100 lines
4.2 KiB
Diff
100 lines
4.2 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Eric Neulight <Eric.Neulight@linuxdev.slmail.me>
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Date: Fri, 16 Jan 2026 23:02:20 -0500
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Subject: Eliminate Odroid HC4 power glitches during boot.
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Fix issue with Odroid HC4 (and all meson-sm1-odroid) DTS that causes
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regulator power to momentarily glitch OFF-ON during boot. Add
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regulator-boot-on to all regulator-fixed and regulator-gpio entries
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that (1) define a gpio AND (2) define regulator-always-on.
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U-boot powers on devices necessary for boot then hands off the DTB to
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the kernel. During probe, linux drivers/regulator/fixed.c and
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gpio-regulator.c both first set the regulator control gpio (that U-boot
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already turned ON) to default OFF before then setting it to the defined
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(ON) state. This glitches the power to the affected devices, unless
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regulator-boot-on is specified with it. In fact, U-boot has the same
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behavior. So, during reboot, a power glitch can actually happen twice:
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once when U-boot reads the DTB and probes the gpio and again when the
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kernel reads the DTB and probes the gpio.
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Problem this fixes: On the Odroid HC4, power to the SATA ports glitches
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during boot and causes some HDDs to do emergency head retract, which
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should be avoided. On the HC4, power glitches to the SD card, USB,
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SATA, and HDMI interfaces during boot. These are all boot devices.
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A power glitch can potentially cause a problem for any sensitive devices
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during boot.
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NOTE: This is not limited to just the HC4, likely an issue with ALL DTS
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with regulator-fixed or regulator-gpio entries that (1) define a gpio
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AND (2) define regulator-always-on. All such entries should also
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include regulator-boot-on in order to avoid potential power glitches.
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At worst, adding regulator-boot-on in such cases is harmless because of
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regulator-always-on, and, at best, it eliminates detrimental power
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glitches during boot. So, this is best-practice.
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Fixes: 164147f094ec5d0fc2c2098a888f4b50cf3096a7 ("arm64: dts: meson-sm1-odroid-hc4: add regulators controlled by GPIOH_8")
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Fixes: 45d736ab17b44257e15e75e0dba364139fdb0983 ("arm64: dts: meson-sm1-odroid: add 5v regulator gpio")
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Fixes: 1f80a5cf74a60997b92d2cde772edec093bec4d9 ("arm64: dts: meson-sm1-odroid: add missing enable gpio and supply for tf_io regulator")
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Fixes: 88d537bc92ca035e2a9920b0abc750dd62146520 ("arm64: dts: meson: convert meson-sm1-odroid-c4 to dtsi")
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Signed-off-by: Eric Neulight <Eric.Neulight@linuxdev.slmail.me>
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Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
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Link: https://lore.kernel.org/r/20260116-odroid-hc4-dts-v1-1-459b601cd5cf@linuxdev.slmail.me
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---
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arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts | 2 ++
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arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi | 3 +++
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2 files changed, 5 insertions(+)
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diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts
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index 111111111111..222222222222 100644
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--- a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts
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+++ b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts
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@@ -52,6 +52,7 @@ p12v_0: regulator-p12v-0 {
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gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>;
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enable-active-high;
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+ regulator-boot-on;
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regulator-always-on;
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};
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@@ -65,6 +66,7 @@ p12v_1: regulator-p12v-1 {
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gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>;
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enable-active-high;
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+ regulator-boot-on;
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regulator-always-on;
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};
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diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi
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index 111111111111..222222222222 100644
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--- a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi
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+++ b/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi
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@@ -37,6 +37,7 @@ tflash_vdd: regulator-tflash-vdd {
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gpio = <&gpio_ao GPIOAO_3 GPIO_OPEN_DRAIN>;
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enable-active-high;
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+ regulator-boot-on;
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regulator-always-on;
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};
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@@ -50,6 +51,7 @@ tf_io: gpio-regulator-tf-io {
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enable-gpios = <&gpio_ao GPIOE_2 GPIO_OPEN_DRAIN>;
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enable-active-high;
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+ regulator-boot-on;
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regulator-always-on;
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gpios = <&gpio_ao GPIOAO_6 GPIO_OPEN_SOURCE>;
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@@ -81,6 +83,7 @@ vcc_5v: regulator-vcc-5v {
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regulator-name = "5V";
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regulator-min-microvolt = <5000000>;
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regulator-max-microvolt = <5000000>;
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+ regulator-boot-on;
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regulator-always-on;
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vin-supply = <&main_12v>;
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gpio = <&gpio GPIOH_8 GPIO_OPEN_DRAIN>;
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--
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Armbian
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