iio: amplifiers: ada4250: add support for ADA4250

The ADA4250 is an instrumentation amplifier with SPI/pin-strap
progammable gains that is optimized for ultra-low power systems.
With a minimum supply voltage of 1.7V, 26uA of quiescent current,
a shutdown mode, a sleep mode, and a fast wake up settling time,
ADA4250 can be power cycled on a battery powered system for even
futher savings.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20220223120112.8067-2-antoniu.miclaus@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/amplifiers/Kconfig

@@ -23,6 +23,17 @@ config AD8366
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad8366.
 
+config ADA4250
+	tristate "Analog Devices ADA4250 Instrumentation Amplifier"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices ADA4250
+	  SPI Amplifier's support. The driver provides direct access via
+	  sysfs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ada4250.
+
 config HMC425
 	tristate "Analog Devices HMC425A and similar GPIO Gain Amplifiers"
 	depends on GPIOLIB

drivers/iio/amplifiers/Makefile

@@ -5,4 +5,5 @@
 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AD8366) += ad8366.o
+obj-$(CONFIG_ADA4250) += ada4250.o
 obj-$(CONFIG_HMC425) += hmc425a.o