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