1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
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
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
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.
15 */
16
17 #ifndef ANDROID_SENSORS_INTERFACE_H
18 #define ANDROID_SENSORS_INTERFACE_H
19
20 #include <stdint.h>
21 #include <sys/cdefs.h>
22 #include <sys/types.h>
23
24 #include <hardware/hardware.h>
25 #include <cutils/native_handle.h>
26
27 __BEGIN_DECLS
28
29 /**
30 * The id of this module
31 */
32 #define SENSORS_HARDWARE_MODULE_ID "sensors"
33
34 /**
35 * Name of the sensors device to open
36 */
37 #define SENSORS_HARDWARE_POLL "poll"
38
39 /**
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.
44 */
45 #define SENSORS_HANDLE_BASE 0
46 #define SENSORS_HANDLE_BITS 8
47 #define SENSORS_HANDLE_COUNT (1<<SENSORS_HANDLE_BITS)
48
49
50 /**
51 * Sensor types
52 */
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 // deprecated
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
64 #define SENSOR_TYPE_RELATIVE_HUMIDITY 12
65 #define SENSOR_TYPE_AMBIENT_TEMPERATURE 13
66
67 /**
68 * Values returned by the accelerometer in various locations in the universe.
69 * all values are in SI units (m/s^2)
70 */
71
72 #define GRAVITY_SUN (275.0f)
73 #define GRAVITY_EARTH (9.80665f)
74
75 /** Maximum magnetic field on Earth's surface */
76 #define MAGNETIC_FIELD_EARTH_MAX (60.0f)
77
78 /** Minimum magnetic field on Earth's surface */
79 #define MAGNETIC_FIELD_EARTH_MIN (30.0f)
80
81
82 /**
83 * status of each sensor
84 */
85
86 #define SENSOR_STATUS_UNRELIABLE 0
87 #define SENSOR_STATUS_ACCURACY_LOW 1
88 #define SENSOR_STATUS_ACCURACY_MEDIUM 2
89 #define SENSOR_STATUS_ACCURACY_HIGH 3
90
91 /**
92 * Definition of the axis
93 * ----------------------
94 *
95 * This API is relative to the screen of the device in its default orientation,
96 * that is, if the device can be used in portrait or landscape, this API
97 * is only relative to the NATURAL orientation of the screen. In other words,
98 * the axis are not swapped when the device's screen orientation changes.
99 * Higher level services /may/ perform this transformation.
100 *
101 * x<0 x>0
102 * ^
103 * |
104 * +-----------+--> y>0
105 * | |
106 * | |
107 * | |
108 * | | / z<0
109 * | | /
110 * | | /
111 * O-----------+/
112 * |[] [ ] []/
113 * +----------/+ y<0
114 * /
115 * /
116 * |/ z>0 (toward the sky)
117 *
118 * O: Origin (x=0,y=0,z=0)
119 *
120 *
121 * SENSOR_TYPE_ORIENTATION
122 * -----------------------
123 *
124 * All values are angles in degrees.
125 *
126 * Orientation sensors return sensor events for all 3 axes at a constant
127 * rate defined by setDelay().
128 *
129 * azimuth: angle between the magnetic north direction and the Y axis, around
130 * the Z axis (0<=azimuth<360).
131 * 0=North, 90=East, 180=South, 270=West
132 *
133 * pitch: Rotation around X axis (-180<=pitch<=180), with positive values when
134 * the z-axis moves toward the y-axis.
135 *
136 * roll: Rotation around Y axis (-90<=roll<=90), with positive values when
137 * the x-axis moves towards the z-axis.
138 *
139 * Note: For historical reasons the roll angle is positive in the clockwise
140 * direction (mathematically speaking, it should be positive in the
141 * counter-clockwise direction):
142 *
143 * Z
144 * ^
145 * (+roll) .--> |
146 * / |
147 * | | roll: rotation around Y axis
148 * X <-------(.)
149 * Y
150 * note that +Y == -roll
151 *
152 *
153 *
154 * Note: This definition is different from yaw, pitch and roll used in aviation
155 * where the X axis is along the long side of the plane (tail to nose).
156 *
157 *
158 * SENSOR_TYPE_ACCELEROMETER
159 * -------------------------
160 *
161 * All values are in SI units (m/s^2) and measure the acceleration of the
162 * device minus the force of gravity.
163 *
164 * Acceleration sensors return sensor events for all 3 axes at a constant
165 * rate defined by setDelay().
166 *
167 * x: Acceleration minus Gx on the x-axis
168 * y: Acceleration minus Gy on the y-axis
169 * z: Acceleration minus Gz on the z-axis
170 *
171 * Examples:
172 * When the device lies flat on a table and is pushed on its left side
173 * toward the right, the x acceleration value is positive.
174 *
175 * When the device lies flat on a table, the acceleration value is +9.81,
176 * which correspond to the acceleration of the device (0 m/s^2) minus the
177 * force of gravity (-9.81 m/s^2).
178 *
179 * When the device lies flat on a table and is pushed toward the sky, the
180 * acceleration value is greater than +9.81, which correspond to the
181 * acceleration of the device (+A m/s^2) minus the force of
182 * gravity (-9.81 m/s^2).
