Line data    Source code

       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           0 : int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len)
      52             : {
      53             :         int status;
      54             : 
      55           0 :         down_write(&__i2c_board_lock);
      56             : 
      57             :         /* dynamic bus numbers will be assigned after the last static one */
      58           0 :         if (busnum >= __i2c_first_dynamic_bus_num)
      59           0 :                 __i2c_first_dynamic_bus_num = busnum + 1;
      60             : 
      61           0 :         for (status = 0; len; len--, info++) {
      62             :                 struct i2c_devinfo      *devinfo;
      63             : 
      64           0 :                 devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL);
      65           0 :                 if (!devinfo) {
      66             :                         pr_debug("i2c-core: can't register boardinfo!\n");
      67             :                         status = -ENOMEM;
      68             :                         break;
      69             :                 }
      70             : 
      71           0 :                 devinfo->busnum = busnum;
      72           0 :                 devinfo->board_info = *info;
      73             : 
      74           0 :                 if (info->resources) {
      75           0 :                         devinfo->board_info.resources =
      76           0 :                                 kmemdup(info->resources,
      77           0 :                                         info->num_resources *
      78             :                                                 sizeof(*info->resources),
      79             :                                         GFP_KERNEL);
      80           0 :                         if (!devinfo->board_info.resources) {
      81           0 :                                 status = -ENOMEM;
      82           0 :                                 kfree(devinfo);
      83           0 :                                 break;
      84             :                         }
      85             :                 }
      86             : 
      87           0 :                 list_add_tail(&devinfo->list, &__i2c_board_list);
      88             :         }
      89             : 
      90           0 :         up_write(&__i2c_board_lock);
      91             : 
      92           0 :         return status;
      93             : }