sensors.h revision 1832f55760fff86d00b5d808b3da8f1e55a889e5 
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
60#define SENSOR_TYPE_PROXIMITY           8
61
62/**
63 * Values returned by the accelerometer in various locations in the universe.
64 * all values are in SI units (m/s^2)
65 */
66
67#define GRAVITY_SUN             (275.0f)
68#define GRAVITY_EARTH           (9.80665f)
69
70/** Maximum magnetic field on Earth's surface */
71#define MAGNETIC_FIELD_EARTH_MAX    (60.0f)
72
73/** Minimum magnetic field on Earth's surface */
74#define MAGNETIC_FIELD_EARTH_MIN    (30.0f)
75
76
77/**
78 * status of each sensor
79 */
80
81#define SENSOR_STATUS_UNRELIABLE        0
82#define SENSOR_STATUS_ACCURACY_LOW      1
83#define SENSOR_STATUS_ACCURACY_MEDIUM   2
84#define SENSOR_STATUS_ACCURACY_HIGH     3
85
86/**
87 * Definition of the axis
88 * ----------------------
89 *
90 * This API is relative to the screen of the device in its default orientation,
91 * that is, if the device can be used in portrait or landscape, this API
92 * is only relative to the NATURAL orientation of the screen. In other words,
93 * the axis are not swapped when the device's screen orientation changes.
94 * Higher level services /may/ perform this transformation.
95 *
96 *   x<0         x>0
97 *                ^
98 *                |
99 *    +-----------+-->  y>0
100 *    |           |
101 *    |           |
102 *    |           |
103 *    |           |   / z<0
104 *    |           |  /
105 *    |           | /
106 *    O-----------+/
107 *    |[]  [ ]  []/
108 *    +----------/+     y<0
109 *              /
110 *             /
111 *           |/ z>0 (toward the sky)
112 *
113 *    O: Origin (x=0,y=0,z=0)
114 *
115 *
116 * Orientation
117 * -----------
118 *
119 * All values are angles in degrees.
120 *
121 * Orientation sensors return sensor events for all 3 axes at a constant
122 * rate defined by setDelay().
123 *
124 * azimuth: angle between the magnetic north direction and the Y axis, around
125 *  the Z axis (0<=azimuth<360).
126 *      0=North, 90=East, 180=South, 270=West
127 *
128 * pitch: Rotation around X axis (-180<=pitch<=180), with positive values when
129 *  the z-axis moves toward the y-axis.
130 *
131 * roll: Rotation around Y axis (-90<=roll<=90), with positive values when
132 *  the x-axis moves towards the z-axis.
133 *
134 * Note: For historical reasons the roll angle is positive in the clockwise
135 *  direction (mathematically speaking, it should be positive in the
136 *  counter-clockwise direction):
137 *
138 *                Z
139 *                ^
140 *  (+roll)  .--> |
141 *          /     |
142 *         |      |  roll: rotation around Y axis
143 *     X <-------(.)
144 *                 Y
145 *       note that +Y == -roll
146 *
147 *
148 *
149 * Note: This definition is different from yaw, pitch and roll used in aviation
150 *  where the X axis is along the long side of the plane (tail to nose).
151 *
152 *
153 * Acceleration
154 * ------------
155 *
156 *  All values are in SI units (m/s^2) and measure the acceleration of the
157 *  device minus the force of gravity.
158 *
159 *  Acceleration sensors return sensor events for all 3 axes at a constant
160 *  rate defined by setDelay().
161 *
162 *  x: Acceleration minus Gx on the x-axis
163 *  y: Acceleration minus Gy on the y-axis
164 *  z: Acceleration minus Gz on the z-axis
165 *
166 *  Examples:
167 *    When the device lies flat on a table and is pushed on its left side
168 *    toward the right, the x acceleration value is positive.
169 *
170 *    When the device lies flat on a table, the acceleration value is +9.81,
171 *    which correspond to the acceleration of the device (0 m/s^2) minus the
172 *    force of gravity (-9.81 m/s^2).
173 *
174 *    When the device lies flat on a table and is pushed toward the sky, the
175 *    acceleration value is greater than +9.81, which correspond to the
176 *    acceleration of the device (+A m/s^2) minus the force of
177 *    gravity (-9.81 m/s^2).
178 *
179 *
180 * Magnetic Field
181 * --------------
182 *
183 *  All values are in micro-Tesla (uT) and measure the ambient magnetic
184 *  field in the X, Y and Z axis.
185 *
186 *  Magnetic Field sensors return sensor events for all 3 axes at a constant
187 *  rate defined by setDelay().
188 *
189 * Proximity
190 * ---------
191 *
192 * The distance value is measured in centimeters.  Note that some proximity
193 * sensors only support a binary "close" or "far" measurement.  In this case,
194 * the sensor should report its maxRange value in the "far" state and a value
195 * less than maxRange in the "near" state.
