iio: core: Introduce IIO_VELOCITY and IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z

Some devices export the current speed value of the user.

One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that computes the speed of the user based on the number of steps and
stride length.

Introduce a new channel type VELOCITY and a modifier for the magniture or
norm of the velocity vector, IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z.

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

3 files changed, 14 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index c627a9a1cd56..80b5efb1cdbf 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -295,6 +295,7 @@ What:		/sys/bus/iio/devices/iio:deviceX/in_rot_from_north_true_tilt_comp_scale
 What:           /sys/bus/iio/devices/iio:deviceX/in_pressureY_scale
 What:           /sys/bus/iio/devices/iio:deviceX/in_pressure_scale
 What:           /sys/bus/iio/devices/iio:deviceX/in_humidityrelative_scale
+What:           /sys/bus/iio/devices/iio:deviceX/in_velocity_sqrt(x^2+y^2+z^2)_scale
 KernelVersion:  2.6.35
 Contact:        linux-iio@vger.kernel.org
 Description:
@@ -1164,3 +1165,12 @@ Contact:	linux-iio@vger.kernel.org
 Description:
                 This attribute is used to read the number of steps taken by the user
                 since the last reboot while activated.
+
+What:           /sys/.../iio:deviceX/in_velocity_sqrt(x^2+y^2+z^2)_input
+What:           /sys/.../iio:deviceX/in_velocity_sqrt(x^2+y^2+z^2)_raw
+KernelVersion:  3.19
+Contact:        linux-iio@vger.kernel.org
+Description:
+                This attribute is used to read the current speed value of the
+                user (which is the norm or magnitude of the velocity vector).
+                Units after application of scale are m/s.
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 655755b49ccd..18a8ab911aab 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -74,6 +74,7 @@ static const char * const iio_chan_type_name_spec[] = {
         [IIO_STEPS] = "steps",
         [IIO_ENERGY] = "energy",
         [IIO_DISTANCE] = "distance",
+        [IIO_VELOCITY] = "velocity",
 };
 
 static const char * const iio_modifier_names[] = {
@@ -99,6 +100,7 @@ static const char * const iio_modifier_names[] = {
         [IIO_MOD_JOGGING] = "jogging",
         [IIO_MOD_WALKING] = "walking",
         [IIO_MOD_STILL] = "still",
+        [IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z] = "sqrt(x^2+y^2+z^2)",
 };
 
 /* relies on pairs of these shared then separate */
diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
index a7de445222f4..c3601c2c0a9d 100644
--- a/include/linux/iio/types.h
+++ b/include/linux/iio/types.h
@@ -34,6 +34,7 @@ enum iio_chan_type {
         IIO_STEPS,
         IIO_ENERGY,
         IIO_DISTANCE,
+        IIO_VELOCITY,
 };
 
 enum iio_modifier {
@@ -68,6 +69,7 @@ enum iio_modifier {
         IIO_MOD_JOGGING,
         IIO_MOD_WALKING,
         IIO_MOD_STILL,
+        IIO_MOD_ROOT_SUM_SQUARED_X_Y_Z,
 };
 
 enum iio_event_type {