This patch adds support for the AD5641 single channel,
14-bit, buffered voltage output DAC.
Signed-off-by: NAida Mynzhasova <aida.mynzhasova@skitlab.ru>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>