| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 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 | */ |
| 27 | DECLARE_RWSEM(__i2c_board_lock); |
| 28 | EXPORT_SYMBOL_GPL(__i2c_board_lock); |
| 29 | |
| 30 | LIST_HEAD(__i2c_board_list); |
| 31 | EXPORT_SYMBOL_GPL(__i2c_board_list); |
| 32 | |
| 33 | int __i2c_first_dynamic_bus_num; |
| 34 | EXPORT_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 | */ |
| 59 | int __init |
| 60 | i2c_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 | } |