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1da177e4 LT |
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 | ||
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 | ||
c4982887 LB |
36 | #include <asm/hardware.h> /* Pick up IXP2000-specific bits */ |
37 | #include <asm/arch/gpio.h> | |
1da177e4 LT |
38 | |
39 | static inline int ixp2000_scl_pin(void *data) | |
40 | { | |
41 | return ((struct ixp2000_i2c_pins*)data)->scl_pin; | |
42 | } | |
43 | ||
44 | static inline int ixp2000_sda_pin(void *data) | |
45 | { | |
46 | return ((struct ixp2000_i2c_pins*)data)->sda_pin; | |
47 | } | |
48 | ||
49 | ||
50 | static 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 | ||
62 | static 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 | ||
71 | static int ixp2000_bit_getscl(void *data) | |
72 | { | |
73 | return gpio_line_get(ixp2000_scl_pin(data)); | |
74 | } | |
75 | ||
76 | static int ixp2000_bit_getsda(void *data) | |
77 | { | |
78 | return gpio_line_get(ixp2000_sda_pin(data)); | |
79 | } | |
80 | ||
81 | struct 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 | ||
3ae5eaec | 87 | static int ixp2000_i2c_remove(struct platform_device *plat_dev) |
1da177e4 | 88 | { |
3ae5eaec | 89 | struct ixp2000_i2c_data *drv_data = platform_get_drvdata(plat_dev); |
1da177e4 | 90 | |
3ae5eaec | 91 | platform_set_drvdata(plat_dev, NULL); |
1da177e4 LT |
92 | |
93 | i2c_bit_del_bus(&drv_data->adapter); | |
94 | ||
95 | kfree(drv_data); | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
3ae5eaec | 100 | static int ixp2000_i2c_probe(struct platform_device *plat_dev) |
1da177e4 LT |
101 | { |
102 | int err; | |
1da177e4 LT |
103 | struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data; |
104 | struct ixp2000_i2c_data *drv_data = | |
2286066f | 105 | kzalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL); |
1da177e4 LT |
106 | |
107 | if (!drv_data) | |
108 | return -ENOMEM; | |
1da177e4 LT |
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; | |
1da177e4 LT |
117 | drv_data->algo_data.timeout = 100; |
118 | ||
119 | drv_data->adapter.id = I2C_HW_B_IXP2000, | |
7d78c887 | 120 | strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name, |
8a1b028b | 121 | I2C_NAME_SIZE); |
1da177e4 LT |
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) { | |
7d78c887 | 132 | dev_err(&plat_dev->dev, "Could not install, error %d\n", err); |
1da177e4 LT |
133 | kfree(drv_data); |
134 | return err; | |
135 | } | |
136 | ||
3ae5eaec | 137 | platform_set_drvdata(plat_dev, drv_data); |
1da177e4 LT |
138 | |
139 | return 0; | |
140 | } | |
141 | ||
3ae5eaec | 142 | static struct platform_driver ixp2000_i2c_driver = { |
1da177e4 LT |
143 | .probe = ixp2000_i2c_probe, |
144 | .remove = ixp2000_i2c_remove, | |
3ae5eaec RK |
145 | .driver = { |
146 | .name = "IXP2000-I2C", | |
147 | .owner = THIS_MODULE, | |
148 | }, | |
1da177e4 LT |
149 | }; |
150 | ||
151 | static int __init ixp2000_i2c_init(void) | |
152 | { | |
3ae5eaec | 153 | return platform_driver_register(&ixp2000_i2c_driver); |
1da177e4 LT |
154 | } |
155 | ||
156 | static void __exit ixp2000_i2c_exit(void) | |
157 | { | |
3ae5eaec | 158 | platform_driver_unregister(&ixp2000_i2c_driver); |
1da177e4 LT |
159 | } |
160 | ||
161 | module_init(ixp2000_i2c_init); | |
162 | module_exit(ixp2000_i2c_exit); | |
163 | ||
164 | MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>"); | |
165 | MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver"); | |
166 | MODULE_LICENSE("GPL"); | |
167 |