1/* 2 * Custom GPIO-based I2C driver 3 * 4 * Copyright (C) 2007-2008 Gabor Juhos <juhosg@openwrt.org> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * --------------------------------------------------------------------------- 11 * 12 * The behaviour of this driver can be altered by setting some parameters 13 * from the insmod command line. 14 * 15 * The following parameters are adjustable: 16 * 17 * bus0 These four arguments can be arrays of 18 * bus1 1-8 unsigned integers as follows: 19 * bus2 20 * bus3 <id>,<sda>,<scl>,<udelay>,<timeout>,<sda_od>,<scl_od>,<scl_oo> 21 * 22 * where: 23 * 24 * <id> ID to used as device_id for the corresponding bus (required) 25 * <sda> GPIO pin ID to used for SDA (required) 26 * <scl> GPIO pin ID to used for SCL (required) 27 * <udelay> signal toggle delay. 28 * <timeout> clock stretching timeout. 29 * <sda_od> SDA is configured as open drain. 30 * <scl_od> SCL is configured as open drain. 31 * <scl_oo> SCL output drivers cannot be turned off. 32 * 33 * See include/i2c-gpio.h for more information about the parameters. 34 * 35 * If this driver is built into the kernel, you can use the following kernel 36 * command line parameters, with the same values as the corresponding module 37 * parameters listed above: 38 * 39 * i2c-gpio-custom.bus0 40 * i2c-gpio-custom.bus1 41 * i2c-gpio-custom.bus2 42 * i2c-gpio-custom.bus3 43 */ 44 45#include <linux/kernel.h> 46#include <linux/module.h> 47#include <linux/init.h> 48#include <linux/platform_device.h> 49 50#include <linux/i2c-gpio.h> 51 52#define DRV_NAME "i2c-gpio-custom" 53#define DRV_DESC "Custom GPIO-based I2C driver" 54#define DRV_VERSION "0.1.1" 55 56#define PFX DRV_NAME ": " 57 58#define BUS_PARAM_ID 0 59#define BUS_PARAM_SDA 1 60#define BUS_PARAM_SCL 2 61#define BUS_PARAM_UDELAY 3 62#define BUS_PARAM_TIMEOUT 4 63#define BUS_PARAM_SDA_OD 5 64#define BUS_PARAM_SCL_OD 6 65#define BUS_PARAM_SCL_OO 7 66 67#define BUS_PARAM_REQUIRED 3 68#define BUS_PARAM_COUNT 8 69#define BUS_COUNT_MAX 4 70 71static unsigned int bus0[BUS_PARAM_COUNT] __initdata; 72static unsigned int bus1[BUS_PARAM_COUNT] __initdata; 73static unsigned int bus2[BUS_PARAM_COUNT] __initdata; 74static unsigned int bus3[BUS_PARAM_COUNT] __initdata; 75 76static unsigned int bus_nump[BUS_COUNT_MAX] __initdata; 77 78#define BUS_PARM_DESC \ 79 " config -> id,sda,scl[,udelay,timeout,sda_od,scl_od,scl_oo]" 80 81module_param_array(bus0, uint, &bus_nump[0], 0); 82MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC); 83module_param_array(bus1, uint, &bus_nump[1], 0); 84MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC); 85module_param_array(bus2, uint, &bus_nump[2], 0); 86MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC); 87module_param_array(bus3, uint, &bus_nump[3], 0); 88MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC); 89 90static struct platform_device *devices[BUS_COUNT_MAX]; 91static unsigned int nr_devices; 92 93static void i2c_gpio_custom_cleanup(void) 94{ 95 int i; 96 97 for (i = 0; i < nr_devices; i++) 98 if (devices[i]) 99 platform_device_put(devices[i]); 100} 101 102static int __init i2c_gpio_custom_add_one(unsigned int id, unsigned int *params) 103{ 104 struct platform_device *pdev; 105 struct i2c_gpio_platform_data pdata; 106 int err; 107 108 if (!bus_nump[id]) 109 return 0; 110 111 if (bus_nump[id] < BUS_PARAM_REQUIRED) { 112 printk(KERN_ERR PFX "not enough parameters for bus%d\n", id); 113 err = -EINVAL; 114 goto err; 115 } 116 117 pdev = platform_device_alloc("i2c-gpio", params[BUS_PARAM_ID]); 118 if (!pdev) { 119 err = -ENOMEM; 120 goto err; 121 } 122 123 pdata.sda_pin = params[BUS_PARAM_SDA]; 124 pdata.scl_pin = params[BUS_PARAM_SCL]; 125 pdata.udelay = params[BUS_PARAM_UDELAY]; 126 pdata.timeout = params[BUS_PARAM_TIMEOUT]; 127 pdata.sda_is_open_drain = params[BUS_PARAM_SDA_OD] != 0; 128 pdata.scl_is_open_drain = params[BUS_PARAM_SCL_OD] != 0; 129 pdata.scl_is_output_only = params[BUS_PARAM_SCL_OO] != 0; 130 131 err = platform_device_add_data(pdev, &pdata, sizeof(pdata)); 132 if (err) 133 goto err_put; 134 135 err = platform_device_add(pdev); 136 if (err) 137 goto err_put; 138 139 devices[nr_devices++] = pdev; 140 return 0; 141 142err_put: 143 platform_device_put(pdev); 144err: 145 return err; 146} 147 148static int __init i2c_gpio_custom_probe(void) 149{ 150 int err; 151 152 printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n"); 153 154 err = i2c_gpio_custom_add_one(0, bus0); 155 if (err) 156 goto err; 157 158 err = i2c_gpio_custom_add_one(1, bus1); 159 if (err) 160 goto err; 161 162 err = i2c_gpio_custom_add_one(2, bus2); 163 if (err) 164 goto err; 165 166 err = i2c_gpio_custom_add_one(3, bus3); 167 if (err) 168 goto err; 169 170 if (!nr_devices) { 171 printk(KERN_ERR PFX "no bus parameter(s) specified\n"); 172 err = -ENODEV; 173 goto err; 174 } 175 176 return 0; 177 178err: 179 i2c_gpio_custom_cleanup(); 180 return err; 181} 182 183#ifdef MODULE 184static int __init i2c_gpio_custom_init(void) 185{ 186 return i2c_gpio_custom_probe(); 187} 188module_init(i2c_gpio_custom_init); 189 190static void __exit i2c_gpio_custom_exit(void) 191{ 192 i2c_gpio_custom_cleanup(); 193} 194module_exit(i2c_gpio_custom_exit); 195#else 196subsys_initcall(i2c_gpio_custom_probe); 197#endif /* MODULE*/ 198 199MODULE_LICENSE("GPL v2"); 200MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org >"); 201MODULE_DESCRIPTION(DRV_DESC); 202MODULE_VERSION(DRV_VERSION); 203