I've been doing some work on L3 standby power this afternoon, the
primary upshot of which is that there are now hooks in
/arch/arm/mach-pxa/balloon3.c for doing things on the way into and out
of standby. I cribbed most of the code straight from palmz72.c which
seemed to have the right sort of things in it, so if there's a
better/more legitimate way to do it, I'm open to ideas.

At the moment all it's used for is shutting down the console serial port
transceiver which can save anything up to 2mA depending on what's
plugged in to the serial port.

I tried to add shutdown of the NAND flash chips too but unsuccessfully
because the NAND data and control lines need to be parked at the same
time, and balloon3.c isn't really the place to do it.

I had a rummage around in drivers/mtd/nand/balloon3.c but there don't
seem to be power management hooks in there.

The same issue arises with the Samosa bus - did parking the bus lines
ever get in after the grand TCL kernel hacking session? I can't see it
in the code.

Thinking about these things and looking at the code indicates to me that
making the relevant control registers in Balloon 3's programmable logic
read/write or at least set/reset rather than write-only would make life
somewhat easier in the kernel, but could introduce incompatibilities.

I'm going to be having a go at the logic on Friday anyway, with a view
to sorting out variable latency IO, so that could be the time if we're
feeling brave...

Chris
-- 
Chris Jones - chris@martin-jones.com
Martin-Jones Technology Ltd, makers of Solidlights
148 Catharine Street, Cambridge, CB1 3AR, UK
Phone +44 (0) 1223 655611 Fax +44 (0) 870 112 3908
http://www.solidlights.co.uk/