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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * i2c-boardinfo.c - collect pre-declarations of I2C devices4 */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 */19DECLARE_RWSEM(__i2c_board_lock);20EXPORT_SYMBOL_GPL(__i2c_board_lock);21 22LIST_HEAD(__i2c_board_list);23EXPORT_SYMBOL_GPL(__i2c_board_list);24 25int __i2c_first_dynamic_bus_num;26EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num);27 28 29/**30 * i2c_register_board_info - statically declare I2C devices31 * @busnum: identifies the bus to which these devices belong32 * @info: vector of i2c device descriptors33 * @len: how many descriptors in the vector; may be zero to reserve34 * the specified bus number.35 *36 * Systems using the Linux I2C driver stack can declare tables of board info37 * while they initialize. This should be done in board-specific init code38 * near arch_initcall() time, or equivalent, before any I2C adapter driver is39 * 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 relevant43 * bus has been registered. After that moment, standard driver model tools44 * are used to bind "new style" I2C drivers to the devices. The bus number45 * for any device declared using this routine is not available for dynamic46 * allocation.47 *48 * The board info passed can safely be __initdata, but be careful of embedded49 * pointers (for platform_data, functions, etc) since that won't be copied.50 */51int 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