drivers/platform/x86/lenovo-wmi-camera.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Lenovo WMI Camera Button Driver
   4  *
   5  * Author: Ai Chao <aichao@kylinos.cn>
   6  * Copyright (C) 2024 KylinSoft Corporation.
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/device.h>
  11 #include <linux/input.h>
  12 #include <linux/types.h>
  13 #include <linux/module.h>
  14 #include <linux/mutex.h>
  15 #include <linux/wmi.h>
  16
  17 #define WMI_LENOVO_CAMERABUTTON_EVENT_GUID "50C76F1F-D8E4-D895-0A3D-62F4EA400013"
  18
  19 struct lenovo_wmi_priv {
  20         struct input_dev *idev;
  21         struct mutex notify_lock;       /* lenovo WMI camera button notify lock */
  22 };
  23
  24 enum {
  25         SW_CAMERA_OFF   = 0,
  26         SW_CAMERA_ON    = 1,
  27 };
  28
  29 static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
  30 {
  31         struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
  32         unsigned int keycode;
  33         u8 camera_mode;
  34
  35         if (obj->type != ACPI_TYPE_BUFFER) {
  36                 dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
  37                 return;
  38         }
  39
  40         if (obj->buffer.length != 1) {
  41                 dev_err(&wdev->dev, "Invalid buffer length %u\n", obj->buffer.length);
  42                 return;
  43         }
  44
  45         /*
  46          * obj->buffer.pointer[0] is camera mode:
  47          *      0 camera close
  48          *      1 camera open
  49          */
  50         camera_mode = obj->buffer.pointer[0];
  51         if (camera_mode > SW_CAMERA_ON) {
  52                 dev_err(&wdev->dev, "Unknown camera mode %u\n", camera_mode);
  53                 return;
  54         }
  55
  56         mutex_lock(&priv->notify_lock);
  57
  58         keycode = camera_mode == SW_CAMERA_ON ?
  59                    KEY_CAMERA_ACCESS_ENABLE : KEY_CAMERA_ACCESS_DISABLE;
  60         input_report_key(priv->idev, keycode, 1);
  61         input_sync(priv->idev);
  62         input_report_key(priv->idev, keycode, 0);
  63         input_sync(priv->idev);
  64
  65         mutex_unlock(&priv->notify_lock);
  66 }
  67
  68 static int lenovo_wmi_probe(struct wmi_device *wdev, const void *context)
  69 {
  70         struct lenovo_wmi_priv *priv;
  71         int ret;
  72
  73         priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
  74         if (!priv)
  75                 return -ENOMEM;
  76
  77         dev_set_drvdata(&wdev->dev, priv);
  78
  79         priv->idev = devm_input_allocate_device(&wdev->dev);
  80         if (!priv->idev)
  81                 return -ENOMEM;
  82
  83         priv->idev->name = "Lenovo WMI Camera Button";
  84         priv->idev->phys = "wmi/input0";
  85         priv->idev->id.bustype = BUS_HOST;
  86         priv->idev->dev.parent = &wdev->dev;
  87         input_set_capability(priv->idev, EV_KEY, KEY_CAMERA_ACCESS_ENABLE);
  88         input_set_capability(priv->idev, EV_KEY, KEY_CAMERA_ACCESS_DISABLE);
  89
  90         ret = input_register_device(priv->idev);
  91         if (ret)
  92                 return ret;
  93
  94         mutex_init(&priv->notify_lock);
  95
  96         return 0;
  97 }
  98
  99 static void lenovo_wmi_remove(struct wmi_device *wdev)
 100 {
 101         struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
 102
 103         mutex_destroy(&priv->notify_lock);
 104 }
 105
 106 static const struct wmi_device_id lenovo_wmi_id_table[] = {
 107         { .guid_string = WMI_LENOVO_CAMERABUTTON_EVENT_GUID },
 108         {  }
 109 };
 110 MODULE_DEVICE_TABLE(wmi, lenovo_wmi_id_table);
 111
 112 static struct wmi_driver lenovo_wmi_driver = {
 113         .driver = {
 114                 .name = "lenovo-wmi-camera",
 115                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 116         },
 117         .id_table = lenovo_wmi_id_table,
 118         .no_singleton = true,
 119         .probe = lenovo_wmi_probe,
 120         .notify = lenovo_wmi_notify,
 121         .remove = lenovo_wmi_remove,
 122 };
 123 module_wmi_driver(lenovo_wmi_driver);
 124
 125 MODULE_AUTHOR("Ai Chao <aichao@kylinos.cn>");
 126 MODULE_DESCRIPTION("Lenovo WMI Camera Button Driver");
 127 MODULE_LICENSE("GPL");