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From: Andrejs Cainikovs <andrejs.cainikovs@gmail.com>
To: Nishanth Menon <nm@ti.com>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Tero Kristo <kristo@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Aswath Govindraju <a-govindraju@ti.com>,
	Sjoerd Simons <sjoerd@collabora.com>
Cc: Andrejs Cainikovs <andrejs.cainikovs@toradex.com>,
	linux-arm-kernel@lists.infradead.org,
	devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v1] arm64: dts: ti: k3-am62-main: disable usb lpm
Date: Fri,  9 Feb 2024 14:02:12 +0100
Message-Id: <20240209130213.38908-1-andrejs.cainikovs@gmail.com>
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From: Andrejs Cainikovs <andrejs.cainikovs@toradex.com>

AM62 USB works with some devices, while failing to operate with others.

[  560.189822] xhci-hcd xhci-hcd.4.auto: xHCI Host Controller
[  560.195631] xhci-hcd xhci-hcd.4.auto: new USB bus registered, assigned bus number 2
[  574.388509] xhci-hcd xhci-hcd.4.auto: can't setup: -110
[  574.393814] xhci-hcd xhci-hcd.4.auto: USB bus 2 deregistered
[  574.399544] xhci-hcd: probe of xhci-hcd.4.auto failed with error -110

This seems to be related to LPM (Link Power Management), and disabling it
turns USB into reliable working state.

As per AM62 reference manual:

> 4.8.2.1 USB2SS Unsupported Features
>
> The following features are not supported on this family of devices:
> ...
> - USB 2.0 ECN: Link Power Management (LPM)
> ...

Fixes: 2240f96cf3cd ("arm64: dts: ti: k3-am62-main: Add support for USB")
Signed-off-by: Andrejs Cainikovs <andrejs.cainikovs@toradex.com>
---
 arch/arm64/boot/dts/ti/k3-am62-main.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/ti/k3-am62-main.dtsi b/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
index 464b7565d085..c49fbce5cb70 100644
--- a/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62-main.dtsi
@@ -640,6 +640,8 @@ usb0: usb@31000000 {
 			interrupt-names = "host", "peripheral";
 			maximum-speed = "high-speed";
 			dr_mode = "otg";
+			snps,usb2-gadget-lpm-disable;
+			snps,usb2-lpm-disable;
 		};
 	};
 
@@ -663,6 +665,8 @@ usb1: usb@31100000 {
 			interrupt-names = "host", "peripheral";
 			maximum-speed = "high-speed";
 			dr_mode = "otg";
+			snps,usb2-gadget-lpm-disable;
+			snps,usb2-lpm-disable;
 		};
 	};
 
-- 
2.34.1