linux-kernel - Re: [PATCH] regulator: core: Fix enable GPIO reference counting

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Date:	Wed, 4 Mar 2015 09:13:52 -0800
From:	Doug Anderson <dianders@...omium.org>
To:	Mark Brown <broonie@...nel.org>
Cc:	milo.kim@...com, Axel Lin <axel.lin@...ics.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Olof Johansson <olof@...om.net>,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	Paul Stewart <pstew@...omium.org>,
	"stable@...r.kernel.org" <stable@...r.kernel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regulator: core: Fix enable GPIO reference counting

Mark,

On Wed, Mar 4, 2015 at 3:27 AM, Mark Brown <broonie@...nel.org> wrote:
> On Tue, Mar 03, 2015 at 03:21:21PM -0800, Doug Anderson wrote:
>
>> It looks as if "ena_gpio_state" is not quite what I thought it was and
>> I think is not actually consistent in the regulator framework itself.
>> In _regulator_do_enable() and _regulator_do_disable() is clear that
>> ena_gpio_state is 1 when an "rdev" is enabled and 0 when the "rdev" is
>> disabled.  That was my assumption.  It's also clear in
>> _regulator_is_enabled().
>
>> ...but then I looked in regulator_register().  There you can see that
>> ena_gpio_state could be set to 1 if you've got an active low GPIO that
>> is disabled at boot.  That totally throws my logic for a loop.  Also
>> with my patch the reference counting will be all messed up for active
>> high / boot on regulators.  :(
>
> Isn't that just a bug in the registration code?  I'd not be entirely
> surprised if that were the case.

Yes, I'm pretty sure that's the case too and that's what I've assumed
in V2 of the patch that I sent up yesterday.  In my testing is caused
no problems, but of course my testing of my previous version also
showed no problems on my particular boards until I found the right
place to put printouts to show that the internal state was a bit
confused...

-Doug
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