From: Sakari Ailus <sakari.ailus@iki.fi>
To: Pavel Machek <pavel@ucw.cz>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>, linux-media@vger.kernel.org
Subject: Re: [PATCH v3 1/2] v4l: Add camera voice coil lens control class, current control
Date: Tue, 21 Feb 2017 00:26:18 +0200 [thread overview]
Message-ID: <20170220222618.GZ16975@valkosipuli.retiisi.org.uk> (raw)
In-Reply-To: <20170215080909.GA3693@amd>
Hi Pavel,
On Wed, Feb 15, 2017 at 09:09:09AM +0100, Pavel Machek wrote:
> Hi!
>
> > On 02/15/17 00:47, Pavel Machek wrote:
> > > 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.
> >
> > It'd certainly be useful to be able to provide more information.
> >
> > The question is: where to store it, and how? It depends on the voice
> > coil, the spring constant, the lens and the distance of the lens from
> > the sensor --- at least. Probably the sensor size as well.
> >
> > On voice coil lenses it is also somewhat inexact.
>
> I was thinking read-only attribute providing minimum and maximum
> diopters in case there's linear relationship as on N900.
>
> +#define V4L2_CID_VOICE_DIOPTERS_AT_REST (V4L2_CID_VOICE_COIL_CLASS_BASE + 2)
> +#define V4L2_CID_VOICE_DIOPTERS_AT_MAX (V4L2_CID_VOICE_COIL_CLASS_BASE + 3)
Where do you store that information and how? Should the user be also told
how the applied current affects the value?
I also wonder whether that's the best way to provide the information to the
user --- we have things such as devices that are a part of a camera module
and telling the user on which side of the device the camera is located.
We've been planning to have a property API for this to provide the user with
a tree of key-value pairs, with details unsettled as of yet, so it's
certainly nothing that could be used yet.
Do you have a user application that could make use of such information?
--
Regards,
Sakari Ailus
e-mail: sakari.ailus@iki.fi XMPP: sailus@retiisi.org.uk
next prev parent reply other threads:[~2017-02-20 22:26 UTC|newest]
Thread overview: 152+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-14 12:20 [PATCH v3 0/2] v4l: Add camera voice coil lens control class, current control Sakari Ailus
2017-02-14 12:20 ` [PATCH v3 1/2] " Sakari Ailus
2017-02-14 22:47 ` Pavel Machek
2017-02-15 7:15 ` Sakari Ailus
2017-02-15 8:09 ` Pavel Machek
2017-02-20 22:26 ` Sakari Ailus [this message]
2017-02-20 22:48 ` Pavel Machek
2017-04-15 2:23 ` Mauro Carvalho Chehab
2017-04-15 7:12 ` Pavel Machek
2017-04-16 9:12 ` Sakari Ailus
2017-04-19 13:51 ` Mauro Carvalho Chehab
2017-04-24 9:30 ` support autofocus / autogain in libv4l2 Pavel Machek
2017-04-24 13:38 ` Mauro Carvalho Chehab
2017-04-24 13:38 ` Mauro Carvalho Chehab
2017-04-24 21:29 ` Pavel Machek
2017-04-24 21:29 ` Pavel Machek
2017-04-25 1:47 ` Mauro Carvalho Chehab