196 *
197 * Proximity sensors report a value only when it changes and each time the
198 * sensor is enabled. setDelay() is ignored.
199 *
200 * Light
201 * -----
202 *
203 * The light sensor value is returned in SI lux units.
204 *
205 * Light sensors report a value only when it changes and each time the
206 * sensor is enabled. setDelay() is ignored.
207 *
208 * Pressure
209 * --------
210 *
211 * The pressure sensor value is returned in hectopascal (hPa)
212 *
213 * Pressure sensors report events at a constant rate defined by setDelay().
214 *
215 */
216typedef struct {
217    union {
218        float v[3];
219        struct {
220            float x;
221            float y;
222            float z;
223        };
224        struct {
225            float azimuth;
226            float pitch;
227            float roll;
228        };
229    };
230    int8_t status;
231    uint8_t reserved[3];
232} sensors_vec_t;
233
234/**
235 * Union of the various types of sensor data
236 * that can be returned.
237 */
238typedef struct sensors_event_t {
239    /* must be sizeof(struct sensors_event_t) */
240    int32_t version;
241
242    /* sensor identifier */
243    int32_t sensor;
244
245    /* sensor type */
246    int32_t type;
247
248    /* reserved */
249    int32_t reserved0;
250
251    /* time is in nanosecond */
252    int64_t timestamp;
253
254    union {
255        float           data[16];
256
257        /* acceleration values are in meter per second per second (m/s^2) */
258        sensors_vec_t   acceleration;
259
260        /* magnetic vector values are in micro-Tesla (uT) */
261        sensors_vec_t   magnetic;
262
263        /* orientation values are in degrees */
264        sensors_vec_t   orientation;
265
266        /* temperature is in degrees centigrade (Celsius) */
267        float           temperature;
268
269        /* distance in centimeters */
270        float           distance;
271
272        /* light in SI lux units */
273        float           light;
274
275        /* pressure in hectopascal (hPa) */
276        float           pressure;
277    };
278    uint32_t        reserved1[4];
279} sensors_event_t;
280
281
282
283struct sensor_t;
284
285/**
286 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
287 * and the fields of this data structure must begin with hw_module_t
288 * followed by module specific information.
289 */
290struct sensors_module_t {
291    struct hw_module_t common;
292
293    /**
294     * Enumerate all available sensors. The list is returned in "list".
295     * @return number of sensors in the list
296     */
297    int (*get_sensors_list)(struct sensors_module_t* module,
298            struct sensor_t const** list);
299};
300
301struct sensor_t {
302    /* name of this sensors */
303    const char*     name;
304    /* vendor of the hardware part */
305    const char*     vendor;
306    /* version of the hardware part + driver. The value of this field is
307     * left to the implementation and doesn't have to be monotonically
308     * increasing.
309     */
310    int             version;
311    /* handle that identifies this sensors. This handle is used to activate
312     * and deactivate this sensor. The value of the handle must be 8 bits
313     * in this version of the API.
314     */
315    int             handle;
316    /* this sensor's type. */
317    int             type;
318    /* maximaum range of this sensor's value in SI units */
319    float           maxRange;
320    /* smallest difference between two values reported by this sensor */
321    float           resolution;
322    /* rough estimate of this sensor's power consumption in mA */
323    float           power;
324    /* reserved fields, must be zero */
325    void*           reserved[9];
326};
327
328
329/**
330 * Every device data structure must begin with hw_device_t
331 * followed by module specific public methods and attributes.
332 */
333struct sensors_poll_device_t {
334    struct hw_device_t common;
335
336    /** Activate/deactivate one sensor.
337     *
338     * @param handle is the handle of the sensor to change.
339     * @param enabled set to 1 to enable, or 0 to disable the sensor.
340     *
341     * @return 0 on success, negative errno code otherwise
342     */
343    int (*activate)(struct sensors_poll_device_t *dev,
344            int handle, int enabled);
345
346    /**
347     * Set the delay between sensor events in nanoseconds for a given sensor
348     *
349     * @return 0 if successful, < 0 on error
350     */
351    int (*setDelay)(struct sensors_poll_device_t *dev,
352            int handle, int64_t ns);
353
354    /**
355     * Returns an array of sensor data.
356     *
357     * @return the number of events read on success, or -errno in case of an error.
358     *
359     */
360    int (*poll)(struct sensors_poll_device_t *dev,
361            sensors_event_t* data, int count);
362};
363
364/** convenience API for opening and closing a device */
365
366static inline int sensors_open(const struct hw_module_t* module,
367        struct sensors_poll_device_t** device) {
368    return module->methods->open(module,
369            SENSORS_HARDWARE_POLL, (struct hw_device_t**)device);
370}
371
372static inline int sensors_close(struct sensors_poll_device_t* device) {
373    return device->common.close(&device->common);
374}
375
376__END_DECLS
377
378#include <hardware/sensors_deprecated.h>
379
380#endif  // ANDROID_SENSORS_INTERFACE_H
381