Error initializing wifi module with SDIO and voltage translation

[DmnSd]

Hello all,

I'm getting following error on our custom board while initializing sdmmc3 as wifi module with SDIO:

~# dmesg | grep -i sdio -B 1
[    3.410271] mmci-pl18x 48004000.sdmmc: no support for card's volts
[    3.415001] mmc0: error -22 whilst initialising SDIO card
--
[    5.298030] mmci-pl18x 48004000.sdmmc: no support for card's volts
[    5.302938] mmc0: error -22 whilst initialising SDIO card
--
[    7.140215] mmci-pl18x 48004000.sdmmc: no support for card's volts
[    7.144982] mmc0: error -22 whilst initialising SDIO card
--
[    8.930932] mmci-pl18x 48004000.sdmmc: no support for card's volts
[    8.935676] mmc0: error -22 whilst initialising SDIO card

Wifi module is a ST60-2230C (https://www.lairdconnect.com/documentation/datasheet-st60-2230c) with I/O signalling voltage 1V8.

Between STM32MP and ST60 module there are three voltage translators which translate 3V3 (STM32MP) to 1V8 (ST-60). See attached schematics snippet.

This is device tree configuration:

&sdmmc3{
	arm,primecell-periphid = <0x10153180>;
	pinctrl-names = "default", "opendrain", "sleep";
	pinctrl-0 = <&sdmmc3_pins_mx>;
	pinctrl-1 = <&sdmmc3_opendrain_pins_mx>;
	pinctrl-2 = <&sdmmc3_sleep_pins_mx>;
	non-removable;
	st,neg-edge;
	st,use-ckin;
	bus-width = <4>;
	vmmc-supply = <&v3v3>;
	mmc-pwrseq = <&wifi_pwrseq>;
	#address-cells = <1>;
	#size-cells = <0>;
	status = "okay";
 
	brcmf: bcrmf@1 {
		reg = <1>;
		compatible = "brcm,bcm4329-fmac";
	};
};
 
wifi_pwrseq: wifi-pwrseq {
	compatible = "mmc-pwrseq-simple";
	/* reset-gpios = <&gpioe 2 GPIO_ACTIVE_LOW>; */
	post-power-on-delay-ms = <100>;
	power-off-delay-us = <200000>;
};

and pin definition:

sdmmc3_pins_mx: sdmmc3_mx-0 {
	pins1 {
		pinmux = <STM32_PINMUX('D', 0, AF10)>; /* SDMMC3_CMD */
		bias-pull-down;
		drive-push-pull;
		slew-rate = <1>;
	};
	pins2 {
		pinmux = <STM32_PINMUX('D', 1, AF10)>, /* SDMMC3_D0 */
				 <STM32_PINMUX('D', 4, AF10)>, /* SDMMC3_D1 */
				 <STM32_PINMUX('D', 7, AF10)>, /* SDMMC3_D3 */
				 <STM32_PINMUX('F', 1, AF10)>, /* SDMMC3_CDIR */
				 <STM32_PINMUX('F', 2, AF10)>, /* SDMMC3_D0DIR */
				 <STM32_PINMUX('F', 4, AF10)>, /* SDMMC3_D123DIR */
				 <STM32_PINMUX('F', 5, AF9)>; /* SDMMC3_D2 */
		bias-disable;
		drive-push-pull;
		slew-rate = <1>;
	};
	pins3 {
		pinmux = <STM32_PINMUX('F', 0, AF10)>; /* SDMMC3_CKIN */
		bias-disable;
	};
	pins4 {
		pinmux = <STM32_PINMUX('G', 15, AF10)>; /* SDMMC3_CK */
		bias-disable;
		drive-push-pull;
		slew-rate = <3>;
	};
};

Can I configure STM32MP to use 1V8 I/O signalling? Or any other solutions?

Thanks for help!

Kind regards

Dmn

[PatrickF · Accepted solution]

Hi,

I'm not sure this setting will work, I'm not expert of this driver, but I hope driver is generic enough.

Did you cross check the level translator you used are using correct _DIR defaut polarity, i.e. 0 = Card -> MPU input , 1 = MPU output -> Card.

Check if this is missing

       st,sig-dir;

not sure if also

vqmmc-supply = <&xxxx>;

is required in your case.

see https://wiki.st.com/stm32mpu/wiki/SDMMC_device_tree_configuration

Regards,

[DmnSd]

Thanks @PatrickF​ .

st,sig-dir;

did the trick.

My wifi module works!

Many thanks for fast & good answer!