AM3351: MMC3 problem

Hello,

I'm trying to connect an SD card to the MMC3 on the Beaglebone black. I created a custom board with an SD card holder. I've written a device tree overlay (I'm still learning it) to enable this peripheral.

In /sys/class I can see the MMC3 as MMC1 with the correct parameters. However under /dev I can't see the SD card. Furthermore under /sys/kernel/debug/mmc1/ios I get strange values, for example the VDD is 0 (invalid), the clock is 0Hz etc. (See the attached image)

And here is my complete device tree overlay:

/dts-v1/; 
/plugin/;

#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/pinctrl/am33xx.h>

/ {

	compatible = "ti,am335x-bone-black", "ti,am335x-bone";
	
	exclusive-use = 
		"P8.12";

	fragment@0 {
		target = <&i2c2>;
		__overlay__ {
			rtc@68 {
				compatible = "maxim,ds1307";
				reg = <0x68>;
			};
		};

	};

	fragment@1 {
		target = <&am33xx_pinmux>;
		__overlay__ {
			mmc3_pins: pinmux_mmc3_pins {
				pinctrl-single,pins = <
					0x30 (PIN_INPUT_PULLUP | MUX_MODE3) /* gpmc_a1.mmc2_dat0, INPUT_PULLUP | MODE3 */
					0x34 (PIN_INPUT_PULLUP | MUX_MODE3) /* gpmc_a2.mmc2_dat1, INPUT_PULLUP | MODE3 */ 
					0x38 (PIN_INPUT_PULLUP | MUX_MODE3) /* gpmc_a3.mmc2_dat2, INPUT_PULLUP | MODE3 */ 
					0x3C (PIN_INPUT_PULLUP | MUX_MODE3) /* gpmc_ben1.mmc2_dat3, INPUT_PULLUP | MODE3 */
					0x88 (PIN_INPUT_PULLUP | MUX_MODE3) /* gpmc_csn3.mmc2_cmd, INPUT_PULLUP | MODE3 */ 
					0x8C (PIN_INPUT_PULLUP | MUX_MODE3) /* gpmc_clk.mmc2_clk, INPUT_PULLUP | MODE3 */ 
					0x40 (PIN_OUTPUT_PULLDOWN | MUX_MODE7) /* gpmc_a0.gpio1_16 */ 
					/* 0x74 (PIN_INPUT_PULLDOWN | MUX_MODE7) */ /* mmc2_sdcd, p9_13, Note: Dont know why but we set card detect pinout to be GPIO */ 
					/* 0x15c (PIN_INPUT_PULLDOWN | MUX_MODE1) */ /* mmc2_sdwp, p9_17, Note: Write protect is not configured in the device tree settings*/     				>; 
			};
		};
	};

	fragment@2 {
		target = <&mmc3>;
		__overlay__ {
			compatible = "ti,omap4-hsmmc";
			vmmc-supply = <&vmmcsd_fixed>;
			interrupts = <29>;
			reg = <0x47810000 0x1000>;
			ti,dual-volt;
			ti,needs-special-reset;
			ti,needs-special-hs-handling;
			pinctrl-names = "default";
			pinctrl-0 = <&mmc3_pins>;
			/* cd-gpios = <&gpio0 31 GPIO_ACTIVE_HIGH>;
			cd-inverted; */
			broken-cd;
			bus-width = <4>;
			/* max-frequency = <25000000>; */
			dmas = <&edma_xbar 12 0 1 
				&edma_xbar 13 0 2>;
			dma-names = "tx", "rx";
			status = "okay";
		};
	};

	fragment@3 {
		target = <&edma>;
		__overlay__ {
			ti,edma-xbar-event-map = /bits/ 16 <1 12 2 13>;
		};
	};


};

Thanks,

Gábor