linux-kernel - Re: [PATCH 1/3] regulator: core: fix boot-on regulators use

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Date:   Tue, 24 Sep 2019 11:27:58 -0700
From:   Mark Brown <broonie@...nel.org>
To:     Doug Anderson <dianders@...omium.org>
Cc:     Marco Felsch <m.felsch@...gutronix.de>,
        Chunyan Zhang <zhang.chunyan@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        ckeepax@...nsource.cirrus.com, LKML <linux-kernel@...r.kernel.org>,
        Sascha Hauer <kernel@...gutronix.de>
Subject: Re: [PATCH 1/3] regulator: core: fix boot-on regulators use_count
 usage

On Mon, Sep 23, 2019 at 03:40:09PM -0700, Doug Anderson wrote:
> On Mon, Sep 23, 2019 at 11:49 AM Mark Brown <broonie@...nel.org> wrote:
> > On Mon, Sep 23, 2019 at 11:36:11AM -0700, Doug Anderson wrote:

> > > 1. Would it be valid to say that it's always incorrect to set this
> > > property if there is a way to read the status back from the regulator?

> > As originally intended, yes.  I'm now not 100% sure that it won't
> > break any existing systems though :/

> Should I change the bindings doc to say that?

Sure.

> > It should be possible to do a regulator_disable() though I'm not
> > sure anyone actually uses that.  The pattern for a regular
> > consumer should be the normal enable/disable pair to handle
> > shared usage, only an exclusive consumer should be able to use
> > just a straight disable.

> Ah, I see, I wasn't aware of the "exclusive" special case!  Marco: is
> this working for you?  I wonder if we need to match
> "regulator->enable_count" to "rdev->use_count" at the end of
> _regulator_get() in the exclusive case...

Yes, I think that case has been missed when adding the enable
counts - I've never actually had a system myself that made any
use of this stuff.  It probably needs an audit of the users to
make sure nobody's relying on the current behaviour though I
can't think how they would.

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