blob: 90e32295930332ec9fa92fd9f9ab153ee9b6e840 [file] [log] [blame]
David Brownell9c1600e2007-05-01 23:26:31 +02001/*
Wolfram Sang950a5092011-03-20 14:50:52 +01002 * i2c-boardinfo.c - collect pre-declarations of I2C devices
David Brownell9c1600e2007-05-01 23:26:31 +02003 *
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.
David Brownell9c1600e2007-05-01 23:26:31 +020013 */
14
15#include <linux/kernel.h>
16#include <linux/i2c.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090017#include <linux/slab.h>
Paul Gortmaker345df512011-05-27 10:46:24 -040018#include <linux/export.h>
Rodolfo Giomettif18c41d2009-06-19 16:58:20 +020019#include <linux/rwsem.h>
David Brownell9c1600e2007-05-01 23:26:31 +020020
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 */
Rodolfo Giomettif18c41d2009-06-19 16:58:20 +020027DECLARE_RWSEM(__i2c_board_lock);
David Brownell9c1600e2007-05-01 23:26:31 +020028EXPORT_SYMBOL_GPL(__i2c_board_lock);
29
30LIST_HEAD(__i2c_board_list);
31EXPORT_SYMBOL_GPL(__i2c_board_list);
32
33int __i2c_first_dynamic_bus_num;
34EXPORT_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 */
59int __init
60i2c_register_board_info(int busnum,
61 struct i2c_board_info const *info, unsigned len)
62{
63 int status;
64
Rodolfo Giomettif18c41d2009-06-19 16:58:20 +020065 down_write(&__i2c_board_lock);
David Brownell9c1600e2007-05-01 23:26:31 +020066
67 /* dynamic bus numbers will be assigned after the last static one */
68 if (busnum >= __i2c_first_dynamic_bus_num)
69 __i2c_first_dynamic_bus_num = busnum + 1;
70
71 for (status = 0; len; len--, info++) {
72 struct i2c_devinfo *devinfo;
73
74 devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL);
75 if (!devinfo) {
76 pr_debug("i2c-core: can't register boardinfo!\n");
77 status = -ENOMEM;
78 break;
79 }
80
81 devinfo->busnum = busnum;
82 devinfo->board_info = *info;
83 list_add_tail(&devinfo->list, &__i2c_board_list);
84 }
85
Rodolfo Giomettif18c41d2009-06-19 16:58:20 +020086 up_write(&__i2c_board_lock);
David Brownell9c1600e2007-05-01 23:26:31 +020087
88 return status;
89}