/* * 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/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 IXP2000-specific bits */#include <asm/arch/gpio.h>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");