irq)\n");
} else
dev_err(dev, "Please specify I/O base\n");
return match;
}
static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
{
init_waitqueue_head(&pca_wait);
dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);
#ifdef CONFIG_PPC
if (check_legacy_ioport(base)) {
dev_err(dev, "I/O address %#08lx is not available\n", base);
goto out;
}
#endif
if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
dev_err(dev, "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) {
dev_err(dev, "Request irq%d failed\n", irq);
goto out_region;
}
}
pca_isa_data.i2c_clock = clock;
if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
dev_err(dev, "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 int __devexit pca_isa_remove(struct device *dev, unsigned int id)
{
i2c_del_adapter(&pca_isa_ops);
if (irq > -1) {
disable_irq(irq);
free_irq(irq, &pca_isa_ops);
}
release_region(base, IO_SIZE);
return 0;
}
static struct isa_driver pca_isa_driver = {
.match = pca_isa_match,
.probe = pca_isa_probe,
.remove = __devexit_p(pca_isa_remove),
.driver = {
.owner = THIS_MODULE,
.name = DRIVER,
}
};
static int __init pca_isa_init(void)
{
return isa_register_driver(&pca_isa_driver, 1);
}
static void __exit pca_isa_exit(void)
{
isa_unregister_driver(&pca_isa_driver);
}
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_init(pca_isa_init);
module_exit(pca_isa_exit);
