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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20151224193538.GJ579@sirena.org.uk>
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.

Download attachment "signature.asc" of type "application/pgp-signature" (474 bytes)