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