Re: [PATCH 1/2] dt-bindings: usb/ti,am62-usb.yaml: Add ti,lane-reverse property

[Richard GENOUD <richard.genoud@bootlin.com>]

Hi Krzysztof,
Le 14/09/2025 à 16:55, Krzysztof Kozlowski a écrit :
> On 09/09/2025 11:11, Richard GENOUD wrote:
>>>> diff --git a/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>>> index f6e6d084d1c5..ba894d610af0 100644
>>>> --- a/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>>> +++ b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>>> @@ -36,6 +36,11 @@ properties:
>>>>        items:
>>>>          - const: ref
>>>>    
>>>> +  ti,lane-reverse:
>>>> +    description:
>>>> +      Should be present if D+ and D- lanes have to be swapped.
>>>> +    type: boolean
>>>
>>> What is not working with existing data-lanes property?
>> Hum, indeed. data-lanes could definitely be used here.
>>
>>>
>>> Plus, lanes are swapped per port, not for entire device, no?
>> I'm not sure to get what you mean here.
>> The use case I'm trying to address is:
>> pin AD10(USB1_DM) of the AM625 is routed to USB_DP pin of an USB connector.
>> And pin AE9(USB1_DP) of the AM625 is routed to USB_DM pin of an USB
> 
> I understand what you are trying to achieve and my comment was exactly
> about it. You want to change properties of specific connection, high
> speed in that case, right? So this belongs to specific port. Just do the
> homework and run `git grep data-lanes`.
I'm ok with data-lanes, I'm not arguing on that part.

I'm being confused by using it on the port, it doesn't seem to fit the 
hardware.
Let me show the example with the dts k3-am62-main.dtsi:
	usbss0: dwc3-usb@f900000 {
		compatible = "ti,am62-usb";
		reg = <0x00 0x0f900000 0x00 0x800>,
		      <0x00 0x0f908000 0x00 0x400>;
		clocks = <&k3_clks 161 3>;
		clock-names = "ref";
		ti,syscon-phy-pll-refclk = <&usb0_phy_ctrl 0x0>;
		#address-cells = <2>;
		#size-cells = <2>;
		power-domains = <&k3_pds 178 TI_SCI_PD_EXCLUSIVE>;
		ranges;
		status = "disabled";

		usb0: usb@31000000 {
			compatible = "snps,dwc3";
			reg = <0x00 0x31000000 0x00 0x50000>;
			interrupts = <GIC_SPI 188 IRQ_TYPE_LEVEL_HIGH>,
				     <GIC_SPI 188 IRQ_TYPE_LEVEL_HIGH>;
			interrupt-names = "host", "peripheral";
			maximum-speed = "high-speed";
			dr_mode = "otg";
			snps,usb2-gadget-lpm-disable;
			snps,usb2-lpm-disable;
		};
	};
The bit used to swap data lanes is in MMR_USB2SS_CFG_PHY_CONFIG Register 
at address 0x0F900008, so it should be in usbss0 node to match the 
hardware right?

(I've checked on all ti,am62-usb devices, they have only one port)

Thanks for your inputs,
Regards,
Richard

[ Source: https://www.ti.com/lit/pdf/spruiv7 p12003 ]

> 
> 
> Best regards,
> Krzysztof


-- 
Richard Genoud, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com