linux-kernel - Re: [PATCH] platform/x86:lenovo-wmi-camera: Use SW_CAMERA_LENS_COVER instead of KEY_CAMERA

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Message-ID: <f9cd4fb3-520c-4229-a5a1-96d0221f4924@redhat.com>
Date: Wed, 18 Dec 2024 12:01:28 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Ai Chao <aichao@...inos.cn>, platform-driver-x86@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform/x86:lenovo-wmi-camera: Use SW_CAMERA_LENS_COVER
 instead of KEY_CAMERA_ACESS

Hi Ai,

On 18-Dec-24 7:03 AM, Ai Chao wrote:
> Use SW_CAMERA_LENS_COVER instead of KEY_CAMERA_ACESS_ENABLE and
> KEY_CAMERA_ACESS_DISABLE. When the camera toggle switch was hit,
> the lenovo-wmi-camera driver would report an event code.
> 
> Signed-off-by: Ai Chao <aichao@...inos.cn>

Thank you for your patch, but this patch does a lot more then
just switching to instantiating the input device on the first
event and reporting SW_CAMERA_LENS_COVER.

You are also switching away from using the new WMI bus /
wmi_driver model to using the old deprecated please WMI
functions.

Please post a new version which keeps the wmi_driver and
only delays the input-device registration and switches
to reporting SW_CAMERA_LENS_COVER.

Regards,

Hans



> ---
>  drivers/platform/x86/lenovo-wmi-camera.c | 139 +++++++++++------------
>  1 file changed, 66 insertions(+), 73 deletions(-)
> 
> diff --git a/drivers/platform/x86/lenovo-wmi-camera.c b/drivers/platform/x86/lenovo-wmi-camera.c
> index 0c0bedaf7407..fc9efd5beda8 100644
> --- a/drivers/platform/x86/lenovo-wmi-camera.c
> +++ b/drivers/platform/x86/lenovo-wmi-camera.c
> @@ -16,29 +16,52 @@
>  
>  #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 */
> -};
> +static struct input_dev *camera_shutter_input_dev;
> +static struct mutex notify_lock; /* lenovo WMI camera button notify lock */
>  
>  enum {
>  	SW_CAMERA_OFF	= 0,
>  	SW_CAMERA_ON	= 1,
>  };
>  
> -static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
> +static int camera_shutter_input_setup(void)
> +{
> +	int err;
> +
> +	camera_shutter_input_dev = input_allocate_device();
> +	if (!camera_shutter_input_dev)
> +		return -ENOMEM;
> +
> +	camera_shutter_input_dev->name = "Lenovo WMI Camera Button";
> +	camera_shutter_input_dev->phys = "wmi/input0";
> +	camera_shutter_input_dev->id.bustype = BUS_HOST;
> +
> +	__set_bit(EV_SW, camera_shutter_input_dev->evbit);
> +	__set_bit(SW_CAMERA_LENS_COVER, camera_shutter_input_dev->swbit);
> +
> +	err = input_register_device(camera_shutter_input_dev);
> +	if (err) {
> +		input_free_device(camera_shutter_input_dev);
> +		camera_shutter_input_dev = NULL;
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static void lenovo_wmi_notify(union acpi_object *obj, void *context)
>  {
> -	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
> -	unsigned int keycode;
> -	u8 camera_mode;
> +	u32 event_data;
>  
> +	if (!obj)
> +		return;
>  	if (obj->type != ACPI_TYPE_BUFFER) {
> -		dev_err(&wdev->dev, "Bad response type %u\n", obj->type);
> +		pr_info("Unknown response received %d\n", obj->type);
>  		return;
>  	}
>  
>  	if (obj->buffer.length != 1) {
> -		dev_err(&wdev->dev, "Invalid buffer length %u\n", obj->buffer.length);
> +		pr_info("Invalid buffer length %u\n", obj->buffer.length);
>  		return;
>  	}
>  
> @@ -47,80 +70,50 @@ static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
>  	 *      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;
> -	}
> -
> -	mutex_lock(&priv->notify_lock);
> -
> -	keycode = camera_mode == SW_CAMERA_ON ?
> -		   KEY_CAMERA_ACCESS_ENABLE : KEY_CAMERA_ACCESS_DISABLE;
> -	input_report_key(priv->idev, keycode, 1);
> -	input_sync(priv->idev);
> -	input_report_key(priv->idev, keycode, 0);
> -	input_sync(priv->idev);
> -
> -	mutex_unlock(&priv->notify_lock);
> +	event_data = obj->buffer.pointer[0];
> +
> +	mutex_lock(&notify_lock);
> +	if (!camera_shutter_input_dev)
> +		if (camera_shutter_input_setup()) {
> +			pr_err("Failed to setup camera shutter input device\n");
> +			mutex_unlock(&notify_lock);
> +			return;
> +		}
> +
> +	if (event_data == SW_CAMERA_ON)
> +		input_report_switch(camera_shutter_input_dev, SW_CAMERA_LENS_COVER, 1);
> +	else if (event_data == SW_CAMERA_OFF)
> +		input_report_switch(camera_shutter_input_dev, SW_CAMERA_LENS_COVER, 0);
> +	else
> +		pr_info("Unknown camera shutter state - 0x%x\n", event_data);
> +	input_sync(camera_shutter_input_dev);
> +
> +	mutex_unlock(&notify_lock);
>  }
>  
> -static int lenovo_wmi_probe(struct wmi_device *wdev, const void *context)
> +static __init int lenovo_wmi_init(void)
>  {
> -	struct lenovo_wmi_priv *priv;
> -	int ret;
> -
> -	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
> -	if (!priv)
> -		return -ENOMEM;
> -
> -	dev_set_drvdata(&wdev->dev, priv);
> +	int event_capable = wmi_has_guid(WMI_LENOVO_CAMERABUTTON_EVENT_GUID);
> +	acpi_status status;
>  
> -	priv->idev = devm_input_allocate_device(&wdev->dev);
> -	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_KEY, KEY_CAMERA_ACCESS_ENABLE);
> -	input_set_capability(priv->idev, EV_KEY, KEY_CAMERA_ACCESS_DISABLE);
> +	if (!event_capable)
> +		return -ENODEV;
>  
> -	ret = input_register_device(priv->idev);
> -	if (ret)
> -		return ret;
> -
> -	mutex_init(&priv->notify_lock);
> +	status = wmi_install_notify_handler(WMI_LENOVO_CAMERABUTTON_EVENT_GUID,
> +					    lenovo_wmi_notify, NULL);
> +	if (ACPI_FAILURE(status))
> +		return -EIO;
>  
>  	return 0;
>  }
> +module_init(lenovo_wmi_init);
>  
> -static void lenovo_wmi_remove(struct wmi_device *wdev)
> +static __exit void lenovo_wmi_exit(void)
>  {
> -	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
> -
> -	mutex_destroy(&priv->notify_lock);
> +	if (camera_shutter_input_dev)
> +		input_unregister_device(camera_shutter_input_dev);
>  }
> -
> -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_exit(lenovo_wmi_exit);
>  
>  MODULE_AUTHOR("Ai Chao <aichao@...inos.cn>");
>  MODULE_DESCRIPTION("Lenovo WMI Camera Button Driver");