Thread (6 messages) 6 messages, 3 authors, 2021-11-21
STALE1706d

[PATCH devicetree 3/3] arm64: dts: lx2160abluebox3: update RGMII delays for sja1105 switch

From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2021-10-20 11:36:48
Also in: linux-arm-kernel, linux-devicetree, lkml
Subsystem: arm/freescale layerscape arm architecture, the rest · Maintainers: Frank Li, Linus Torvalds

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 apply both RX and
TX delays. To preserve that, add explicit 2 nanosecond delays, which are
identical with what the driver used to add (a 90 degree phase shift).
The delays from the phy-mode are 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>
---
 arch/arm64/boot/dts/freescale/fsl-lx2160a-bluebox3.dts | 4 ++++
 1 file changed, 4 insertions(+)
diff --git a/arch/arm64/boot/dts/freescale/fsl-lx2160a-bluebox3.dts b/arch/arm64/boot/dts/freescale/fsl-lx2160a-bluebox3.dts
index b21be03da0af..042c486bdda2 100644
--- a/arch/arm64/boot/dts/freescale/fsl-lx2160a-bluebox3.dts
+++ b/arch/arm64/boot/dts/freescale/fsl-lx2160a-bluebox3.dts
@@ -386,6 +386,8 @@ port@2 {
 				reg = <2>;
 				ethernet = <&dpmac17>;
 				phy-mode = "rgmii-id";
+				rx-internal-delay-ps = <2000>;
+				tx-internal-delay-ps = <2000>;
 
 				fixed-link {
 					speed = <1000>;
@@ -529,6 +531,8 @@ port@2 {
 				reg = <2>;
 				ethernet = <&dpmac18>;
 				phy-mode = "rgmii-id";
+				rx-internal-delay-ps = <2000>;
+				tx-internal-delay-ps = <2000>;
 
 				fixed-link {
 					speed = <1000>;
-- 
2.25.1
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