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/*
* drivers/i2c/busses/i2c-ixp2000.c
*
* I2C adapter for IXP2000 systems using GPIOs for I2C bus
*
* Author: Deepak Saxena <dsaxena@plexity.net>
* Based on IXDP2400 code by: Naeem M. Afzal <naeem.m.afzal@intel.com>
* Made generic by: Jeff Daly <jeffrey.daly@intel.com>
*
* Copyright (c) 2003-2004 MontaVista Software Inc.
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* From Jeff Daly:
*
* I2C adapter driver for Intel IXDP2xxx platforms. This should work for any
* IXP2000 platform if it uses the HW GPIO in the same manner. Basically,
* SDA and SCL GPIOs have external pullups. Setting the respective GPIO to
* an input will make the signal a '1' via the pullup. Setting them to
* outputs will pull them down.
*
* The GPIOs are open drain signals and are used as configuration strap inputs
* during power-up so there's generally a buffer on the board that needs to be
* 'enabled' to drive the GPIOs.
*/
#include <linux/config.h>
#ifdef CONFIG_I2C_DEBUG_BUS
#define DEBUG 1
#endif
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <asm/hardware.h> /* Pick up IXP42000-specific bits */
static inline int ixp2000_scl_pin(void *data)
{
return ((struct ixp2000_i2c_pins*)data)->scl_pin;
}
static inline int ixp2000_sda_pin(void *data)
{
return ((struct ixp2000_i2c_pins*)data)->sda_pin;
}
static void ixp2000_bit_setscl(void *data, int val)
{
int i = 5000;
if (val) {
gpio_line_config(ixp2000_scl_pin(data), GPIO_IN);
while(!gpio_line_get(ixp2000_scl_pin(data)) && i--);
} else {
gpio_line_config(ixp2000_scl_pin(data), GPIO_OUT);
}
}
static void ixp2000_bit_setsda(void *data, int val)
{
if (val) {
gpio_line_config(ixp2000_sda_pin(data), GPIO_IN);
} else {
gpio_line_config(ixp2000_sda_pin(data), GPIO_OUT);
}
}
static int ixp2000_bit_getscl(void *data)
{
return gpio_line_get(ixp2000_scl_pin(data));
}
static int ixp2000_bit_getsda(void *data)
{
return gpio_line_get(ixp2000_sda_pin(data));
}
struct ixp2000_i2c_data {
struct ixp2000_i2c_pins *gpio_pins;
struct i2c_adapter adapter;
struct i2c_algo_bit_data algo_data;
};
static int ixp2000_i2c_remove(struct device *dev)
{
struct platform_device *plat_dev = to_platform_device(dev);
struct ixp2000_i2c_data *drv_data = dev_get_drvdata(&plat_dev->dev);
dev_set_drvdata(&plat_dev->dev, NULL);
i2c_bit_del_bus(&drv_data->adapter);
kfree(drv_data);
return 0;
}
static int ixp2000_i2c_probe(struct device *dev)
{
int err;
struct platform_device *plat_dev = to_platform_device(dev);
struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data;
struct ixp2000_i2c_data *drv_data =
kmalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL);
if (!drv_data)
return -ENOMEM;
memzero(drv_data, sizeof(*drv_data));
drv_data->gpio_pins = gpio;
drv_data->algo_data.data = gpio;
drv_data->algo_data.setsda = ixp2000_bit_setsda;
drv_data->algo_data.setscl = ixp2000_bit_setscl;
drv_data->algo_data.getsda = ixp2000_bit_getsda;
drv_data->algo_data.getscl = ixp2000_bit_getscl;
drv_data->algo_data.udelay = 6;
drv_data->algo_data.mdelay = 6;
drv_data->algo_data.timeout = 100;
drv_data->adapter.id = I2C_HW_B_IXP2000,
drv_data->adapter.algo_data = &drv_data->algo_data,
drv_data->adapter.dev.parent = &plat_dev->dev;
gpio_line_config(gpio->sda_pin, GPIO_IN);
gpio_line_config(gpio->scl_pin, GPIO_IN);
gpio_line_set(gpio->scl_pin, 0);
gpio_line_set(gpio->sda_pin, 0);
if ((err = i2c_bit_add_bus(&drv_data->adapter)) != 0) {
dev_err(dev, "Could not install, error %d\n", err);
kfree(drv_data);
return err;
}
dev_set_drvdata(&plat_dev->dev, drv_data);
return 0;
}
static struct device_driver ixp2000_i2c_driver = {
.name = "IXP2000-I2C",
.bus = &platform_bus_type,
.probe = ixp2000_i2c_probe,
.remove = ixp2000_i2c_remove,
};
static int __init ixp2000_i2c_init(void)
{
return driver_register(&ixp2000_i2c_driver);
}
static void __exit ixp2000_i2c_exit(void)
{
driver_unregister(&ixp2000_i2c_driver);
}
module_init(ixp2000_i2c_init);
module_exit(ixp2000_i2c_exit);
MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver");
MODULE_LICENSE("GPL");
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