Re: [PATCH] of: support an enumerated-bus compatible value

On Tue, Jul 03, 2012 at 04:00:37PM +0200, Segher Boessenkool wrote:

So you *can* address the device, you just don't want to show that
in the device tree (I don't blame you, it's quite impossible to
design a sane addressing scheme for this, all this stuff is so
ad-hoc).  I see.  You could make it the kid of a GPIO controller
node, but then what if it is controlled by two (or more!) GPIO
controllers?

Yes, exactly - there's a bunch of random incoming signals which aren't
reliably going to fit in with the tree structure (and of course we do
already have a GPIO binding which isn't anything like the bus you're
suggesting above).

There is still no reason for the fake bus node to have a "compatible"
property though.  What could it possibly mean?  "This bus does not
exist at all but you access it in bla bla bla way"?  That just doesn't
make sense.  It doesn't exist, you do not access it, it has no
programming model, it has no "compatible" property.

Well, as everyone keeps saying this seems to be a limitation of the
current device tree rather than something that's actually sensible in
and of itself.