iio: Add Nuvoton NAU7802 ADC driver

The Nuvoton NAU7802 ADC is a 24-bit 2-channels I2C ADC, with adjustable
gain and sampling rates.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 93129ec..2eced9d 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -143,6 +143,15 @@
 	  This driver can also be built as a module. If so, the module will be
 	  called mcp320x.
 
+config NAU7802
+	tristate "Nuvoton NAU7802 ADC driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Nuvoton NAU7802 ADC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called nau7802.
+
 config TI_ADC081C
 	tristate "Texas Instruments ADC081C021/027"
 	depends on I2C