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

Source file repositories/reference/linux-study-clean/drivers/platform/x86/lenovo/wmi-camera.c

File Facts

System
Linux kernel
Corpus path
drivers/platform/x86/lenovo/wmi-camera.c
Extension
.c
Size
3498 bytes
Lines
148
Domain
Driver Families
Bucket
drivers/platform
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

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);

Annotation

Implementation Notes