4

My board boots via U-Boot and AFAIK that bootloader does not support device tree overlays, so I'm probably forced to generate a single, static .dtb will all relevant overlays (and settings??) already applied to it. In principle that would be okay for me, but how to do that?

Is there some command line tool that takes .dtb and .dtbo files resp. .dts and .dtsi files and combines them into a single .dtb / .dts?

dtc doesn't seem to do that job.

The ultimate goal is to get I²C working on a Raspberry B+ that boots via U-Boot.

3

You don't need to do this.

With this change, overlays are in u-boot! https://github.com/u-boot/u-boot/commit/e6628ad7b99b285b25147366c68a7b956e362878

Enjoy :)

  • 2
    @dr01 the link is pointing to a particular commit in the u-boot code. it isn't pointing to the answer. What this answer is saying (as far as I can tell) is that updating u-boot is all that's needed to solve the issue. – terdon Sep 11 '16 at 12:27
0

The format of the dts makes merging trivial: all you need to do is to cat or #include the separate dts, because:

/dts-v1/;

/ {
    a;
};

/ {
    b;
};

is the same as:

/dts-v1/;

/ {
        a;
        b;
};

because both specify a property for node /.

This can be observed with:

dtc a.dts

on the first dts above.

I couldn't however found a more automated way to do this with the Linux kernel build system yet.

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