tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
29#include <linux/kernel.h>
30#include <linux/init.h>
31#include <linux/platform_device.h>
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 IXP2000-specific bits */
37#include <asm/arch/gpio.h>
38
39static inline int ixp2000_scl_pin(void *data)
40{
41 return ((struct ixp2000_i2c_pins*)data)->scl_pin;
42}
43
44static inline int ixp2000_sda_pin(void *data)
45{
46 return ((struct ixp2000_i2c_pins*)data)->sda_pin;
47}
48
49
50static 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
62static 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
71static int ixp2000_bit_getscl(void *data)
72{
73 return gpio_line_get(ixp2000_scl_pin(data));
74}
75
76static int ixp2000_bit_getsda(void *data)
77{
78 return gpio_line_get(ixp2000_sda_pin(data));
79}
80
81struct 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
87static int ixp2000_i2c_remove(struct platform_device *plat_dev)
88{
89 struct ixp2000_i2c_data *drv_data = platform_get_drvdata(plat_dev);
90
91 platform_set_drvdata(plat_dev, NULL);
92
93 i2c_del_adapter(&drv_data->adapter);
94
95 kfree(drv_data);
96
97 return 0;
98}
99
100static int ixp2000_i2c_probe(struct platform_device *plat_dev)
101{
102 int err;
103 struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data;
104 struct ixp2000_i2c_data *drv_data =
105 kzalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL);
106
107 if (!drv_data)
108 return -ENOMEM;
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;
117 drv_data->algo_data.timeout = 100;
118
119 drv_data->adapter.id = I2C_HW_B_IXP2000,
120 strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name,
121 I2C_NAME_SIZE);
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) {
132 dev_err(&plat_dev->dev, "Could not install, error %d\n", err);
133 kfree(drv_data);
134 return err;
135 }
136
137 platform_set_drvdata(plat_dev, drv_data);
138
139 return 0;
140}
141
142static struct platform_driver ixp2000_i2c_driver = {
143 .probe = ixp2000_i2c_probe,
144 .remove = ixp2000_i2c_remove,
145 .driver = {
146 .name = "IXP2000-I2C",
147 .owner = THIS_MODULE,
148 },
149};
150
151static int __init ixp2000_i2c_init(void)
152{
153 return platform_driver_register(&ixp2000_i2c_driver);
154}
155
156static void __exit ixp2000_i2c_exit(void)
157{
158 platform_driver_unregister(&ixp2000_i2c_driver);
159}
160
161module_init(ixp2000_i2c_init);
162module_exit(ixp2000_i2c_exit);
163
164MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>");
165MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver");
166MODULE_LICENSE("GPL");
167