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

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Date:   Thu, 26 Sep 2019 12:44:53 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Mark Brown <broonie@...nel.org>,
        Marco Felsch <m.felsch@...gutronix.de>
Cc:     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

Hi,

On Tue, Sep 24, 2019 at 11:28 AM Mark Brown <broonie@...nel.org> wrote:
> 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.

Sent ("regulator: Document "regulator-boot-on" binding more thoroughly").

https://lore.kernel.org/r/20190926124115.1.Ice34ad5970a375c3c03cb15c3859b3ee501561bf@changeid


> > > 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.

Marco: I'm going to assume you'll tackle this since I don't actually
have any use cases that need this.

-Doug