iio: frequency: admv4420.c: Add support for ADMV4420

Add support for K Band Downconverter with Integrated
Fractional-N PLL and VCO.
More info:
https://www.analog.com/en/products/admv4420.htmlSigned-off-by: Cristian Pop <cristian.pop@analog.com>
Link: https://lore.kernel.org/r/20220223130808.13352-2-cristian.pop@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/frequency/Kconfig

@@ -70,6 +70,16 @@ config ADMV1014
 	  To compile this driver as a module, choose M here: the
 	  module will be called admv1014.
 
+config ADMV4420
+       tristate "Analog Devices ADMV4420 K Band Downconverter"
+       depends on SPI
+       help
+         Say yes here to build support for Analog Devices K Band
+         Downconverter with integrated Fractional-N PLL and VCO.
+
+         To compile this driver as a module, choose M here: the
+         module will be called admv4420.
+
 config ADRF6780
         tristate "Analog Devices ADRF6780 Microwave Upconverter"
         depends on SPI

drivers/iio/frequency/Makefile

@@ -9,4 +9,5 @@ obj-$(CONFIG_ADF4350) += adf4350.o
 obj-$(CONFIG_ADF4371) += adf4371.o
 obj-$(CONFIG_ADMV1013) += admv1013.o
 obj-$(CONFIG_ADMV1014) += admv1014.o
+obj-$(CONFIG_ADMV4420) += admv4420.o
 obj-$(CONFIG_ADRF6780) += adrf6780.o