1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * i2c-boardinfo.c - collect pre-declarations of I2C devices 4 */ 5 6 #include <linux/export.h> 7 #include <linux/i2c.h> 8 #include <linux/kernel.h> 9 #include <linux/property.h> 10 #include <linux/rwsem.h> 11 #include <linux/slab.h> 12 13 #include "i2c-core.h" 14 15 16 /* These symbols are exported ONLY FOR the i2c core. 17 * No other users will be supported. 18 */ 19 DECLARE_RWSEM(__i2c_board_lock); 20 EXPORT_SYMBOL_GPL(__i2c_board_lock); 21 22 LIST_HEAD(__i2c_board_list); 23 EXPORT_SYMBOL_GPL(__i2c_board_list); 24 25 int __i2c_first_dynamic_bus_num; 26 EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num); 27 28 29 /** 30 * i2c_register_board_info - statically declare I2C devices 31 * @busnum: identifies the bus to which these devices belong 32 * @info: vector of i2c device descriptors 33 * @len: how many descriptors in the vector; may be zero to reserve 34 * the specified bus number. 35 * 36 * Systems using the Linux I2C driver stack can declare tables of board info 37 * while they initialize. This should be done in board-specific init code 38 * near arch_initcall() time, or equivalent, before any I2C adapter driver is 39 * registered. For example, mainboard init code could define several devices, 40 * as could the init code for each daughtercard in a board stack. 41 * 42 * The I2C devices will be created later, after the adapter for the relevant 43 * bus has been registered. After that moment, standard driver model tools 44 * are used to bind "new style" I2C drivers to the devices. The bus number 45 * for any device declared using this routine is not available for dynamic 46 * allocation. 47 * 48 * The board info passed can safely be __initdata, but be careful of embedded 49 * pointers (for platform_data, functions, etc) since that won't be copied. 50 */ 51 int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len) 52 { 53 int status; 54 55 down_write(&__i2c_board_lock); 56 57 /* dynamic bus numbers will be assigned after the last static one */ 58 if (busnum >= __i2c_first_dynamic_bus_num) 59 __i2c_first_dynamic_bus_num = busnum + 1; 60 61 for (status = 0; len; len--, info++) { 62 struct i2c_devinfo *devinfo; 63 64 devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL); 65 if (!devinfo) { 66 pr_debug("i2c-core: can't register boardinfo!\n"); 67 status = -ENOMEM; 68 break; 69 } 70 71 devinfo->busnum = busnum; 72 devinfo->board_info = *info; 73 74 if (info->resources) { 75 devinfo->board_info.resources = 76 kmemdup(info->resources, 77 info->num_resources * 78 sizeof(*info->resources), 79 GFP_KERNEL); 80 if (!devinfo->board_info.resources) { 81 status = -ENOMEM; 82 kfree(devinfo); 83 break; 84 } 85 } 86 87 list_add_tail(&devinfo->list, &__i2c_board_list); 88 } 89 90 up_write(&__i2c_board_lock); 91 92 return status; 93 } 94