linux-kernel - Re: [PATCH v6] platform/x86: lenovo-wmi-camera: Use SW_CAMERA_LENS_COVER instead of KEY_CAMERA

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Message-ID: <789984c3-42c9-451e-857d-815d53dedd0b@redhat.com>
Date: Tue, 14 Jan 2025 10:51:30 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Ai Chao <aichao@...inos.cn>, ilpo.jarvinen@...ux.intel.com,
 platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6] platform/x86: lenovo-wmi-camera: Use
 SW_CAMERA_LENS_COVER instead of KEY_CAMERA_ACESS

Hi,

On 14-Jan-25 7:39 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>
> ---
> change for v6
> -Change mutex() to guard().

Thank you for the new version, I see that as part of this change
you have also moved the mutex out of struct lenovo_wmi_priv making
it a global variable.

Making the mutex global is not necessary for the use of guard()
and is undesirable.

Please submit a new version where the mutex is kept as part of
struct lenovo_wmi_priv.

Regards,

Hans


> change for v5
> -Add input_report_switch before input_register_device.
> change for v4
> -Add mutex_unlock and report a switch state of 0 if SW_CAMERA_ON.
> change for v3
> -Used input_register_device and input_allocate_device.
> change for v2
> -Only delays the input-device registration and switches to reporting SW_CAMERA_LENS_COVER.
> 
>  drivers/platform/x86/lenovo-wmi-camera.c | 75 +++++++++++++++---------
>  1 file changed, 46 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/platform/x86/lenovo-wmi-camera.c b/drivers/platform/x86/lenovo-wmi-camera.c
> index 0c0bedaf7407..36835cd64758 100644
> --- a/drivers/platform/x86/lenovo-wmi-camera.c
> +++ b/drivers/platform/x86/lenovo-wmi-camera.c
> @@ -13,12 +13,15 @@
>  #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"
>  
> +/* Lenovo WMI camera button notify lock */
> +static DEFINE_MUTEX(notify_lock);
> +
>  struct lenovo_wmi_priv {
>  	struct input_dev *idev;
> -	struct mutex notify_lock;	/* lenovo WMI camera button notify lock */
>  };
>  
>  enum {
> @@ -26,10 +29,38 @@ enum {
>  	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);
> -	unsigned int keycode;
>  	u8 camera_mode;
>  
>  	if (obj->type != ACPI_TYPE_BUFFER) {
> @@ -53,22 +84,24 @@ static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
>  		return;
>  	}
>  
> -	mutex_lock(&priv->notify_lock);
> +	guard(mutex)(&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);
> +	if (!priv->idev) {
> +		if (camera_shutter_input_setup(wdev, camera_mode))
> +			dev_warn(&wdev->dev, "Failed to register input device\n");
> +		return;
> +	}
>  
> -	mutex_unlock(&priv->notify_lock);
> +	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;
> -	int ret;
>  
>  	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
>  	if (!priv)
> @@ -76,23 +109,6 @@ static int lenovo_wmi_probe(struct wmi_device *wdev, const void *context)
>  
>  	dev_set_drvdata(&wdev->dev, priv);
>  
> -	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);
> -
> -	ret = input_register_device(priv->idev);
> -	if (ret)
> -		return ret;
> -
> -	mutex_init(&priv->notify_lock);
> -
>  	return 0;
>  }
>  
> @@ -100,7 +116,8 @@ static void lenovo_wmi_remove(struct wmi_device *wdev)
>  {
>  	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
>  
> -	mutex_destroy(&priv->notify_lock);
> +	if (priv->idev)
> +		input_unregister_device(priv->idev);
>  }
>  
>  static const struct wmi_device_id lenovo_wmi_id_table[] = {