9d62a2d9096c4615b67bb588ef99bc0164e5f325
[openwrt/svn-archive/archive.git] / target / linux / adm5120 / files / drivers / i2c / busses / i2c-gpio-custom.c
1 /*
2 * Custom GPIO-based I2C driver
3 *
4 * Copyright (C) 2007 Gabor Juhos <juhosg at 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 "0.1.0"
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_unregister(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 devices[nr_devices++] = pdev;
124
125 pdata.sda_pin = params[BUS_PARAM_SDA];
126 pdata.scl_pin = params[BUS_PARAM_SCL];
127 pdata.udelay = params[BUS_PARAM_UDELAY];
128 pdata.timeout = params[BUS_PARAM_TIMEOUT];
129 pdata.sda_is_open_drain = params[BUS_PARAM_SDA_OD] != 0;
130 pdata.scl_is_open_drain = params[BUS_PARAM_SCL_OD] != 0;
131 pdata.scl_is_output_only = params[BUS_PARAM_SCL_OO] != 0;
132
133 err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
134 if (err)
135 goto err;
136
137 err = platform_device_register(pdev);
138 if (err)
139 goto err;
140
141 return 0;
142
143 err:
144 return err;
145 }
146
147 static int __init i2c_gpio_custom_init(void)
148 {
149 int err;
150
151 printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
152
153 err = i2c_gpio_custom_add_one(0, bus0);
154 if (err) goto err;
155
156 err = i2c_gpio_custom_add_one(1, bus1);
157 if (err) goto err;
158
159 err = i2c_gpio_custom_add_one(2, bus2);
160 if (err) goto err;
161
162 err = i2c_gpio_custom_add_one(3, bus3);
163 if (err) goto err;
164
165 if (!nr_devices) {
166 printk(KERN_ERR PFX "no bus parameter(s) specified\n");
167 err = -ENODEV;
168 goto err;
169 }
170
171 return 0;
172
173 err:
174 i2c_gpio_custom_cleanup();
175 return err;
176 }
177 module_init(i2c_gpio_custom_init);
178
179 static void __exit i2c_gpio_custom_exit(void)
180 {
181 i2c_gpio_custom_cleanup();
182 }
183 module_exit(i2c_gpio_custom_exit);
184
185
186 MODULE_LICENSE("GPL v2");
187 MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org >");
188 MODULE_DESCRIPTION(DRV_DESC);
189 MODULE_VERSION(DRV_VERSION);
190