linux-kernel - Re: [PATCH 1/3] regulator: core: fix boot-on regulators use

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Date:   Tue, 8 Oct 2019 16:56:05 +0200
From:   Marco Felsch <m.felsch@...gutronix.de>
To:     Mark Brown <broonie@...nel.org>
Cc:     Doug Anderson <dianders@...omium.org>,
        Chunyan Zhang <zhang.chunyan@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        ckeepax@...nsource.cirrus.com, LKML <linux-kernel@...r.kernel.org>,
        Sascha Hauer <kernel@...gutronix.de>
Subject: Re: [PATCH 1/3] regulator: core: fix boot-on regulators use_count
 usage

On 19-10-08 13:51, Mark Brown wrote:
> On Tue, Oct 08, 2019 at 08:03:11AM +0200, Marco Felsch wrote:
> > On 19-10-07 19:29, Mark Brown wrote:
> > > On Mon, Oct 07, 2019 at 11:34:29AM +0200, Marco Felsch wrote:
> 
> > > > Sorry that won't fix my problem. If I drop the regulator-boot-on state
> > > > the fixed-regulator will disable this regulator but disable/enable this
> > > > regulator is only valid during suspend/resume. I don't say that my fix
> > > > is correct but we should fix this.
> 
> > > I'm having a bit of trouble parsing this but it sounds like you want the
> > > regulator to be always on in which case you should use the property
> > > specifically for that.
> 
> > Sorry my english wasn't the best.. Imagine this case: The bootloader
> > turned the display on to show an early bootlogo. Now if I miss the
> > regulator-boot-on property the display is turned off and on. The turn
> > off comes from the regulator probe, the turn on comes from the cosumer.
> > Is that assumption correct?
> 
> No, we shouldn't do anything when the regulator probes - we'll only
> disable unused regulators when we get to the end of boot (currently we
> delay this by 30s to give userspace a chance to run, that's a hack but
> we're fresh out of better ideas).  During boot the regulator state will
> only be changed if some consumer appears and changes the state.

Okay, so this won't disable the regualtor?

8<----------------------------------------------------------------
static int reg_fixed_voltage_probe(struct platform_device *pdev)
{
	...

	if (config->enabled_at_boot)
		gflags = GPIOD_OUT_HIGH;
	else
		gflags = GPIOD_OUT_LOW;

	...
}
8<----------------------------------------------------------------

Regards,
  Marco