| 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 | |
| 71 | static unsigned int bus0[BUS_PARAM_COUNT] __initdata; |
| 72 | static unsigned int bus1[BUS_PARAM_COUNT] __initdata; |
| 73 | static unsigned int bus2[BUS_PARAM_COUNT] __initdata; |
| 74 | static unsigned int bus3[BUS_PARAM_COUNT] __initdata; |
| 75 | |
| 76 | static 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 | |
| 81 | module_param_array(bus0, uint, &bus_nump[0], 0); |
| 82 | MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC); |
| 83 | module_param_array(bus1, uint, &bus_nump[1], 0); |
| 84 | MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC); |
| 85 | module_param_array(bus2, uint, &bus_nump[2], 0); |
| 86 | MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC); |
| 87 | module_param_array(bus3, uint, &bus_nump[3], 0); |
| 88 | MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC); |
| 89 | |
| 90 | static struct platform_device *devices[BUS_COUNT_MAX]; |
| 91 | static unsigned int nr_devices; |
| 92 | |
| 93 | static 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 | |
| 102 | static 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 | |
| 142 | err_put: |
| 143 | platform_device_put(pdev); |
| 144 | err: |
| 145 | return err; |
| 146 | } |
| 147 | |
| 148 | static 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) goto err; |
| 156 | |
| 157 | err = i2c_gpio_custom_add_one(1, bus1); |
| 158 | if (err) goto err; |
| 159 | |
| 160 | err = i2c_gpio_custom_add_one(2, bus2); |
| 161 | if (err) goto err; |
| 162 | |
| 163 | err = i2c_gpio_custom_add_one(3, bus3); |
| 164 | if (err) goto err; |
| 165 | |
| 166 | if (!nr_devices) { |
| 167 | printk(KERN_ERR PFX "no bus parameter(s) specified\n"); |
| 168 | err = -ENODEV; |
| 169 | goto err; |
| 170 | } |
| 171 | |
| 172 | return 0; |
| 173 | |
| 174 | err: |
| 175 | i2c_gpio_custom_cleanup(); |
| 176 | return err; |
| 177 | } |
| 178 | |
| 179 | #ifdef MODULE |
| 180 | static int __init i2c_gpio_custom_init(void) |
| 181 | { |
| 182 | return i2c_gpio_custom_probe(); |
| 183 | } |
| 184 | module_init(i2c_gpio_custom_init); |
| 185 | |
| 186 | static void __exit i2c_gpio_custom_exit(void) |
| 187 | { |
| 188 | i2c_gpio_custom_cleanup(); |
| 189 | } |
| 190 | module_exit(i2c_gpio_custom_exit); |
| 191 | #else |
| 192 | subsys_initcall(i2c_gpio_custom_probe); |
| 193 | #endif /* MODULE*/ |
| 194 | |
| 195 | MODULE_LICENSE("GPL v2"); |
| 196 | MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org >"); |
| 197 | MODULE_DESCRIPTION(DRV_DESC); |
| 198 | MODULE_VERSION(DRV_VERSION); |
| 199 | |
