Factor out some boilerplate code.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>
Acked-by: NDong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>