2017-04-25 1:47 ` Mauro Carvalho Chehab
2017-04-25 8:05 ` Pavel Machek
2017-04-25 8:05 ` Pavel Machek
2017-04-25 8:08 ` Pali Rohár
2017-04-25 8:08 ` Pali Rohár
2017-04-25 8:08 ` Pali Rohár
2017-04-25 11:23 ` Pavel Machek
2017-04-25 11:23 ` Pavel Machek
2017-04-25 11:30 ` Pali Rohár
2017-04-25 11:30 ` Pali Rohár
2017-04-25 12:28 ` Pavel Machek
2017-04-25 12:28 ` Pavel Machek
2017-04-25 12:51 ` Pali Rohár
2017-04-25 12:51 ` Pali Rohár
2017-04-25 16:55 ` Nicolas Dufresne
2017-04-25 16:55 ` Nicolas Dufresne
2017-04-25 16:51 ` Nicolas Dufresne
2017-04-25 16:51 ` Nicolas Dufresne
2017-04-25 16:53 ` Nicolas Dufresne
2017-04-25 16:53 ` Nicolas Dufresne
2017-04-25 16:53 ` Nicolas Dufresne
2017-04-26 10:53 ` Pavel Machek
2017-04-26 10:53 ` Pavel Machek
2017-04-26 10:53 ` [patch] propagating controls in libv4l2 was " Pavel Machek
2017-04-26 10:53 ` Pavel Machek
2017-04-26 11:13 ` Mauro Carvalho Chehab
2017-04-26 11:13 ` Mauro Carvalho Chehab
2017-04-26 13:23 ` [patch] autogain support for bayer10 format (was Re: [patch] propagating controls in libv4l2) Pavel Machek
2017-04-26 13:23 ` Pavel Machek
2017-04-26 15:43 ` Ivaylo Dimitrov
2017-04-26 15:43 ` Ivaylo Dimitrov
2017-04-26 22:51 ` Pavel Machek
2017-04-26 22:51 ` Pavel Machek
2017-04-26 22:51 ` Pavel Machek
2017-04-27 5:52 ` Ivaylo Dimitrov
2017-04-27 5:52 ` Ivaylo Dimitrov
2017-07-13 7:57 ` Pavel Machek
2017-07-13 7:57 ` Pavel Machek
2017-05-03 19:05 ` Russell King - ARM Linux
2017-05-03 19:05 ` Russell King - ARM Linux
2017-05-03 19:58 ` Pavel Machek
2017-05-03 19:58 ` Pavel Machek
2017-05-08 22:28 ` [patch, libv4l]: fix integer overflow Pavel Machek
2017-05-09 6:29 ` Hans Verkuil
2017-05-09 6:32 ` Hans Verkuil
2017-05-09 8:02 ` Pavel Machek
2017-05-09 10:59 ` [patch, libv4l]: fix typos Pavel Machek
2017-05-09 11:01 ` [patch, libv4l]: Add support for GRBG10 format conversion Pavel Machek
2017-05-09 11:04 ` [patch, libv4l]: Introduce define for lookup table size Pavel Machek
2017-05-16 11:17 ` Hans Verkuil
2017-05-16 12:45 ` Pavel Machek
2017-05-16 12:56 ` Hans Verkuil
2017-05-16 23:23 ` Pavel Machek
2017-05-19 9:13 ` [libv4l]: How to do 10-bit support? Stand-alone conversions? Pavel Machek
2018-03-16 20:55 ` [RFC, libv4l]: Make libv4l2 usable on devices with complex pipeline Pavel Machek
2018-03-19 9:47 ` Hans Verkuil
2018-03-19 10:23 ` Pavel Machek
2018-03-19 10:47 ` Mauro Carvalho Chehab
2018-03-19 11:11 ` Hans Verkuil
2018-03-19 12:00 ` Pavel Machek
2018-03-19 12:15 ` Hans Verkuil
2018-03-19 12:48 ` Pavel Machek
2018-03-19 13:29 ` Hans Verkuil
2018-03-19 22:18 ` Pavel Machek
2018-03-19 13:45 ` Mauro Carvalho Chehab
2018-03-19 13:26 ` Mauro Carvalho Chehab
2018-03-20 7:50 ` Pavel Machek
2018-05-15 20:01 ` Pavel Machek
2018-05-15 22:03 ` Mauro Carvalho Chehab
2018-05-16 20:53 ` Pavel Machek
