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drivers/i2c/i2c-boardinfo.c
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/*
* i2c-boardinfo.c - collect pre-declarations of I2C devices
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#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(__i2c_board_lock);
EXPORT_SYMBOL_GPL(__i2c_board_lock);
LIST_HEAD(__i2c_board_list);
EXPORT_SYMBOL_GPL(__i2c_board_list);
int __i2c_first_dynamic_bus_num;
EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num);
/**
* 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.
* Device properties are deep-copied though.
*/
int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len)
{
int status;
down_write(&__i2c_board_lock);
/* dynamic bus numbers will be assigned after the last static one */
if (busnum >= __i2c_first_dynamic_bus_num)
__i2c_first_dynamic_bus_num = busnum + 1;
for (status = 0; len; len--, info++) {
struct i2c_devinfo *devinfo;
devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL);
if (!devinfo) {
pr_debug("i2c-core: can't register boardinfo!
");
status = -ENOMEM;
break;
}
devinfo->busnum = busnum;
devinfo->board_info = *info;
if (info->properties) {
devinfo->board_info.properties =
property_entries_dup(info->properties);
if (IS_ERR(devinfo->board_info.properties)) {
status = PTR_ERR(devinfo->board_info.properties);
kfree(devinfo);
break;
}
}
if (info->resources) {
devinfo->board_info.resources =
kmemdup(info->resources,
info->num_resources *
sizeof(*info->resources),
GFP_KERNEL);
if (!devinfo->board_info.resources) {
status = -ENOMEM;
kfree(devinfo);
break;
}
}
list_add_tail(&devinfo->list, &__i2c_board_list);
}
up_write(&__i2c_board_lock);
return status;
}
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