From: Marek Vasut Date: Tue, 5 May 2026 03:42:52 +0000 (+0200) Subject: arm64: dts: renesas: gray-hawk: Specify ethernet PHY reset timings X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0b99c3aa40e7fa98f28a966d96967b5e50946f91;p=thirdparty%2Flinux.git arm64: dts: renesas: gray-hawk: Specify ethernet PHY reset timings The KSZ9031RNX reference manual [1] DS00002117K page 62 FIGURE 7-5: 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] DS00002117K page 62 TABLE 7-4: 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/KSZ9031RNX-Data-Sheet-DS00002117.pdf Signed-off-by: Marek Vasut Tested-by: Geert Uytterhoeven Reviewed-by: Geert Uytterhoeven Link: https://patch.msgid.link/20260505034325.167797-12-marek.vasut+renesas@mailbox.org Signed-off-by: Geert Uytterhoeven --- diff --git a/arch/arm64/boot/dts/renesas/gray-hawk-single.dtsi b/arch/arm64/boot/dts/renesas/gray-hawk-single.dtsi index 792a4aa8f4a9d..274493720b14e 100644 --- a/arch/arm64/boot/dts/renesas/gray-hawk-single.dtsi +++ b/arch/arm64/boot/dts/renesas/gray-hawk-single.dtsi @@ -213,6 +213,8 @@ reg = <0>; interrupts-extended = <&gpio7 5 IRQ_TYPE_LEVEL_LOW>; reset-gpios = <&gpio7 10 GPIO_ACTIVE_LOW>; + reset-assert-us = <10000>; + reset-deassert-us = <300>; }; }; };