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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Thu, 6 Jun 2024 13:57:39 +0200
Message-ID: <CAMuHMdXrR7ymDBvLywYF1YYf894gUTGsQkC+M-1+uxxAEoS+xA@mail.gmail.com>
Subject: Re: [PATCH v4] dt-bindings: pinctrl: renesas: Document RZ/V2H(P) SoC
To: Prabhakar <prabhakar.csengg@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>, Rob Herring <robh@kernel.org>, 
	Krzysztof Kozlowski <krzk+dt@kernel.org>, Conor Dooley <conor+dt@kernel.org>, 
	Magnus Damm <magnus.damm@gmail.com>, linux-renesas-soc@vger.kernel.org, 
	linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, 
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
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On Thu, Jun 6, 2024 at 10:51=E2=80=AFAM Prabhakar <prabhakar.csengg@gmail.c=
om> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Add documentation for the pin controller found on the Renesas RZ/V2H(P)
> (R9A09G057) SoC. The RZ/V2H PFC varies slightly compared to the RZ/G2L
> family:
> - Additional bits need to be set during pinmuxing.
> - The GPIO pin count is different.
>
> Hence, a SoC-specific compatible string, 'renesas,r9a09g057-pinctrl', is
> added for the RZ/V2H(P) SoC.
>
> Also, add the 'renesas,output-impedance' property. The drive strength
> setting on RZ/V2H(P) depends on the different power rails coming out from
> the PMIC (connected via I2C). These power rails (required for drive
> strength) can be 1.2V, 1.8V, or 3.3V.
>
> Pins are grouped into 4 groups:
>
> Group 1: Impedance
> - 150/75/38/25 ohms (at 3.3V)
> - 130/65/33/22 ohms (at 1.8V)
>
> Group 2: Impedance
> - 50/40/33/25 ohms (at 1.8V)
>
> Group 3: Impedance
> - 150/75/37.5/25 ohms (at 3.3V)
> - 130/65/33/22 ohms (at 1.8V)
>
> Group 4: Impedance
> - 110/55/30/20 ohms (at 1.8V)
> - 150/75/38/25 ohms (at 1.2V)
>
> The 'renesas,output-impedance' property, as documented, can be
> [0, 1, 2, 3], these correspond to register bit values that can
> be set in the PFC_IOLH_mn register, which adjusts the drive
> strength value and is pin-dependent.
>
> As power rail information may not be available very early in the boot
> process, the 'renesas,output-impedance' property is added instead of
> reusing the 'output-impedance-ohms' property.
>
> Also, allow bias-disable, bias-pull-down and bias-pull-up properties
> as these can be used to configure the pins.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> Sending just the binding patch of series [0] as reset of the patches have
> been Reviewed.
>
> [0] https://patchwork.kernel.org/project/linux-renesas-soc/cover/20240530=
173857.164073-1-prabhakar.mahadev-lad.rj@bp.renesas.com/
>
> v3->v4
> - Added a conditional schema for ensuring the reset length
>   is 2 for RZ/V2H and 3 otherwise
> - Updated description for renesas,output-impedance property
> - Dropped '|'

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
i.e. will queue in renesas-pinctrl for v6.11.

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
.org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds