extcon: adc_jack: adc-jack driver to support 3.5 pi or simliar devices

External connector devices that decides connection information based on
ADC values may use adc-jack device driver. The user simply needs to
provide a table of adc range and connection states. Then, extcon
framework will automatically notify others.

Changes in V1:
added Lars-Peter Clausen suggested changes:
Using macros to get rid of boiler plate code such as devm_kzalloc
and module_platform_driver.Other changes suggested are related to
coding guidelines.

Changes in V2:
Removed some unnecessary checks and changed the way we are un-regitering
extcon and freeing the irq while removing.

Changes in V3:
Renamed the files to comply with extcon naming.

Changes in V4:
Added the cancel_work_sync during removing of driver.

Changes in V5:
Added the dependency of IIO in Kconfig.

Changes in V6:
Some nitpicks related to naming.

Changes in this version:
V6 patch version patch broke the build:
ERROR: "extcon_cable_name" [drivers/extcon/extcon-adc-jack.ko] undefined!

Fixed it in this version.

Acked-by: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: anish kumar <anish.singh@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index e175c8e..dd5b01b 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -21,6 +21,12 @@
 	  Say Y here to enable GPIO based extcon support. Note that GPIO
 	  extcon supports single state per extcon instance.
 
+config EXTCON_ADC_JACK
+	tristate "ADC Jack extcon support"
+	depends on IIO
+	help
+	  Say Y here to enable extcon device driver based on ADC values.
+
 config EXTCON_MAX77693
 	tristate "MAX77693 EXTCON Support"
 	depends on MFD_MAX77693