2005-04-17 00:20:36 +02:00
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/*
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* drivers/i2c/i2c-adap-ixp4xx.c
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*
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* Intel's IXP4xx XScale NPU chipsets (IXP420, 421, 422, 425) do not have
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* an on board I2C controller but provide 16 GPIO pins that are often
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* used to create an I2C bus. This driver provides an i2c_adapter
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* interface that plugs in under algo_bit and drives the GPIO pins
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* as instructed by the alogorithm driver.
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*
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* Author: Deepak Saxena <dsaxena@plexity.net>
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*
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* Copyright (c) 2003-2004 MontaVista Software Inc.
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*
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* NOTE: Since different platforms will use different GPIO pins for
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* I2C, this driver uses an IXP4xx-specific platform_data
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* pointer to pass the GPIO numbers to the driver. This
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* allows us to support all the different IXP4xx platforms
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* w/o having to put #ifdefs in this driver.
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*
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* See arch/arm/mach-ixp4xx/ixdp425.c for an example of building a
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* device list and filling in the ixp4xx_i2c_pins data structure
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* that is passed as the platform_data to this driver.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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2005-10-29 20:07:23 +02:00
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#include <linux/platform_device.h>
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2005-04-17 00:20:36 +02:00
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-bit.h>
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#include <asm/hardware.h> /* Pick up IXP4xx-specific bits */
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static inline int ixp4xx_scl_pin(void *data)
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{
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return ((struct ixp4xx_i2c_pins*)data)->scl_pin;
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}
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static inline int ixp4xx_sda_pin(void *data)
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{
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return ((struct ixp4xx_i2c_pins*)data)->sda_pin;
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}
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static void ixp4xx_bit_setscl(void *data, int val)
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{
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gpio_line_set(ixp4xx_scl_pin(data), 0);
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gpio_line_config(ixp4xx_scl_pin(data),
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val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT );
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}
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static void ixp4xx_bit_setsda(void *data, int val)
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{
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gpio_line_set(ixp4xx_sda_pin(data), 0);
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gpio_line_config(ixp4xx_sda_pin(data),
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val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT );
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}
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static int ixp4xx_bit_getscl(void *data)
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{
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int scl;
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gpio_line_config(ixp4xx_scl_pin(data), IXP4XX_GPIO_IN );
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gpio_line_get(ixp4xx_scl_pin(data), &scl);
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return scl;
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}
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static int ixp4xx_bit_getsda(void *data)
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{
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int sda;
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gpio_line_config(ixp4xx_sda_pin(data), IXP4XX_GPIO_IN );
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gpio_line_get(ixp4xx_sda_pin(data), &sda);
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return sda;
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}
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struct ixp4xx_i2c_data {
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struct ixp4xx_i2c_pins *gpio_pins;
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struct i2c_adapter adapter;
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struct i2c_algo_bit_data algo_data;
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};
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2005-11-09 23:32:44 +01:00
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static int ixp4xx_i2c_remove(struct platform_device *plat_dev)
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2005-04-17 00:20:36 +02:00
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{
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2005-11-09 23:32:44 +01:00
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struct ixp4xx_i2c_data *drv_data = platform_get_drvdata(plat_dev);
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2005-04-17 00:20:36 +02:00
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2005-11-09 23:32:44 +01:00
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platform_set_drvdata(plat_dev, NULL);
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2005-04-17 00:20:36 +02:00
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i2c_bit_del_bus(&drv_data->adapter);
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kfree(drv_data);
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return 0;
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}
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2005-11-09 23:32:44 +01:00
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static int ixp4xx_i2c_probe(struct platform_device *plat_dev)
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2005-04-17 00:20:36 +02:00
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{
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int err;
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struct ixp4xx_i2c_pins *gpio = plat_dev->dev.platform_data;
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struct ixp4xx_i2c_data *drv_data =
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2005-10-17 23:07:05 +02:00
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kzalloc(sizeof(struct ixp4xx_i2c_data), GFP_KERNEL);
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2005-04-17 00:20:36 +02:00
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if(!drv_data)
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return -ENOMEM;
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drv_data->gpio_pins = gpio;
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/*
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* We could make a lot of these structures static, but
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* certain platforms may have multiple GPIO-based I2C
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* buses for various device domains, so we need per-device
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* algo_data->data.
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*/
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drv_data->algo_data.data = gpio;
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drv_data->algo_data.setsda = ixp4xx_bit_setsda;
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drv_data->algo_data.setscl = ixp4xx_bit_setscl;
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drv_data->algo_data.getsda = ixp4xx_bit_getsda;
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drv_data->algo_data.getscl = ixp4xx_bit_getscl;
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drv_data->algo_data.udelay = 10;
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drv_data->algo_data.mdelay = 10;
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drv_data->algo_data.timeout = 100;
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drv_data->adapter.id = I2C_HW_B_IXP4XX;
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2005-11-17 16:47:30 +01:00
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strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name,
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2005-10-07 23:04:48 +02:00
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I2C_NAME_SIZE);
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2005-04-17 00:20:36 +02:00
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drv_data->adapter.algo_data = &drv_data->algo_data;
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drv_data->adapter.dev.parent = &plat_dev->dev;
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gpio_line_config(gpio->scl_pin, IXP4XX_GPIO_IN);
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gpio_line_config(gpio->sda_pin, IXP4XX_GPIO_IN);
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gpio_line_set(gpio->scl_pin, 0);
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gpio_line_set(gpio->sda_pin, 0);
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if ((err = i2c_bit_add_bus(&drv_data->adapter) != 0)) {
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2005-11-17 16:47:30 +01:00
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printk(KERN_ERR "ERROR: Could not install %s\n", plat_dev->dev.bus_id);
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2005-04-17 00:20:36 +02:00
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kfree(drv_data);
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return err;
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}
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2005-11-09 23:32:44 +01:00
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platform_set_drvdata(plat_dev, drv_data);
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2005-04-17 00:20:36 +02:00
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return 0;
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}
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2005-11-09 23:32:44 +01:00
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static struct platform_driver ixp4xx_i2c_driver = {
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2005-04-17 00:20:36 +02:00
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.probe = ixp4xx_i2c_probe,
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.remove = ixp4xx_i2c_remove,
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2005-11-09 23:32:44 +01:00
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.driver = {
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.name = "IXP4XX-I2C",
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.owner = THIS_MODULE,
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},
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2005-04-17 00:20:36 +02:00
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};
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static int __init ixp4xx_i2c_init(void)
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{
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2005-11-09 23:32:44 +01:00
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return platform_driver_register(&ixp4xx_i2c_driver);
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2005-04-17 00:20:36 +02:00
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}
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static void __exit ixp4xx_i2c_exit(void)
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{
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2005-11-09 23:32:44 +01:00
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platform_driver_unregister(&ixp4xx_i2c_driver);
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2005-04-17 00:20:36 +02:00
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}
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module_init(ixp4xx_i2c_init);
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module_exit(ixp4xx_i2c_exit);
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MODULE_DESCRIPTION("GPIO-based I2C adapter for IXP4xx systems");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
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