linux/drivers/acpi/acpi_platform.c
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   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
  23ACPI_MODULE_NAME("platform");
  24
  25/*
  26 * The following ACPI IDs are known to be suitable for representing as
  27 * platform devices.
  28 */
  29static 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 */
  47int 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
 122static struct acpi_scan_handler platform_handler = {
 123        .ids = acpi_platform_device_ids,
 124        .attach = acpi_create_platform_device,
 125};
 126
 127void __init acpi_platform_init(void)
 128{
 129        acpi_scan_add_handler(&platform_handler);
 130}
 131
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