iio: adc: add IMX7D ADC driver support

Freescale i.MX7D soc contains a new ADC IP. This patch add this ADC
driver support, and the driver only support ADC software trigger.
Signed-off-by: Haibo Chen <haibo.chen@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/Kconfig

@@ -204,6 +204,15 @@ config INA2XX_ADC
 	  Say yes here to build support for TI INA2xx family of Power Monitors.
 	  This driver is mutually exclusive with the HWMON version.
 
+config IMX7D_ADC
+	tristate "IMX7D ADC driver"
+	depends on ARCH_MXC || COMPILE_TEST
+	help
+	  Say yes here to build support for IMX7D ADC.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called imx7d_adc.
+
 config LP8788_ADC
 	tristate "LP8788 ADC driver"
 	depends on MFD_LP8788

drivers/iio/adc/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
 obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o
 obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
 obj-$(CONFIG_HI8435) += hi8435.o
+obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
 obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
 obj-$(CONFIG_MAX1027) += max1027.o