Re: [PATCH v3 1/2] v4l: Add camera voice coil lens control class, current control

[Pavel Machek <pavel@ucw.cz>]

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On Tue 2017-02-14 14:20:22, Sakari Ailus wrote:
> Add a V4L2 control class for voice coil lens driver devices. These are
> simple devices that are used to move a camera lens from its resting
> position.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Looks good to me.

I wonder... should we somehow expose the range of diopters to
userspace? I believe userland camera application will need that
information.

Thanks,
							Pavel

> ---
>  Documentation/media/uapi/v4l/extended-controls.rst | 28 ++++++++++++++++++++++
>  include/uapi/linux/v4l2-controls.h                 |  8 +++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/Documentation/media/uapi/v4l/extended-controls.rst b/Documentation/media/uapi/v4l/extended-controls.rst
> index abb1057..a75451a 100644
> --- a/Documentation/media/uapi/v4l/extended-controls.rst
> +++ b/Documentation/media/uapi/v4l/extended-controls.rst
> @@ -3022,6 +3022,34 @@ Image Process Control IDs
>      driver specific and are documented in :ref:`v4l-drivers`.
>  
>  
> +.. _voice-coil-lens-controls:
> +
> +Voice Coil Lens Control Reference
> +=================================
> +
> +The Voice Coil class controls are used to control voice coil lens
> +devices. These are very simple devices that consist of a voice coil, a
> +spring and a lens. The current applied on the voice coil is used to
> +move the lens away from the resting position which typically is (close
> +to) infinity. The higher the current applied, the closer the lens is
> +typically focused.
> +
> +.. _voice-coil-lens-control-is:
> +
> +Voice Coil Lens Control IDs
> +---------------------------
> +
> +``V4L2_CID_VOICE_COIL_CLASS (class)``
> +    The VOICE_COIL class descriptor.
> +
> +``V4L2_CID_VOICE_COIL_CURRENT (integer)``
> +    Current applied on a voice coil. The more current is applied, the
> +    more is the position of the lens moved from its resting position.
> +    Do note that there may be a ringing effect; the lens will
> +    oscillate after changing the current applied unless the device
> +    implements ringing compensation.
> +
> +
>  .. _dv-controls:
>  
>  Digital Video Control Reference
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 0d2e1e0..9ef152b 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -62,6 +62,7 @@
>  #define V4L2_CTRL_CLASS_FM_RX		0x00a10000	/* FM Receiver controls */
>  #define V4L2_CTRL_CLASS_RF_TUNER	0x00a20000	/* RF tuner controls */
>  #define V4L2_CTRL_CLASS_DETECT		0x00a30000	/* Detection controls */
> +#define V4L2_CTRL_CLASS_VOICE_COIL	0x00a40000	/* Voice coil lens driver controls */
>  
>  /* User-class control IDs */
>  
> @@ -894,6 +895,13 @@ enum v4l2_jpeg_chroma_subsampling {
>  #define V4L2_CID_TEST_PATTERN			(V4L2_CID_IMAGE_PROC_CLASS_BASE + 3)
>  #define V4L2_CID_DEINTERLACING_MODE		(V4L2_CID_IMAGE_PROC_CLASS_BASE + 4)
>  
> +/* Voice coil lens driver controls */
> +
> +#define V4L2_CID_VOICE_COIL_CLASS_BASE		(V4L2_CTRL_CLASS_VOICE_COIL | 0x900)
> +#define V4L2_CID_VOICE_COIL_CLASS		(V4L2_CTRL_CLASS_VOICE_COIL | 1)
> +
> +#define V4L2_CID_VOICE_COIL_CURRENT		(V4L2_CID_VOICE_COIL_CLASS_BASE + 1)
> +
>  
>  /*  DV-class control IDs defined by V4L2 */
>  #define V4L2_CID_DV_CLASS_BASE			(V4L2_CTRL_CLASS_DV | 0x900)

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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