1 files changed, 146 insertions, 0 deletions
diff --git a/drivers/platform/x86/lenovo-wmi-camera.c b/drivers/platform/x86/lenovo-wmi-camera.c
new file mode 100644
index 000000000000..eb60fb9a5b3f
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-camera.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Lenovo WMI Camera Button Driver
+ *
+ * Author: Ai Chao <aichao@kylinos.cn>
+ * Copyright (C) 2024 KylinSoft Corporation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/wmi.h>
+#include <linux/cleanup.h>
+
+#define WMI_LENOVO_CAMERABUTTON_EVENT_GUID "50C76F1F-D8E4-D895-0A3D-62F4EA400013"
+
+struct lenovo_wmi_priv {
+	struct input_dev *idev;
+	struct mutex notify_lock;	/* lenovo WMI camera button notify lock */
+};
+
+enum {
+	SW_CAMERA_OFF	= 0,
+	SW_CAMERA_ON	= 1,
+};
+
+static int camera_shutter_input_setup(struct wmi_device *wdev, u8 camera_mode)
+{
+	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+	int err;
+
+	priv->idev = input_allocate_device();
+	if (!priv->idev)
+		return -ENOMEM;
+
+	priv->idev->name = "Lenovo WMI Camera Button";
+	priv->idev->phys = "wmi/input0";
+	priv->idev->id.bustype = BUS_HOST;
+	priv->idev->dev.parent = &wdev->dev;
+
+	input_set_capability(priv->idev, EV_SW, SW_CAMERA_LENS_COVER);
+
+	input_report_switch(priv->idev, SW_CAMERA_LENS_COVER,
+			    camera_mode == SW_CAMERA_ON ? 0 : 1);
+	input_sync(priv->idev);
+
+	err = input_register_device(priv->idev);
+	if (err) {
+		input_free_device(priv->idev);
+		priv->idev = NULL;
+	}
+
+	return err;
+}
+
+static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
+{
+	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+	u8 camera_mode;
+
+	if (obj->type != ACPI_TYPE_BUFFER) {
+		dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
+		return;
+	}
+
+	if (obj->buffer.length != 1) {
+		dev_err(&wdev->dev, "Invalid buffer length %u\n", obj->buffer.length);
+		return;
+	}
+
+	/*
+	 * obj->buffer.pointer[0] is camera mode:
+	 *      0 camera close
+	 *      1 camera open
+	 */
+	camera_mode = obj->buffer.pointer[0];
+	if (camera_mode > SW_CAMERA_ON) {
+		dev_err(&wdev->dev, "Unknown camera mode %u\n", camera_mode);
+		return;
+	}
+
+	guard(mutex)(&priv->notify_lock);
+
+	if (!priv->idev) {
+		if (camera_shutter_input_setup(wdev, camera_mode))
+			dev_warn(&wdev->dev, "Failed to register input device\n");
+		return;
+	}
+
+	if (camera_mode == SW_CAMERA_ON)
+		input_report_switch(priv->idev, SW_CAMERA_LENS_COVER, 0);
+	else
+		input_report_switch(priv->idev, SW_CAMERA_LENS_COVER, 1);
+	input_sync(priv->idev);
+}
+
+static int lenovo_wmi_probe(struct wmi_device *wdev, const void *context)
+{
+	struct lenovo_wmi_priv *priv;
+
+	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	dev_set_drvdata(&wdev->dev, priv);
+
+	mutex_init(&priv->notify_lock);
+
+	return 0;
+}
+
+static void lenovo_wmi_remove(struct wmi_device *wdev)
+{
+	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
+
+	if (priv->idev)
+		input_unregister_device(priv->idev);
+
+	mutex_destroy(&priv->notify_lock);
+}
+
+static const struct wmi_device_id lenovo_wmi_id_table[] = {
+	{ .guid_string = WMI_LENOVO_CAMERABUTTON_EVENT_GUID },
+	{  }
+};
+MODULE_DEVICE_TABLE(wmi, lenovo_wmi_id_table);
+
+static struct wmi_driver lenovo_wmi_driver = {
+	.driver = {
+		.name = "lenovo-wmi-camera",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+	.id_table = lenovo_wmi_id_table,
+	.no_singleton = true,
+	.probe = lenovo_wmi_probe,
+	.notify = lenovo_wmi_notify,
+	.remove = lenovo_wmi_remove,
+};
+module_wmi_driver(lenovo_wmi_driver);
+
+MODULE_AUTHOR("Ai Chao <aichao@kylinos.cn>");
+MODULE_DESCRIPTION("Lenovo WMI Camera Button Driver");
+MODULE_LICENSE("GPL");