Merge branch 'linus' into x86/header-guards
[linux-2.6] / drivers / of / of_i2c.c
1 /*
2  * OF helpers for the I2C API
3  *
4  * Copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
5  *
6  * Based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  */
13
14 #include <linux/i2c.h>
15 #include <linux/of.h>
16 #include <linux/of_i2c.h>
17 #include <linux/module.h>
18
19 struct i2c_driver_device {
20         char    *of_device;
21         char    *i2c_type;
22 };
23
24 static struct i2c_driver_device i2c_devices[] = {
25 };
26
27 static int of_find_i2c_driver(struct device_node *node,
28                               struct i2c_board_info *info)
29 {
30         int i, cplen;
31         const char *compatible;
32         const char *p;
33
34         /* 1. search for exception list entry */
35         for (i = 0; i < ARRAY_SIZE(i2c_devices); i++) {
36                 if (!of_device_is_compatible(node, i2c_devices[i].of_device))
37                         continue;
38                 if (strlcpy(info->type, i2c_devices[i].i2c_type,
39                             I2C_NAME_SIZE) >= I2C_NAME_SIZE)
40                         return -ENOMEM;
41
42                 return 0;
43         }
44
45         compatible = of_get_property(node, "compatible", &cplen);
46         if (!compatible)
47                 return -ENODEV;
48
49         /* 2. search for linux,<i2c-type> entry */
50         p = compatible;
51         while (cplen > 0) {
52                 if (!strncmp(p, "linux,", 6)) {
53                         p += 6;
54                         if (strlcpy(info->type, p,
55                                     I2C_NAME_SIZE) >= I2C_NAME_SIZE)
56                                 return -ENOMEM;
57                         return 0;
58                 }
59
60                 i = strlen(p) + 1;
61                 p += i;
62                 cplen -= i;
63         }
64
65         /* 3. take fist compatible entry and strip manufacturer */
66         p = strchr(compatible, ',');
67         if (!p)
68                 return -ENODEV;
69         p++;
70         if (strlcpy(info->type, p, I2C_NAME_SIZE) >= I2C_NAME_SIZE)
71                 return -ENOMEM;
72         return 0;
73 }
74
75 void of_register_i2c_devices(struct i2c_adapter *adap,
76                              struct device_node *adap_node)
77 {
78         void *result;
79         struct device_node *node;
80
81         for_each_child_of_node(adap_node, node) {
82                 struct i2c_board_info info = {};
83                 const u32 *addr;
84                 int len;
85
86                 addr = of_get_property(node, "reg", &len);
87                 if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
88                         printk(KERN_ERR
89                                "of-i2c: invalid i2c device entry\n");
90                         continue;
91                 }
92
93                 info.irq = irq_of_parse_and_map(node, 0);
94
95                 if (of_find_i2c_driver(node, &info) < 0) {
96                         irq_dispose_mapping(info.irq);
97                         continue;
98                 }
99
100                 info.addr = *addr;
101
102                 request_module(info.type);
103
104                 result = i2c_new_device(adap, &info);
105                 if (result == NULL) {
106                         printk(KERN_ERR
107                                "of-i2c: Failed to load driver for %s\n",
108                                info.type);
109                         irq_dispose_mapping(info.irq);
110                         continue;
111                 }
112         }
113 }
114 EXPORT_SYMBOL(of_register_i2c_devices);
115
116 MODULE_LICENSE("GPL");