linux-kernel - Re: [PATCH] regulator: core: Skip balancing of the enabled regulators in regulator

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Message-ID: <20191008161535.GN4382@sirena.co.uk>
Date:   Tue, 8 Oct 2019 17:15:35 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        linux-kernel@...r.kernel.org, Liam Girdwood <lgirdwood@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        linux-samsung-soc@...r.kernel.org,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Kamil Konieczny <k.konieczny@...sung.com>
Subject: Re: [PATCH] regulator: core: Skip balancing of the enabled
 regulators in regulator_enable()

On Tue, Oct 08, 2019 at 06:02:36PM +0300, Dmitry Osipenko wrote:

Please fix your mail client to word wrap within paragraphs at something
substantially less than 80 columns.  Doing this makes your messages much
easier to read and reply to.

> That OPP patch caused the same problem for the NVIDIA Tegra20 CPUFreq
> driver (in-progress) and I resolved it in the coupler's code [0].
> Perhaps the generic coupler could do the same thing by assuming that
> min_uV=current_uV until any consumer sets the voltage, i.e. if
> regulator_check_consumers(min_uV=0) returns min_uV=0.

That sounds like it might just postpone the inevitable - if you set the
wrong voltage first it might decide to drop down some voltage that
wasn't expected.  There's a bit of a bootstrapping issue.  I think it
would be safer to just say that anything that is within spec won't get
changed any time we balance, we'd only change things if needed to bring
them back into spec.

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