166 строки
3.5 KiB
C
166 строки
3.5 KiB
C
/*
|
|
* 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.
|
|
*/
|
|
|
|
#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)
|
|
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_mem_region(pd->ioarea->start, size);
|
|
|
|
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_mem_region(pd->ioarea->start, resource_size(pd->ioarea));
|
|
kfree(pd);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* device driver */
|
|
|
|
static struct platform_driver simtec_i2c_driver = {
|
|
.driver = {
|
|
.name = "simtec-i2c",
|
|
},
|
|
.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");
|