iio: adc: Add support for AD4170

Add support for the AD4170 ADC with the following features:
- Single-shot read (read_raw), scale, sampling freq
- Multi channel buffer support
- Buffered capture in triggered mode
- Buffered capture with SPI-Engine
- Gain and offset calibration
- Support for gpio controller
- chop_iexc and chop_adc device configuration
- Powerdown switch configuration

Signed-off-by: Ana-Maria Cusco <ana-maria.cusco@analog.com>
Signed-off-by: Dragos Bogdan <dragos.bogdan@analog.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>

drivers/iio/Kconfig.adi

@@ -40,6 +40,7 @@ config IIO_ALL_ADI_DRIVERS
 	imply AD400X
 	imply AD4630
 	imply AD4130
+	imply AD4170
 	imply AD4134
 	imply AD6676
 	imply AD7091R5

drivers/iio/adc/Kconfig

@@ -59,6 +59,22 @@ config AD4130
 	  To compile this driver as a module, choose M here: the module will be
 	  called ad4130.
 
+
+config AD4170
+	tristate "Analog Device AD4170 ADC Driver"
+	depends on SPI
+	depends on GPIOLIB
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select REGMAP_SPI
+	depends on COMMON_CLK
+	help
+	  Say yes here to build support for Analog Devices AD4170 SPI analog
+	  to digital converters (ADC).
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ad4170.
+
 config AD4630
 	tristate "Analog Device AD4630 ADC Driver"
 	depends on SPI_MASTER

drivers/iio/adc/Makefile

@@ -9,6 +9,7 @@ obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
 obj-$(CONFIG_AD_PULSAR) += ad_pulsar.o
 obj-$(CONFIG_AD400X) += ad400x.o
 obj-$(CONFIG_AD4130) += ad4130.o
+obj-$(CONFIG_AD4170) += ad4170.o
 obj-$(CONFIG_AD4134) += ad4134.o
 obj-$(CONFIG_AD4630) += ad4630.o
 obj-$(CONFIG_AD6676) += ad6676.o