iio: adc: Add driver for Microchip MCP3422/3/4 high resolution ADC

Sysfs access to all channels.

Signed-off-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 09371cb..0cf5c61 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -145,6 +145,16 @@
 	  This driver can also be built as a module. If so, the module will be
 	  called mcp320x.
 
+config MCP3422
+	tristate "Microchip Technology MCP3422/3/4 driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Microchip Technology's MCP3422,
+	  MCP3423 or MCP3424 analog to digital converters.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called mcp3422.
+
 config NAU7802
 	tristate "Nuvoton NAU7802 ADC driver"
 	depends on I2C