Messages in this thread | | | Date | Thu, 21 Jun 2012 00:46:48 +0100 | From | Mark Brown <> | Subject | Re: boot_on regulator constraint vs. regulator-boot-on DT property |
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On Wed, Jun 20, 2012 at 02:55:37PM -0600, Stephen Warren wrote:
> include/linux/regulator/machine.h says:
> > * @boot_on: Set if the regulator is enabled when the system is initially > > * started. If the regulator is not enabled by the hardware or > > * bootloader then it will be enabled when the constraints are > > * applied.
> Documentation/devicetree/bindings/regulator/regulator.txt says:
> > - regulator-boot-on: bootloader/firmware enabled regulator
> ... and of_regulator.c sets the boot_on constraint based on this property.
> The former quote implies that this is a flag to tell Linux to turn on > the regulator when it's first registered, whereas the latter quote > implies that it's guaranteeing the state that previous SW placed the > regulator into already.
> I assume the documentation from machine.h is correct, and I should send > a patch to make regulator.txt match it?
There's no great inconsistency between the two, this is only supposed to be used for supplies which are already enabled on boot but if the supply is not already enabled then currently the API will try to make it so since probably there's some reason for that. Generally it's supposed to be used as a crutch to keep hotplug going.
I'm not sure we should clarify this since I'm not sure that for DT setups which (as we were discussing in the other thread) are supposed to be usable over many software versions it's something that should really be used. We ought to in the endgame be able to have DT systems turn on full constraints and that probably breaks anything relying too much on boot-on, I'd expect they either need the regulator to be always on or some more consumers. [unhandled content-type:application/pgp-signature] | |