linux-kernel - Re: [RFC PATCH v1 6/6] soc/tegra: regulators: Add regulators coupler for Tegra30

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Date:   Mon, 13 May 2019 18:40:00 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v1 6/6] soc/tegra: regulators: Add regulators coupler
 for Tegra30

On Sun, May 12, 2019 at 09:29:54PM +0300, Dmitry Osipenko wrote:
> 12.05.2019 12:04, Mark Brown пишет:
> > On Wed, May 08, 2019 at 04:27:42PM +0300, Dmitry Osipenko wrote:

> > Those seem like they should be doable in generic code, though the fact
> > that the constraint is variable makes it annoying to specify - otherwise
> > it'd just be a minimum and maximum spread.  I'm not really coming up
> > with any great ideas right now, it's getting into OPP type territory but
> > it sounds like there's more flexibility for ramping the core voltage so
> > you'd end up with silly numbers of OPPs.

> The OPP shouldn't have to do anything in regards to the regulators
> coupling. The whole idea of the regulators coupling is to make device
> drivers to not churn with the coupling. The coupling in this case is
> specific to SoC and not to a particular board.

The thing with OPPs is that they specify a whole table of values that
work together including regulator settings, the result being that you
have many fewer options but don't need to think about constraints.

> I think the current approach with the customized regulators coupler is
> the best solution for the time being. We may consider something more
> generic if there will be other users with a similar coupling
> requirements, otherwise it's quite difficult to judge what is "generic".
> Do you agree?

Some of the constraints (like having drivers loaded) are kind of fun...

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