linux-kernel - Re: [PATCH v4 1/4] regulator: helper routine to extract regulator_init

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Date:	Fri, 4 Nov 2011 15:50:05 -0700
From:	Olof Johansson <olof@...om.net>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	Rajendra Nayak <rnayak@...com>, grant.likely@...retlab.ca,
	patches@...aro.org, tony@...mide.com,
	devicetree-discuss@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
	linux-omap@...r.kernel.org, lrg@...com,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 1/4] regulator: helper routine to extract regulator_init_data

On Fri, Nov 4, 2011 at 3:35 PM, Mark Brown
<broonie@...nsource.wolfsonmicro.com> wrote:
> On Fri, Nov 04, 2011 at 03:16:12PM -0700, Olof Johansson wrote:
>> On Fri, Nov 4, 2011 at 2:46 PM, Mark Brown
>
>> >> Describing that in the device tree using regulator-specifiers
>> >> shouldn't be too bad? The LDO will reference the DCDC as the parent
>> >> supply (or input or whatever language you prefer). They don't have to
>> >> be in the same topology, they will instead be under whatever
>> >> controller/bus they are on for control -- i2c, etc.
>
>> > That's not great as it means you've got a separate binding for supplies
>> > that happen to be connected to another regulator from that used for
>> > other supplies on the device which is particularly confusing in the
>> > fairly common case where a regulator chip has multiple supplies.  Using
>> > the same method for binding all supplies seems much neater.
>
>> I'm not following the above 100%, but I think you are saying that you
>> would prefer to describe the regulator / power hierarchy in the
>> functional topology instead of how the various regulators and supplies
>> are organized on i2c busses and other controllers?  And the obvious
>> one that would be less than trivial to find a home for would be the
>> top-level or freestanding fixed regulators that don't sit on a
>> controlling bus.
>
> No, that's not the issue at all.  The issue is that we want a single way
> of describing the supplies a device has regardless of their function
> (which is what the existing stuff does).
>
> Consider the case of a simple regulator with register control.  It is
> going to have a supply used for the regulator itself and almost
> certainly also a separate digital buffer supply used to reference the
> digital I/O.  It seems bad to specify the first supply in a different
> manner to the second, and there are more complex examples where a supply
> can be both a regulator input and also a more general purpose supply.

Ah, we're misunderstanding each other again (as just discussed on irc
as well), and we're in agreement here as far as I can tell.

Named properties using regulator-specifiers to reference upstream
supplies should work well enough for any use today, and if it needs to
be reconsidered in the future we can revisit it then.


-Olof
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