linux-kernel - Re: [libcamera-devel] [PATCH RFC 1/4] media: v4l2-ctrls: add lens group status controls for zoom and focus

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Message-ID: <ZDaa+qhoZxZ5ymxL@kekkonen.localdomain>
Date:   Wed, 12 Apr 2023 14:50:18 +0300
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Michael Riesch <michael.riesch@...fvision.net>
Cc:     Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Michael Riesch via B4 Relay 
        <devnull+michael.riesch.wolfvision.net@...nel.org>,
        linux-kernel@...r.kernel.org,
        Matthias Fend <Matthias.Fend@...fvision.net>,
        libcamera-devel@...ts.libcamera.org, linux-media@...r.kernel.org
Subject: Re: [libcamera-devel] [PATCH RFC 1/4] media: v4l2-ctrls: add lens
 group status controls for zoom and focus

Hi Michael,

On Wed, Apr 12, 2023 at 10:00:26AM +0200, Michael Riesch wrote:
>  - Different controls: If moving = (V4L2_CID_FOCUS_ABSOLUTE == current),
>    then what happens if the application performs a
>    V4L2_CID_FOCUS_RELATIVE with -3? current should reach 39,
>    V4L2_CID_FOCUS_ABSOLUTE is still at 42, the lens is still moving from
>    the application's point of view.

Would there be a reason to implement both of these controls in a single
driver? AFAIU, the relative one should be used if there absolute value
isn't known to the driver.

-- 
Kind regards,

Sakari Ailus