/* * 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/platform_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 platform_device *plat_dev) { struct ixp4xx_i2c_data *drv_data = platform_get_drvdata(plat_dev); platform_set_drvdata(plat_dev, NULL); i2c_bit_del_bus(&drv_data->adapter); kfree(drv_data); return 0; } static int ixp4xx_i2c_probe(struct platform_device *plat_dev) { int err; struct ixp4xx_i2c_pins *gpio = plat_dev->dev.platform_data; struct ixp4xx_i2c_data *drv_data = kzalloc(sizeof(struct ixp4xx_i2c_data), GFP_KERNEL); if(!drv_data) return -ENOMEM; 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; strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name, I2C_NAME_SIZE); 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", plat_dev->dev.bus_id); kfree(drv_data); return err; } platform_set_drvdata(plat_dev, drv_data); return 0; } static struct platform_driver ixp4xx_i2c_driver = { .probe = ixp4xx_i2c_probe, .remove = ixp4xx_i2c_remove, .driver = { .name = "IXP4XX-I2C", .owner = THIS_MODULE, }, }; static int __init ixp4xx_i2c_init(void) { return platform_driver_register(&ixp4xx_i2c_driver); } static void __exit ixp4xx_i2c_exit(void) { platform_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>");