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 } 90