On Fri, Nov 04, 2011 at 03:09:32PM -0700, Olof Johansson wrote:

But even things like allowing (optional) attributes such as
startup-delay on non-fixed regulators could make sense. Keep in mind
that the device tree should focus on describing the hardware, not just
what the linux driver needs from it. So maybe instead of
startup-delay, specifying ramp-up speed instead of time needed until
power is good could be the way to go there.

This is in general something that a driver should know as a result of
knowing which regulator it's dealing with - in many cases these are
properties which can be varied at runtime on hardware which has register
control.  Replicating this into the device tree would make things more
error prone.