Re: [REVIEW PATCH 11/14] OMAP34XXCAM: Add driver

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tuesday 03 March 2009 06:13:11 DongSoo(Nathaniel) Kim wrote:
> Thank you for your reply.
>
> This is quite confusing because in case of mine, I wanna make
> switchable between different cameras attached to omap camera
> interface.
> Which idea do I have to follow? Comparing with multiple video input
> devices and multiple cameras attached to single camera interface is
> giving me no answer.
>
> Perhaps multiple cameras with single camera interface couldn't make
> sense at the first place because single camera interface can go with
> only one camera module at one time.
> But we are using like that. I mean dual cameras with single camera
> interface. There is no choice except that when we are using dual
> camera without stereo camera controller.

If you have multiple inputs (cameras in this case) that the user can choose 
from, then you need to implement S_INPUT/G_INPUT/ENUMINPUTS. That's what 
they are there for. Any decent V4L2 app should support these ioctls.

> By the way, I cannot find any API documents about
> VIDIOC_INT_S_VIDEO_ROUTING but it seems to be all about "how to route
> between input device with output device".

The description of this internal ioctl is in v4l2-common.h. It is used to 
tell the i2c module how it is hooked up to the rest of the system. I.e. 
what pin(s) is used for the input signal and what pin(s) is used for the 
output signal.

Typically the main v4l2 driver will map a user-level input (as set with 
VIDIOC_S_INPUT) to the low-level routing information and pass that on to 
the i2c device using VIDIOC_INT_S_VIDEO_ROUTING.

Regards,

	Hans

> What exactly I need is "how to make switchable with multiple camera as
> an input for camera interface", which means just about an input
> device. In my opinion, those are different issues each other..(Am I
> right?)
> Cheers,
>
> Nate
>
> On Tue, Mar 3, 2009 at 12:53 PM, Hiremath, Vaibhav <hvaibhav@xxxxxx> 
wrote:
> > Thanks,
> > Vaibhav Hiremath
> >
> >> -----Original Message-----
> >> From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap-
> >> owner@xxxxxxxxxxxxxxx] On Behalf Of DongSoo(Nathaniel) Kim
> >> Sent: Tuesday, March 03, 2009 8:18 AM
> >> To: Tuukka.O Toivonen
> >> Cc: Aguirre Rodriguez, Sergio Alberto; linux-omap@xxxxxxxxxxxxxxx;
> >> Ailus Sakari (Nokia-D/Helsinki); Nagalla, Hari
> >> Subject: Re: [REVIEW PATCH 11/14] OMAP34XXCAM: Add driver
> >>
> >> Hi Tuukka,
> >>
> >> I understand that it is a huge thing to support VIDIOC_S_INPUT.
> >> But without that, we don't have any proper "V4L2" api to get
> >> information about how many devices are attached to camera interface,
> >> and names of input devices...and so on. Because VIDIOC_ENUMINPUT and
> >> VIDIOC_G_INPUT needs VIDIOC_S_INPUT for prior. Of course we can
> >> refer
> >> to sysfs, but using only single set of APIs like V4L2 looks more
> >> decent.
> >>
> >> What do you think about this?
> >> If you think that it is a big burden, can I make a patch for this?
> >> Cheers,
> >
> > [Hiremath, Vaibhav] You may want to refer to the thread on this
> > subject.
> >
> > http://marc.info/?l=linux-omap&m=122772175002777&w=2
> > http://marc.info/?l=linux-omap&m=122823846806440&w=2
> >
> >> Nate
> >>
> >> On Mon, Feb 23, 2009 at 5:50 PM, Tuukka.O Toivonen
> >>
> >> <tuukka.o.toivonen@xxxxxxxxx> wrote:
> >> > On Monday 23 February 2009 10:08:54 ext DongSoo(Nathaniel) Kim
> >>
> >> wrote:
> >> >> So, logically it does not make sense with making device nodes of
> >>
> >> every
> >>
> >> >> single slave attached with OMAP3camera interface. Because they
> >>
> >> can't
> >>
> >> >> be opened at the same time,even if it is possible it should not
> >>
> >> work
> >>
> >> >> properly.
> >> >>
> >> >> So.. how about making only single device node like /dev/video0
> >>
> >> for
> >>
> >> >> OMAP3 camera interface and make it switchable through V4L2 API.
> >>
> >> Like
> >>
> >> >> VIDIOC_S_INPUT?
> >> >
> >> > You are right that if the OMAP3 has several camera sensors
> >>
> >> attached
> >>
> >> > to its camera interface, generally just one can be used at once.
> >> >
> >> > However, from user's perspective those are still distinct
> >> > cameras. Many v4l2 applications don't support VIDIOC_S_INPUT
> >> > or at least it will be more difficult to use than just pointing
> >> > an app to the correct video device. Logically they are two
> >> > independent cameras, which can't be used simultaneously
> >> > due to HW restrictions.
> >> >
> >> > - Tuukka
> >>
> >> --
> >> ========================================================
> >> DongSoo(Nathaniel), Kim
> >> Engineer
> >> Mobile S/W Platform Lab. S/W centre
> >> Telecommunication R&D Centre
> >> Samsung Electronics CO., LTD.
> >> e-mail : dongsoo.kim@xxxxxxxxx
> >>           dongsoo45.kim@xxxxxxxxxxx
> >> ========================================================
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-
> >> omap" in
> >> the body of a message to majordomo@xxxxxxxxxxxxxxx
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Hans Verkuil - video4linux developer - sponsored by TANDBERG
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]
  Powered by Linux