iio: Add gravity sensor support

Gravity sensor is a soft sensor, which derives value from
standard accelerometer device by filtering out the acceleration
which is not caused by gravity.

Gravity sensor provides a three dimensional vector indicating
the direction and magnitude of gravity. Typically, this sensor
is used to determine the device's relative orientation in space.
The units and the coordinate system is the same as the one used by
the acceleration sensor.
When a device is at rest, the output of the gravity sensor should
be identical to that of the accelerometer.

More information can be found in:
http://www.usb.org/developers/hidpage/HUTRR59_-_Usages_for_Wearables.pdf

Gravity sensor and accelerometer have similar channels and
share channel usage ids. So the most of the code for accel_3d
can be reused.

Signed-off-by: Song Hongyan <hongyan.song@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Song Hongyan 2017-01-05 18:24:04 +08:00 committed by Jonathan Cameron
parent 571299d099
commit 0e377f3b9a
2 changed files with 64 additions and 13 deletions

View file

@ -52,6 +52,9 @@
#define HID_USAGE_SENSOR_ANGL_VELOCITY_Y_AXIS 0x200458
#define HID_USAGE_SENSOR_ANGL_VELOCITY_Z_AXIS 0x200459
/* Gravity vector */
#define HID_USAGE_SENSOR_GRAVITY_VECTOR 0x20007B
/* ORIENTATION: Compass 3D: (200083) */
#define HID_USAGE_SENSOR_COMPASS_3D 0x200083
#define HID_USAGE_SENSOR_DATA_ORIENTATION 0x200470