183 *
184 *
185 * SENSOR_TYPE_MAGNETIC_FIELD
186 * --------------------------
187 *
188 * All values are in micro-Tesla (uT) and measure the ambient magnetic
189 * field in the X, Y and Z axis.
190 *
191 * Magnetic Field sensors return sensor events for all 3 axes at a constant
192 * rate defined by setDelay().
193 *
194 * SENSOR_TYPE_GYROSCOPE
195 * ---------------------
196 *
197 * All values are in radians/second and measure the rate of rotation
198 * around the X, Y and Z axis. The coordinate system is the same as is
199 * used for the acceleration sensor. Rotation is positive in the
200 * counter-clockwise direction (right-hand rule). That is, an observer
201 * looking from some positive location on the x, y or z axis at a device
202 * positioned on the origin would report positive rotation if the device
203 * appeared to be rotating counter clockwise. Note that this is the
204 * standard mathematical definition of positive rotation and does not agree
205 * with the definition of roll given earlier.
206 * The range should at least be 17.45 rad/s (ie: ~1000 deg/s).
207 *
208 * SENSOR_TYPE_PROXIMITY
209 * ----------------------
210 *
211 * The distance value is measured in centimeters. Note that some proximity
212 * sensors only support a binary "close" or "far" measurement. In this case,
213 * the sensor should report its maxRange value in the "far" state and a value
214 * less than maxRange in the "near" state.
215 *
216 * Proximity sensors report a value only when it changes and each time the
217 * sensor is enabled.
218 *
219 * SENSOR_TYPE_LIGHT
220 * -----------------
221 *
222 * The light sensor value is returned in SI lux units.
223 *
224 * Light sensors report a value only when it changes and each time the
225 * sensor is enabled.
226 *
227 * SENSOR_TYPE_PRESSURE
228 * --------------------
229 *
230 * The pressure sensor return the athmospheric pressure in hectopascal (hPa)
231 *
232 * Pressure sensors report events at a constant rate defined by setDelay().
233 *
234 * SENSOR_TYPE_GRAVITY
235 * -------------------
236 *
237 * A gravity output indicates the direction of and magnitude of gravity in
238 * the devices's coordinates. On Earth, the magnitude is 9.8 m/s^2.
239 * Units are m/s^2. The coordinate system is the same as is used for the
240 * acceleration sensor. When the device is at rest, the output of the
241 * gravity sensor should be identical to that of the accelerometer.
242 *
243 * SENSOR_TYPE_LINEAR_ACCELERATION
244 * --------------------------------
245 *
246 * Indicates the linear acceleration of the device in device coordinates,
247 * not including gravity.
248 * This output is essentially Acceleration - Gravity. Units are m/s^2.
249 * The coordinate system is the same as is used for the acceleration sensor.
250 *
251 *
252 * SENSOR_TYPE_ROTATION_VECTOR
253 * ---------------------------
254 *
255 * A rotation vector represents the orientation of the device as a combination
256 * of an angle and an axis, in which the device has rotated through an angle
257 * theta around an axis <x, y, z>. The three elements of the rotation vector
258 * are <x*sin(theta/2), y*sin(theta/2), z*sin(theta/2)>, such that the magnitude
259 * of the rotation vector is equal to sin(theta/2), and the direction of the
260 * rotation vector is equal to the direction of the axis of rotation. The three
261 * elements of the rotation vector are equal to the last three components of a
262 * unit quaternion <cos(theta/2), x*sin(theta/2), y*sin(theta/2), z*sin(theta/2)>.
263 * Elements of the rotation vector are unitless. The x, y, and z axis are defined
264 * in the same was as for the acceleration sensor.
265 *
266 * The reference coordinate system is defined as a direct orthonormal basis,
267 * where:
268 *
269 * - X is defined as the vector product Y.Z (It is tangential to
270 * the ground at the device's current location and roughly points East).
271 *
272 * - Y is tangential to the ground at the device's current location and
273 * points towards the magnetic North Pole.
274 *
275 * - Z points towards the sky and is perpendicular to the ground.
276 *
277 *
278 * The rotation-vector is stored as:
279 *
280 * sensors_event_t.data[0] = x*sin(theta/2)
281 * sensors_event_t.data[1] = y*sin(theta/2)
282 * sensors_event_t.data[2] = z*sin(theta/2)
283 * sensors_event_t.data[3] = cos(theta/2)
284 *
285 *
286 * SENSOR_TYPE_RELATIVE_HUMIDITY
287 * ------------------------------
288 *
289 * A relative humidity sensor measures relative ambient air humidity and
290 * returns a value in percent.
291 *
292 * Relative humidity sensors report a value only when it changes and each
293 * time the sensor is enabled.
294 *
295 *
296 * SENSOR_TYPE_AMBIENT_TEMPERATURE
297 * -------------------------------
298 *
299 * The ambient (room) temperature in degree Celsius.
300 *
301 * Temperature sensors report a value only when it changes and each time the
302 * sensor is enabled.
