Re: [PATCH 1/1] arm64: dts: rockchip: default to host mode for USB on Radxa E25

[Chukun Pan]

Hi,
> I would advise against using any sd-uhs- mode for sd-card on Rockchip
> RK356x boards because of a timing issue during boot between mmc,
> regulator and IO-domain drivers.

This problem seems to occur only on rk356x?

> Ideally this race condition should be solved instead of limiting use
> of UHS modes. However, use of sd-uhs-sdr50 is typically more forgiving
> and has been used on other boards.

It seems that sd-uhs-sdr50 does not need 1.8V IO voltage.
I tested the speed on a rk3528 board with sdio wifi:
(The IO voltage of sdio on this board is 3.3V)

highspeed: 170Mbps DL
sdr50:     290Mbps DL
sdr104:    290Mbps DL

So sdr50 should be safe.

Thanks,
Chukun

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