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 * 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., 51 Franklin Street, Fifth Floor, Boston, 17 * MA 02110-1301 USA. 18 */ 19 20 #include <linux/kernel.h> 21 #include <linux/i2c.h> 22 #include <linux/slab.h> 23 #include <linux/export.h> 24 #include <linux/rwsem.h> 25 26 #include "i2c-core.h" 27 28 29 /* These symbols are exported ONLY FOR the i2c core. 30 * No other users will be supported. 31 */ 32 DECLARE_RWSEM(__i2c_board_lock); 33 EXPORT_SYMBOL_GPL(__i2c_board_lock); 34 35 LIST_HEAD(__i2c_board_list); 36 EXPORT_SYMBOL_GPL(__i2c_board_list); 37 38 int __i2c_first_dynamic_bus_num; 39 EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num); 40 41 42 /** 43 * i2c_register_board_info - statically declare I2C devices 44 * @busnum: identifies the bus to which these devices belong 45 * @info: vector of i2c device descriptors 46 * @len: how many descriptors in the vector; may be zero to reserve 47 * the specified bus number. 48 * 49 * Systems using the Linux I2C driver stack can declare tables of board info 50 * while they initialize. This should be done in board-specific init code 51 * near arch_initcall() time, or equivalent, before any I2C adapter driver is 52 * registered. For example, mainboard init code could define several devices, 53 * as could the init code for each daughtercard in a board stack. 54 * 55 * The I2C devices will be created later, after the adapter for the relevant 56 * bus has been registered. After that moment, standard driver model tools 57 * are used to bind "new style" I2C drivers to the devices. The bus number 58 * for any device declared using this routine is not available for dynamic 59 * allocation. 60 * 61 * The board info passed can safely be __initdata, but be careful of embedded 62 * pointers (for platform_data, functions, etc) since that won't be copied. 63 */ 64 int __init 65 i2c_register_board_info(int busnum, 66 struct i2c_board_info const *info, unsigned len) 67 { 68 int status; 69 70 down_write(&__i2c_board_lock); 71 72 /* dynamic bus numbers will be assigned after the last static one */ 73 if (busnum >= __i2c_first_dynamic_bus_num) 74 __i2c_first_dynamic_bus_num = busnum + 1; 75 76 for (status = 0; len; len--, info++) { 77 struct i2c_devinfo *devinfo; 78 79 devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL); 80 if (!devinfo) { 81 pr_debug("i2c-core: can't register boardinfo!\n"); 82 status = -ENOMEM; 83 break; 84 } 85 86 devinfo->busnum = busnum; 87 devinfo->board_info = *info; 88 list_add_tail(&devinfo->list, &__i2c_board_list); 89 } 90 91 up_write(&__i2c_board_lock); 92 93 return status; 94 } 95