[PATCH 2/2] arm: dts: renesas: armadillo800eva: Specify ethernet PHY reset timings

[Marek Vasut]

The LAN8710Ai reference manual [1] DS00002164C page 61 FIGURE 5-3:
POWER-ON NRST & CONFIGURATION STRAP TIMING 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 300 us
which should cover every timing option, including the 16 us delay
required for MDIO to switch to 25 MHz listed in Note: in Chapter
3.8.5 RESETS.

The LAN8710Ai reference manual [1] DS00002164C page 61 TABLE 5-8:
POWER-ON NRST & CONFIGURATION STRAP TIMING VALUES row tSR Stable
supply voltages to reset high is at minimum 10 ms. Set DT property
reset-assert-us to 25ms because the LAN8710Ai 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/LAN8710A-LAN8710Ai-Data-Sheet-DS00002164.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/r8a7740-armadillo800eva.dts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/renesas/r8a7740-armadillo800eva.dts b/arch/arm/boot/dts/renesas/r8a7740-armadillo800eva.dts
index 1d56bdef54539..eb65a54d0e511 100644
--- a/arch/arm/boot/dts/renesas/r8a7740-armadillo800eva.dts
+++ b/arch/arm/boot/dts/renesas/r8a7740-armadillo800eva.dts
@@ -194,12 +194,14 @@ &ether {
 
 	phy0: ethernet-phy@0 {
 		compatible = "ethernet-phy-id0007.c0f1",
 			     "ethernet-phy-ieee802.3-c22";
 		reg = <0>;
 		reset-gpios = <&pfc 18 GPIO_ACTIVE_LOW>;
+		reset-assert-us = <25000>;
+		reset-deassert-us = <300>;
 	};
 };
 
 &extal1_clk {
 	clock-frequency = <24000000>;
 };
-- 
2.53.0