linux-kernel - Re: [PATCH v5 15/22] arm64: dts: renesas: r9a09g057: Add USB2.0 VBUS

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Message-ID: <CAMuHMdVfsO1NVv6+N37C8ss3thKz+sANCtO00PRhgnD5M1cs0Q@mail.gmail.com>
Date: Mon, 26 Jan 2026 17:59:02 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
Cc: tomm.merciai@...il.com, linux-renesas-soc@...r.kernel.org, 
	biju.das.jz@...renesas.com, Peter Rosin <peda@...ntia.se>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Vinod Koul <vkoul@...nel.org>, 
	Kishon Vijay Abraham I <kishon@...nel.org>, Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>, 
	Philipp Zabel <p.zabel@...gutronix.de>, 
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>, Magnus Damm <magnus.damm@...il.com>, 
	Guenter Roeck <linux@...ck-us.net>, Mark Brown <broonie@...nel.org>, 
	Jonathan Cameron <jonathan.cameron@...wei.com>, Georgi Djakov <djakov@...nel.org>, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>, Arnd Bergmann <arnd@...db.de>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-phy@...ts.infradead.org
Subject: Re: [PATCH v5 15/22] arm64: dts: renesas: r9a09g057: Add USB2.0
 VBUS_SEL mux-controller support

Hi Tommaso,

On Thu, 27 Nov 2025 at 12:51, Tommaso Merciai
<tommaso.merciai.xr@...renesas.com> wrote:
> Enable control of USB2.0 VBUSEN via the VBUS_SEL bit in the VBENCTL
> register. According to the RZ/V2H(P) SoC hardware manual, OTG channels
> require VBUS_SEL set, while HOST-only channels require it cleared.
>
> Add `#mux-state-cell` to the usb20phyrst and usb21phyrst reset
> nodes to expose them as mux controllers.
>
> Set the required mux-states in usb2_phy0 (OTG: state 1) and usb2_phy1
> (HOST: state 0) nodes.
>
> This enables proper VBUSEN management for OTG and HOST-only USB2.0
> channels.
>
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>

Thanks for your patch!

> --- a/arch/arm64/boot/dts/renesas/r9a09g057.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r9a09g057.dtsi
> @@ -1034,6 +1034,7 @@ usb2_phy0: usb-phy@...00200 {
>                         resets = <&usb20phyrst>;
>                         #phy-cells = <1>;
>                         power-domains = <&cpg>;
> +                       mux-states = <&usb20phyrst 1>;

I am no USB expert, and didn't really follow the USB specifics of
this series, but isn't the selection of host (VBUSEN = 1) or function
(VBUSEN = 0) mode decided at runtime?

>                         status = "disabled";
>                 };
>
> @@ -1047,6 +1048,7 @@ usb2_phy1: usb-phy@...10200 {
>                         resets = <&usb21phyrst>;
>                         #phy-cells = <1>;
>                         power-domains = <&cpg>;
> +                       mux-states = <&usb21phyrst 0>;

The second controller is always used in host mode, so 0 is correct.

>                         status = "disabled";
>                 };
>

Gr{oetje,eeting}s,

                        Geert

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

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds