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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a4ec438d-b563-4d5d-ade6-92d216bee9f5@bootlin.com>
Date: Thu, 18 Sep 2025 17:41:41 +0200
From: Richard GENOUD <richard.genoud@...tlin.com>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Thinh Nguyen
 <Thinh.Nguyen@...opsys.com>, Aswath Govindraju <a-govindraju@...com>,
 linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH 1/2] dt-bindings: usb/ti,am62-usb.yaml: Add
 ti,lane-reverse property

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@...0000 {
		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@...00000 {
			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