Re: [PATCH v1 11/30] drm/tegra: dc: Support OPP and SoC core voltage scaling

Mark Brown
2020-11-10T20:33:18Z

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On Tue, Nov 10, 2020 at 09:29:45PM +0100, Thierry Reding wrote:
> On Thu, Nov 05, 2020 at 02:44:08AM +0300, Dmitry Osipenko wrote:

> > + /*
> > + * Voltage scaling is optional and trying to set voltage for a dummy
> > + * regulator will error out.
> > + */
> > + if (!device_property_present(dc->dev, "core-supply"))
> > + return;

> This is a potentially heavy operation, so I think we should avoid that
> here. How about you use devm_regulator_get_optional() in ->probe()? That
> returns -ENODEV if no regulator was specified, in which case you can set
> dc->core_reg = NULL and use that as the condition here.

Or enumerate the configurable voltages after getting the regulator and
handle that appropriately which would be more robust in case there's
missing or unusual constraints.

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