linux-kernel - Re: Regulator supplies when using Device Tree

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Message-ID: <20120402212232.GA3160@opensource.wolfsonmicro.com>
Date:	Mon, 2 Apr 2012 22:22:33 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Michael Bohan <mbohan@...eaurora.org>
Cc:	rnayak@...com, lrg@...com, LKML <linux-kernel@...r.kernel.org>,
	linux-arm-msm@...r.kernel.org
Subject: Re: Regulator supplies when using Device Tree

On Mon, Apr 02, 2012 at 10:35:22AM -0700, Michael Bohan wrote:
> On 3/30/2012 3:36 AM, Mark Brown wrote:

> >The support for regulator-regulator supplies has always been problematic
> >and infrequently used -

> Hmm, I'd be interested to know the history there.

git logs should be instructive.  The use part is just because most board
designs end up thinking of better things to do with their DCDCs than
drop the supply for LDOs.

> >Please be more specific about what you're actually trying to physically
> >accomplish here.  It would be *extremely* unusual to see a regulator

> Some of our regulators take inputs from other regulators. Some
> regulators take their input from the battery. We support both types

Oh, if that's all it is that's totally normal and unsurprising.  Just
tell the regulator API about the battery supply, typically people use
a fixed regulator for this.  You don't have to specify a voltage when
you use them.

> I don't disagree that the new scheme makes supplies more like normal
> supplies. I'm just pointing out the solution doesn't appear perfect
> since extraneous code is put in the driver in this case.

To repeat yet again if you're putting code for this in the driver you've
got a clear abstraction failure.

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