[meta-xilinx] modify the device tree in custom layer

[Nathan Rossi]

On Fri, Nov 20, 2015 at 9:34 PM, Toby Gomersall
<toby.gomersall at smartacoustics.co.uk> wrote:
> Hi,
>
> I'm trying to modify the device tree from my own layer. What is the best
> way to do this?

There is no 'best' way IMO, but instead a few different ways depending
on your use case and intended goal.

Some users like to make use of the kernel device trees either by
providing patches to the kernel to adding their device tree or
upstreaming changes to mainline/linux-xlnx. Other users prefer to keep
static device trees that are either hand crafted or generated by the
Xilinx tools. It really does depend on how you want to work.

>
> I have got the system working by adding to the zedboard-zynq7-board.dtsi
> within meta-xilinx but I want to move this modification to my own layer.
>
> I have tried Creating my own custom.dts and custom.dtsi files, then
> appended the MACHINE_DEVICETREE variable to point to them. I thought
> that the device-tree.bb recipe in meta-xilinx would pull in my additions
> but I just get errors when I try to build.
>
> Have I missed a step or is there a better way to achieve this?

MACHINE_DEVICETREE can use device trees put into the device-tree
recipe (via bbappend/etc) or automatically located from the
conf/machine/boards directory of any available layer. For example see
how the meta-parallella layer uses MACHINE_DEVICETREE.

https://github.com/nathanrossi/meta-parallella/tree/master/conf/machine/boards/parallella

You will also note that it takes advantage of the device trees
provided in the linux-parallella kernel when available:

https://github.com/nathanrossi/meta-parallella/blob/master/recipes-kernel/linux/linux-parallella-machines.inc

Regards,
Nathan

>
> Thanks,
> Toby
>
>
> --
> _______________________________________________
> meta-xilinx mailing list
> meta-xilinx at yoctoproject.org
> https://lists.yoctoproject.org/listinfo/meta-xilinx
>