[LEDE-DEV] clarifying how trivial it is to define a couple new IMX6QDL targets

[Florian Fainelli]

On 09/29/2017 10:33 AM, Robert P. J. Day wrote:
> 
>   i was just looking at using latest LEDE to define a couple new
> IMX6QDL targets, and after a few minutes, it looks as if, at least to
> get a minimal bootable system and as long as i'm not doing anything
> drastically weird, it should be wickedly simple and i just want to
> verify that.
> 
>   it's all based on the fact that, with the current kernel, the only
> selection you need to make is CONFIG_SOC_IMX6Q, which will build a
> suitable kernel, whereupon the file arch/arm/boot/dts/Makefile
> contains the directive:
> 
>     dtb-$(CONFIG_SOC_IMX6Q) += \
>        ... over 100 target dtb files ...
> 
>   under the circumstances, given that that single kernel is compatible
> with that many targets, it would appear that, as long as i don't care
> that 100+ other dtb files will be compiled, i can just add, under the
> LEDE directory target/linux/imx6/files-4.9/arch/arm/boot/dts, a couple
> new .dts files, like:
> 
>   acme_coyote_1.dts
>   acme_coyote_2.dts
> 
> and that's it.
> 
>   of course, there might be enhancements down the road but, for now,
> just to get something bootable, it seems all i need to do is patch a
> couple entries into arch/arm/boot/dts/Makefile, and add the dts files.
> 
>   am i understanding this correctly?

As far as the kernel and DTS build is concerned that is pretty much all
that is needed, you will need a patch to arch/arm/boot/dts/Makefile to
make sure that your DTS get built into a DTB AFAICT.

You will probably need to pair the DTS file(s) with an appropriate
change under target/linux/imx6/image/Makefile that adds a new
Device/acme-coyote1 and has at least a DEVICE_DTS := acme_coyote_1.dts
to build a kernel with an appended DTB image.
-- 
Florian