drivers/acpi/acpi_platform.c

   1 /*
   2  * ACPI support for platform bus type.
   3  *
   4  * Copyright (C) 2012, Intel Corporation
   5  * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
   6  *          Mathias Nyman <mathias.nyman@linux.intel.com>
   7  *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/acpi.h>
  15 #include <linux/device.h>
  16 #include <linux/err.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20
  21 #include "internal.h"
  22
  23 ACPI_MODULE_NAME("platform");
  24
  25 /*
  26  * The following ACPI IDs are known to be suitable for representing as
  27  * platform devices.
  28  */
  29 static const struct acpi_device_id acpi_platform_device_ids[] = {
  30
  31         { "PNP0D40" },
  32
  33         { }
  34 };
  35
  36 /**
  37  * acpi_create_platform_device - Create platform device for ACPI device node
  38  * @adev: ACPI device node to create a platform device for.
  39  * @id: ACPI device ID used to match @adev.
  40  *
  41  * Check if the given @adev can be represented as a platform device and, if
  42  * that's the case, create and register a platform device, populate its common
  43  * resources and returns a pointer to it.  Otherwise, return %NULL.
  44  *
  45  * Name of the platform device will be the same as @adev's.
  46  */
  47 int acpi_create_platform_device(struct acpi_device *adev,
  48                                 const struct acpi_device_id *id)
  49 {
  50         struct platform_device *pdev = NULL;
  51         struct acpi_device *acpi_parent;
  52         struct platform_device_info pdevinfo;
  53         struct resource_list_entry *rentry;
  54         struct list_head resource_list;
  55         struct resource *resources = NULL;
  56         int count;
  57
  58         /* If the ACPI node already has a physical device attached, skip it. */
  59         if (adev->physical_node_count)
  60                 return 0;
  61
  62         INIT_LIST_HEAD(&resource_list);
  63         count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
  64         if (count < 0) {
  65                 return 0;
  66         } else if (count > 0) {
  67                 resources = kmalloc(count * sizeof(struct resource),
  68                                     GFP_KERNEL);
  69                 if (!resources) {
  70                         dev_err(&adev->dev, "No memory for resources\n");
  71                         acpi_dev_free_resource_list(&resource_list);
  72                         return -ENOMEM;
  73                 }
  74                 count = 0;
  75                 list_for_each_entry(rentry, &resource_list, node)
  76                         resources[count++] = rentry->res;
  77
  78                 acpi_dev_free_resource_list(&resource_list);
  79         }
  80
  81         memset(&pdevinfo, 0, sizeof(pdevinfo));
  82         /*
  83          * If the ACPI node has a parent and that parent has a physical device
  84          * attached to it, that physical device should be the parent of the
  85          * platform device we are about to create.
  86          */
  87         pdevinfo.parent = NULL;
  88         acpi_parent = adev->parent;
  89         if (acpi_parent) {
  90                 struct acpi_device_physical_node *entry;
  91                 struct list_head *list;
  92
  93                 mutex_lock(&acpi_parent->physical_node_lock);
  94                 list = &acpi_parent->physical_node_list;
  95                 if (!list_empty(list)) {
  96                         entry = list_first_entry(list,
  97                                         struct acpi_device_physical_node,
  98                                         node);
  99                         pdevinfo.parent = entry->dev;
 100                 }
 101                 mutex_unlock(&acpi_parent->physical_node_lock);
 102         }
 103         pdevinfo.name = dev_name(&adev->dev);
 104         pdevinfo.id = -1;
 105         pdevinfo.res = resources;
 106         pdevinfo.num_res = count;
 107         pdevinfo.acpi_node.handle = adev->handle;
 108         pdev = platform_device_register_full(&pdevinfo);
 109         if (IS_ERR(pdev)) {
 110                 dev_err(&adev->dev, "platform device creation failed: %ld\n",
 111                         PTR_ERR(pdev));
 112                 pdev = NULL;
 113         } else {
 114                 dev_dbg(&adev->dev, "created platform device %s\n",
 115                         dev_name(&pdev->dev));
 116         }
 117
 118         kfree(resources);
 119         return 1;
 120 }
 121
 122 static struct acpi_scan_handler platform_handler = {
 123         .ids = acpi_platform_device_ids,
 124         .attach = acpi_create_platform_device,
 125 };
 126
 127 void __init acpi_platform_init(void)
 128 {
 129         acpi_scan_add_handler(&platform_handler);
 130 }