CY43455 and Cortex A5 (SAMA5D27) SDIO issues

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jribot
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First solution authored First reply posted First question asked

I have a working custom board design based on SAMA5D27-D5M-CU where we are trying to connect a commercial M.2 WirelessLan adapter based on CY43455 via the SDMMC0 port (using SDIO interface). Our issue comes at the very beginning
stage, as the SDIO device is not being detected during bootup. We are suspecting that the bus is not correctly configured

It seems we are facing a similar issue than the one explained in: https://community.cypress.com/t5/Wi-Fi-Bluetooth-for-Linux/How-to-configure-SDIO-interface-on-CYW434... and we are still blocked in the "detection" part.

Below, part of my dts regarding the SDMMC part:

		sdmmc0: sdio-host@a0000000 {
			#address-cells = <1>;
			#size-cells = <0>;
			bus-width = <4>;
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_sdmmc0_default>;
			no-1-8-v; /* force 3.3V VIO */
			non-removable;
			/*
			broken-cd;
			pm-ignore-notify;
			max-frequency = <10000000>;
			*/
			status = "okay";

			brcmf: bcrmf@1 {
				reg = <1>;
				compatible = "brcm,bcm4329-fmac";
			};
		};

When board starts, seems the SDHCI driver is correctly loaded, but no device is detected on the bus:

...
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
sdhci-pltfm: SDHCI platform and OF driver helper
mmc0: SDHCI controller on a0000000.sdio-host [a0000000.sdio-host] using ADMA
...

As comment, we are measuring SD_CLK and SD_CMD lines with an oscilloscope during driver bootup, and we are seeing a 400KHz clock on the SD_CLK line (as expected) but no activity in the SD_CMD, as we are suspecting the issue comes from this.

Any idea where the problem could be?

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1 Solution
jribot
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Level 1
First solution authored First reply posted First question asked

Thanks for your answer DS_Lin.

I finally found the error...I missed something in the HW! I have just left the 32.768KHz XTAL unconnected...I thought this XTAL was not mandatory but in a try/error test, I've just connect it and after that everything started to work! Now Wifi module is working!

I just post for reference the "wrong" schematic with the required patches just if anyone faces a similar issue

jribot_0-1620861829260.png

 

View solution in original post

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3 Replies
DS_Lin
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Distributor - Zenitron(GC)
First comment on blog 100 sign-ins 50 replies posted

Hi Jribot,

Can you recheck your the SDMMC0 port on SAMA5D27-D5M-CU board

kernel driver sdio clock 200Mz? 100Mz? default clock speed?

performed any sort of tuning for the external crystal?

=========================================================================

if your using M.2 WirelessLan adapter based on CY43455 via the SDMMC0 port (using SDIO interface) success ,kernel dmesg similar to the following example

mmc0: queuing unknown CIS tuple 0x80 (2 bytes)
mmc0: queuing unknown CIS tuple 0x80 (3 bytes)
mmc0: queuing unknown CIS tuple 0x80 (3 bytes)
mmc0: queuing unknown CIS tuple 0x80 (7 bytes)
mmc0: new ultra high speed SDR104 SDIO card at address 0001

Br,

DS

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jribot
Level 1
Level 1
First solution authored First reply posted First question asked

Thanks for your answer DS_Lin.

I finally found the error...I missed something in the HW! I have just left the 32.768KHz XTAL unconnected...I thought this XTAL was not mandatory but in a try/error test, I've just connect it and after that everything started to work! Now Wifi module is working!

I just post for reference the "wrong" schematic with the required patches just if anyone faces a similar issue

jribot_0-1620861829260.png

 

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DS_Lin
Level 5
Level 5
Distributor - Zenitron(GC)
First comment on blog 100 sign-ins 50 replies posted

Hi Jribot,

get it, thanks for the quick response.

 

Br,
DS

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