linux-kernel - Re: [PATCH] regulator: pwm: Fix regulator ramp delay for continuous mode

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Message-ID: <CAD=FV=WKR_Fq6o34886RCY-T-6AKdRqFz9H1aTiRq7Zu=o8TWA@mail.gmail.com>
Date:	Fri, 1 Jul 2016 13:17:48 -0700
From:	Doug Anderson <dianders@...omium.org>
To:	Mark Brown <broonie@...nel.org>,
	Boris Brezillon <boris.brezillon@...e-electrons.com>
Cc:	Lee Jones <lee.jones@...aro.org>,
	Brian Norris <briannorris@...omium.org>,
	"open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
	Heiko Stuebner <heiko@...ech.de>,
	Liam Girdwood <lgirdwood@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] regulator: pwm: Fix regulator ramp delay for continuous mode

Mark,

On Fri, Jul 1, 2016 at 1:06 AM, Mark Brown <broonie@...nel.org> wrote:
> On Mon, Jun 27, 2016 at 09:53:11PM -0700, Douglas Anderson wrote:
>
>> Note that this patch is atop Boris's recent PWM regulator fixes.  If
>> desired it wouldn't be too hard to write it atop the old code, though
>> quite honestly anyone using a PWM regulator should probably be using his
>> new code.
>
> Given that those don't seem likely to go in any time soon and aren't
> going to go in as a fix can you please respin against current code?

I went to write this patch and it was pretty easy to write.  ...but
then I realized that I had no real way to test it.  I can compile test
it, but that's it.  Do you still want it?

Specifically without Boris's patches then I don't believe the devices
I have access to are bootable when I tell Linux about the PWM
regulator, especially when I configure the PWM regulator to use
continuous mode (which is where the bug is).  As I understand from
<https://patchwork.kernel.org/patch/9175279/> the current PWM
regulator assumes that 0% duty cycle is the lowest voltage and 100% is
the highest voltage.  My system is backwards (0% is highest, 100%
lowest).  Also: last I tried even the non-continuous mode without
Boris's patches the regulator would glitch enough at bootup that my
system would crash (the PWM regulator affects the memory controller).

Anyway, let me know if you want me to post the untested, rebased
patch...  Personally I'd prefer to wait for Boris's patches and the
land the tested version.

Boris: any idea for what the next steps on your series are?

-Doug