Re: [PATCH 5/5] arm64: tegra: smaug: Add usb-role-switch support

Diogo Ivo
2026-01-13T15:11:36Z

On 1/13/26 14:49, Jon Hunter wrote:
>
> On 13/01/2026 14:20, Diogo Ivo wrote:
>>
>>
>> On 1/12/26 22:03, Jon Hunter wrote:
>>>
>>> On 04/12/2025 21:27, Diogo Ivo wrote:
>>>> The USB2 port on Smaug is configured for OTG operation but lacked the
>>>> required 'usb-role-switch' property, leading to a failed probe and a
>>>> non-functioning USB port. Add the property along with setting the
>>>> default
>>>> role to host.
>>>>
>>>> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
>>>> ---
>>>> arch/arm64/boot/dts/nvidia/tegra210-smaug.dts | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts b/arch/
>>>> arm64/boot/dts/nvidia/tegra210-smaug.dts
>>>> index b8d854f90be7..49bf23d6f593 100644
>>>> --- a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
>>>> +++ b/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
>>>> @@ -1809,6 +1809,8 @@ usb2-0 {
>>>> status = "okay";
>>>> vbus-supply = <&usbc_vbus>;
>>>> mode = "otg";
>>>> + usb-role-switch;
>>>> + role-switch-default-mode = "host";
>>>> };
>>>
>>>
>>> This change does add the following warning when building with CHECK_DTBS
>>> ...
>>>
>>> arch/arm64/boot/dts/nvidia/tegra210-smaug.dtb: padctl@7009f000
>>> (nvidia,tegra210-xusb-padctl): ports:usb2-0: 'role-switch-default-
>>> mode' does not match any of the regexes: '^pinctrl-[0-9]+$'
>>> from schema $id: http://devicetree.org/schemas/phy/
>>> nvidia,tegra210- xusb-padctl.yaml
>>>
>>> I know that there are many warnings seen for the smaug DTB, but it would
>>> be good to ensure we don't add more.
>>
>> The 'role-switch-default-mode' property is read by the driver to set the
>> initial role for the port [0] and is needed in order for the port to work
>> when booting so in order to fix the warning this property needs to be
>> added
>> to the binding.
>
> Correct.
>
>> As for the other warning ('connector' is a dependency of 'usb-role-
>> switch')
>> again I think the binding needs to be adjusted since in the Pixel C the
>> connector node should be under the (as for now not present)
>> cros-ec-typec node and the usb2-0 is then modeled as a remote-endpoint
>> for the full connector. I am currently working on fixing the cros-ec-
>> typec
>> driver and already have a working fix for automatic role switching but
>> in any case I think the binding is what needs changing. If you agree
>> with this then I will add the necessary changes to the DT binding in v2.
>
> Yes in both cases we need fixes to the DT binding that's all.

Perfect, will do for v2.

Diogo

> Jon
>