From nobody Sun Feb 8 04:52:31 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2438D52F88; Sat, 17 Jan 2026 04:02:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768622577; cv=none; b=ebZ5rxg/S3R/uH/w5TxYFxxFJNdoXIsNwLnrVNmVfeeOuyKBNGGtQbZitrdHy5g16jWdxaSPpNqa51umAr/YUwLvgReYeGMWHbcoNxP16pCaulU9rJNGnTRIWWqAaWLw47KGzBvoWx9yIvkFNBCji5+Ksf/YHe+OkxXxWEfy3L8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768622577; c=relaxed/simple; bh=50TUX+3d5K0vnVqShqXZBJO+XBBciVmNK+6gK3etOaQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=BcuHXKsTabRvZqLOC6V92nmM3xB6bAST7H+ZkWkWryXOpIUYFfOUIJ3PwgsFsXi0/sann+KBT92Ll4KZVM41+v85BubVid1UC1vtJi1IaEQlwRhmEaR3QE+bbM8ov6luWXVLdXlau553LHo0VZWShD3a53RhRRHNtrX50RqwMQs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aPf53Vx+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aPf53Vx+" Received: by smtp.kernel.org (Postfix) with ESMTPS id B207EC4CEF7; Sat, 17 Jan 2026 04:02:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768622576; bh=50TUX+3d5K0vnVqShqXZBJO+XBBciVmNK+6gK3etOaQ=; h=From:Date:Subject:To:Cc:Reply-To:From; b=aPf53Vx+dHa60p3bH0ImYYM5dOUMCHI5w4g3rIEzFiA/9M27/KlveqvQX3WYd6yT6 /2H53PSK/+lMRGjHSiYtkGgBj1Tf4TXWAZy2jYHL0GeT/ft5SbfsOcC/Zgr62UX3dW gfZXQiCX/lohMdnS4nvf4YWZbk81oEsQNOj/XMod1wzV1HTmBtnNPagxsuFcziHqye 5dwWjW+X8kWs31tmY6KfUeZrwwIX3/2EOqv84eVSD7BEokjjof2x0zC6St3F9F4RGj 8yjt/53yVyZxNj8cjV1nKfqWS2jG9yhYiUCWrvVY0PYBOTOAdCAe6GVy3jzWVXtcUW VBGw34tLy48fA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E3A5C982C5; Sat, 17 Jan 2026 04:02:56 +0000 (UTC) From: Eric Neulight via B4 Relay Date: Fri, 16 Jan 2026 23:02:20 -0500 Subject: [PATCH] Eliminate Odroid HC4 power glitches during boot. Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260116-odroid-hc4-dts-v1-1-459b601cd5cf@linuxdev.slmail.me> X-B4-Tracking: v=1; b=H4sIAMsJa2kC/x3MMQqAMAxA0atIZgNtSUW8ijhIk2qWVloRQby7x fEN/z9QpahUmLoHilxaNacG23cQ9jVtgsrN4IwbjLUDZi5ZGfdAyGdFT5GcJx69J2jRUSTq/Q/ n5X0/vDgxLGAAAAA= X-Change-ID: 20260116-odroid-hc4-dts-54f4254d8554 To: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org, Eric Neulight X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=4323; i=Eric.Neulight@linuxdev.slmail.me; h=from:subject:message-id; bh=D6GTcwhfX7GFqFVPwCE7THDsRVZibUMqyLB6SBdfMzo=; b=owGbwMvMwCX22yMi/F2X5g7G02pJDJnZnB8enpnGXpJYs7jxUr1Do5TgrreOtnuYrpx221HuN VXAb/HfjlIWBjEuBlkxRZaPK29Nn6k9Ta3o5frVMHNYmUCGMHBxCsBEMqcy/OHf9XHK1h/+L0r0 b7JEbVJ8ffiJZs7ChQ5GLzak/j50r3IKw1/hswYaNlEiNcxbN0ibTuCw2i7Zl3JRq9XkRlZihHH gCx4A X-Developer-Key: i=Eric.Neulight@linuxdev.slmail.me; a=openpgp; fpr=F1A9DA97992B962672E9AFABFB485857EE8A29B8 X-Endpoint-Received: by B4 Relay for Eric.Neulight@linuxdev.slmail.me/default with auth_id=606 X-Original-From: Eric Neulight Reply-To: Eric.Neulight@linuxdev.slmail.me From: Eric Neulight 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-odr= oid-hc4: add regulators controlled by GPIOH_8") Fixes: 45d736ab17b44257e15e75e0dba364139fdb0983 ("arm64: dts: meson-sm1-odr= oid: add 5v regulator gpio") Fixes: 1f80a5cf74a60997b92d2cde772edec093bec4d9 ("arm64: dts: meson-sm1-odr= oid: add missing enable gpio and supply for tf_io regulator") Fixes: 88d537bc92ca035e2a9920b0abc750dd62146520 ("arm64: dts: meson: conver= t meson-sm1-odroid-c4 to dtsi") Signed-off-by: Eric Neulight Acked-by: Viacheslav Bocharov Reviewed-by: Neil Armstrong Tested-by: Ricardo Pardini # on Odroid-HC4 5V HDD --- 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/ar= m64/boot/dts/amlogic/meson-sm1-odroid-hc4.dts index 0170139b8d32f4274ad991b0f3d9a0f6c67969ce..3ece30a0a1fff736c544cf89ed0= a8cca0890f128 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 @@ p12v_0: regulator-p12v-0 { =20 gpio =3D <&gpio GPIOH_8 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; }; =20 @@ -65,6 +66,7 @@ p12v_1: regulator-p12v-1 { =20 gpio =3D <&gpio GPIOH_8 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; }; =20 diff --git a/arch/arm64/boot/dts/amlogic/meson-sm1-odroid.dtsi b/arch/arm64= /boot/dts/amlogic/meson-sm1-odroid.dtsi index c4524eb4f0996dfbccec16ca5b936a5c3b2663a5..0bce4e8d965f2c83e6ba677fef2= ede2726de6ed1 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 @@ tflash_vdd: regulator-tflash-vdd { =20 gpio =3D <&gpio_ao GPIOAO_3 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; }; =20 @@ -50,6 +51,7 @@ tf_io: gpio-regulator-tf-io { =20 enable-gpios =3D <&gpio_ao GPIOE_2 GPIO_OPEN_DRAIN>; enable-active-high; + regulator-boot-on; regulator-always-on; =20 gpios =3D <&gpio_ao GPIOAO_6 GPIO_OPEN_SOURCE>; @@ -81,6 +83,7 @@ vcc_5v: regulator-vcc-5v { regulator-name =3D "5V"; regulator-min-microvolt =3D <5000000>; regulator-max-microvolt =3D <5000000>; + regulator-boot-on; regulator-always-on; vin-supply =3D <&main_12v>; gpio =3D <&gpio GPIOH_8 GPIO_OPEN_DRAIN>; --- base-commit: b71e635feefc852405b14620a7fc58c4c80c0f73 change-id: 20260116-odroid-hc4-dts-54f4254d8554 Best regards, --=20 Eric Neulight