]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * i2c-boardinfo.c - collect pre-declarations of I2C devices | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | */ | |
14 | ||
15 | #include <linux/export.h> | |
16 | #include <linux/i2c.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/rwsem.h> | |
19 | #include <linux/slab.h> | |
20 | ||
21 | #include "i2c-core.h" | |
22 | ||
23 | ||
24 | /* These symbols are exported ONLY FOR the i2c core. | |
25 | * No other users will be supported. | |
26 | */ | |
27 | DECLARE_RWSEM(__i2c_board_lock); | |
28 | EXPORT_SYMBOL_GPL(__i2c_board_lock); | |
29 | ||
30 | LIST_HEAD(__i2c_board_list); | |
31 | EXPORT_SYMBOL_GPL(__i2c_board_list); | |
32 | ||
33 | int __i2c_first_dynamic_bus_num; | |
34 | EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num); | |
35 | ||
36 | ||
37 | /** | |
38 | * i2c_register_board_info - statically declare I2C devices | |
39 | * @busnum: identifies the bus to which these devices belong | |
40 | * @info: vector of i2c device descriptors | |
41 | * @len: how many descriptors in the vector; may be zero to reserve | |
42 | * the specified bus number. | |
43 | * | |
44 | * Systems using the Linux I2C driver stack can declare tables of board info | |
45 | * while they initialize. This should be done in board-specific init code | |
46 | * near arch_initcall() time, or equivalent, before any I2C adapter driver is | |
47 | * registered. For example, mainboard init code could define several devices, | |
48 | * as could the init code for each daughtercard in a board stack. | |
49 | * | |
50 | * The I2C devices will be created later, after the adapter for the relevant | |
51 | * bus has been registered. After that moment, standard driver model tools | |
52 | * are used to bind "new style" I2C drivers to the devices. The bus number | |
53 | * for any device declared using this routine is not available for dynamic | |
54 | * allocation. | |
55 | * | |
56 | * The board info passed can safely be __initdata, but be careful of embedded | |
57 | * pointers (for platform_data, functions, etc) since that won't be copied. | |
58 | */ | |
59 | int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len) | |
60 | { | |
61 | int status; | |
62 | ||
63 | down_write(&__i2c_board_lock); | |
64 | ||
65 | /* dynamic bus numbers will be assigned after the last static one */ | |
66 | if (busnum >= __i2c_first_dynamic_bus_num) | |
67 | __i2c_first_dynamic_bus_num = busnum + 1; | |
68 | ||
69 | for (status = 0; len; len--, info++) { | |
70 | struct i2c_devinfo *devinfo; | |
71 | ||
72 | devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL); | |
73 | if (!devinfo) { | |
74 | pr_debug("i2c-core: can't register boardinfo!\n"); | |
75 | status = -ENOMEM; | |
76 | break; | |
77 | } | |
78 | ||
79 | devinfo->busnum = busnum; | |
80 | devinfo->board_info = *info; | |
81 | list_add_tail(&devinfo->list, &__i2c_board_list); | |
82 | } | |
83 | ||
84 | up_write(&__i2c_board_lock); | |
85 | ||
86 | return status; | |
87 | } |