linux/drivers/i2c/i2c-boardinfo.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * i2c-boardinfo.c - collect pre-declarations of I2C devices
 */

#include <linux/export.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/property.h>
#include <linux/rwsem.h>
#include <linux/slab.h>

#include "i2c-core.h"


/* These symbols are exported ONLY FOR the i2c core.
 * No other users will be supported.
 */
DECLARE_RWSEM(…) …;
EXPORT_SYMBOL_GPL(…);

LIST_HEAD(…);
EXPORT_SYMBOL_GPL(…);

int __i2c_first_dynamic_bus_num;
EXPORT_SYMBOL_GPL(…);


/**
 * i2c_register_board_info - statically declare I2C devices
 * @busnum: identifies the bus to which these devices belong
 * @info: vector of i2c device descriptors
 * @len: how many descriptors in the vector; may be zero to reserve
 *	the specified bus number.
 *
 * Systems using the Linux I2C driver stack can declare tables of board info
 * while they initialize.  This should be done in board-specific init code
 * near arch_initcall() time, or equivalent, before any I2C adapter driver is
 * registered.  For example, mainboard init code could define several devices,
 * as could the init code for each daughtercard in a board stack.
 *
 * The I2C devices will be created later, after the adapter for the relevant
 * bus has been registered.  After that moment, standard driver model tools
 * are used to bind "new style" I2C drivers to the devices.  The bus number
 * for any device declared using this routine is not available for dynamic
 * allocation.
 *
 * The board info passed can safely be __initdata, but be careful of embedded
 * pointers (for platform_data, functions, etc) since that won't be copied.
 */
int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len)
{ … }