Input: tsc2007 - add iio interface to read external ADC input and temperature

The tsc2007 chip not only has a resistive touch screen controller but
also an external AUX adc imput which can be used for an ambient
light sensor, battery voltage monitoring or any general purpose.

Additionally it can measure the chip temperature.

This extension provides an iio interface for these adc channels.

Since it is not wasting much resources and is very straightforward,
we simply provide all other adc channels as optional iio interfaces
as weel. This can be used for debugging or special applications.

This patch also splits the tsc2007 driver in several source files:
tsc2007.h -- constants, structs and stubs
tsc2007_core.c -- functional parts of the original driver
tsc2007_iio.c -- the optional iio stuff

Makefile magic allows to conditionally link the iio stuff
if CONFIG_IIO=y or =m in a way that it works with
CONFIG_TOUCHSCREEN_TSC2007=m.

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index efca0133e266..1616a8d0bc7c 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1035,6 +1035,16 @@ config TOUCHSCREEN_TSC2007
 	  To compile this driver as a module, choose M here: the
 	  module will be called tsc2007.
 
+config TOUCHSCREEN_TSC2007_IIO
+	bool "IIO interface for external ADC input and temperature"
+	depends on TOUCHSCREEN_TSC2007
+	depends on IIO=y || IIO=TOUCHSCREEN_TSC2007
+	help
+	  Saying Y here adds an iio interface to the tsc2007 which
+	  provides values for the AUX input (used for e.g. battery
+	  or ambient light monitoring), temperature and raw input
+	  values.
+
 config TOUCHSCREEN_W90X900
 	tristate "W90P910 touchscreen driver"
 	depends on ARCH_W90X900