303 *
304 */
305
306 typedef struct {
307 union {
308 float v[3];
309 struct {
310 float x;
311 float y;
312 float z;
313 };
314 struct {
315 float azimuth;
316 float pitch;
317 float roll;
318 };
319 };
320 int8_t status;
321 uint8_t reserved[3];
322 } sensors_vec_t;
323
324 /**
325 * Union of the various types of sensor data
326 * that can be returned.
327 */
328 typedef struct sensors_event_t {
329 /* must be sizeof(struct sensors_event_t) */
330 int32_t version;
331
332 /* sensor identifier */
333 int32_t sensor;
334
335 /* sensor type */
336 int32_t type;
337
338 /* reserved */
339 int32_t reserved0;
340
341 /* time is in nanosecond */
342 int64_t timestamp;
343
344 union {
345 float data[16];
346
347 /* acceleration values are in meter per second per second (m/s^2) */
348 sensors_vec_t acceleration;
349
350 /* magnetic vector values are in micro-Tesla (uT) */
351 sensors_vec_t magnetic;
352
353 /* orientation values are in degrees */
354 sensors_vec_t orientation;
355
356 /* gyroscope values are in rad/s */
357 sensors_vec_t gyro;
358
359 /* temperature is in degrees centigrade (Celsius) */
360 float temperature;
361
362 /* distance in centimeters */
363 float distance;
364
365 /* light in SI lux units */
366 float light;
367
368 /* pressure in hectopascal (hPa) */
369 float pressure;
370
371 /* relative humidity in percent */
372 float relative_humidity;
373 };
374 uint32_t reserved1[4];
375 } sensors_event_t;
376
377
378
379 struct sensor_t;
380
381 /**
382 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
383 * and the fields of this data structure must begin with hw_module_t
384 * followed by module specific information.
385 */
386 struct sensors_module_t {
387 struct hw_module_t common;
388
389 /**
390 * Enumerate all available sensors. The list is returned in "list".
391 * @return number of sensors in the list
392 */
393 int (*get_sensors_list)(struct sensors_module_t* module,
394 struct sensor_t const** list);
395 };
396
397 struct sensor_t {
398 /* name of this sensors */
399 const char* name;
400 /* vendor of the hardware part */
401 const char* vendor;
402 /* version of the hardware part + driver. The value of this field
403 * must increase when the driver is updated in a way that changes the
404 * output of this sensor. This is important for fused sensors when the
405 * fusion algorithm is updated.
406 */
407 int version;
408 /* handle that identifies this sensors. This handle is used to activate
409 * and deactivate this sensor. The value of the handle must be 8 bits
410 * in this version of the API.
411 */
412 int handle;
413 /* this sensor's type. */
414 int type;
415 /* maximaum range of this sensor's value in SI units */
416 float maxRange;
417 /* smallest difference between two values reported by this sensor */
418 float resolution;
419 /* rough estimate of this sensor's power consumption in mA */
420 float power;
421 /* minimum delay allowed between events in microseconds. A value of zero
422 * means that this sensor doesn't report events at a constant rate, but
423 * rather only when a new data is available */
424 int32_t minDelay;
425 /* reserved fields, must be zero */
426 void* reserved[8];
427 };
428
429
430 /**
431 * Every device data structure must begin with hw_device_t
432 * followed by module specific public methods and attributes.
433 */
434 struct sensors_poll_device_t {
435 struct hw_device_t common;
436
437 /** Activate/deactivate one sensor.
438 *
439 * @param handle is the handle of the sensor to change.
440 * @param enabled set to 1 to enable, or 0 to disable the sensor.
441 *
442 * @return 0 on success, negative errno code otherwise
443 */
444 int (*activate)(struct sensors_poll_device_t *dev,
445 int handle, int enabled);
446
447 /**
448 * Set the delay between sensor events in nanoseconds for a given sensor.
449 *
450 * If the requested value is less than sensor_t::minDelay, then it's
451 * silently clamped to sensor_t::minDelay unless sensor_t::minDelay is
452 * 0, in which case it is clamped to >= 1ms.
453 *
454 * @return 0 if successful, < 0 on error
455 */
456 int (*setDelay)(struct sensors_poll_device_t *dev,
457 int handle, int64_t ns);
458
459 /**
460 * Returns an array of sensor data.
461 * This function must block until events are available.
462 *
463 * @return the number of events read on success, or -errno in case of an error.
464 * This function should never return 0 (no event).
465 *
466 */
467 int (*poll)(struct sensors_poll_device_t *dev,
468 sensors_event_t* data, int count);
469 };
470
471 /** convenience API for opening and closing a device */
472
sensors_open(const struct hw_module_t * module,struct sensors_poll_device_t ** device)473 static inline int sensors_open(const struct hw_module_t* module,
474 struct sensors_poll_device_t** device) {
475 return module->methods->open(module,
476 SENSORS_HARDWARE_POLL, (struct hw_device_t**)device);
477 }
478
sensors_close(struct sensors_poll_device_t * device)479 static inline int sensors_close(struct sensors_poll_device_t* device) {
480 return device->common.close(&device->common);
481 }
482
483 __END_DECLS
484
485 #endif // ANDROID_SENSORS_INTERFACE_H
486