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From: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
To: linux-next@vger.kernel.org
Cc: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Rob Herring <robh+dt@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Shawn Guo <shawnguo@kernel.org>, Stefan Agner <stefan@agner.ch>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2] ARM: dts: colibri-imx6ull: limit SDIO clock to 25MHz
Date: Tue, 13 Jul 2021 23:21:07 +0300	[thread overview]
Message-ID: <20210713202108.449831-1-oleksandr.suvorov@toradex.com> (raw)

NXP and AzureWave don't recommend using SDIO bus mode 3.3V@50MHz due
to noise affecting the wireless throughput. Colibri iMX6ULL uses only
3.3V signaling for Wi-Fi module AW-CM276NF.

Limit the SDIO Clock on Colibri iMX6ULL to 25MHz.

Fixes: c2e4987e0e02 ("ARM: dts: imx6ull: add Toradex Colibri iMX6ULL support")
Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
---

Changes in v2:
- add Fixes field
- add Reviewed-by taken from Fabio
END

 arch/arm/boot/dts/imx6ull-colibri-wifi.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/imx6ull-colibri-wifi.dtsi b/arch/arm/boot/dts/imx6ull-colibri-wifi.dtsi
index a0545431b3dc..9f1e38282bee 100644
--- a/arch/arm/boot/dts/imx6ull-colibri-wifi.dtsi
+++ b/arch/arm/boot/dts/imx6ull-colibri-wifi.dtsi
@@ -43,6 +43,7 @@ &usdhc2 {
 	assigned-clock-rates = <0>, <198000000>;
 	cap-power-off-card;
 	keep-power-in-suspend;
+	max-frequency = <25000000>;
 	mmc-pwrseq = <&wifi_pwrseq>;
 	no-1-8-v;
 	non-removable;
-- 
2.31.1


             reply	other threads:[~2021-07-13 20:21 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-13 20:21 Oleksandr Suvorov [this message]
2021-07-23  2:56 ` [PATCH v2] ARM: dts: colibri-imx6ull: limit SDIO clock to 25MHz Shawn Guo

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