[UPSTREAM PATCH] remove_pcf50633_voltage_rails_and_friends.patch

Balaji Rao balajirrao at openmoko.org
Fri Oct 31 15:11:57 CET 2008

On Fri, Oct 31, 2008 at 01:58:15PM +0000, Andy Green wrote:
> Hash: SHA1
> Somebody in the thread at some point said:
> | It did work though. OK. I know the problem. My bad. My understanding
> | that the pmu will be put to standby when we suspend is fundamentally
> | wrong!
> Auto really needs to stay up, it's the source of the "always on" IO_3V3
> and that's the source of any high levels on the CPU GPIO during suspend.

OK. MEMLDO is used to keep the SDRAM powerd when we are in pmu-standby.
Doesn't this tell us that we can actually put the pmu into standby when
we suspend and keep _the_ essential component of the otherwise asleep CPU
alive using some voltage regulator ?

One question. Which one of the low power states mentioned in the manual
do we get into when we suspend ?

> | That's brings one question to my mind. Why do we need to save the
> | registers that don't "survive" standby (a comment in pcf50633_suspend
> | says so), if we are not going into standby at all ? Please explain.
> It's a good question... those i2c actions are pretty slow, if we can
> abandon them it's good.

Ah, ok. Let me remove it and see what happens..

	- Balaji

More information about the openmoko-kernel mailing list