[PATCH v2 2/2] regulator: rpi-panel-v2: Add required vcc-supply support
Shashank Maurya
shashank.maurya at oss.qualcomm.com
Thu Sep 10 22:16:37 PDT 2026
On Mon, Sep 07, 2026 at 07:04:21PM +0100, Conor Dooley wrote:
> On Mon, Sep 07, 2026 at 06:09:57PM +0100, Mark Brown wrote:
> > On Mon, Sep 07, 2026 at 06:06:24PM +0100, Conor Dooley wrote:
> > > On Mon, Sep 07, 2026 at 11:16:08AM +0530, Shashank Maurya wrote:
> >
> > > > + vcc = devm_regulator_get(&i2c->dev, "vcc");
> > > > + if (IS_ERR(vcc))
> > > > + return dev_err_probe(&i2c->dev, PTR_ERR(vcc),
> > > > + "Failed to get vcc supply\n");
> >
> > > This needs to be optional, because without it you'll break existing
> > > devicetrees. Unless you can explain how all existing users are
> > > nonfunctional (e.g. nothing ever enabled the supply, which seems
> > > doubtful given this surely worked when it was added) this must remain
> > > optional.
> >
> > The core will stub in a dummy regulator for mandatory supplies that
> > don't have anything mapped by firmware, otherwise essentially all
> > regualtors would be optional and our error handling would be a disaster
> > zone.
>
> I always forget how this works. Thanks for the reminder.
>
>
Thanks Mark and Conor for the clarification.
To summarize: the binding marks vcc-supply as required
(since the hardware genuinely needs this rail), and the driver uses
devm_regulator_get() which lets the regulator core provide a dummy
stub for existing devicetrees that don't specify the supply.
This keeps backward compatibility intact.
Is the series good to go as-is, or is there anything else you'd like
me to address in a v3?
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