iio: core: Introduce IIO_CHAN_INFO_CALIBHEIGHT

Some devices need the height of the user to compute various
parameters. One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that needs the height of the user to compute the stride length which
is used further to determine distance, speed and activity type.
Signed-off-by: NIrina Tirdea <irina.tirdea@intel.com>
Signed-off-by: NDaniel Baluta <daniel.baluta@intel.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Documentation/ABI/testing/sysfs-bus-iio

@@ -323,6 +323,14 @@ Description:
 		production inaccuracies).  If shared across all channels,
 		<type>_calibscale is used.
 
+What:		/sys/bus/iio/devices/iio:deviceX/in_steps_calibheight
+KernelVersion:	3.19
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Height of the user (in centimeters) used by some pedometers
+		to compute the stride length, distance, speed and activity
+		type.
+
 What:		/sys/bus/iio/devices/iio:deviceX/in_accel_scale_available
 What:		/sys/.../iio:deviceX/in_voltageX_scale_available
 What:		/sys/.../iio:deviceX/in_voltage-voltage_scale_available

drivers/iio/industrialio-core.c

@@ -120,6 +120,7 @@ static const char * const iio_chan_info_postfix[] = {
 	[IIO_CHAN_INFO_HYSTERESIS] = "hysteresis",
 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
 	[IIO_CHAN_INFO_ENABLE] = "en",
+	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
 };
 
 /**

include/linux/iio/iio.h

@@ -39,6 +39,7 @@ enum iio_chan_info_enum {
 	IIO_CHAN_INFO_HYSTERESIS,
 	IIO_CHAN_INFO_INT_TIME,
 	IIO_CHAN_INFO_ENABLE,
+	IIO_CHAN_INFO_CALIBHEIGHT,
 };
 
 enum iio_shared_by {