From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Vladimir Oltean <vladimir.oltean@nxp.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Shawn Guo <shawnguo@kernel.org>,
        Sasha Levin <sashal@kernel.org>, leoyang.li@nxp.com,
        robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org,
        devicetree@vger.kernel.org
Subject: [PATCH AUTOSEL 5.15 02/29] ARM: dts: ls1021a-tsn: update RGMII delays for sja1105 switch
Date:   Mon, 20 Dec 2021 20:57:23 -0500
Message-Id: <20211221015751.116328-2-sashal@kernel.org>
In-Reply-To: <20211221015751.116328-1-sashal@kernel.org>
References: <20211221015751.116328-1-sashal@kernel.org>
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From: Vladimir Oltean <vladimir.oltean@nxp.com>

[ Upstream commit e691f9282a89e24a8e87cdb91a181c6283ee5124 ]

In the new behavior, the sja1105 driver expects there to be explicit
RGMII delays present on the fixed-link ports, otherwise it will complain
that it falls back to legacy behavior, which is to apply RGMII delays
incorrectly derived from the phy-mode string.

In this case, the legacy behavior of the driver is to not apply delays
in any direction (mostly because the SJA1105T can't do that, so this
board uses PCB traces). To preserve that but also silence the driver,
use explicit delays of 0 ns. The delay information from the phy-mode is
ignored by new kernels (it's still RGMII as long as it's "rgmii*"
something), and the explicit {rx,tx}-internal-delay-ps properties are
ignored by old kernels, so the change works both ways.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/boot/dts/ls1021a-tsn.dts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/ls1021a-tsn.dts b/arch/arm/boot/dts/ls1021a-tsn.dts
index aca78b5eddf20..194748737724c 100644
--- a/arch/arm/boot/dts/ls1021a-tsn.dts
+++ b/arch/arm/boot/dts/ls1021a-tsn.dts
@@ -90,6 +90,8 @@ port@4 {
 				/* Internal port connected to eth2 */
 				ethernet = <&enet2>;
 				phy-mode = "rgmii";
+				rx-internal-delay-ps = <0>;
+				tx-internal-delay-ps = <0>;
 				reg = <4>;
 
 				fixed-link {
-- 
2.34.1