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: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index c60b0a1..4a9e29a 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -323,6 +323,14 @@
 		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