Re: [PATCH v4] media: Driver for Toshiba et8ek8 5MP sensor

From: Ivaylo Dimitrov
Date: Tue Nov 01 2016 - 02:37:10 EST


On 1.11.2016 00:54, Sakari Ailus wrote:
Hi Pavel,

On Sun, Oct 23, 2016 at 10:33:15PM +0200, Pavel Machek wrote:

Thanks, this answered half of my questions already. ;-)


I'll have to go through the patches, et8ek8 driver is probably not
enough to get useful video. platform/video-bus-switch.c is needed for
camera switching, then some omap3isp patches to bind flash and
autofocus into the subdevice.

Then, device tree support on n900 can be added.

I briefly discussed with with Sebastian.

Do you think the elusive support for the secondary camera is worth keeping
out the main camera from the DT in mainline? As long as there's a reasonable
way to get it working, I'd just merge that. If someone ever gets the
secondary camera working properly and nicely with the video bus switch,
that's cool, we'll somehow deal with the problem then. But frankly I don't
think it's very useful even if we get there: the quality is really bad.

Yes, lets merge what we have till now, it will be way easier to improve on it once it is part of the mainline.

BTW, I have (had) patched VBS working almost without problems, when it comes to it I'll dig it.

Do all the modes work for you currently btw.?

I don't think I got 5MP mode to work. Even 2.5MP mode is tricky (needs
a lot of continuous memory).

The OMAP 3 ISP has got an MMU, getting some contiguous memory is not really
a problem when you have a 4 GiB empty space to use.

Anyway, I have to start somewhere, and I believe this is a good
starting place; I'd like to get the code cleaned up and merged, then
move to the next parts.

I wonder if something else could be the problem. I think the data rate is
higher in the 5 MP mode, and that might be the reason. I don't remember how
similar is the clock tree in the 3430 to the 3630. Could it be that the ISP
clock is lower than it should be for some reason, for instance?

IIRC I checked what Nokia kernel does, and according to my vague memories the frequency was the same. Still, it seems the problem is in ISP, it has some very fragile calculations. Yet again, having main camera merged will ease the problem hunting.