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 = 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
  67 static 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
  77 static 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
 111 static 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
 124 static 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 };
 132 MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
 133
 134 static acpi_status __init
 135 check_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
 151 static 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 }
 159 module_init(intel_vbtn_init);
 160
 161 static void __exit intel_vbtn_exit(void)
 162 {
 163         platform_driver_unregister(&intel_vbtn_pl_driver);
 164 }
 165 module_exit(intel_vbtn_exit);