Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Uwe Zeisberger | f30c226 | 2006-10-03 23:01:26 +0200 | [diff] [blame] | 2 | * drivers/i2c/busses/i2c-ixp4xx.c |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * |
| 4 | * Intel's IXP4xx XScale NPU chipsets (IXP420, 421, 422, 425) do not have |
| 5 | * an on board I2C controller but provide 16 GPIO pins that are often |
| 6 | * used to create an I2C bus. This driver provides an i2c_adapter |
| 7 | * interface that plugs in under algo_bit and drives the GPIO pins |
| 8 | * as instructed by the alogorithm driver. |
| 9 | * |
| 10 | * Author: Deepak Saxena <dsaxena@plexity.net> |
| 11 | * |
| 12 | * Copyright (c) 2003-2004 MontaVista Software Inc. |
| 13 | * |
| 14 | * This file is licensed under the terms of the GNU General Public |
| 15 | * License version 2. This program is licensed "as is" without any |
| 16 | * warranty of any kind, whether express or implied. |
| 17 | * |
| 18 | * NOTE: Since different platforms will use different GPIO pins for |
| 19 | * I2C, this driver uses an IXP4xx-specific platform_data |
| 20 | * pointer to pass the GPIO numbers to the driver. This |
| 21 | * allows us to support all the different IXP4xx platforms |
| 22 | * w/o having to put #ifdefs in this driver. |
| 23 | * |
| 24 | * See arch/arm/mach-ixp4xx/ixdp425.c for an example of building a |
| 25 | * device list and filling in the ixp4xx_i2c_pins data structure |
| 26 | * that is passed as the platform_data to this driver. |
| 27 | */ |
| 28 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | #include <linux/kernel.h> |
| 30 | #include <linux/init.h> |
Russell King | d052d1b | 2005-10-29 19:07:23 +0100 | [diff] [blame] | 31 | #include <linux/platform_device.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 IXP4xx-specific bits */ |
| 37 | |
| 38 | static inline int ixp4xx_scl_pin(void *data) |
| 39 | { |
| 40 | return ((struct ixp4xx_i2c_pins*)data)->scl_pin; |
| 41 | } |
| 42 | |
| 43 | static inline int ixp4xx_sda_pin(void *data) |
| 44 | { |
| 45 | return ((struct ixp4xx_i2c_pins*)data)->sda_pin; |
| 46 | } |
| 47 | |
| 48 | static void ixp4xx_bit_setscl(void *data, int val) |
| 49 | { |
| 50 | gpio_line_set(ixp4xx_scl_pin(data), 0); |
| 51 | gpio_line_config(ixp4xx_scl_pin(data), |
| 52 | val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT ); |
| 53 | } |
| 54 | |
| 55 | static void ixp4xx_bit_setsda(void *data, int val) |
| 56 | { |
| 57 | gpio_line_set(ixp4xx_sda_pin(data), 0); |
| 58 | gpio_line_config(ixp4xx_sda_pin(data), |
| 59 | val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT ); |
| 60 | } |
| 61 | |
| 62 | static int ixp4xx_bit_getscl(void *data) |
| 63 | { |
| 64 | int scl; |
| 65 | |
| 66 | gpio_line_config(ixp4xx_scl_pin(data), IXP4XX_GPIO_IN ); |
| 67 | gpio_line_get(ixp4xx_scl_pin(data), &scl); |
| 68 | |
| 69 | return scl; |
| 70 | } |
| 71 | |
| 72 | static int ixp4xx_bit_getsda(void *data) |
| 73 | { |
| 74 | int sda; |
| 75 | |
| 76 | gpio_line_config(ixp4xx_sda_pin(data), IXP4XX_GPIO_IN ); |
| 77 | gpio_line_get(ixp4xx_sda_pin(data), &sda); |
| 78 | |
| 79 | return sda; |
| 80 | } |
| 81 | |
| 82 | struct ixp4xx_i2c_data { |
| 83 | struct ixp4xx_i2c_pins *gpio_pins; |
| 84 | struct i2c_adapter adapter; |
| 85 | struct i2c_algo_bit_data algo_data; |
| 86 | }; |
| 87 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 88 | static int ixp4xx_i2c_remove(struct platform_device *plat_dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | { |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 90 | struct ixp4xx_i2c_data *drv_data = platform_get_drvdata(plat_dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 92 | platform_set_drvdata(plat_dev, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | |
Jean Delvare | 3269711 | 2006-12-10 21:21:33 +0100 | [diff] [blame] | 94 | i2c_del_adapter(&drv_data->adapter); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | |
| 96 | kfree(drv_data); |
| 97 | |
| 98 | return 0; |
| 99 | } |
