/sys/kernel/debug/mmc0/ios

clock:		0 Hz
vdd:		0 (invalid)
bus mode:	2 (push-pull)
chip select:	0 (don't care)
power mode:	0 (off)
bus width:	0 (1 bits)
timing spec:	0 (legacy)
signal voltage:	0 (3.30 V)
driver type:	0 (driver type B)

/sys/kernel/debug/mmc1/ios

clock:		52000000 Hz
actual clock:	50000000 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:	3 (8 bits)
timing spec:	8 (mmc DDR52)
signal voltage:	0 (3.30 V)
driver type:	0 (driver type B)