On Sun, Oct 28, 2012 at 09:12:52PM +0100, Linus Walleij wrote:

The answer is that it does not know. Because drivers have
different needs. Depending on how the hardware and
system is done.

...

I'm not making this up, it is a very real phenomenon on the
Ux500 and I don't think we are unique.

Moving this handling to bus code or anywhere else
invariably implies that resource acquisition/release order
does not matter, and my point is that it does.

Doing this in the buses is definitely wrong, as you say it's not bus
specific.  I do however think we can usefully do this stuff in a SoC
specific place like a power domain, keeping the SoC integration code
together and out of the drivers.  IME the SoCs where you need to do
different things for different IPs shoudl mostly still get some reuse
out of such an approach.