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how to implement imx6ull interface to SDIO3.0 module?

Question asked by Joe Bin on Dec 24, 2018
Latest reply on Jan 9, 2019 by Joan Xie


     My custom boards implement SD0 to boot up and SD1 to interface to wifi module. My wifi module support SD3.0 spec. So I provide 1.8v to sdio signals of wifi module. Meanwhile I also notice NVCC_NAND from imx6ull should be connected with 1.8v.

    after boot up, I noticed kernel found a new high speed SDIO card but not a ultra high speed SDIO card.

    After I ran "cat /sys/kernel/debug/mmc1/ios", I got that system found a sd2.0 card. That's a problem.


imx6ull14x14evk login: root
root@imx6ull14x14evk:~# cat /sys/kernel/debug/mmc1/ios
clock:        50000000 Hz
actual clock:    44000000 Hz
vdd:        21 (3.3 ~ 3.4 V)
bus mode:    2 (push-pull)
chip select:    0 (don't care)
power mode:    2 (on)
bus width:    2 (4 bits)
timing spec:    2 (sd high-speed)
signal voltage:    0 (3.30 V)


    My dts is almost the same as imx6ull-14x14-evk.dts.  What else should I be concerned?

The log file and dts file are attached.