iio: adc: hi8435: Holt HI-8435 threshold detector

Add Holt threshold detector driver for HI-8435 chip
Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/ABI/testing/sysfs-bus-iio

@@ -581,6 +581,7 @@ What:		/sys/.../iio:deviceX/events/in_voltageY_supply_thresh_rising_en
 What:		/sys/.../iio:deviceX/events/in_voltageY_supply_thresh_falling_en
 What:		/sys/.../iio:deviceX/events/in_voltageY_thresh_rising_en
 What:		/sys/.../iio:deviceX/events/in_voltageY_thresh_falling_en
+What:		/sys/.../iio:deviceX/events/in_voltageY_thresh_either_en
 What:		/sys/.../iio:deviceX/events/in_tempY_thresh_rising_en
 What:		/sys/.../iio:deviceX/events/in_tempY_thresh_falling_en
 KernelVersion:	2.6.37

Documentation/ABI/testing/sysfs-bus-iio-adc-hi8435

+What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_sensing_mode
+Date:		August 2015
+KernelVersion:	4.2.0
+Contact:	source@cogentembedded.com
+Description:
+		Program sensor type for threshold detector inputs.
+		Could be either "GND-Open" or "Supply-Open" mode. Y is a
+		threshold detector input channel. Channels 0..7, 8..15, 16..23
+		and 24..31 has common sensor types.
+
+What:		/sys/bus/iio/devices/iio:deviceX/events/in_voltageY_thresh_falling_value
+Date:		August 2015
+KernelVersion:	4.2.0
+Contact:	source@cogentembedded.com
+Description:
+		Channel Y low voltage threshold. If sensor input voltage goes lower then
+		this value then the threshold falling event is pushed.
+		Depending on in_voltageY_sensing_mode the low voltage threshold
+		is separately set for "GND-Open" and "Supply-Open" modes.
+		Channels 0..31 have common low threshold values, but could have different
+		sensing_modes.
+		The low voltage threshold range is between 2..21V.
+		Hysteresis between low and high thresholds can not be lower then 2 and
+		can not be odd.
+		If falling threshold results hysteresis to odd value then rising
+		threshold is automatically subtracted by one.
+
+What:		/sys/bus/iio/devices/iio:deviceX/events/in_voltageY_thresh_rising_value
+Date:		August 2015
+KernelVersion:	4.2.0
+Contact:	source@cogentembedded.com
+Description:
+		Channel Y high voltage threshold. If sensor input voltage goes higher then
+		this value then the threshold rising event is pushed.
+		Depending on in_voltageY_sensing_mode the high voltage threshold
+		is separately set for "GND-Open" and "Supply-Open" modes.
+		Channels 0..31 have common high threshold values, but could have different
+		sensing_modes.
+		The high voltage threshold range is between 3..22V.
+		Hysteresis between low and high thresholds can not be lower then 2 and
+		can not be odd.
+		If rising threshold results hysteresis to odd value then falling
+		threshold is automatically appended by one.

drivers/iio/adc/Kconfig

@@ -183,6 +183,17 @@ config EXYNOS_ADC
 	  To compile this driver as a module, choose M here: the module will be
 	  called exynos_adc.
 
+config HI8435
+	tristate "Holt Integrated Circuits HI-8435 threshold detector"
+	select IIO_TRIGGERED_EVENT
+	depends on SPI
+	help
+	  If you say yes here you get support for Holt Integrated Circuits
+	  HI-8435 chip.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called hi8435.
+
 config LP8788_ADC
 	tristate "LP8788 ADC driver"
 	depends on MFD_LP8788

drivers/iio/adc/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_BERLIN2_ADC) += berlin2-adc.o
 obj-$(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_LP8788_ADC) += lp8788_adc.o
 obj-$(CONFIG_MAX1027) += max1027.o
 obj-$(CONFIG_MAX1363) += max1363.o