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Device tree overlays in 5.14
Posted: Sat Oct 09, 2021 2:28 pm
by foft
Hi,
I was applying a device tree overlay in kernel 4.19 by mounting configfs, upon which I'd see the device-tree. After upgrading to 5.14 I no longer see this, does anyone know how to do the same thing in 5.14?
Is there a new system to provide configuration to custom modules in Linux 5?
Thanks,
Mark
Re: Device tree overlays in 5.14
Posted: Sat Oct 09, 2021 2:36 pm
by foft
Re: Device tree overlays in 5.14
Posted: Sun Oct 10, 2021 8:12 pm
by foft
Still struggling to make this work.
The .dts override I had before no longer works. I did manage to apply it but seems to be an issue with how the references work. So I need to reference intc, previous I added an intc block. That needs to no longer work and the right was is to using /plugin/;. However that fails to find intc when I apply the overlay.
One possible lead:
Was the dts in the kernel compiled using -@ on the command line?
./dtc -O dtb -o /lib/firmware/minimig.dtbo -@ -b 0 ./minimig.dts
cp /lib/firmware/minimig.dtbo /sys/kernel/config/device-tree/overlays/minimig/dtbo
echo 1 > /sys/kernel/config/device-tree/overlays/minimig/status
359.342349] OF: resolver: no symbols in root of device tree.
[ 359.348096] OF: resolver: overlay phandle fixup failed: -22
[ 359.353711] dtbocfg_overlay_item_create: Failed to apply overlay (ret_val=-22)
Code: Select all
/dts-v1/;
/plugin/;
/{
fragment@0 {
target-path = "/";
__overlay__ {
minimig_irq {
compatible = "minimig_irq";
interrupt-parent = <&intc>;
interrupts = <0 42 1>;
};
};
};
};
Re: Device tree overlays in 5.14
Posted: Sun Oct 10, 2021 8:20 pm
by foft
Managed to work around by using an explicit interrupt-parent, it complains then works!
Code: Select all
/dts-v1/;
/plugin/;
/{
fragment@0 {
target-path = "/";
__overlay__ {
minimig_irq {
compatible = "minimig_irq";
interrupt-parent = <0x02>;
interrupts = <0 42 1>;
};
};
};
};
Re: Device tree overlays in 5.14
Posted: Sun Oct 10, 2021 8:36 pm
by LamerDeluxe
Thanks for documenting your progress here!