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