2 * Copyright (C) 2008 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #ifndef ANDROID_SENSORS_INTERFACE_H
18 #define ANDROID_SENSORS_INTERFACE_H
21 #include <sys/cdefs.h>
22 #include <sys/types.h>
24 #include <hardware/hardware.h>
25 #include <cutils/native_handle.h>
30 * The id of this module
32 #define SENSORS_HARDWARE_MODULE_ID "sensors"
35 * Name of the sensors device to open
37 #define SENSORS_HARDWARE_POLL "poll"
40 * Handles must be higher than SENSORS_HANDLE_BASE and must be unique.
41 * A Handle identifies a given sensors. The handle is used to activate
42 * and/or deactivate sensors.
43 * In this version of the API there can only be 256 handles.
45 #define SENSORS_HANDLE_BASE 0
46 #define SENSORS_HANDLE_BITS 8
47 #define SENSORS_HANDLE_COUNT (1<<SENSORS_HANDLE_BITS)
53 #define SENSOR_TYPE_ACCELEROMETER 1
54 #define SENSOR_TYPE_MAGNETIC_FIELD 2
55 #define SENSOR_TYPE_ORIENTATION 3
56 #define SENSOR_TYPE_GYROSCOPE 4
57 #define SENSOR_TYPE_LIGHT 5
58 #define SENSOR_TYPE_PRESSURE 6
59 #define SENSOR_TYPE_TEMPERATURE 7
60 #define SENSOR_TYPE_PROXIMITY 8
61 #define SENSOR_TYPE_GRAVITY 9
62 #define SENSOR_TYPE_LINEAR_ACCELERATION 10
63 #define SENSOR_TYPE_ROTATION_VECTOR 11
66 * Values returned by the accelerometer in various locations in the universe.
67 * all values are in SI units (m/s^2)
70 #define GRAVITY_SUN (275.0f)
71 #define GRAVITY_EARTH (9.80665f)
73 /** Maximum magnetic field on Earth's surface */
74 #define MAGNETIC_FIELD_EARTH_MAX (60.0f)
76 /** Minimum magnetic field on Earth's surface */
77 #define MAGNETIC_FIELD_EARTH_MIN (30.0f)
81 * status of each sensor
84 #define SENSOR_STATUS_UNRELIABLE 0
85 #define SENSOR_STATUS_ACCURACY_LOW 1
86 #define SENSOR_STATUS_ACCURACY_MEDIUM 2
87 #define SENSOR_STATUS_ACCURACY_HIGH 3
90 * Definition of the axis
91 * ----------------------
93 * This API is relative to the screen of the device in its default orientation,
94 * that is, if the device can be used in portrait or landscape, this API
95 * is only relative to the NATURAL orientation of the screen. In other words,
96 * the axis are not swapped when the device's screen orientation changes.
97 * Higher level services /may/ perform this transformation.
102 * +-----------+--> y>0
114 * |/ z>0 (toward the sky)
116 * O: Origin (x=0,y=0,z=0)
122 * All values are angles in degrees.
124 * Orientation sensors return sensor events for all 3 axes at a constant
125 * rate defined by setDelay().
127 * azimuth: angle between the magnetic north direction and the Y axis, around
128 * the Z axis (0<=azimuth<360).
129 * 0=North, 90=East, 180=South, 270=West
131 * pitch: Rotation around X axis (-180<=pitch<=180), with positive values when
132 * the z-axis moves toward the y-axis.
134 * roll: Rotation around Y axis (-90<=roll<=90), with positive values when
135 * the x-axis moves towards the z-axis.
137 * Note: For historical reasons the roll angle is positive in the clockwise
138 * direction (mathematically speaking, it should be positive in the
139 * counter-clockwise direction):
145 * | | roll: rotation around Y axis
148 * note that +Y == -roll
152 * Note: This definition is different from yaw, pitch and roll used in aviation
153 * where the X axis is along the long side of the plane (tail to nose).
159 * All values are in SI units (m/s^2) and measure the acceleration of the
160 * device minus the force of gravity.
162 * Acceleration sensors return sensor events for all 3 axes at a constant
163 * rate defined by setDelay().
165 * x: Acceleration minus Gx on the x-axis
166 * y: Acceleration minus Gy on the y-axis
167 * z: Acceleration minus Gz on the z-axis
170 * When the device lies flat on a table and is pushed on its left side
171 * toward the right, the x acceleration value is positive.
173 * When the device lies flat on a table, the acceleration value is +9.81,
174 * which correspond to the acceleration of the device (0 m/s^2) minus the
175 * force of gravity (-9.81 m/s^2).
177 * When the device lies flat on a table and is pushed toward the sky, the
178 * acceleration value is greater than +9.81, which correspond to the
179 * acceleration of the device (+A m/s^2) minus the force of
180 * gravity (-9.81 m/s^2).
186 * All values are in micro-Tesla (uT) and measure the ambient magnetic
187 * field in the X, Y and Z axis.
189 * Magnetic Field sensors return sensor events for all 3 axes at a constant
190 * rate defined by setDelay().
194 * All values are in radians/second and measure the rate of rotation
195 * around the X, Y and Z axis. The coordinate system is the same as is
196 * used for the acceleration sensor. Rotation is positive in the
197 * counter-clockwise direction (right-hand rule). That is, an observer
198 * looking from some positive location on the x, y or z axis at a device
199 * positioned on the origin would report positive rotation if the device
200 * appeared to be rotating counter clockwise. Note that this is the
201 * standard mathematical definition of positive rotation and does not agree
202 * with the definition of roll given earlier.
