The uSDHC supports DDR modes for eMMC devices running at 3.3V. This
allows to run eMMC with 3.3V signaling voltage at DDR52 mode:
# cat /sys/kernel/debug/mmc1/ios
clock: 52000000 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)
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
09c8192be7