Messages in this thread |  | | From | David Brownell <> | Subject | Re: [patch 2.6.28-rc3] regulator: add REGULATOR_MODE_OFF | Date | Wed, 14 Jan 2009 23:03:09 -0800 |
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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
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