[PATCH 8/9] arm: dts: renesas: sk-rzg1m: Specify ethernet PHY reset timings
From: Marek Vasut
Date: Tue Jul 14 2026 - 09:06:24 EST
The KSZ8041RNL reference manual [1] DS00002245C page 47 TABLE 7-10:
POWER-UP/RESET TIMING PARAMETERS does not indicate how long should
the system wait after deassertion of the PHY reset and before start
of communication with the PHY via MDIO. Opt for the same value as
used for KSZ9031RNX, which is 300 us.
The KSZ8041RNL reference manual [1] DS00002245C page 47 TABLE 7-10:
POWER-UP/RESET TIMING PARAMETERS row tSR Stable supply voltages to
reset high is at minimum 10 ms. Set the DT property reset-assert-us
to 10ms because the KSZ8041RNL RM does not explicitly spell out how
long the reset has to be asserted, but this at least covers the worst
case scenario.
[1] https://ww1.microchip.com/downloads/aemDocuments/documents/UNG/ProductDocuments/DataSheets/00002841D.pdf
Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxxxx>
---
Cc: Conor Dooley <conor+dt@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: Krzysztof Kozlowski <krzk+dt@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
---
arch/arm/boot/dts/renesas/r8a7743-sk-rzg1m.dts | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/boot/dts/renesas/r8a7743-sk-rzg1m.dts b/arch/arm/boot/dts/renesas/r8a7743-sk-rzg1m.dts
index 60217797e5345..dc1b4ca944622 100644
--- a/arch/arm/boot/dts/renesas/r8a7743-sk-rzg1m.dts
+++ b/arch/arm/boot/dts/renesas/r8a7743-sk-rzg1m.dts
@@ -72,8 +72,10 @@ ðer {
phy1: ethernet-phy@1 {
compatible = "ethernet-phy-id0022.1537";
reg = <1>;
interrupts-extended = <&irqc 0 IRQ_TYPE_LEVEL_LOW>;
micrel,led-mode = <1>;
reset-gpios = <&gpio5 22 GPIO_ACTIVE_LOW>;
+ reset-assert-us = <10000>;
+ reset-deassert-us = <300>;
};
};
--
2.53.0