1/* 2 * drivers/i2c/busses/i2c-ixp2000.c 3 * 4 * I2C adapter for IXP2000 systems using GPIOs for I2C bus 5 * 6 * Author: Deepak Saxena <dsaxena@plexity.net> 7 * Based on IXDP2400 code by: Naeem M. Afzal <naeem.m.afzal@intel.com> 8 * Made generic by: Jeff Daly <jeffrey.daly@intel.com> 9 * 10 * Copyright (c) 2003-2004 MontaVista Software Inc. 11 * 12 * This file is licensed under the terms of the GNU General Public 13 * License version 2. This program is licensed "as is" without any 14 * warranty of any kind, whether express or implied. 15 * 16 * From Jeff Daly: 17 * 18 * I2C adapter driver for Intel IXDP2xxx platforms. This should work for any 19 * IXP2000 platform if it uses the HW GPIO in the same manner. Basically, 20 * SDA and SCL GPIOs have external pullups. Setting the respective GPIO to 21 * an input will make the signal a '1' via the pullup. Setting them to 22 * outputs will pull them down. 23 * 24 * The GPIOs are open drain signals and are used as configuration strap inputs 25 * during power-up so there's generally a buffer on the board that needs to be 26 * 'enabled' to drive the GPIOs. 27 */ 28 29#include <linux/kernel.h> 30#include <linux/init.h> 31#include <linux/platform_device.h> 32#include <linux/module.h> 33#include <linux/i2c.h> 34#include <linux/i2c-algo-bit.h> 35 36#include <asm/hardware.h> /* Pick up IXP2000-specific bits */ 37#include <asm/arch/gpio.h> 38 39static inline int ixp2000_scl_pin(void *data) 40{ 41 return ((struct ixp2000_i2c_pins*)data)->scl_pin; 42} 43 44static inline int ixp2000_sda_pin(void *data) 45{ 46 return ((struct ixp2000_i2c_pins*)data)->sda_pin; 47} 48 49 50static void ixp2000_bit_setscl(void *data, int val) 51{ 52 int i = 5000; 53 54 if (val) { 55 gpio_line_config(ixp2000_scl_pin(data), GPIO_IN); 56 while(!gpio_line_get(ixp2000_scl_pin(data)) && i--); 57 } else { 58 gpio_line_config(ixp2000_scl_pin(data), GPIO_OUT); 59 } 60} 61 62static void ixp2000_bit_setsda(void *data, int val) 63{ 64 if (val) { 65 gpio_line_config(ixp2000_sda_pin(data), GPIO_IN); 66 } else { 67 gpio_line_config(ixp2000_sda_pin(data), GPIO_OUT); 68 } 69} 70 71static int ixp2000_bit_getscl(void *data) 72{ 73 return gpio_line_get(ixp2000_scl_pin(data)); 74} 75 76static int ixp2000_bit_getsda(void *data) 77{ 78 return gpio_line_get(ixp2000_sda_pin(data)); 79} 80 81struct ixp2000_i2c_data { 82 struct ixp2000_i2c_pins *gpio_pins; 83 struct i2c_adapter adapter; 84 struct i2c_algo_bit_data algo_data; 85}; 86 87static int ixp2000_i2c_remove(struct platform_device *plat_dev) 88{ 89 struct ixp2000_i2c_data *drv_data = platform_get_drvdata(plat_dev); 90 91 platform_set_drvdata(plat_dev, NULL); 92 93 i2c_del_adapter(&drv_data->adapter); 94 95 kfree(drv_data); 96 97 return 0; 98} 99 100static int ixp2000_i2c_probe(struct platform_device *plat_dev) 101{ 102 int err; 103 struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data; 104 struct ixp2000_i2c_data *drv_data = 105 kzalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL); 106 107 if (!drv_data) 108 return -ENOMEM; 109 drv_data->gpio_pins = gpio; 110 111 drv_data->algo_data.data = gpio; 112 drv_data->algo_data.setsda = ixp2000_bit_setsda; 113 drv_data->algo_data.setscl = ixp2000_bit_setscl; 114 drv_data->algo_data.getsda = ixp2000_bit_getsda; 115 drv_data->algo_data.getscl = ixp2000_bit_getscl; 116 drv_data->algo_data.udelay = 6; 117 drv_data->algo_data.timeout = 100; 118 119 drv_data->adapter.id = I2C_HW_B_IXP2000, 120 strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name, 121 sizeof(drv_data->adapter.name)); 122 drv_data->adapter.algo_data = &drv_data->algo_data, 123 124 drv_data->adapter.dev.parent = &plat_dev->dev; 125 126 gpio_line_config(gpio->sda_pin, GPIO_IN); 127 gpio_line_config(gpio->scl_pin, GPIO_IN); 128 gpio_line_set(gpio->scl_pin, 0); 129 gpio_line_set(gpio->sda_pin, 0); 130 131 if ((err = i2c_bit_add_bus(&drv_data->adapter)) != 0) { 132 dev_err(&plat_dev->dev, "Could not install, error %d\n", err); 133 kfree(drv_data); 134 return err; 135 } 136 137 platform_set_drvdata(plat_dev, drv_data); 138 139 return 0; 140} 141 142static struct platform_driver ixp2000_i2c_driver = { 143 .probe = ixp2000_i2c_probe, 144 .remove = ixp2000_i2c_remove, 145 .driver = { 146 .name = "IXP2000-I2C", 147 .owner = THIS_MODULE, 148 }, 149}; 150 151static int __init ixp2000_i2c_init(void) 152{ 153 return platform_driver_register(&ixp2000_i2c_driver); 154} 155 156static void __exit ixp2000_i2c_exit(void) 157{ 158 platform_driver_unregister(&ixp2000_i2c_driver); 159} 160 161module_init(ixp2000_i2c_init); 162module_exit(ixp2000_i2c_exit); 163 164MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>"); 165MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver"); 166MODULE_LICENSE("GPL"); 167