Re: [PATCH RFC v2 4/6] media: v4l2-ctrls: add lens group speed controls for zoom and focus

Laurent Pinchart
2023-06-07T07:08:10Z

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