iio: core: Introduce IIO_CHAN_INFO_CALIBWEIGHT

Some devices need the weight of the user to compute other
parameters. One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that needs the weight of the user to compute the number of calories burnt.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/ABI/testing/sysfs-bus-iio

@@ -351,6 +351,13 @@ Description:
 		to compute the stride length, distance, speed and activity
 		type.
 
+What:		/sys/bus/iio/devices/iio:deviceX/in_energy_calibweight
+KernelVersion:	3.20
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Weight of the user (in kg). It is needed by some pedometers
+		to compute the calories burnt by the user.
+
 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

@@ -125,6 +125,7 @@ static const char * const iio_chan_info_postfix[] = {
 	[IIO_CHAN_INFO_INT_TIME] = "integration_time",
 	[IIO_CHAN_INFO_ENABLE] = "en",
 	[IIO_CHAN_INFO_CALIBHEIGHT] = "calibheight",
+	[IIO_CHAN_INFO_CALIBWEIGHT] = "calibweight",
 };
 
 /**

include/linux/iio/iio.h

@@ -40,6 +40,7 @@ enum iio_chan_info_enum {
 	IIO_CHAN_INFO_INT_TIME,
 	IIO_CHAN_INFO_ENABLE,
 	IIO_CHAN_INFO_CALIBHEIGHT,
+	IIO_CHAN_INFO_CALIBWEIGHT,
 };
 
 enum iio_shared_by {