[Gta04-owner] GTA04 camera in VGA mode starts working

H. Nikolaus Schaller hns at goldelico.com
Mon Nov 27 21:37:03 CET 2017


Hi,

> Am 27.11.2017 um 21:24 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> Hi,
> 
> On Tue, 12 Sep 2017 20:59:56 +0200
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
> 
>> Hi,
>> I have some progress to report.
>> 
>> We finally found what was missing to make the VGA mode basically
>> work: there are two undocumented registers (one called "RSVD")
>> where a bit has to be changed.
>> 
>> Otherwise the video ADC seems not to work in VGA mode.
>> 
>> Maybe some voltages or dividers or whatever are switched
>> inside the camera chip to compensate for the 30fps sampling
>> rate (SXGA has 15fps).
>> 
>> So, this is a big step forwards to completely support all
>> GTA04 hardware features.
>> 
>> There are still some things to be fixed. For example the picture
>> is shifted a little.
>> 
>> And for some unknown reasons we should program the camera
>> in VYUY mode and the OMAP3 in UYVY... Otherwise we get "yellow"
>> and "blue" swapped. I.e. a rainbow will show reversed colors :)
>> or a blue pen is yellow and a yellow one is blue.
>> 
>> And some filters should be enabled to improve image quality.
>> 
>> Otherwise the camera module works quite well now.
>> 
>> So stay tuned for updates for the kernel tree :)
>> 
>> Maybe someone also finds time to add a camera driver to
>> Replicant or QtMoko2...
>> 
> ok, with a fresh camera,
> my ancient 3.7 kernel and camera program work well (as well as I
> remembered it)

Oh great! Then, the camera module was broken :(

> Now I tried with 4.14:
> root at gta04:~/4.14-root# ./capture-demo
> make: 'capture' is up to date.
> Camera ov9650 not found!

Maybe the camera-demo script hard-codes something and is broken.

Unfortunately the file names to access and parameters for
media-ctl aren't very stable and heavily depend on driver details...

I'll take a look into it when I update/test the camera for 4.15-rc1.

> 
> ./camera-demo seems to work, at least with sxga,
> colors are wrong, red is e.g. blue.

Yes, this is a known bug with UYVY being interpreted as VYUY somewhere.
There is a hack in the driver which makes it work, but it contradicts the
data sheet (and other drivers).

> 
> ./capture -d /dev/video2 (got that from camera-demo output)
> [ 2662.126983] ov9655 1-0030: ov9655_get_format
> [ 2662.131622] ov9655 1-0030: __ov9655_get_pad_format: pad=0 which=1 V4L2_SUBDE
> [ 2662.141174] ov9655 1-0030: busfmt: h=1024 w=1280 code=8198 field=1 csp=8
> VIDIOC_STREAMON error 22, Invalid argument

The capture-demo does some camera-setup before, which is also required here.
But the capture.c tool may also be broken now...

BR,
Nikolaus

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