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From: Alexander Stein <alexander.stein@ew.tq-group.com>
To: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>, Frank Li <Frank.Li@nxp.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>
Cc: Markus Niebel <Markus.Niebel@ew.tq-group.com>,
	linux@ew.tq-group.com, devicetree@vger.kernel.org,
	imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Alexander Stein <alexander.stein@ew.tq-group.com>
Subject: [PATCH 1/2] arm64: dts: imx95-tqma9596sa-mb-smarc-2.dts: improve SD reset pulse
Date: Mon, 28 Sep 2026 13:21:41 +0200	[thread overview]
Message-ID: <20260928112143.294091-1-alexander.stein@ew.tq-group.com> (raw)

From: Markus Niebel <Markus.Niebel@ew.tq-group.com>

SD card spec says that at least 1 msec of power cut is needed
to reset an SD card. This is needed to get out of UHS-I mode.

In fact this pulse length alone is far too short in real world
environment due to capacitance etc. Implement a longer pulse using
regulator settings: 200 msec as working for other SoM using MB-SMARC-2.

Signed-off-by: Markus Niebel <Markus.Niebel@ew.tq-group.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
 arch/arm64/boot/dts/freescale/imx95-tqma9596sa-mb-smarc-2.dts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx95-tqma9596sa-mb-smarc-2.dts b/arch/arm64/boot/dts/freescale/imx95-tqma9596sa-mb-smarc-2.dts
index 97726eded0f86..e376d3a9d6180 100644
--- a/arch/arm64/boot/dts/freescale/imx95-tqma9596sa-mb-smarc-2.dts
+++ b/arch/arm64/boot/dts/freescale/imx95-tqma9596sa-mb-smarc-2.dts
@@ -243,6 +243,8 @@ &pcie1 {
 };
 
 &reg_sdvmmc {
+	startup-delay-us = <100>;
+	off-on-delay-us = <200000>;
 	status = "okay";
 };
 
-- 
2.55.0


             reply	other threads:[~2026-09-28 11:22 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-28 11:21 Alexander Stein [this message]
2026-09-28 11:21 ` [PATCH 2/2] arm64: dts: imx95-tqma9596sa: Add thermal zones Alexander Stein
2026-10-01 14:53 ` [PATCH 1/2] arm64: dts: imx95-tqma9596sa-mb-smarc-2.dts: improve SD reset pulse Frank.Li

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