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/kernel.h>
16#include <linux/i2c.h>
17#include <linux/slab.h>
18#include <linux/export.h>
19#include <linux/rwsem.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 */
27DECLARE_RWSEM(__i2c_board_lock);
28EXPORT_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
65	down_write(&__i2c_board_lock);
66
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
86	up_write(&__i2c_board_lock);
87
88	return status;
89}
90