Merge branch 'for-2.6.26' of git://git.kernel.dk/linux-2.6-block
[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
17 struct i2c_driver_device {
18         char    *of_device;
19         char    *i2c_type;
20 };
21
22 static struct i2c_driver_device i2c_devices[] = {
23         { "dallas,ds1374", "rtc-ds1374" },
24 };
25
26 static int of_find_i2c_driver(struct device_node *node,
27                               struct i2c_board_info *info)
28 {
29         int i, cplen;
30         const char *compatible;
31         const char *p;
32
33         /* 1. search for exception list entry */
34         for (i = 0; i < ARRAY_SIZE(i2c_devices); i++) {
35                 if (!of_device_is_compatible(node, i2c_devices[i].of_device))
36                         continue;
37                 if (strlcpy(info->type, i2c_devices[i].i2c_type,
38                             I2C_NAME_SIZE) >= I2C_NAME_SIZE)
39                         return -ENOMEM;
40
41                 return 0;
42         }
43
44         compatible = of_get_property(node, "compatible", &cplen);
45         if (!compatible)
46                 return -ENODEV;
47
48         /* 2. search for linux,<i2c-type> entry */
49         p = compatible;
50         while (cplen > 0) {
51                 if (!strncmp(p, "linux,", 6)) {
52                         p += 6;
53                         if (strlcpy(info->type, p,
54                                     I2C_NAME_SIZE) >= I2C_NAME_SIZE)
55                                 return -ENOMEM;
56                         return 0;
57                 }
58
59                 i = strlen(p) + 1;
60                 p += i;
61                 cplen -= i;
62         }
63
64         /* 3. take fist compatible entry and strip manufacturer */
65         p = strchr(compatible, ',');
66         if (!p)
67                 return -ENODEV;
68         p++;
69         if (strlcpy(info->type, p, I2C_NAME_SIZE) >= I2C_NAME_SIZE)
70                 return -ENOMEM;
71         return 0;
72 }
73
74 void of_register_i2c_devices(struct i2c_adapter *adap,
75                              struct device_node *adap_node)
76 {
77         void *result;
78         struct device_node *node;
79
80         for_each_child_of_node(adap_node, node) {
81                 struct i2c_board_info info = {};
82                 const u32 *addr;
83                 int len;
84
85                 addr = of_get_property(node, "reg", &len);
86                 if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
87                         printk(KERN_ERR
88                                "of-i2c: invalid i2c device entry\n");
89                         continue;
90                 }
91
92                 info.irq = irq_of_parse_and_map(node, 0);
93                 if (info.irq == NO_IRQ)
94                         info.irq = -1;
95
96                 if (of_find_i2c_driver(node, &info) < 0) {
97                         irq_dispose_mapping(info.irq);
98                         continue;
99                 }
100
101                 info.addr = *addr;
102
103                 request_module(info.type);
104
105                 result = i2c_new_device(adap, &info);
106                 if (result == NULL) {
107                         printk(KERN_ERR
108                                "of-i2c: Failed to load driver for %s\n",
109                                info.type);
110                         irq_dispose_mapping(info.irq);
111                         continue;
112                 }
113         }
114 }
115 EXPORT_SYMBOL(of_register_i2c_devices);