From 436418ef5baa024b7b15dd730c36d651c6aaaf47 Mon Sep 17 00:00:00 2001 From: Eric Neulight Date: Fri, 16 Jan 2026 23:02:20 -0500 Subject: [PATCH] arm64: dts: amlogic: meson-sm1-odroid: Eliminate Odroid HC4 power glitches during boot. Fix issue with Odroid HC4 (and all meson-sm1-odroid) DTS that causes regulator power to momentarily glitch OFF-ON during boot. Add regulator-boot-on to all regulator-fixed and regulator-gpio entries that (1) define a gpio AND (2) define regulator-always-on. U-boot powers on devices necessary for boot then hands off the DTB to the kernel. During probe, linux drivers/regulator/fixed.c and gpio-regulator.c both first set the regulator control gpio (that U-boot already turned ON) to default OFF before then setting it to the defined (ON) state. This glitches the power to the affected devices, unless regulator-boot-on is specified with it. In fact, U-boot has the same behavior. So, during reboot, a power glitch can actually happen twice: once when U-boot reads the DTB and probes the gpio and again when the kernel reads the DTB and probes the gpio. Problem this fixes: On the Odroid HC4, power to the SATA ports glitches during boot and causes some HDDs to do emergency head retract, which should be avoided. On the HC4, power glitches to the SD card, USB, SATA, and HDMI interfaces during boot. These are all boot devices. A power glitch can potentially cause a problem for any sensitive devices during boot. NOTE: This is not limited to just the HC4, likely an issue with ALL DTS with regulator-fixed or regulator-gpio entries that (1) define a gpio AND (2) define regulator-always-on. All such entries should also include regulator-boot-on in order to avoid potential power glitches. At worst, adding regulator-boot-on in such cases is harmless because of regulator-always-on, and, at best, it eliminates detrimental power glitches during boot. So, this is best-practice. Fixes: 164147f094ec5d0fc2c2098a888f4b50cf3096a7 ("arm64: dts: meson-sm1-odroid-hc4: add regulators controlled by GPIOH_8") Fixes: 45d736ab17b44257e15e75e0dba364139fdb0983 ("arm64: dts: meson-sm1-odroid: add 5v regulator gpio") Fixes: 1f80a5cf74a60997b92d2cde772edec093bec4d9 ("arm64: dts: meson-sm1-odroid: add missing enable gpio and supply for tf_io regulator") Fixes: 88d537bc92ca035e2a9920b0abc750dd62146520 ("arm64: dts: meson: convert meson-sm1-odroid-c4 to dtsi") Signed-off-by: Eric Neulight Reviewed-by: Neil Armstrong Acked-by: Viacheslav Bocharov Tested-by: Ricardo Pardini # on Odroid-HC4 5V HDD Link: https://patch.msgid.link/20260116-odroid-hc4-dts-v1-1-459b601cd5cf@linuxdev.slmail.me [narmstrong: fixed subject prefix] Signed-off-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts | 2 ++ arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi | 3 +++ 2 files changed, 5 insertions(+) diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts index 0170139b8d32f..3ece30a0a1fff 100644 --- a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts +++ b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts @@ -52,6 +52,7 @@ gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; }; @@ -65,6 +66,7 @@ gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; }; diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi index db9124779b87b..e6f02d738a21f 100644 --- a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi @@ -37,6 +37,7 @@ gpio = <&gpio_ao GPIOAO_3 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; }; @@ -50,6 +51,7 @@ enable-gpios = <&gpio_ao GPIOE_2 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; gpios = <&gpio_ao GPIOAO_6 GPIO_OPEN_SOURCE>; @@ -81,6 +83,7 @@ regulator-name = "5V"; regulator-min-microvolt = <5000000>; regulator-max-microvolt = <5000000>; + regulator-boot-on; regulator-always-on; vin-supply = <&main_12v>; gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>; -- 2.47.3