This is a conversion queue driver for the mx25 SoC. It uses the central
ADC which is used by two seperate independent queues. This driver
prepares different conversion configurations for each possible input.
For a conversion it creates a conversionqueue of one item with the
correct configuration for the chosen channel. It then executes the queue
once and disables the conversion queue afterwards.

The reference voltages are configurable through devicetree subnodes,
depending on the connections of the ADC inputs.
Signed-off-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NDenis Carikli <denis@eukrea.com>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>