linux-kernel - Re: [RFC PATCH v1] regulator: pwm-regulator: Fix continuous get

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Message-ID: <e32e0ccd-0e7c-4d74-aa2c-0b8155d97698@sirena.org.uk>
Date: Fri, 22 Dec 2023 11:54:54 +0000
From: Mark Brown <broonie@...nel.org>
To: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Cc: lgirdwood@...il.com,
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
	linux-pwm@...r.kernel.org, linux-amlogic@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Thierry Reding <thierry.reding@...il.com>,
	Heiner Kallweit <hkallweit1@...il.com>,
	Dmitry Rokosov <ddrokosov@...rdevices.ru>
Subject: Re: [RFC PATCH v1] regulator: pwm-regulator: Fix continuous
 get_voltage for disabled PWM

On Thu, Dec 21, 2023 at 11:42:29PM +0100, Martin Blumenstingl wrote:
> On Thu, Dec 21, 2023 at 10:45 PM Mark Brown <broonie@...nel.org> wrote:

> > Hrm.  Perhaps the regulator should figure out that it's on with a
> > minimum voltage of 1.14V in this case - AIUI that broadly corresponds to
> > your change except for the fact that it doesn't recognise that there's
> > actually an output in this case since it assumes that disabling the PWM
> > disables the output which isn't the case with this hardware.  We'd need
> > to know more about the PWM in that case though I think.

> If you have any specific questions then feel free to ask.
> Generally it's a very simple PWM controller:
> - when disabled the output is LOW
> - when enabled the output matches the requested period and duty cycle
> as best as possible (depending on the available input clocks)

We would need to know more at runtime to do the correct thing I think.

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