203 * The range should at least be 17.45 rad/s (ie: ~1000 deg/s).
208 * The distance value is measured in centimeters. Note that some proximity
209 * sensors only support a binary "close" or "far" measurement. In this case,
210 * the sensor should report its maxRange value in the "far" state and a value
211 * less than maxRange in the "near" state.
213 * Proximity sensors report a value only when it changes and each time the
214 * sensor is enabled. setDelay() is ignored.
219 * The light sensor value is returned in SI lux units.
221 * Light sensors report a value only when it changes and each time the
222 * sensor is enabled. setDelay() is ignored.
227 * The pressure sensor value is returned in hectopascal (hPa)
229 * Pressure sensors report events at a constant rate defined by setDelay().
234 * The gyroscope sensor values are returned in degrees per second (dps)
236 * Gyroscope sensor report events at a constant rate defined by setDelay().
240 * A gravity output indicates the direction of and magnitude of gravity in the devices's
241 * coordinates. On Earth, the magnitude is 9.8. Units are m/s^2. The coordinate system
242 * is the same as is used for the acceleration sensor.
244 * Linear Acceleration
245 * -------------------
246 * Indicates the linear acceleration of the device in device coordinates, not including gravity.
247 * This output is essentially Acceleration - Gravity. Units are m/s^2. The coordinate system is
248 * the same as is used for the acceleration sensor.
252 * A rotation vector represents the orientation of the device as a combination
253 * of an angle and an axis, in which the device has rotated through an angle
254 * theta around an axis <x, y, z>. The three elements of the rotation vector
255 * are <x*sin(theta/2), y*sin(theta/2), z*sin(theta/2)>, such that the magnitude
256 * of the rotation vector is equal to sin(theta/2), and the direction of the
257 * rotation vector is equal to the direction of the axis of rotation. The three
258 * elements of the rotation vector are equal to the last three components of a
259 * unit quaternion <cos(theta/2), x*sin(theta/2), y*sin(theta/2), z*sin(theta/2)>.
260 * Elements of the rotation vector are unitless. The x, y, and z axis are defined
261 * in the same was as for the acceleration sensor.
283 * Union of the various types of sensor data
284 * that can be returned.
286 typedef struct sensors_event_t {
287 /* must be sizeof(struct sensors_event_t) */
290 /* sensor identifier */
299 /* time is in nanosecond */
305 /* acceleration values are in meter per second per second (m/s^2) */
306 sensors_vec_t acceleration;
308 /* magnetic vector values are in micro-Tesla (uT) */
309 sensors_vec_t magnetic;
311 /* orientation values are in degrees */
312 sensors_vec_t orientation;
314 /* gyroscope values are in rad/s */
317 /* temperature is in degrees centigrade (Celsius) */
320 /* distance in centimeters */
323 /* light in SI lux units */
326 /* pressure in hectopascal (hPa) */
329 uint32_t reserved1[4];
337 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
338 * and the fields of this data structure must begin with hw_module_t
339 * followed by module specific information.
341 struct sensors_module_t {
342 struct hw_module_t common;
345 * Enumerate all available sensors. The list is returned in "list".
346 * @return number of sensors in the list
348 int (*get_sensors_list)(struct sensors_module_t* module,
349 struct sensor_t const** list);
353 /* name of this sensors */
355 /* vendor of the hardware part */
357 /* version of the hardware part + driver. The value of this field is
358 * left to the implementation and doesn't have to be monotonically
362 /* handle that identifies this sensors. This handle is used to activate
363 * and deactivate this sensor. The value of the handle must be 8 bits
364 * in this version of the API.
367 /* this sensor's type. */
369 /* maximaum range of this sensor's value in SI units */
371 /* smallest difference between two values reported by this sensor */
373 /* rough estimate of this sensor's power consumption in mA */
375 /* minimum delay allowed between events in microseconds. A value of zero
376 * means that this sensor doesn't report events at a constant rate, but
377 * rather only when a new data is available */
379 /* reserved fields, must be zero */
385 * Every device data structure must begin with hw_device_t
386 * followed by module specific public methods and attributes.
388 struct sensors_poll_device_t {
389 struct hw_device_t common;
391 /** Activate/deactivate one sensor.
393 * @param handle is the handle of the sensor to change.
394 * @param enabled set to 1 to enable, or 0 to disable the sensor.
396 * @return 0 on success, negative errno code otherwise
398 int (*activate)(struct sensors_poll_device_t *dev,
399 int handle, int enabled);
402 * Set the delay between sensor events in nanoseconds for a given sensor.
403 * It is an error to set a delay inferior to the value defined by
404 * sensor_t::minDelay. If sensor_t::minDelay is zero, setDelay() is
405 * ignored and returns 0.
407 * @return 0 if successful, < 0 on error
409 int (*setDelay)(struct sensors_poll_device_t *dev,
410 int handle, int64_t ns);
413 * Returns an array of sensor data.
414 * This function must block until events are available.
416 * @return the number of events read on success, or -errno in case of an error.
417 * This function should never return 0 (no event).
420 int (*poll)(struct sensors_poll_device_t *dev,
421 sensors_event_t* data, int count);
424 /** convenience API for opening and closing a device */
426 static inline int sensors_open(const struct hw_module_t* module,
427 struct sensors_poll_device_t** device) {
428 return module->methods->open(module,
429 SENSORS_HARDWARE_POLL, (struct hw_device_t**)device);
432 static inline int sensors_close(struct sensors_poll_device_t* device) {
433 return device->common.close(&device->common);
438 #include <hardware/sensors_deprecated.h>
440 #endif // ANDROID_SENSORS_INTERFACE_H