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
lenovo_wmi_notify(struct wmi_device * wdev,union acpi_object * obj)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
lenovo_wmi_probe(struct wmi_device * wdev,const void * context)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
lenovo_wmi_remove(struct wmi_device * wdev)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");
128