168 lines
4.2 KiB
C
168 lines
4.2 KiB
C
/*
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* drivers/i2c/busses/i2c-ixp2000.c
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*
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* I2C adapter for IXP2000 systems using GPIOs for I2C bus
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*
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* Author: Deepak Saxena <dsaxena@plexity.net>
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* Based on IXDP2400 code by: Naeem M. Afzal <naeem.m.afzal@intel.com>
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* Made generic by: Jeff Daly <jeffrey.daly@intel.com>
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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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* From Jeff Daly:
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*
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* I2C adapter driver for Intel IXDP2xxx platforms. This should work for any
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* IXP2000 platform if it uses the HW GPIO in the same manner. Basically,
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* SDA and SCL GPIOs have external pullups. Setting the respective GPIO to
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* an input will make the signal a '1' via the pullup. Setting them to
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* outputs will pull them down.
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*
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* The GPIOs are open drain signals and are used as configuration strap inputs
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* during power-up so there's generally a buffer on the board that needs to be
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* 'enabled' to drive the GPIOs.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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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 <mach/hardware.h> /* Pick up IXP2000-specific bits */
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#include <mach/gpio.h>
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static inline int ixp2000_scl_pin(void *data)
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{
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return ((struct ixp2000_i2c_pins*)data)->scl_pin;
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}
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static inline int ixp2000_sda_pin(void *data)
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{
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return ((struct ixp2000_i2c_pins*)data)->sda_pin;
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}
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static void ixp2000_bit_setscl(void *data, int val)
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{
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int i = 5000;
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if (val) {
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gpio_line_config(ixp2000_scl_pin(data), GPIO_IN);
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while(!gpio_line_get(ixp2000_scl_pin(data)) && i--);
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} else {
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gpio_line_config(ixp2000_scl_pin(data), GPIO_OUT);
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}
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}
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static void ixp2000_bit_setsda(void *data, int val)
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{
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if (val) {
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gpio_line_config(ixp2000_sda_pin(data), GPIO_IN);
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} else {
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gpio_line_config(ixp2000_sda_pin(data), GPIO_OUT);
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}
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}
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static int ixp2000_bit_getscl(void *data)
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{
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return gpio_line_get(ixp2000_scl_pin(data));
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}
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static int ixp2000_bit_getsda(void *data)
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{
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return gpio_line_get(ixp2000_sda_pin(data));
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}
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struct ixp2000_i2c_data {
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struct ixp2000_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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static int ixp2000_i2c_remove(struct platform_device *plat_dev)
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{
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struct ixp2000_i2c_data *drv_data = platform_get_drvdata(plat_dev);
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platform_set_drvdata(plat_dev, NULL);
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i2c_del_adapter(&drv_data->adapter);
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kfree(drv_data);
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return 0;
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}
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static int ixp2000_i2c_probe(struct platform_device *plat_dev)
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{
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int err;
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struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data;
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struct ixp2000_i2c_data *drv_data =
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kzalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL);
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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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drv_data->algo_data.data = gpio;
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drv_data->algo_data.setsda = ixp2000_bit_setsda;
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drv_data->algo_data.setscl = ixp2000_bit_setscl;
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drv_data->algo_data.getsda = ixp2000_bit_getsda;
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drv_data->algo_data.getscl = ixp2000_bit_getscl;
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drv_data->algo_data.udelay = 6;
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drv_data->algo_data.timeout = HZ;
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strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name,
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sizeof(drv_data->adapter.name));
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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->sda_pin, GPIO_IN);
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gpio_line_config(gpio->scl_pin, 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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dev_err(&plat_dev->dev, "Could not install, error %d\n", err);
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kfree(drv_data);
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return err;
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}
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platform_set_drvdata(plat_dev, drv_data);
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return 0;
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}
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static struct platform_driver ixp2000_i2c_driver = {
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.probe = ixp2000_i2c_probe,
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.remove = ixp2000_i2c_remove,
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.driver = {
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.name = "IXP2000-I2C",
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.owner = THIS_MODULE,
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},
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};
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static int __init ixp2000_i2c_init(void)
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{
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return platform_driver_register(&ixp2000_i2c_driver);
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}
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static void __exit ixp2000_i2c_exit(void)
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{
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platform_driver_unregister(&ixp2000_i2c_driver);
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}
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module_init(ixp2000_i2c_init);
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module_exit(ixp2000_i2c_exit);
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MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>");
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MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:IXP2000-I2C");
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