linux-kernel - Re: [PATCH v4 4/4] ARM: mvebu: Armada 385 GP: Add regulators to the SATA port

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Date:	Fri, 16 Jan 2015 15:34:51 +0000
From:	Mark Brown <broonie@...nel.org>
To:	Gregory CLEMENT <gregory.clement@...e-electrons.com>
Cc:	Hans de Goede <hdegoede@...hat.com>, Tejun Heo <tj@...nel.org>,
	linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org,
	Antoine Ténart 
	<antoine.tenart@...e-electrons.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>,
	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Boris BREZILLON <boris.brezillon@...e-electrons.com>,
	Jason Cooper <jason@...edaemon.net>,
	Andrew Lunn <andrew@...n.ch>,
	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
	linux-arm-kernel@...ts.infradead.org,
	Lior Amsalem <alior@...vell.com>,
	Tawfik Bayouk <tawfik@...vell.com>,
	Nadav Haklai <nadavh@...vell.com>,
	Mark Rutland <mark.rutland@....com>, devicetree@...r.kernel.org
Subject: Re: [PATCH v4 4/4] ARM: mvebu: Armada 385 GP: Add regulators to the
 SATA port

On Fri, Jan 16, 2015 at 03:27:00PM +0100, Gregory CLEMENT wrote:
> On 16/01/2015 13:37, Mark Brown wrote:

> > regulator-always-on is a bit fuzzy for suspend, if the regulator has
> > suspend control it'll kick in - it's really about the Linux refcounting
> > while it's running.  What's more concerning here is that the quick
> > sample of the regulators flagged as always on like the above that I
> > looked at in the patch don't seem to have any enable control in the DT
> > so this will have absolutely no effect.

> Actually the reg_sata[0-4] are controlled by gpio, so there is a mean
> to enable/disable them. For the reg_5v_sata[0-4] and reg_12v_sata[0-4]
> they depend on their respective reg_sata and I just propagated the
> regulator-always-on, this was maybe a mistake.

It certainly makes everything confusing if you have control related
stuff on regulators that are not directly controllable.

> >> It is probably a good idea to use regulator-boot-on and
> >> then test things this way, and if that works use
> >> regulator-boot-on.

> > No, it's unlikely that boot-on makes sense here - it's there for cases
> > where we can't read back the hardware state at power on.  Generally
> > drivers should work regardless of the initial state of the regulator
> > (and modular drivers will actually break if they try to rely on boot-on
> > since we clean up unused regulators at boot).

> As pointed by Hans my concern here was be sure that during boot the disk
> are not power off. In this case which property would be accurate?

None, the core won't do anything with the regulator until the end of
init anyway.

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