[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <200901142303.09217.david-b@pacbell.net>
Date: Wed, 14 Jan 2009 23:03:09 -0800
From: David Brownell <david-b@...bell.net>
To: Mark Brown <broonie@...ena.org.uk>
Cc: Liam Girdwood <lrg@...mlogic.co.uk>,
lkml <linux-kernel@...r.kernel.org>
Subject: Re: [patch 2.6.28-rc3] regulator: add REGULATOR_MODE_OFF
On Sunday 16 November 2008, Mark Brown wrote:
> > Are you arguing that there should be some new regulator_ops call to
> > expose the actual regulator state? If so, then what should happen to
>
> Yes, exactly - possibly multiple calls.
OK, so I finally got back to this issue. I'll post a patch
with such a separate call in a moment ... just a single status
value, sufficient for the need I observe, and only exposed
through sysfs since it's more useful just now as a kind of
introspection. Example: troubleshooting, as we previously
discussed; or, I can see some regulators that are wrongly
enabled, primarily because of bootloader goofage.
That raises an issue: how can Linux get such regulators to
turn off? Clock frameworks have the same issue, and they
tend to resolve this with a SoC-specific Kconfig option to
disable unused clocks (in a late_initcall, after everthing
has had a chance to start up). That conserves power.
I'm thinking it'd be worth having a similar Kconfig option
for regulators too. It could kick in regulator core code to
call regulator_ops.disable() whenever regulator_dev.use_count
is zero, possibly warning if !regulator_ops.is_disabled().
(Handling constraints.always_on too.)
Comments?
- Dave
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists