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From: Tim Harvey <tharvey@gateworks.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	devicetree@vger.kernel.org, imx@lists.linux.dev,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Tim Harvey <tharvey@gateworks.com>
Subject: [PATCH 1/7] arm64: dts: imx8mm-venice-gw700x: Increase HS400 USDHC clock speed
Date: Mon,  7 Jul 2025 13:16:56 -0700	[thread overview]
Message-ID: <20250707201702.2930066-1-tharvey@gateworks.com> (raw)

The IMX8M reference manuals indicate in the USDHC Clock generator section
that the clock rate for DDR is 1/2 the input clock therefore HS400 rates
clocked at 200Mhz require a 400Mhz SDHC clock.

This showed about a 1.5x improvement in read performance for the eMMC's
used on the various imx8m{m,n,p}-venice boards.

Fixes: 6f30b27c5ef5 ("arm64: dts: imx8mm: Add Gateworks i.MX 8M Mini Development Kits")
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
 arch/arm64/boot/dts/freescale/imx8mm-venice-gw700x.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-venice-gw700x.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw700x.dtsi
index 5a3b1142ddf4..37db4f0dd505 100644
--- a/arch/arm64/boot/dts/freescale/imx8mm-venice-gw700x.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-venice-gw700x.dtsi
@@ -418,6 +418,8 @@ &usdhc3 {
 	pinctrl-0 = <&pinctrl_usdhc3>;
 	pinctrl-1 = <&pinctrl_usdhc3_100mhz>;
 	pinctrl-2 = <&pinctrl_usdhc3_200mhz>;
+	assigned-clocks = <&clk IMX8MM_CLK_USDHC3>;
+	assigned-clock-rates = <400000000>;
 	bus-width = <8>;
 	non-removable;
 	status = "okay";
-- 
2.25.1


             reply	other threads:[~2025-07-07 20:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-07 20:16 Tim Harvey [this message]
2025-07-07 20:16 ` [PATCH 2/7] arm64: dts: imx8mp-venice-gw702x: Increase HS400 USDHC clock speed Tim Harvey
2025-07-07 20:16 ` [PATCH 3/7] arm64: dts: imx8mm-venice-gw7901: " Tim Harvey
2025-07-07 20:16 ` [PATCH 4/7] arm64: dts: imx8mm-venice-gw7902: " Tim Harvey
2025-07-07 20:17 ` [PATCH 5/7] arm64: dts: imx8mn-venice-gw7902: " Tim Harvey
2025-07-07 20:17 ` [PATCH 6/7] arm64: dts: imx8mm-venice-gw7903: " Tim Harvey
2025-07-07 20:17 ` [PATCH 7/7] arm64: dts: imx8mm-venice-gw7904: " Tim Harvey
2025-07-11  8:04 ` [PATCH 1/7] arm64: dts: imx8mm-venice-gw700x: " Shawn Guo

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