/* * drivers/i2c/i2c-adap-ixp4xx.c * * Intel's IXP4xx XScale NPU chipsets (IXP420, 421, 422, 425) do not have * an on board I2C controller but provide 16 GPIO pins that are often * used to create an I2C bus. This driver provides an i2c_adapter  * interface that plugs in under algo_bit and drives the GPIO pins * as instructed by the alogorithm driver. * * Author: Deepak Saxena <dsaxena@plexity.net> * * 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. * * NOTE: Since different platforms will use different GPIO pins for *       I2C, this driver uses an IXP4xx-specific platform_data *       pointer to pass the GPIO numbers to the driver. This  *       allows us to support all the different IXP4xx platforms *       w/o having to put #ifdefs in this driver. * *       See arch/arm/mach-ixp4xx/ixdp425.c for an example of building a  *       device list and filling in the ixp4xx_i2c_pins data structure  *       that is passed as the platform_data to this driver. */#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 IXP4xx-specific bits */static inline int ixp4xx_scl_pin(void *data){	return ((struct ixp4xx_i2c_pins*)data)->scl_pin;}static inline int ixp4xx_sda_pin(void *data){	return ((struct ixp4xx_i2c_pins*)data)->sda_pin;}static void ixp4xx_bit_setscl(void *data, int val){	gpio_line_set(ixp4xx_scl_pin(data), 0);	gpio_line_config(ixp4xx_scl_pin(data),		val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT );}static void ixp4xx_bit_setsda(void *data, int val){	gpio_line_set(ixp4xx_sda_pin(data), 0);	gpio_line_config(ixp4xx_sda_pin(data),		val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT );}static int ixp4xx_bit_getscl(void *data){	int scl;	gpio_line_config(ixp4xx_scl_pin(data), IXP4XX_GPIO_IN );	gpio_line_get(ixp4xx_scl_pin(data), &scl);	return scl;}	static int ixp4xx_bit_getsda(void *data){	int sda;	gpio_line_config(ixp4xx_sda_pin(data), IXP4XX_GPIO_IN );	gpio_line_get(ixp4xx_sda_pin(data), &sda);	return sda;}	struct ixp4xx_i2c_data {	struct ixp4xx_i2c_pins *gpio_pins;	struct i2c_adapter adapter;	struct i2c_algo_bit_data algo_data;};static int ixp4xx_i2c_remove(struct device *dev){	struct platform_device *plat_dev = to_platform_device(dev);	struct ixp4xx_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 ixp4xx_i2c_probe(struct device *dev){	int err;	struct platform_device *plat_dev = to_platform_device(dev);	struct ixp4xx_i2c_pins *gpio = plat_dev->dev.platform_data;	struct ixp4xx_i2c_data *drv_data = 		kmalloc(sizeof(struct ixp4xx_i2c_data), GFP_KERNEL);	if(!drv_data)		return -ENOMEM;	memzero(drv_data, sizeof(struct ixp4xx_i2c_data));	drv_data->gpio_pins = gpio;	/*	 * We could make a lot of these structures static, but	 * certain platforms may have multiple GPIO-based I2C	 * buses for various device domains, so we need per-device	 * algo_data->data. 	 */	drv_data->algo_data.data = gpio;	drv_data->algo_data.setsda = ixp4xx_bit_setsda;	drv_data->algo_data.setscl = ixp4xx_bit_setscl;	drv_data->algo_data.getsda = ixp4xx_bit_getsda;	drv_data->algo_data.getscl = ixp4xx_bit_getscl;	drv_data->algo_data.udelay = 10;	drv_data->algo_data.mdelay = 10;	drv_data->algo_data.timeout = 100;	drv_data->adapter.id = I2C_HW_B_IXP4XX;	drv_data->adapter.algo_data = &drv_data->algo_data;	drv_data->adapter.dev.parent = &plat_dev->dev;	gpio_line_config(gpio->scl_pin, IXP4XX_GPIO_IN);	gpio_line_config(gpio->sda_pin, IXP4XX_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)) {		printk(KERN_ERR "ERROR: Could not install %s\n", dev->bus_id);		kfree(drv_data);		return err;	}	dev_set_drvdata(&plat_dev->dev, drv_data);	return 0;}static struct device_driver ixp4xx_i2c_driver = {	.name		= "IXP4XX-I2C",	.bus		= &platform_bus_type,	.probe		= ixp4xx_i2c_probe,	.remove		= ixp4xx_i2c_remove,};static int __init ixp4xx_i2c_init(void){	return driver_register(&ixp4xx_i2c_driver);}static void __exit ixp4xx_i2c_exit(void){	driver_unregister(&ixp4xx_i2c_driver);}module_init(ixp4xx_i2c_init);module_exit(ixp4xx_i2c_exit);MODULE_DESCRIPTION("GPIO-based I2C adapter for IXP4xx systems");MODULE_LICENSE("GPL");MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");