LXR linux/drivers/platform/x86/intel-vbtn.c

   1/*
   2 *  Intel Virtual Button driver for Windows 8.1+
   3 *
   4 *  Copyright (C) 2016 AceLan Kao <acelan.kao@canonical.com>
   5 *  Copyright (C) 2016 Alex Hung <alex.hung@canonical.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 as published by
   9 *  the Free Software Foundation; either version 2 of the License, or
  10 *  (at your option) any later version.
  11 *
  12 *  This program is distributed in the hope that it will be useful,
  13 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 *  GNU General Public License for more details.
  16 *
  17 */
  18
  19#include <linux/kernel.h>
  20#include <linux/module.h>
  21#include <linux/init.h>
  22#include <linux/input.h>
  23#include <linux/platform_device.h>
  24#include <linux/input/sparse-keymap.h>
  25#include <linux/acpi.h>
  26#include <acpi/acpi_bus.h>
  27
  28MODULE_LICENSE("GPL");
  29MODULE_AUTHOR("AceLan Kao");
  30
  31static const struct acpi_device_id intel_vbtn_ids[] = {
  32        {"INT33D6", 0},
  33        {"", 0},
  34};
  35
  36/* In theory, these are HID usages. */
  37static const struct key_entry intel_vbtn_keymap[] = {
  38        { KE_IGNORE, 0xC0, { KEY_POWER } },     /* power key press */
  39        { KE_KEY, 0xC1, { KEY_POWER } },        /* power key release */
  40        { KE_END },
  41};
  42
  43struct intel_vbtn_priv {
  44        struct input_dev *input_dev;
  45};
  46
  47static int intel_vbtn_input_setup(struct platform_device *device)
  48{
  49        struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  50        int ret;
  51
  52        priv->input_dev = devm_input_allocate_device(&device->dev);
  53        if (!priv->input_dev)
  54                return -ENOMEM;
  55
  56        ret = sparse_keymap_setup(priv->input_dev, intel_vbtn_keymap, NULL);
  57        if (ret)
  58                return ret;
  59
  60        priv->input_dev->dev.parent = &device->dev;
  61        priv->input_dev->name = "Intel Virtual Button driver";
  62        priv->input_dev->id.bustype = BUS_HOST;
  63
  64        return input_register_device(priv->input_dev);
  65}
  66
  67static void notify_handler(acpi_handle handle, u32 event, void *context)
  68{
  69        struct platform_device *device = context;
  70        struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  71
  72        if (!sparse_keymap_report_event(priv->input_dev, event, 1, true))
  73                dev_info(&device->dev, "unknown event index 0x%x\n",
  74                         event);
  75}
  76
  77static int intel_vbtn_probe(struct platform_device *device)
  78{
  79        acpi_handle handle = ACPI_HANDLE(&device->dev);
  80        struct intel_vbtn_priv *priv;
  81        acpi_status status;
  82        int err;
  83
  84        status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
  85        if (ACPI_FAILURE(status)) {
  86                dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
  87                return -ENODEV;
  88        }
  89
  90        priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
  91        if (!priv)
  92                return -ENOMEM;
  93        dev_set_drvdata(&device->dev, priv);
  94
  95        err = intel_vbtn_input_setup(device);
  96        if (err) {
  97                pr_err("Failed to setup Intel Virtual Button\n");
  98                return err;
  99        }
 100
 101        status = acpi_install_notify_handler(handle,
 102                                             ACPI_DEVICE_NOTIFY,
 103                                             notify_handler,
 104                                             device);
 105        if (ACPI_FAILURE(status))
 106                return -EBUSY;
 107
 108        return 0;
 109}
 110
 111static int intel_vbtn_remove(struct platform_device *device)
 112{
 113        acpi_handle handle = ACPI_HANDLE(&device->dev);
 114
 115        acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
 116
 117        /*
 118         * Even if we failed to shut off the event stream, we can still
 119         * safely detach from the device.
 120         */
 121        return 0;
 122}
 123
 124static struct platform_driver intel_vbtn_pl_driver = {
 125        .driver = {
 126                .name = "intel-vbtn",
 127                .acpi_match_table = intel_vbtn_ids,
 128        },
 129        .probe = intel_vbtn_probe,
 130        .remove = intel_vbtn_remove,
 131};
 132MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
 133
 134static acpi_status __init
 135check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
 136{
 137        const struct acpi_device_id *ids = context;
 138        struct acpi_device *dev;
 139
 140        if (acpi_bus_get_device(handle, &dev) != 0)
 141                return AE_OK;
 142
 143        if (acpi_match_device_ids(dev, ids) == 0)
 144                if (acpi_create_platform_device(dev, NULL))
 145                        dev_info(&dev->dev,
 146                                 "intel-vbtn: created platform device\n");
 147
 148        return AE_OK;
 149}
 150
 151static int __init intel_vbtn_init(void)
 152{
 153        acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 154                            ACPI_UINT32_MAX, check_acpi_dev, NULL,
 155                            (void *)intel_vbtn_ids, NULL);
 156
 157        return platform_driver_register(&intel_vbtn_pl_driver);
 158}
 159module_init(intel_vbtn_init);
 160
 161static void __exit intel_vbtn_exit(void)
 162{
 163        platform_driver_unregister(&intel_vbtn_pl_driver);
 164}
 165module_exit(intel_vbtn_exit);
 166