linux-kernel - Re: boot_on regulator constraint vs. regulator-boot-on DT property

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Message-ID: <4FE27835.5070705@wwwdotorg.org>
Date:	Wed, 20 Jun 2012 19:26:13 -0600
From:	Stephen Warren <swarren@...dotorg.org>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
CC:	Liam Girdwood <lrg@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: boot_on regulator constraint vs. regulator-boot-on DT property

On 06/20/2012 05:46 PM, Mark Brown wrote:
> 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

Hmm. Perhaps I was misreading machine.h, and "when the system is
initially started" refers to the first firmware start, rather than
when /Linux/ starts. If so, then yes I can see it isn't really
inconsistent.
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