iio: frequency: adrf6780: add support for ADRF6780

The ADRF6780 is a silicon germanium (SiGe) design, wideband,
microwave upconverter optimized for point to point microwave
radio designs operating in the 5.9 GHz to 23.6 GHz frequency
range.

Datasheet:
https://www.analog.com/media/en/technical-documentation/data-sheets/ADRF6780.pdf

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20211021113244.56936-1-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/frequency/Kconfig

@@ -49,5 +49,17 @@ config ADF4371
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called adf4371.
+
+config ADRF6780
+        tristate "Analog Devices ADRF6780 Microwave Upconverter"
+        depends on SPI
+        depends on COMMON_CLK
+        help
+          Say yes here to build support for Analog Devices ADRF6780
+          5.9 GHz to 23.6 GHz, Wideband, Microwave Upconverter.
+
+          To compile this driver as a module, choose M here: the
+          module will be called adrf6780.
+
 endmenu
 endmenu

drivers/iio/frequency/Makefile

@@ -7,3 +7,4 @@
 obj-$(CONFIG_AD9523) += ad9523.o
 obj-$(CONFIG_ADF4350) += adf4350.o
 obj-$(CONFIG_ADF4371) += adf4371.o
+obj-$(CONFIG_ADRF6780) += adrf6780.o