[Gta04-owner] GTA04 camera driver

H. Nikolaus Schaller hns at goldelico.com
Thu Sep 8 18:42:38 CEST 2016


Hi,
we have some nice progress towards a working camera in 4.8ff kernels :)

During our openphoenux/tinkerphones hacking weekend in June I was able
to extend the ov9650 driver to enable power and clocks and detect the
ov9655 module we use in the GTA04 design.

The next hurdle was to make the media-ctl work and configure the
omap3isp (image signal processor) inside the OMAP3 SoC. This simply
did not work. It complained about a missing /dev/media0 :(

After discussion with the author of the DT patches for the omap3isp
he suggested to add a simple patch:

https://lkml.org/lkml/2016/9/8/437

After applying this patch we have the /dev/media0 and our camera-demo
script starts mplayer. It still shows a green image (indicating missing
video sync), but this shouldn't be too difficult to debug and fix.

The main reason why it can't work yet is that all i2c writing to the
camera module is still disabled. Because the code assumes ov9650 and
ov9652 register numbers. But there are a handful of small changes in
the ov9655 register model but a big overlap.

This needs careful comparison of the data sheets and extend register
address constant definitions for the ov9655 and make some conditionals.

And, it is not exactly clear if we have the correct DT setup for the
sync and clock polarity.

If anyone wants to experiment, here is the most recent code:

http://git.goldelico.com/?p=gta04-kernel.git;a=shortlog;h=refs/heads/letux-4.8-rc5
http://git.goldelico.com/?p=gta04-kernel.git;a=shortlog;h=refs/heads/work/hns/video/ov9655
http://git.goldelico.com/?p=gta04-kernel.git;a=blob;f=Letux/root/camera-demo;hb=refs/heads/letux-4.8-rc5

Patches and test reports are welcome!

BR and happy hacking,
Nikolaus



More information about the Gta04-owner mailing list