linux-kernel - Re: [RFC PATCH 02/13] dt-bindings: pinctrl: renesas: Document RZ/V2H(P) SoC

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Message-ID: <CA+V-a8t5KyDZ3FCP2GqYwK8AY_x0++HB471KxQgAbPdLTVHzGw@mail.gmail.com>
Date: Wed, 27 Mar 2024 18:58:53 +0000
From: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To: Rob Herring <robh@...nel.org>
Cc: Geert Uytterhoeven <geert+renesas@...der.be>, Linus Walleij <linus.walleij@...aro.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Magnus Damm <magnus.damm@...il.com>, linux-renesas-soc@...r.kernel.org, 
	linux-gpio@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [RFC PATCH 02/13] dt-bindings: pinctrl: renesas: Document
 RZ/V2H(P) SoC

Hi Rob,

Thank you for the review.

On Wed, Mar 27, 2024 at 5:24 PM Rob Herring <robh@...nel.org> wrote:
>
> On Tue, Mar 26, 2024 at 10:28:33PM +0000, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> >
> > Add documentation for the pin controller found on the Renesas RZ/V2H(P)
> > (R9A09G057) SoC. Compared to RZ/G2L family of SoCs there are slight
> > differences on the RZ/V2H(P) SoC for pinmuxing.
> >
> > Also add 'renesas-rzv2h,output-impedance' property. Drive strength
> > setting on RZ/V2H(P) depends on the different power rails which are
> > coming out from the PMIC (connected via i2c). These power rails
> > (required for drive strength) can be 1.2/1.8/3.3V.
> >
> > Pin are grouped into 4 groups,
> >
> > Group1: Impedance
> > - 150/75/38/25 ohms (at 3.3 V)
> > - 130/65/33/22 ohms (at 1.8 V)
> >
> > Group2: Impedance
> > - 50/40/33/25 ohms (at 1.8 V)
> >
> > Group3: Impedance
> > - 150/75/37.5/25 ohms (at 3.3 V)
> > - 130/65/33/22 ohms (at 1.8 V)
> >
> > Group4: Impedance
> > - 110/55/30/20 ohms (at 1.8 V)
> > - 150/75/38/25 ohms (at 1.2 V)
> >
> > 'renesas-rzv2h,output-impedance' property as documented which can be
> > [1, 2, 4, 6] indicates x Value strength.
>
> Looks like the values are x1, x1.5, x3ish, x6...
>
> >
> > As the power rail information cannot be available very early in the
> > boot process as 'renesas-rzv2h,output-impedance' property is added
> > instead of reusing output-impedance-ohms property.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > ---
> >  .../pinctrl/renesas,rzg2l-pinctrl.yaml        | 22 +++++++++++++++----
> >  1 file changed, 18 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
> > index 881e992adca3..77f4fc7f4a21 100644
> > --- a/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
> > +++ b/Documentation/devicetree/bindings/pinctrl/renesas,rzg2l-pinctrl.yaml
> > @@ -26,6 +26,7 @@ properties:
> >                - renesas,r9a07g043-pinctrl # RZ/G2UL{Type-1,Type-2} and RZ/Five
> >                - renesas,r9a07g044-pinctrl # RZ/G2{L,LC}
> >                - renesas,r9a08g045-pinctrl # RZ/G3S
> > +              - renesas,r9a09g057-pinctrl # RZ/V2H(P)
> >
> >        - items:
> >            - enum:
> > @@ -66,10 +67,14 @@ properties:
> >      maxItems: 1
> >
> >    resets:
> > -    items:
> > -      - description: GPIO_RSTN signal
> > -      - description: GPIO_PORT_RESETN signal
> > -      - description: GPIO_SPARE_RESETN signal
> > +    oneOf:
> > +      - items:
> > +          - description: GPIO_RSTN signal
> > +          - description: GPIO_PORT_RESETN signal
> > +          - description: GPIO_SPARE_RESETN signal
> > +      - items:
> > +          - description: PFC main reset
> > +          - description: Reset for the control register related to WDTUDFCA and WDTUDFFCM pins
> >
> >  additionalProperties:
> >    anyOf:
> > @@ -111,6 +116,15 @@ additionalProperties:
> >          output-high: true
> >          output-low: true
> >          line-name: true
> > +        renesas-rzv2h,output-impedance:
>
> 'renesas-rzv2h' is not a vendor.
>
I will update this to "renesas,output-impedance".

> That should give you a warning if you actually used this somewhere.
>
I did run dtbs_check with this property in the DTS and haven't seen
any warning. Also now I included this property in the example node in
the binding doc and seen no warnings reported by dt_binding_check too.

> > +          description: |
> > +            Output impedance for pins on RZ/V2H(P) SoC.
> > +            x1: Corresponds to 0 in IOLH register.
> > +            x2: Corresponds to 1 in IOLH register.
> > +            x4: Corresponds to 2 in IOLH register.
> > +            x6: Corresponds to 3 in IOLH register.
>
> Why not just use 0-3 for the values?
>
Fine by me. I'll update this in the next version.

Cheers,
Prabhakar