root@odroid:/home/brad# cat /sys/kernel/debug/mmc0/ios
clock:          50000000 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:      2 (4 bits)
timing spec:    2 (sd high-speed)
signal voltage: 1 (1.80 V)
driver type:    0 (driver type B)