| 100 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 101 | static int ixp4xx_i2c_probe(struct platform_device *plat_dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | { |
| 103 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | struct ixp4xx_i2c_pins *gpio = plat_dev->dev.platform_data; |
| 105 | struct ixp4xx_i2c_data *drv_data = |
Deepak Saxena | 2286066 | 2005-10-17 23:07:05 +0200 | [diff] [blame] | 106 | kzalloc(sizeof(struct ixp4xx_i2c_data), GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | |
| 108 | if(!drv_data) |
| 109 | return -ENOMEM; |
| 110 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | drv_data->gpio_pins = gpio; |
| 112 | |
| 113 | /* |
| 114 | * We could make a lot of these structures static, but |
| 115 | * certain platforms may have multiple GPIO-based I2C |
| 116 | * buses for various device domains, so we need per-device |
| 117 | * algo_data->data. |
| 118 | */ |
| 119 | drv_data->algo_data.data = gpio; |
| 120 | drv_data->algo_data.setsda = ixp4xx_bit_setsda; |
| 121 | drv_data->algo_data.setscl = ixp4xx_bit_setscl; |
| 122 | drv_data->algo_data.getsda = ixp4xx_bit_getsda; |
| 123 | drv_data->algo_data.getscl = ixp4xx_bit_getscl; |
| 124 | drv_data->algo_data.udelay = 10; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | drv_data->algo_data.timeout = 100; |
| 126 | |
| 127 | drv_data->adapter.id = I2C_HW_B_IXP4XX; |
Alessandro Zummo | 7cd30b2 | 2006-02-27 23:12:58 +0100 | [diff] [blame] | 128 | drv_data->adapter.class = I2C_CLASS_HWMON; |
Russell King | 7d78c88 | 2005-11-17 15:47:30 +0000 | [diff] [blame] | 129 | strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name, |
David Brownell | 2096b95 | 2007-05-01 23:26:28 +0200 | [diff] [blame^] | 130 | sizeof(drv_data->adapter.name)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | drv_data->adapter.algo_data = &drv_data->algo_data; |
| 132 | |
| 133 | drv_data->adapter.dev.parent = &plat_dev->dev; |
| 134 | |
| 135 | gpio_line_config(gpio->scl_pin, IXP4XX_GPIO_IN); |
| 136 | gpio_line_config(gpio->sda_pin, IXP4XX_GPIO_IN); |
| 137 | gpio_line_set(gpio->scl_pin, 0); |
| 138 | gpio_line_set(gpio->sda_pin, 0); |
| 139 | |
Alexey Dobriyan | a6cd2d9 | 2006-11-18 22:19:36 -0800 | [diff] [blame] | 140 | err = i2c_bit_add_bus(&drv_data->adapter); |
Jean Delvare | 0b1082e | 2006-11-23 13:28:50 +0100 | [diff] [blame] | 141 | if (err) { |
Russell King | 7d78c88 | 2005-11-17 15:47:30 +0000 | [diff] [blame] | 142 | printk(KERN_ERR "ERROR: Could not install %s\n", plat_dev->dev.bus_id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | |
| 144 | kfree(drv_data); |
| 145 | return err; |
| 146 | } |
| 147 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 148 | platform_set_drvdata(plat_dev, drv_data); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | |
| 150 | return 0; |
| 151 | } |
| 152 | |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 153 | static struct platform_driver ixp4xx_i2c_driver = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | .probe = ixp4xx_i2c_probe, |
| 155 | .remove = ixp4xx_i2c_remove, |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 156 | .driver = { |
| 157 | .name = "IXP4XX-I2C", |
| 158 | .owner = THIS_MODULE, |
| 159 | }, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | }; |
| 161 | |
| 162 | static int __init ixp4xx_i2c_init(void) |
| 163 | { |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 164 | return platform_driver_register(&ixp4xx_i2c_driver); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | } |
| 166 | |
| 167 | static void __exit ixp4xx_i2c_exit(void) |
| 168 | { |
Russell King | 3ae5eae | 2005-11-09 22:32:44 +0000 | [diff] [blame] | 169 | platform_driver_unregister(&ixp4xx_i2c_driver); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | } |
| 171 | |
| 172 | module_init(ixp4xx_i2c_init); |
| 173 | module_exit(ixp4xx_i2c_exit); |
| 174 | |
| 175 | MODULE_DESCRIPTION("GPIO-based I2C adapter for IXP4xx systems"); |
| 176 | MODULE_LICENSE("GPL"); |
| 177 | MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>"); |
| 178 | |