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
 19struct lenovo_wmi_priv {
 20	struct input_dev *idev;
 21	struct mutex notify_lock;	/* lenovo WMI camera button notify lock */
 22};
 23
 24enum {
 25	SW_CAMERA_OFF	= 0,
 26	SW_CAMERA_ON	= 1,
 27};
 28
 29static 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
 68static 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
 99static 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
106static const struct wmi_device_id lenovo_wmi_id_table[] = {
107	{ .guid_string = WMI_LENOVO_CAMERABUTTON_EVENT_GUID },
108	{  }
109};
110MODULE_DEVICE_TABLE(wmi, lenovo_wmi_id_table);
111
112static 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};
123module_wmi_driver(lenovo_wmi_driver);
124
125MODULE_AUTHOR("Ai Chao <aichao@kylinos.cn>");
126MODULE_DESCRIPTION("Lenovo WMI Camera Button Driver");
127MODULE_LICENSE("GPL");