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