On Fri, Nov 04, 2011 at 03:16:12PM -0700, Olof Johansson wrote:

On Fri, Nov 4, 2011 at 2:46 PM, Mark Brown

quoted

quoted

Describing that in the device tree using regulator-specifiers
shouldn't be too bad? The LDO will reference the DCDC as the parent
supply (or input or whatever language you prefer). They don't have to
be in the same topology, they will instead be under whatever
controller/bus they are on for control -- i2c, etc.

quoted

That's not great as it means you've got a separate binding for supplies
that happen to be connected to another regulator from that used for
other supplies on the device which is particularly confusing in the
fairly common case where a regulator chip has multiple supplies. ?Using
the same method for binding all supplies seems much neater.

I'm not following the above 100%, but I think you are saying that you
would prefer to describe the regulator / power hierarchy in the
functional topology instead of how the various regulators and supplies
are organized on i2c busses and other controllers?  And the obvious
one that would be less than trivial to find a home for would be the
top-level or freestanding fixed regulators that don't sit on a
controlling bus.

No, that's not the issue at all.  The issue is that we want a single way
of describing the supplies a device has regardless of their function
(which is what the existing stuff does).

Consider the case of a simple regulator with register control.  It is
going to have a supply used for the regulator itself and almost
certainly also a separate digital buffer supply used to reference the
digital I/O.  It seems bad to specify the first supply in a different
manner to the second, and there are more complex examples where a supply
can be both a regulator input and also a more general purpose supply.