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Message-ID: <8c3835c4-3602-4cee-9631-0551b0341918@kernel.org>
Date: Sat, 7 Feb 2026 14:44:59 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Ze Huang <huang.ze@...ux.dev>, Chukun Pan <amadeus@....edu.cn>
Cc: Yixun Lan <dlan@...nel.org>, Vinod Koul <vkoul@...nel.org>,
Rob Herring <robh@...nel.org>, Mark Brown <broonie@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, Liam Girdwood <lgirdwood@...il.com>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Neil Armstrong <neil.armstrong@...aro.org>, linux-riscv@...ts.infradead.org,
linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org, spacemit@...ts.linux.dev
Subject: Re: [PATCH 1/2] dt-bindings: phy: spacemit: add regulator support to
K1 USB2 PHY
On 07/02/2026 13:30, Ze Huang wrote:
> On Sat Feb 7, 2026 at 6:48 PM CST, Krzysztof Kozlowski wrote:
>> On Fri, Feb 06, 2026 at 06:00:08PM +0800, Chukun Pan wrote:
>>> Add an optional phy-supply property to describe the regulator
>>> supplying for USB VBUS.
>>
>> Why wasn't it there before? USB did not have VBUS?
>
> Previously, the VBUS regulator was defined as regulator-always-on in
> the device tree as a workaround.
Bindings are supposed to be complete regardless what driver does (or
does not).
You must list all supplies with proper names.
If this regulator was missing, then what else?
>
>>
>> Explanation is so incomplete I suspect you are patching broken things,
>> so as well this could be completely different hardware (e.g. there is no
>> regulator for this block but e.g. connector).
>>
>
> usb ports under usb hub node can describe the topology well, but
> still regulator always-on is necessary as no driver toggles it.
>
> usb3 {
> dr_mode = "host";
> #address-cells = <1>;
> #size-cells = <0>;
> status = "okay";
>
> hub_2_0: hub@1 {
> compatible = "usb2109,2817";
> reg = <0x1>;
> #address-cells = <1>;
> #size-cells = <0>;
> vdd-supply = <&usb3_vhub>;
> peer-hub = <&hub_3_0>;
> reset-gpios = <&gpio K1_GPIO(124) GPIO_ACTIVE_LOW>;
>
> port@1 {
> reg = <1>;
> vbus-supply = <&usb3_vbus>;
> };
>
> port@2 {
> reg = <2>;
> vbus-supply = <&usb3_vbus>;
> };
>
> ...
>
> hub_3_0: hub@2 {
> ...
> };
> };
>
> Here is the diagram for the USB2, USB3 controller on K1 Jupiter board [1] (page 21)
>
> +-----------------------+
> | K1 SoC |
> | |
> | +-----------------+ | (USB 3.0)
> | | USB3 Controller |--|---------------------------------->+--------------------------+
> | +-----------------+ | | VL817 Hub |
> | | | |---> [USB3 Ports]
> | HUB_PWREN | | +----------------------+ | ^
> | (GPIO) --------|---------------------------------->| | Enable Chip Power | | |
> | | | +----------------------+ | |
> | | +--------------------------+ |
> | USB3_PWREN | |
> | (GPIO) -------|----------------------------------------------------------> [VBUS of USB3 Ports]
> | |
> | |
> |~~~~~~~~~~~~~~~~~~~~~~~|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> | |
> | +-----------------+ | (USB 2.0)
> | | USB2 Controller |--|---------------------------------->+--------------------------+
> | +-----------------+ | | FE1_1S Hub |---> [USB2 Ports]
> | | +--------------------------+ ^
> | USB_HOST_PWREN_H | |
> | (GPIO) ----|-----------------------------------------------------------> [VBUS of USB2 Ports]
> | |
> | |
> +-----------------------+
I do not see here a "phy" regulator supply. Are you sure this is how
your pin or supply is called?
>
> [1] https://github.com/milkv-jupiter/jupiter-files/blob/main/hardware/v1_0/jupiter-sch-v1_0.pdf
This page shows the connector, so not the phy.
>
>>
>>>
>>> Signed-off-by: Chukun Pan <amadeus@....edu.cn>
>>> ---
>>> Documentation/devicetree/bindings/phy/spacemit,usb2-phy.yaml | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/phy/spacemit,usb2-phy.yaml b/Documentation/devicetree/bindings/phy/spacemit,usb2-phy.yaml
>>> index 43eaca90d88c..74a1cd5bcdbe 100644
>>> --- a/Documentation/devicetree/bindings/phy/spacemit,usb2-phy.yaml
>>> +++ b/Documentation/devicetree/bindings/phy/spacemit,usb2-phy.yaml
>>> @@ -19,6 +19,10 @@ properties:
>>> clocks:
>>> maxItems: 1
>>>
>>> + phy-supply:
>>> + description:
>>> + Phandle to a regulator that provides power to VBUS.
>>
>
> "vbus-supply" should be more accurate.
>
>> Drop redundant part. This cannot be anything else than phandle and
>> regulator.
>>
>> "VBUS power supply" for example.
>>
>
>> But anyway, I don't have certainty that
>> this is correct hardware representation. It's your task to provide that.
>>
>> Best regards,
>> Krzysztof
>
> I initially considered handling VBUS via the onboard_usb_dev driver, as
> we discussed previously for the BananaPi-F3 board (which uses a VL817
> Hub) [2]. I was waiting for Marco Felsch's patch series "onboard-dev USB
> hub host managed vbus" to land [3].
>
> [2] https://lore.kernel.org/linux-riscv/aWJAT3n_KcND8bOz@monica.localdomain/
> [3] https://lore.kernel.org/all/20250911-v6-16-topic-usb-onboard-dev-v4-0-1af288125d74@pengutronix.de/
>
> I am not certain if managing VBUS in the PHY driver (e.g.,
> phy-stm32-usbphyc.c and phy-rockchip-usb.c) is the standard method.
> I would not insist on the "onboard_usb_dev managed vbus" if this patch
> (PHY managed) is considered proper way.
I am not talking about driver here at all.
Please start describing in the bindings your complete hardware, not your
drivers.
That's a no for this patch, because phy does not have such supply.
Best regards,
Krzysztof
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