On Mon, Jan 20, 2020 at 02:43:10PM +0000, Steven Price wrote:

> From discussions offline, I think I've come round to the view that
> having a "soft PDC" in device tree isn't the right solution. Device tree
> should be describing the hardware and that isn't actually a hardware
> component.

You can use an implementation like that separately to it being in the
device tree, it is perfectly possible to instantiate devices that have
no representation at all in device tree based on other things that are
there like board or SoC information, or as subdevices of things that are
there.