The LED can be either one of the two colors or off. Swapping the
polarity on the two LED pins changes the color.

O.K, so it is using the diode property of a Light Emitting Diode, to
support two colours.

I am currently playing with the idea to create a multicolor LED kernel 
driver which is being controlled via GPIOs, but I still have not found 
the proper abstraction for it.

Maybe multi-colour is too far. Just support bi-colour via two gpios.
Still, it is not so simple. As you said, the led class does not give
too good an abstraction. I guess the best you can do is that when you
turn one on, it automagically turns the other off.

The point is, that even though this functionality must currently be
handled by user space (some combination of sysfs writes and a shell
script) at the moment, the rest of the system is usable.

Sure, we will take the DT file without support for the bicolour
LED. It can be added later.

      Andrew