2021-07-13 20:26:55

by Oleksandr Suvorov

Subject: [PATCH v2] ARM: dts: colibri-imx6ull: limit SDIO clock to 25MHz

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 <[email protected]>
Reviewed-by: Fabio Estevam <[email protected]>
---

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

2021-07-23 02:58:53

by Shawn Guo

Subject: Re: [PATCH v2] ARM: dts: colibri-imx6ull: limit SDIO clock to 25MHz

On Tue, Jul 13, 2021 at 11:21:07PM +0300, Oleksandr Suvorov wrote:
> 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 <[email protected]>
> Reviewed-by: Fabio Estevam <[email protected]>

Applied, thanks!