linux-kernel - Re: [PATCH 1/4] mfd: arizona: Export function to control subsystem DVFS

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Date:	Mon, 16 Jun 2014 17:48:58 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Lee Jones <lee.jones@...aro.org>
Cc:	Richard Fitzgerald <rf@...nsource.wolfsonmicro.com>,
	sameo@...ux.intel.com, ckeepax@...nsource.wolfsonmicro.com,
	lgirdwood@...il.com, perex@...ex.cz, tiwai@...e.de,
	alsa-devel@...a-project.org, patches@...nsource.wolfsonmicro.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] mfd: arizona: Export function to control subsystem
 DVFS

On Mon, Jun 16, 2014 at 05:42:42PM +0100, Lee Jones wrote:
> On Mon, 09 Jun 2014, Richard Fitzgerald wrote:

> > +	if (arizona->subsys_max_rq != new_flags) {

> I don't really get this.  What's the point in passing the mask
> parameter - I don't see it being used for anything in this routine? No
> matter what is passed in you always just turn on the same regulator.

> What am I missing?

AFAICT it's a bunch of different independently selectable requests for
the voltage to ramped with any one of them causing it to happen.

I did wonder why this wasn't just done by refcounting, that's the more
normal pattern in the kernel, though I guess it's possible some of them
need different ramps on different devices.

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