i2c-simtec.c
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/*
* Copyright (C) 2005 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* Simtec Generic I2C Controller
*
* 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
*
* 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/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
struct simtec_i2c_data {
struct resource *ioarea;
void __iomem *reg;
struct i2c_adapter adap;
struct i2c_algo_bit_data bit;
};
#define CMD_SET_SDA (1<<2)
#define CMD_SET_SCL (1<<3)
#define STATE_SDA (1<<0)
#define STATE_SCL (1<<1)
/* i2c bit-bus functions */
static void simtec_i2c_setsda(void *pw, int state)
{
struct simtec_i2c_data *pd = pw;
writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
}
static void simtec_i2c_setscl(void *pw, int state)
{
struct simtec_i2c_data *pd = pw;
writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
}
static int simtec_i2c_getsda(void *pw)
{
struct simtec_i2c_data *pd = pw;
return readb(pd->reg) & STATE_SDA ? 1 : 0;
}
static int simtec_i2c_getscl(void *pw)
{
struct simtec_i2c_data *pd = pw;
return readb(pd->reg) & STATE_SCL ? 1 : 0;
}
/* device registration */
static int simtec_i2c_probe(struct platform_device *dev)
{
struct simtec_i2c_data *pd;
struct resource *res;
int size;
int ret;
pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
if (pd == NULL) {
dev_err(&dev->dev, "cannot allocate private data\n");
return -ENOMEM;
}
platform_set_drvdata(dev, pd);
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&dev->dev, "cannot find IO resource\n");
ret = -ENOENT;
goto err;
}
size = resource_size(res);
pd->ioarea = request_mem_region(res->start, size, dev->name);
if (pd->ioarea == NULL) {
dev_err(&dev->dev, "cannot request IO\n");
ret = -ENXIO;
goto err;
}
pd->reg = ioremap(res->start, size);
if (pd->reg == NULL) {
dev_err(&dev->dev, "cannot map IO\n");
ret = -ENXIO;
goto err_res;
}
/* setup the private data */
pd->adap.owner = THIS_MODULE;
pd->adap.algo_data = &pd->bit;
pd->adap.dev.parent = &dev->dev;
strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
pd->bit.data = pd;
pd->bit.setsda = simtec_i2c_setsda;
pd->bit.setscl = simtec_i2c_setscl;
pd->bit.getsda = simtec_i2c_getsda;
pd->bit.getscl = simtec_i2c_getscl;
pd->bit.timeout = HZ;
pd->bit.udelay = 20;
ret = i2c_bit_add_bus(&pd->adap);
if (ret)
goto err_all;
return 0;
err_all:
iounmap(pd->reg);
err_res:
release_resource(pd->ioarea);
kfree(pd->ioarea);
err:
kfree(pd);
return ret;
}
static int simtec_i2c_remove(struct platform_device *dev)
{
struct simtec_i2c_data *pd = platform_get_drvdata(dev);
i2c_del_adapter(&pd->adap);
iounmap(pd->reg);
release_resource(pd->ioarea);
kfree(pd->ioarea);
kfree(pd);
return 0;
}
/* device driver */
static struct platform_driver simtec_i2c_driver = {
.driver = {
.name = "simtec-i2c",
.owner = THIS_MODULE,
},
.probe = simtec_i2c_probe,
.remove = simtec_i2c_remove,
};
module_platform_driver(simtec_i2c_driver);
MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:simtec-i2c");