1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * i2c-boardinfo.c - collect pre-declarations of I2C devices
4 */
5
6 #include <linux/export.h>
7 #include <linux/i2c.h>
8 #include <linux/kernel.h>
9 #include <linux/property.h>
10 #include <linux/rwsem.h>
11 #include <linux/slab.h>
12
13 #include "i2c-core.h"
14
15
16 /* These symbols are exported ONLY FOR the i2c core.
17 * No other users will be supported.
18 */
19 DECLARE_RWSEM(__i2c_board_lock);
20 EXPORT_SYMBOL_GPL(__i2c_board_lock);
21
22 LIST_HEAD(__i2c_board_list);
23 EXPORT_SYMBOL_GPL(__i2c_board_list);
24
25 int __i2c_first_dynamic_bus_num;
26 EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num);
27
28
29 /**
30 * i2c_register_board_info - statically declare I2C devices
31 * @busnum: identifies the bus to which these devices belong
32 * @info: vector of i2c device descriptors
33 * @len: how many descriptors in the vector; may be zero to reserve
34 * the specified bus number.
35 *
36 * Systems using the Linux I2C driver stack can declare tables of board info
37 * while they initialize. This should be done in board-specific init code
38 * near arch_initcall() time, or equivalent, before any I2C adapter driver is
39 * registered. For example, mainboard init code could define several devices,
40 * as could the init code for each daughtercard in a board stack.
41 *
42 * The I2C devices will be created later, after the adapter for the relevant
43 * bus has been registered. After that moment, standard driver model tools
44 * are used to bind "new style" I2C drivers to the devices. The bus number
45 * for any device declared using this routine is not available for dynamic
46 * allocation.
47 *
48 * The board info passed can safely be __initdata, but be careful of embedded
49 * pointers (for platform_data, functions, etc) since that won't be copied.
50 * Device properties are deep-copied though.
51 */
52 int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len)
53 {
54 int status;
55
56 down_write(&__i2c_board_lock);
57
58 /* dynamic bus numbers will be assigned after the last static one */
59 if (busnum >= __i2c_first_dynamic_bus_num)
60 __i2c_first_dynamic_bus_num = busnum + 1;
61
62 for (status = 0; len; len--, info++) {
63 struct i2c_devinfo *devinfo;
64
65 devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL);
66 if (!devinfo) {
67 pr_debug("i2c-core: can't register boardinfo!\n");
68 status = -ENOMEM;
69 break;
70 }
71
72 devinfo->busnum = busnum;
73 devinfo->board_info = *info;
74
75 if (info->properties) {
76 devinfo->board_info.properties =
77 property_entries_dup(info->properties);
78 if (IS_ERR(devinfo->board_info.properties)) {
79 status = PTR_ERR(devinfo->board_info.properties);
80 kfree(devinfo);
81 break;
82 }
83 }
84
85 if (info->resources) {
86 devinfo->board_info.resources =
87 kmemdup(info->resources,
88 info->num_resources *
89 sizeof(*info->resources),
90 GFP_KERNEL);
91 if (!devinfo->board_info.resources) {
92 status = -ENOMEM;
93 kfree(devinfo);
94 break;
95 }
96 }
97
98 list_add_tail(&devinfo->list, &__i2c_board_list);
99 }
100
101 up_write(&__i2c_board_lock);
102
103 return status;
104 }