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Subject[PATCH 05/11] arm64: dts: renesas: condor-common: Specify ethernet PHY reset timings
Date
The KSZ9031RNX reference manual [1] DS00002096H page 60 FIGURE 7-7:
POWER-UP/POWER-DOWN/RESET TIMING Note 2 states, that after the
de-assertion of reset, wait a minimum of 100 us before starting
programming on the MIIM (MDC/MDIO) interface. Set DT property
reset-deassert-us to three times that, 300 us, to provide ample
time between reset deassertion and MDIO access.

The KSZ9031RNX reference manual [1] DS00002096H page 60 TABLE 7-7:
POWER-UP/POWER-DOWN/RESET TIMING PARAMETERS row tSR Stable supply
voltages to de-assertion of reset is at minimum 10 ms. Set DT
property reset-assert-us to 10ms because the KSZ9031RNX 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/KSZ9031MNX-Data-Sheet-DS00002096.pdf

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
---
arch/arm64/boot/dts/renesas/condor-common.dtsi | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/condor-common.dtsi b/arch/arm64/boot/dts/renesas/condor-common.dtsi
index 6b22cc0b05b19..9d55509b00b15 100644
--- a/arch/arm64/boot/dts/renesas/condor-common.dtsi
+++ b/arch/arm64/boot/dts/renesas/condor-common.dtsi
@@ -168,6 +168,8 @@ phy0: ethernet-phy@0 {
reg = <0>;
interrupts-extended = <&gpio4 23 IRQ_TYPE_LEVEL_LOW>;
reset-gpios = <&gpio4 22 GPIO_ACTIVE_LOW>;
+ reset-assert-us = <10000>;
+ reset-deassert-us = <300>;
};
};

--
2.53.0

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