drivers/acpi/acpi_i2c.c

   1 /*
   2  * ACPI I2C enumeration support
   3  *
   4  * Copyright (C) 2012, Intel Corporation
   5  * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/acpi.h>
  13 #include <linux/device.h>
  14 #include <linux/export.h>
  15 #include <linux/i2c.h>
  16 #include <linux/ioport.h>
  17
  18 ACPI_MODULE_NAME("i2c");
  19
  20 static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
  21 {
  22         struct i2c_board_info *info = data;
  23
  24         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
  25                 struct acpi_resource_i2c_serialbus *sb;
  26
  27                 sb = &ares->data.i2c_serial_bus;
  28                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
  29                         info->addr = sb->slave_address;
  30                         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
  31                                 info->flags |= I2C_CLIENT_TEN;
  32                 }
  33         } else if (info->irq < 0) {
  34                 struct resource r;
  35
  36                 if (acpi_dev_resource_interrupt(ares, 0, &r))
  37                         info->irq = r.start;
  38         }
  39
  40         /* Tell the ACPI core to skip this resource */
  41         return 1;
  42 }
  43
  44 static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
  45                                        void *data, void **return_value)
  46 {
  47         struct i2c_adapter *adapter = data;
  48         struct list_head resource_list;
  49         struct i2c_board_info info;
  50         struct acpi_device *adev;
  51         int ret;
  52
  53         if (acpi_bus_get_device(handle, &adev))
  54                 return AE_OK;
  55         if (acpi_bus_get_status(adev) || !adev->status.present)
  56                 return AE_OK;
  57
  58         memset(&info, 0, sizeof(info));
  59         info.acpi_node.handle = handle;
  60         info.irq = -1;
  61
  62         INIT_LIST_HEAD(&resource_list);
  63         ret = acpi_dev_get_resources(adev, &resource_list,
  64                                      acpi_i2c_add_resource, &info);
  65         acpi_dev_free_resource_list(&resource_list);
  66
  67         if (ret < 0 || !info.addr)
  68                 return AE_OK;
  69
  70         strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
  71         if (!i2c_new_device(adapter, &info)) {
  72                 dev_err(&adapter->dev,
  73                         "failed to add I2C device %s from ACPI\n",
  74                         dev_name(&adev->dev));
  75         }
  76
  77         return AE_OK;
  78 }
  79
  80 /**
  81  * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
  82  * @adapter: pointer to adapter
  83  *
  84  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
  85  * namespace. When a device is found it will be added to the Linux device
  86  * model and bound to the corresponding ACPI handle.
  87  */
  88 void acpi_i2c_register_devices(struct i2c_adapter *adapter)
  89 {
  90         acpi_handle handle;
  91         acpi_status status;
  92
  93         handle = ACPI_HANDLE(adapter->dev.parent);
  94         if (!handle)
  95                 return;
  96
  97         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
  98                                      acpi_i2c_add_device, NULL,
  99                                      adapter, NULL);
 100         if (ACPI_FAILURE(status))
 101                 dev_warn(&adapter->dev, "failed to enumerate I2C slaves\n");
 102 }
 103 EXPORT_SYMBOL_GPL(acpi_i2c_register_devices);