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Date:   Wed, 7 Jun 2023 10:07:59 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Michael Riesch <michael.riesch@wolfvision.net>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        libcamera-devel@lists.libcamera.org,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Matthias Fend <Matthias.Fend@wolfvision.net>,
        Dave Stevenson <dave.stevenson@raspberrypi.com>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC v2 4/6] media: v4l2-ctrls: add lens group speed
 controls for zoom and focus
Message-ID: <20230607070759.GI14101@pendragon.ideasonboard.com>
References: <20230406-feature-controls-lens-v2-0-faa8ad2bc404@wolfvision.net>
 <20230406-feature-controls-lens-v2-4-faa8ad2bc404@wolfvision.net>
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In-Reply-To: <20230406-feature-controls-lens-v2-4-faa8ad2bc404@wolfvision.net>
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Hi Michael,

Thank you for the patch.

On Tue, Apr 25, 2023 at 11:45:14AM +0200, Michael Riesch wrote:
> Add the controls V4L2_CID_FOCUS_SPEED and V4L2_CID_ZOOM_SPEED that set
> the speed of the zoom lens group and focus lens group, respectively.

Ah, now the UVC relative focus and zoom controls could be implemented
;-) They still don't match the definition of the corresponding V4L2
controls, so I'm still tempted to deprecate both.

> Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
> ---
>  Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst | 10 ++++++++++
>  drivers/media/v4l2-core/v4l2-ctrls-defs.c                  |  2 ++
>  include/uapi/linux/v4l2-controls.h                         |  2 ++
>  3 files changed, 14 insertions(+)
> 
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> index 3ea4175f9619..a17620ab03b9 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> @@ -174,6 +174,11 @@ enum v4l2_exposure_metering -
>  	will not transition from this state until another action is performed
>  	by an application.
>  
> +``V4L2_CID_FOCUS_SPEED (integer)``
> +    Set the speed with which the focus lens group of the camera is moved
> +    (V4L2_CID_FOCUS_ABSOLUTE and V4L2_CID_FOCUS_RELATIVE). The unit is
> +    driver-specific. The value should be a positive integer.
> +

Could you explain your expected use cases for focus and zoom speed ?

>  ``V4L2_CID_FOCUS_AUTO (boolean)``
>      Enables continuous automatic focus adjustments. The effect of manual
>      focus adjustments while this feature is enabled is undefined,
> @@ -287,6 +292,11 @@ enum v4l2_auto_focus_range -
>  	not transition from this state until another action is performed by an
>  	application.
>  
> +``V4L2_CID_ZOOM_SPEED (integer)``
> +    Set the speed with which the zoom lens group of the camera is moved
> +    (V4L2_CID_ZOOM_ABSOLUTE and V4L2_CID_ZOOM_RELATIVE). The unit is
> +    driver-specific. The value should be a positive integer.
> +
>  ``V4L2_CID_IRIS_ABSOLUTE (integer)``
>      This control sets the camera's aperture to the specified value. The
>      unit is undefined. Larger values open the iris wider, smaller values
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> index 794ef3ab0c02..3ef465ba73bd 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> @@ -1048,6 +1048,8 @@ const char *v4l2_ctrl_get_name(u32 id)
>  	case V4L2_CID_FOCUS_STATUS:		return "Focus, Status";
>  	case V4L2_CID_ZOOM_CURRENT:		return "Zoom, Current";
>  	case V4L2_CID_ZOOM_STATUS:		return "Zoom, Status";
> +	case V4L2_CID_FOCUS_SPEED:		return "Focus, Speed";
> +	case V4L2_CID_ZOOM_SPEED:		return "Zoom, Speed";
>  
>  	/* FM Radio Modulator controls */
>  	/* Keep the order of the 'case's the same as in v4l2-controls.h! */
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 793ee8c65e87..8d84508d4db8 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -1001,6 +1001,8 @@ enum v4l2_auto_focus_range {
>  #define V4L2_CID_FOCUS_STATUS			(V4L2_CID_CAMERA_CLASS_BASE+38)
>  #define V4L2_CID_ZOOM_CURRENT			(V4L2_CID_CAMERA_CLASS_BASE+39)
>  #define V4L2_CID_ZOOM_STATUS			(V4L2_CID_CAMERA_CLASS_BASE+40)
> +#define V4L2_CID_FOCUS_SPEED			(V4L2_CID_CAMERA_CLASS_BASE+41)
> +#define V4L2_CID_ZOOM_SPEED			(V4L2_CID_CAMERA_CLASS_BASE+42)
>  
>  /* FM Modulator class control IDs */
>  

-- 
Regards,

Laurent Pinchart