ARM: AT91: IIO: Add AT91 ADC driver.

Add the ADC driver for Atmel's AT91SAM9G20-EK, AT91SAM9M10G45-EK
and AT91SAM9X5 family boards.

It has support for both software and hardware triggers.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/iio/Kconfig

@@ -48,6 +48,7 @@ config IIO_CONSUMERS_PER_TRIGGER
 	This value controls the maximum number of consumers that a
 	given trigger may handle. Default is 2.
 
+source "drivers/iio/adc/Kconfig"
 source "drivers/iio/amplifiers/Kconfig"
 
 endif # IIO

drivers/iio/Makefile

@@ -9,4 +9,5 @@ industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
 
 obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
 
+obj-y += adc/
 obj-y += amplifiers/

drivers/iio/adc/Kconfig

+#
+# ADC drivers
+#
+menu "Analog to digital converters"
+
+config AT91_ADC
+	tristate "Atmel AT91 ADC"
+	depends on ARCH_AT91
+	select IIO_BUFFER
+	select IIO_KFIFO_BUF
+	select IIO_TRIGGER
+	select SYSFS
+	help
+	  Say yes here to build support for Atmel AT91 ADC.
+
+endmenu

drivers/iio/adc/Makefile

+#
+# Makefile for IIO ADC drivers
+#
+
+obj-$(CONFIG_AT91_ADC) += at91_adc.o