Branch data     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                 :            :  * Device properties are deep-copied though.
      51                 :            :  */
      52                 :          0 : int i2c_register_board_info(int busnum, struct i2c_board_info const *info, unsigned len)
      53                 :            : {
      54                 :          0 :         int status;
      55                 :            : 
      56                 :          0 :         down_write(&__i2c_board_lock);
      57                 :            : 
      58                 :            :         /* dynamic bus numbers will be assigned after the last static one */
      59         [ #  # ]:          0 :         if (busnum >= __i2c_first_dynamic_bus_num)
      60                 :          0 :                 __i2c_first_dynamic_bus_num = busnum + 1;
      61                 :            : 
      62         [ #  # ]:          0 :         for (status = 0; len; len--, info++) {
      63                 :          0 :                 struct i2c_devinfo      *devinfo;
      64                 :            : 
      65                 :          0 :                 devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL);
      66         [ #  # ]:          0 :                 if (!devinfo) {
      67                 :            :                         pr_debug("i2c-core: can't register boardinfo!\n");
      68                 :            :                         status = -ENOMEM;
      69                 :            :                         break;
      70                 :            :                 }
      71                 :            : 
      72                 :          0 :                 devinfo->busnum = busnum;
      73                 :          0 :                 devinfo->board_info = *info;
      74                 :            : 
      75         [ #  # ]:          0 :                 if (info->properties) {
      76                 :          0 :                         devinfo->board_info.properties =
      77                 :          0 :                                         property_entries_dup(info->properties);
      78         [ #  # ]:          0 :                         if (IS_ERR(devinfo->board_info.properties)) {
      79                 :          0 :                                 status = PTR_ERR(devinfo->board_info.properties);
      80                 :          0 :                                 kfree(devinfo);
      81                 :          0 :                                 break;
      82                 :            :                         }
      83                 :            :                 }
      84                 :            : 
      85         [ #  # ]:          0 :                 if (info->resources) {
      86                 :          0 :                         devinfo->board_info.resources =
      87                 :          0 :                                 kmemdup(info->resources,
      88                 :          0 :                                         info->num_resources *
      89                 :            :                                                 sizeof(*info->resources),
      90                 :            :                                         GFP_KERNEL);
      91         [ #  # ]:          0 :                         if (!devinfo->board_info.resources) {
      92                 :          0 :                                 status = -ENOMEM;
      93                 :          0 :                                 kfree(devinfo);
      94                 :          0 :                                 break;
      95                 :            :                         }
      96                 :            :                 }
      97                 :            : 
      98                 :          0 :                 list_add_tail(&devinfo->list, &__i2c_board_list);
      99                 :            :         }
     100                 :            : 
     101                 :          0 :         up_write(&__i2c_board_lock);
     102                 :            : 
     103                 :          0 :         return status;
     104                 :            : }