LXR linux/drivers/i2c/i2c-boardinfo.c

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