iio: Add IIO support for the Measurement Computing CIO-DAC family

The Measurement Computing CIO-DAC is a family of 16-bit and 12-bit
analog output devices. The analog outputs are from AD660BN/AD7237
converters with each output buffered by an OP-27. Voltage ranges are
configured via physical jumpers on the device.

This driver does not support the devices' simulataneous update mode; the
XFER jumper option should be deselected for all analog output channels.

This driver provides IIO support for the Measurement Computing CIO-DAC
family: CIO-DAC16, CIO-DAC08, and PC104-DAC06. The base port addresses
for the devices may be configured via the base array module parameter.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 345e757..b5c802d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7318,6 +7318,12 @@
 S:	Maintained
 F:	drivers/iio/potentiometer/mcp4531.c
 
+MEASUREMENT COMPUTING CIO-DAC IIO DRIVER
+M:	William Breathitt Gray <vilhelm.gray@gmail.com>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	drivers/iio/dac/cio-dac.c
+
 MEDIA DRIVERS FOR RENESAS - VSP1
 M:	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 L:	linux-media@vger.kernel.org