2018-06-02 21:01 ` Pavel Machek
2018-06-06 6:18 ` Tomasz Figa
2018-06-06 8:46 ` Pavel Machek
2018-06-06 8:53 ` Tomasz Figa
2018-06-06 10:01 ` Pavel Machek
2018-06-06 16:57 ` Mauro Carvalho Chehab
2018-06-06 21:27 ` Pavel Machek
2018-06-07 12:22 ` [PATCH, " Pavel Machek
2018-06-06 10:51 ` [RFC, " Pavel Machek
2018-06-06 11:16 ` Tomasz Figa
2018-06-06 20:37 ` Pavel Machek
2018-06-06 17:13 ` Mauro Carvalho Chehab
2018-06-06 10:23 ` Pavel Machek
2018-06-07 7:25 ` Pavel Machek
2017-05-09 11:10 ` [patch, libv4l]: fix integer overflow Pavel Machek
2017-05-16 10:42 ` Pavel Machek
2017-05-21 10:33 ` [patch, libv4l]: add sdlcam example for testing digital still camera functionality Pavel Machek
2017-05-26 20:41 ` Pavel Machek
2017-05-27 9:27 ` Hans Verkuil
2017-05-29 6:13 ` Hans Verkuil
2017-05-29 7:32 ` Pavel Machek
2017-05-29 8:02 ` Hans Verkuil
2017-06-14 11:16 ` Sakari Ailus
2017-06-14 20:41 ` Pavel Machek
2017-07-13 8:36 ` Pavel Machek
2017-05-09 8:07 ` [patch, libv4l]: fix integer overflow Pavel Machek
2017-04-30 22:48 ` [patch] autogain support for bayer10 format (was Re: [patch] propagating controls in libv4l2) Pavel Machek
2017-04-30 22:48 ` Pavel Machek
2017-07-13 9:49 ` [patch] propagating controls in libv4l2 was Re: support autofocus / autogain in libv4l2 Pavel Machek
2017-07-13 9:49 ` Pavel Machek
2017-04-26 11:26 ` Mauro Carvalho Chehab
2017-04-26 11:26 ` Mauro Carvalho Chehab
2017-04-29 9:19 ` Pavel Machek
2017-04-29 9:19 ` Pavel Machek
2017-10-21 22:00 ` Camera support, Prague next week, sdlcam Pavel Machek
2017-10-22 7:36 ` Hans Verkuil
2017-10-22 7:36 ` Hans Verkuil
2017-10-22 8:31 ` Pavel Machek
2017-10-22 8:31 ` Pavel Machek
2017-10-23 18:54 ` Pavel Machek
2017-10-23 18:54 ` Pavel Machek
2017-10-23 19:24 ` Hans Verkuil
2017-10-23 19:24 ` Hans Verkuil
2017-10-23 20:15 ` Sakari Ailus
2017-10-23 20:15 ` Sakari Ailus
2017-10-23 21:02 ` Mauro Carvalho Chehab
2017-10-23 21:02 ` Mauro Carvalho Chehab
2017-10-31 21:28 ` Nokia N9: fun with camera Pavel Machek
2017-11-01 6:36 ` Pavel Machek
2017-11-01 6:36 ` Pavel Machek
2017-11-01 15:32 ` Pavel Machek
2017-11-01 15:32 ` Pavel Machek
2017-04-24 22:07 ` support autofocus / autogain in libv4l2 Pavel Machek
2017-04-24 22:07 ` Pavel Machek
2017-04-25 1:57 ` Mauro Carvalho Chehab
2017-04-25 1:57 ` Mauro Carvalho Chehab
2017-04-25 8:20 ` Pavel Machek
2017-04-25 8:20 ` Pavel Machek
2017-04-25 11:23 ` Pavel Machek
2017-04-25 11:23 ` Pavel Machek
2017-04-28 22:00 ` [PATCH v3 1/2] v4l: Add camera voice coil lens control class, current control Pavel Machek
2017-04-29 1:46 ` Mauro Carvalho Chehab
2017-05-12 10:49 ` Sakari Ailus
2017-05-13 11:08 ` Pavel Machek
2017-02-14 12:20 ` [PATCH v3 2/2] ad5820: Use VOICE_COIL_CURRENT control Sakari Ailus
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