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1da177e4 LT |
1 | /* |
2 | * drivers/i2c/i2c-adap-ixp4xx.c | |
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 | ||
1da177e4 LT |
29 | #include <linux/kernel.h> |
30 | #include <linux/init.h> | |
d052d1be | 31 | #include <linux/platform_device.h> |
1da177e4 LT |
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 | ||
3ae5eaec | 88 | static int ixp4xx_i2c_remove(struct platform_device *plat_dev) |
1da177e4 | 89 | { |
3ae5eaec | 90 | struct ixp4xx_i2c_data *drv_data = platform_get_drvdata(plat_dev); |
1da177e4 | 91 | |
3ae5eaec | 92 | platform_set_drvdata(plat_dev, NULL); |
1da177e4 LT |
93 | |
94 | i2c_bit_del_bus(&drv_data->adapter); | |
95 | ||
96 | kfree(drv_data); | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
3ae5eaec | 101 | static int ixp4xx_i2c_probe(struct platform_device *plat_dev) |
1da177e4 LT |
102 | { |
103 | int err; | |
1da177e4 LT |
104 | struct ixp4xx_i2c_pins *gpio = plat_dev->dev.platform_data; |
105 | struct ixp4xx_i2c_data *drv_data = | |
2286066f | 106 | kzalloc(sizeof(struct ixp4xx_i2c_data), GFP_KERNEL); |
1da177e4 LT |
107 | |
108 | if(!drv_data) | |
109 | return -ENOMEM; | |
110 | ||
1da177e4 LT |
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; | |
125 | drv_data->algo_data.mdelay = 10; | |
126 | drv_data->algo_data.timeout = 100; | |
127 | ||
128 | drv_data->adapter.id = I2C_HW_B_IXP4XX; | |
7cd30b26 | 129 | drv_data->adapter.class = I2C_CLASS_HWMON; |
7d78c887 | 130 | strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name, |
8a1b028b | 131 | I2C_NAME_SIZE); |
1da177e4 LT |
132 | drv_data->adapter.algo_data = &drv_data->algo_data; |
133 | ||
134 | drv_data->adapter.dev.parent = &plat_dev->dev; | |
135 | ||
136 | gpio_line_config(gpio->scl_pin, IXP4XX_GPIO_IN); | |
137 | gpio_line_config(gpio->sda_pin, IXP4XX_GPIO_IN); | |
138 | gpio_line_set(gpio->scl_pin, 0); | |
139 | gpio_line_set(gpio->sda_pin, 0); | |
140 | ||
141 | if ((err = i2c_bit_add_bus(&drv_data->adapter) != 0)) { | |
7d78c887 | 142 | printk(KERN_ERR "ERROR: Could not install %s\n", plat_dev->dev.bus_id); |
1da177e4 LT |
143 | |
144 | kfree(drv_data); | |
145 | return err; | |
146 | } | |
147 | ||
3ae5eaec | 148 | platform_set_drvdata(plat_dev, drv_data); |
1da177e4 LT |
149 | |
150 | return 0; | |
151 | } | |
152 | ||
3ae5eaec | 153 | static struct platform_driver ixp4xx_i2c_driver = { |
1da177e4 LT |
154 | .probe = ixp4xx_i2c_probe, |
155 | .remove = ixp4xx_i2c_remove, | |
3ae5eaec RK |
156 | .driver = { |
157 | .name = "IXP4XX-I2C", | |
158 | .owner = THIS_MODULE, | |
159 | }, | |
1da177e4 LT |
160 | }; |
161 | ||
162 | static int __init ixp4xx_i2c_init(void) | |
163 | { | |
3ae5eaec | 164 | return platform_driver_register(&ixp4xx_i2c_driver); |
1da177e4 LT |
165 | } |
166 | ||
167 | static void __exit ixp4xx_i2c_exit(void) | |
168 | { | |
3ae5eaec | 169 | platform_driver_unregister(&ixp4xx_i2c_driver); |
1da177e4 LT |
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 |