linux-kernel - Re: [PATCH v2 2/3] arm64: dts: exynos: ExynosAutov920: Add regulators for the USB

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Message-ID: <352427f4-144a-4a43-a2f3-dd959302939f@kernel.org>
Date: Thu, 22 Jan 2026 14:34:14 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Pritam Manohar Sutar <pritam.sutar@...sung.com>, robh@...nel.org,
 krzk+dt@...nel.org, conor+dt@...nel.org, alim.akhtar@...sung.com
Cc: devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
 rosa.pila@...sung.com, dev.tailor@...sung.com, faraz.ata@...sung.com,
 muhammed.ali@...sung.com, selvarasu.g@...sung.com
Subject: Re: [PATCH v2 2/3] arm64: dts: exynos: ExynosAutov920: Add regulators
 for the USB

On 22/01/2026 14:07, Pritam Manohar Sutar wrote:
> Add dummy regulator for USB and PHY supplies.
> 
> Add vbus regulator that is enabled by GPIO pin.
> 
> Signed-off-by: Pritam Manohar Sutar <pritam.sutar@...sung.com>
> ---
>  .../boot/dts/exynos/exynosautov920-sadk.dts   | 139 ++++++++++++++++++
>  1 file changed, 139 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/exynos/exynosautov920-sadk.dts b/arch/arm64/boot/dts/exynos/exynosautov920-sadk.dts
> index a397f068ed53..f90f7704597c 100644
> --- a/arch/arm64/boot/dts/exynos/exynosautov920-sadk.dts
> +++ b/arch/arm64/boot/dts/exynos/exynosautov920-sadk.dts
> @@ -52,6 +52,76 @@ memory@...00000 {
>  		      <0x8 0x80000000 0x1 0xfba00000>,
>  		      <0xa 0x00000000 0x2 0x00000000>;
>  	};
> +
> +	/* TODO: Remove this once PMIC is implemented  */
> +	dummy_regulator: regulator-0 {
> +		 compatible = "regulator-fixed";
> +		 regulator-name = "dummy_regulator";
> +	};
> +
> +	usbdrd31_dwc3_vbus: usbdrd31_dwc3-vbus {

Please use name for all fixed regulators which matches current format
recommendation: 'regulator-[0-9]v[0-9]'

https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/regulator/fixed-regulator.yaml

None of the regulators are called like you wrote. Really NONE.

Also, carefully follow DTS coding style.

> +	       compatible = "regulator-fixed";
> +	       regulator-name = "usbdrd31_dwc3-vbus";
> +	       regulator-min-microvolt = <5000000>;
> +	       regulator-max-microvolt = <5000000>;
> +	       enable-active-high;
> +	       regulator-always-on;
> +	       gpio = <&gpp2 0 GPIO_ACTIVE_HIGH>;
> +	};
> +
> +	/* Use gpio for enabling vbus regulator */
> +	usb_phy0: usb-phy0 {

usb-phy-0

> +		compatible = "usb-nop-xceiv";
> +		vbus-supply = <&usbdrd31_dwc3_vbus>;

That's pretty incomplete. Why do you need such node - just to toggle
regulator?

> +	};

...

> +&usbdrd20_phy2 {
> +	dvdd-supply = <&dummy_regulator>;
> +	vdd18-supply = <&dummy_regulator>;
> +	vdd33-supply = <&dummy_regulator>;
> +};
> +
> +&usbdrd20_dwc3_2 {
> +	maximum-speed = "high-speed";
> +	usb-phy = <&usb_phy3>;
> +};
> +
> +&usbdrd20_2 {
> +	vdd10-supply = <&dummy_regulator>;
> +	vdd33-supply = <&dummy_regulator>;
> +};

That's a bit too much of dummies. This is heavily incomplete. You need
to bring back the PMIC first.


Best regards,
Krzysztof