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_END },
  41 };
  42
  43 struct intel_vbtn_priv {
  44         struct input_dev *input_dev;
  45 };
  46
  47 static 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 = input_allocate_device();
  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                 goto err_free_device;
  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         ret = input_register_device(priv->input_dev);
  65         if (ret)
  66                 goto err_free_device;
  67
  68         return 0;
  69
  70 err_free_device:
  71         input_free_device(priv->input_dev);
  72         return ret;
  73 }
  74
  75 static void intel_vbtn_input_destroy(struct platform_device *device)
  76 {
  77         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  78
  79         input_unregister_device(priv->input_dev);
  80 }
  81
  82 static void notify_handler(acpi_handle handle, u32 event, void *context)
  83 {
  84         struct platform_device *device = context;
  85         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  86
  87         if (!sparse_keymap_report_event(priv->input_dev, event, 1, true))
  88                 dev_info(&device->dev, "unknown event index 0x%x\n",
  89                          event);
  90 }
  91
  92 static int intel_vbtn_probe(struct platform_device *device)
  93 {
  94         acpi_handle handle = ACPI_HANDLE(&device->dev);
  95         struct intel_vbtn_priv *priv;
  96         acpi_status status;
  97         int err;
  98
  99         status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
 100         if (!ACPI_SUCCESS(status)) {
 101                 dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
 102                 return -ENODEV;
 103         }
 104
 105         priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
 106         if (!priv)
 107                 return -ENOMEM;
 108         dev_set_drvdata(&device->dev, priv);
 109
 110         err = intel_vbtn_input_setup(device);
 111         if (err) {
 112                 pr_err("Failed to setup Intel Virtual Button\n");
 113                 return err;
 114         }
 115
 116         status = acpi_install_notify_handler(handle,
 117                                              ACPI_DEVICE_NOTIFY,
 118                                              notify_handler,
 119                                              device);
 120         if (ACPI_FAILURE(status)) {
 121                 err = -EBUSY;
 122                 goto err_remove_input;
 123         }
 124
 125         return 0;
 126
 127 err_remove_input:
 128         intel_vbtn_input_destroy(device);
 129
 130         return err;
 131 }
 132
 133 static int intel_vbtn_remove(struct platform_device *device)
 134 {
 135         acpi_handle handle = ACPI_HANDLE(&device->dev);
 136
 137         intel_vbtn_input_destroy(device);
 138         acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
 139
 140         /*
 141          * Even if we failed to shut off the event stream, we can still
 142          * safely detach from the device.
 143          */
 144         return 0;
 145 }
 146
 147 static struct platform_driver intel_vbtn_pl_driver = {
 148         .driver = {
 149                 .name = "intel-vbtn",
 150                 .acpi_match_table = intel_vbtn_ids,
 151         },
 152         .probe = intel_vbtn_probe,
 153         .remove = intel_vbtn_remove,
 154 };
 155 MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
 156
 157 static acpi_status __init
 158 check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
 159 {
 160         const struct acpi_device_id *ids = context;
 161         struct acpi_device *dev;
 162
 163         if (acpi_bus_get_device(handle, &dev) != 0)
 164                 return AE_OK;
 165
 166         if (acpi_match_device_ids(dev, ids) == 0)
 167                 if (acpi_create_platform_device(dev))
 168                         dev_info(&dev->dev,
 169                                  "intel-vbtn: created platform device\n");
 170
 171         return AE_OK;
 172 }
 173
 174 static int __init intel_vbtn_init(void)
 175 {
 176         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 177                             ACPI_UINT32_MAX, check_acpi_dev, NULL,
 178                             (void *)intel_vbtn_ids, NULL);
 179
 180         return platform_driver_register(&intel_vbtn_pl_driver);
 181 }
 182 module_init(intel_vbtn_init);
 183
 184 static void __exit intel_vbtn_exit(void)
 185 {
 186         platform_driver_unregister(&intel_vbtn_pl_driver);
 187 }
 188 module_exit(intel_vbtn_exit);