Currently, the dt node looks like (I think?):

apa {
	compatible = "apa102";
	dimension = <1 1>;
};

Based on leds-spi-byte and a makefile from...
https://blog.sourcerer.io/writing-a-simple-linux-kernel-module-d9dc3762c234

The Makefile is not intended to be used for the target platform, it's
for playing around locally right now.

https://raw.githubusercontent.com/paulbarbu/loadable-kernel-modules/master/.gitignore