device tree on rpi2 not working

Tim Sander tim at
Tue Dec 15 13:18:11 PST 2015


I have already asked a similar question in the raspberry pi forum without an 
answer so i figured that my question might be a bit to deeply technical for 
the forums. Besides i am pretty exited about the work on the free graphics 
driver and would really like to integrate that as time permits later on.

As a hobby project i have put some effort into putting a ptxdist based linux 
distro for the rpi2 into shape. It allows developing with qt, opencv, 3d 
accleration (old style) and camera drivers. The repository is at:

But when trying to integrate the pwm drivers i noticed that device tree is 
somehow not working with my solution. Thats where i am stuck and i have no 
idea whats wrong? I would be really happy if someone could give me a clue.

Thats what i have been trying out so far:
I have been using the kernel from branch rpi-4.1.y

I extracted a kernel config from a running raspian and got the /proc/config.gz 
and used this for building the kernel. It boots and all but there is no 
/proc/device-tree link as with raspbian and device tree overlays are not 
working either. I know with high confidence by exchaning my kernel on a 
raspbian installation that with my kernel the device tree initialization fails 
even on raspbian. So i figure its most likely a kernel problem. But then the 
kernel seems to have the device tree patches and my config is pretty close...

I also tried to find the original raspbian kernel but even so its running a 
4.1 kernel an apt-source get linux-image only turned up older 3.x kernels and 
i could not find any sources in the raspbian repositories which is strange.

It seems to me also that the pwm driver which i am after is also just fully 
enabled by patches which have been seen on this list recently.  And against 
what kernel tree are all these patches?

Best regards

More information about the linux-rpi-kernel mailing list