linux-kernel - Re: [PATCH 1/2] regulator: Add support for power budget

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Message-ID: <bea06b24-a47c-4b9b-8fcb-1ae8494cfcd5@sirena.org.uk>
Date: Tue, 14 Jan 2025 14:15:14 +0000
From: Mark Brown <broonie@...nel.org>
To: Kory Maincent <kory.maincent@...tlin.com>
Cc: Liam Girdwood <lgirdwood@...il.com>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	Oleksij Rempel <o.rempel@...gutronix.de>, kernel@...gutronix.de
Subject: Re: [PATCH 1/2] regulator: Add support for power budget

On Tue, Jan 14, 2025 at 02:53:28PM +0100, Kory Maincent wrote:
> Mark Brown <broonie@...nel.org> wrote:

> > Yup, indeed.  That said I am wondering if it's safer to just configure
> > the constraint in the hardware rather than the currently requested
> > limit, considering what might happen in the case where there's multiple
> > consumers that have only been partially updated.  If the hardware limits
> > or shuts down rather than warning it'll blow up badly so it might be
> > better to be conservative.  Unfortunately we don't distinguish in the
> > ops.  Possibly it should be a policy thing even but then that's better
> > at runtime...

> Indeed, should we begin without it and see later if we add it?

I think so.

> We could simply add an event for now:
> regulator_notifier_call_chain(rdev, REGULATOR_EVENT_OVER_CURRENT, NULL);

We should (TBH I thought that was there already) but part of the problem
is that a bunch of the hardware will shut down or otherwise do something
that we might not want when it hits the limit.  Again something that
could be addressed separately/incrementally.

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