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
  28 MODULE_LICENSE("GPL");
  29 MODULE_AUTHOR("AceLan Kao");
  30
  31 static const struct acpi_device_id intel_vbtn_ids[] = {
  32         {"INT33D6", 0},
  33         {"", 0},
  34 };
  35
  36 /* In theory, these are HID usages. */
  37 static 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_KEY, 0xC4, { KEY_VOLUMEUP } },             /* volume-up key press */
  41         { KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },          /* volume-up key release */
  42         { KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },           /* volume-down key press */
  43         { KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },        /* volume-down key release */
  44         { KE_END },
  45 };
  46
  47 struct intel_vbtn_priv {
  48         struct input_dev *input_dev;
  49 };
  50
  51 static int intel_vbtn_input_setup(struct platform_device *device)
  52 {
  53         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  54         int ret;
  55
  56         priv->input_dev = input_allocate_device();
  57         if (!priv->input_dev)
  58                 return -ENOMEM;
  59
  60         ret = sparse_keymap_setup(priv->input_dev, intel_vbtn_keymap, NULL);
  61         if (ret)
  62                 goto err_free_device;
  63
  64         priv->input_dev->dev.parent = &device->dev;
  65         priv->input_dev->name = "Intel Virtual Button driver";
  66         priv->input_dev->id.bustype = BUS_HOST;
  67
  68         ret = input_register_device(priv->input_dev);
  69         if (ret)
  70                 goto err_free_device;
  71
  72         return 0;
  73
  74 err_free_device:
  75         input_free_device(priv->input_dev);
  76         return ret;
  77 }
  78
  79 static void intel_vbtn_input_destroy(struct platform_device *device)
  80 {
  81         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  82
  83         input_unregister_device(priv->input_dev);
  84 }
  85
  86 static void notify_handler(acpi_handle handle, u32 event, void *context)
  87 {
  88         struct platform_device *device = context;
  89         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  90
  91         if (!sparse_keymap_report_event(priv->input_dev, event, 1, true))
  92                 dev_info(&device->dev, "unknown event index 0x%x\n",
  93                          event);
  94 }
  95
  96 static int intel_vbtn_probe(struct platform_device *device)
  97 {
  98         acpi_handle handle = ACPI_HANDLE(&device->dev);
  99         struct intel_vbtn_priv *priv;
 100         acpi_status status;
 101         int err;
 102
 103         status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
 104         if (!ACPI_SUCCESS(status)) {
 105                 dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
 106                 return -ENODEV;
 107         }
 108
 109         priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
 110         if (!priv)
 111                 return -ENOMEM;
 112         dev_set_drvdata(&device->dev, priv);
 113
 114         err = intel_vbtn_input_setup(device);
 115         if (err) {
 116                 pr_err("Failed to setup Intel Virtual Button\n");
 117                 return err;
 118         }
 119
 120         status = acpi_install_notify_handler(handle,
 121                                              ACPI_DEVICE_NOTIFY,
 122                                              notify_handler,
 123                                              device);
 124         if (ACPI_FAILURE(status)) {
 125                 err = -EBUSY;
 126                 goto err_remove_input;
 127         }
 128
 129         return 0;
 130
 131 err_remove_input:
 132         intel_vbtn_input_destroy(device);
 133
 134         return err;
 135 }
 136
 137 static int intel_vbtn_remove(struct platform_device *device)
 138 {
 139         acpi_handle handle = ACPI_HANDLE(&device->dev);
 140
 141         intel_vbtn_input_destroy(device);
 142         acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
 143
 144         /*
 145          * Even if we failed to shut off the event stream, we can still
 146          * safely detach from the device.
 147          */
 148         return 0;
 149 }
 150
 151 static struct platform_driver intel_vbtn_pl_driver = {
 152         .driver = {
 153                 .name = "intel-vbtn",
 154                 .acpi_match_table = intel_vbtn_ids,
 155         },
 156         .probe = intel_vbtn_probe,
 157         .remove = intel_vbtn_remove,
 158 };
 159 MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
 160
 161 static acpi_status __init
 162 check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
 163 {
 164         const struct acpi_device_id *ids = context;
 165         struct acpi_device *dev;
 166
 167         if (acpi_bus_get_device(handle, &dev) != 0)
 168                 return AE_OK;
 169
 170         if (acpi_match_device_ids(dev, ids) == 0)
 171                 if (!IS_ERR_OR_NULL(acpi_create_platform_device(dev, NULL)))
 172                         dev_info(&dev->dev,
 173                                  "intel-vbtn: created platform device\n");
 174
 175         return AE_OK;
 176 }
 177
 178 static int __init intel_vbtn_init(void)
 179 {
 180         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 181                             ACPI_UINT32_MAX, check_acpi_dev, NULL,
 182                             (void *)intel_vbtn_ids, NULL);
 183
 184         return platform_driver_register(&intel_vbtn_pl_driver);
 185 }
 186 module_init(intel_vbtn_init);
 187
 188 static void __exit intel_vbtn_exit(void)
 189 {
 190         platform_driver_unregister(&intel_vbtn_pl_driver);
 191 }
 192 module_exit(intel_vbtn_exit);