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 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 #include <linux/kernel.h>
20 #include <linux/i2c.h>
21 #include <linux/slab.h>
22 #include <linux/rwsem.h>
23
24 #include "i2c-core.h"
25
26
27 /* These symbols are exported ONLY FOR the i2c core.
28 * No other users will be supported.
29 */
30 DECLARE_RWSEM(__i2c_board_lock);
31 EXPORT_SYMBOL_GPL(__i2c_board_lock);
32
33 LIST_HEAD(__i2c_board_list);
34 EXPORT_SYMBOL_GPL(__i2c_board_list);
35
36 int __i2c_first_dynamic_bus_num;
37 EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num);
38
39
40 /**
41 * i2c_register_board_info - statically declare I2C devices
42 * @busnum: identifies the bus to which these devices belong
43 * @info: vector of i2c device descriptors
44 * @len: how many descriptors in the vector; may be zero to reserve
45 * the specified bus number.
46 *
47 * Systems using the Linux I2C driver stack can declare tables of board info
48 * while they initialize. This should be done in board-specific init code
49 * near arch_initcall() time, or equivalent, before any I2C adapter driver is
50 * registered. For example, mainboard init code could define several devices,
51 * as could the init code for each daughtercard in a board stack.
52 *
53 * The I2C devices will be created later, after the adapter for the relevant
54 * bus has been registered. After that moment, standard driver model tools
55 * are used to bind "new style" I2C drivers to the devices. The bus number
56 * for any device declared using this routine is not available for dynamic
57 * allocation.
58 *
59 * The board info passed can safely be __initdata, but be careful of embedded
60 * pointers (for platform_data, functions, etc) since that won't be copied.
61 */
62 int __init
i2c_register_board_info(int busnum,struct i2c_board_info const * info,unsigned len)63 i2c_register_board_info(int busnum,
64 struct i2c_board_info const *info, unsigned len)
65 {
66 int status;
67
68 down_write(&__i2c_board_lock);
69
70 /* dynamic bus numbers will be assigned after the last static one */
71 if (busnum >= __i2c_first_dynamic_bus_num)
72 __i2c_first_dynamic_bus_num = busnum + 1;
73
74 for (status = 0; len; len--, info++) {
75 struct i2c_devinfo *devinfo;
76
77 devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL);
78 if (!devinfo) {
79 pr_debug("i2c-core: can't register boardinfo!\n");
80 status = -ENOMEM;
81 break;
82 }
83
84 devinfo->busnum = busnum;
85 devinfo->board_info = *info;
86 list_add_tail(&devinfo->list, &__i2c_board_list);
87 }
88
89 up_write(&__i2c_board_lock);
90
91 return status;
92 }
93