[fedora-arm] Device Tree overlays on Fedora

Peter Robinson

2016-04-05 09:57:50 UTC

Post by Ken Harris
How do I use device tree overlays on Fedora (since there
is no "cape manager") ?
I assume I have to modify extlinux.conf to boot with a new device tree
file. Is there a way to use "dtc" to merge the am335x-boneblack.dts
file and the overlay file ?
FYI, the reason I ask this question is that I'm interested in CANbus.
I noticed that Fedora has CANbus drivers now. Great. I have a
BeagleBone Black (with Fedora 23 on a SD card) and a "Serial Cape"
from LogicSupply : http://www.logicsupply.com/cbb-serial/ . There are
https://github.com/lgxlogic/CBB-Serial/tree/master/overlay

Basically the Fedora support is about the equivalent as the upstream
on this. A good overview of this currently was presented at ELC this
week. The following slide deck [1] gives a good overview (starting
from Page 21).

There were patches [2] for the BBone Cape Manager to go upstream but
it's not landed and it appears to be stalled,

Like most things we try to follow upstream on this as it takes a lot
of resources to maintain things out of tree. There's now patches for
u-boot support (was referenced in the sldedeck as not being there) so
we might be starting to have some movement. There is basic kernel
support there in the kernel. I see the big blocker is actually having
people agree on support for compiling them in the DT Compiler. There
have been patches for that but never a consensus on what is the right
way to do it.

[1] http://events.linuxfoundation.org/sites/events/files/slides/tenart-chip-overlays.pdf
[2] http://www.spinics.net/lists/devicetree/msg79541.html