Re: [RFC v1 2/4] pinctrl: add polarfire soc mssio pinctrl driver

[Conor Dooley <conor@kernel.org>]

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On Fri, Nov 21, 2025 at 12:13:21AM +0100, Linus Walleij wrote:
> On Thu, Nov 20, 2025 at 1:26 AM Conor Dooley <conor@kernel.org> wrote:
> > On Wed, Nov 19, 2025 at 10:48:07PM +0100, Linus Walleij wrote:
> > > On Wed, Nov 19, 2025 at 7:23 PM Conor Dooley <conor@kernel.org> wrote:
> 
> > > I looked at the bindings that look like this and are not 1:1 to the
> > > in-kernel configs:
> > >
> > >   input-schmitt-enable:
> > >     type: boolean
> > >     description: enable schmitt-trigger mode
> > >
> > >   input-schmitt-disable:
> > >     type: boolean
> > >     description: disable schmitt-trigger mode
> > >
> > >   input-schmitt-microvolt:
> > >     description: threshold strength for schmitt-trigger
> > >
> > > 1. input-schmitt is missing! But it is right there in
> > > drivers/pinctrl/pinconf-generic.c ... All DTS files appear to be
> > > using input-schmitt-enable/disable and -microvolt.
> > >
> > > 2. input-schmitt-microvolt should probably be used separately
> > > to set the voltage threshold and can be used in conjunction
> > > with input-schmitt-enable in the same node. In your case
> > > you probably don't want to use it at all and disallow it.
> > >
> > > They are all treated individually in the parser.
> > >
> > > Maybe we could patch the docs in pinconf-generic.h to make it clear that
> > > they are all mutually exclusive.
> > >
> > > The DT parser is a bit primitive for these.
> > > For example right now it is fine with the schema
> > > to set input-schmitt-enable and input-schmitt-disable at the same time, and
> > > the result will be enabled because of parse order :/
> >
> > > The real trick would be to also make the
> > > schema in Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml
> > > make them at least mutually exclusive and deprecate the
> > > input-schmitt that noone is using, maybe that is simpler than I think?
> >
> > I think that this is probably what to do. Mutual exclusion isn't
> > difficult to set up there and if there's no property for "input-schmitt"
> > then deprecating it sounds pretty reasonable?
> 
> Yeah I agree.
> 
> Do you want to look into it?
> 
> Otherwise it becomes my problem now that I've noticed it :D

Yeah, it's just a binding patch here I think, so yeah I'll do it.

> 
> Yours,
> Linus Walleij

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