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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Mon, 9 Oct 2023 15:13:24 +0200
Message-ID: <CACRpkdY=eza0TuBRDb_cWk9LM2qNQg76rZSgWa-RP4TYLL=Ppw@mail.gmail.com>
Subject: Re: [RFC v2 5/5] dt-bindings: gpio: Add bindings for pinctrl based
 generic gpio driver
To:     Cristian Marussi <cristian.marussi@arm.com>
Cc:     Rob Herring <robh@kernel.org>,
        AKASHI Takahiro <takahiro.akashi@linaro.org>,
        sudeep.holla@arm.com, krzysztof.kozlowski+dt@linaro.org,
        conor+dt@kernel.org, Oleksii_Moisieiev@epam.com,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org
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On Mon, Oct 9, 2023 at 11:08=E2=80=AFAM Cristian Marussi
<cristian.marussi@arm.com> wrote:

> > > +    gpio0: gpio@0 {
> > > +        compatible =3D "pin-control-gpio";
> > > +        gpio-controller;
> > > +        #gpio-cells =3D <2>;
> > > +        gpio-ranges =3D <&scmi_pinctrl 0 10 5>,
> > > +                      <&scmi_pinctrl 5 0 0>;
> > > +        gpio-ranges-group-names =3D "",
> > > +                                  "pinmux_gpio";
> > > +    };
> >
>
> Assuming the above &scmi_pinctrl refers to the protocol node as we
> usually do,

No it does not, it is a three-layer cake.

scmi <-> scmi_pinctrl <-> scmi_gpio

it refers to the scmi_pinctrl node.

There is no SCMI GPIO protocol, instead SCMI is using the
operations already available in the pin controller to exercise
GPIO. Generic pin control has operations to drive lines for
example, and Takahiro is adding the ability for a generic pin
controller to also read a line.

Yours,
Linus Walleij