linux-kernel - Re: [PATCH 4/6] regulator: lp872x: Add enable GPIO pin support

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Date:	Thu, 24 Dec 2015 19:35:38 +0000
From:	Mark Brown <broonie@...nel.org>
To:	Paul Kocialkowski <contact@...lk.fr>
Cc:	linux-kernel@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Russell King <linux@....linux.org.uk>,
	Benoît Cousson <bcousson@...libre.com>,
	Tony Lindgren <tony@...mide.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Milo Kim <milo.kim@...com>, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org
Subject: Re: [PATCH 4/6] regulator: lp872x: Add enable GPIO pin support

On Thu, Dec 24, 2015 at 07:12:53PM +0100, Paul Kocialkowski wrote:
> Le mercredi 23 décembre 2015 à 11:56 +0000, Mark Brown a écrit :

> > This isn't really adding support for the enable GPIO as the changelog
> > suggests, it's requesting but not managing the GPIO.  Since there is
> > core support for manging enable GPIOs this seems especially silly,
> > please tell the core about the GPIO and then it will work at runtime
> > too.

> It looks like the core bindings for GPIO can only be used instead of the
> rdev->desc->ops->enable callback, not jointly, which doesn't fit my use
> case, where both the GPIO and register write have to be used to enable
> regulators.

> I think it would be worth making it possible to use both in core, since
> that situation is probably shared with other regulators. I suggest the
> following diff (that would be split into a separate patch in v2 of this
> series):

No, that's broken - the whole point with using a GPIO for enable control
on a lot of devices is that it is much faster than doing a register
write.  What I would expect to happen in this case is that when
initialsing the GPIO we set the register to enabled and then only manage
the GPIO at runtime.

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