1/*
2 * Copyright (C) 2010 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#include <stdint.h>
18#include <math.h>
19#include <sys/types.h>
20
21#include <utils/Errors.h>
22
23#include <hardware/sensors.h>
24
25#include "GravitySensor.h"
26#include "SensorDevice.h"
27#include "SensorFusion.h"
28
29namespace android {
30// ---------------------------------------------------------------------------
31
32GravitySensor::GravitySensor(sensor_t const* list, size_t count)
33    : mSensorDevice(SensorDevice::getInstance()),
34      mSensorFusion(SensorFusion::getInstance())
35{
36    for (size_t i=0 ; i<count ; i++) {
37        if (list[i].type == SENSOR_TYPE_ACCELEROMETER) {
38            mAccelerometer = Sensor(list + i);
39            break;
40        }
41    }
42}
43
44bool GravitySensor::process(sensors_event_t* outEvent,
45        const sensors_event_t& event)
46{
47    const static double NS2S = 1.0 / 1000000000.0;
48    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
49        vec3_t g;
50        if (!mSensorFusion.hasEstimate())
51            return false;
52        const mat33_t R(mSensorFusion.getRotationMatrix());
53        // FIXME: we need to estimate the length of gravity because
54        // the accelerometer may have a small scaling error. This
55        // translates to an offset in the linear-acceleration sensor.
56        g = R[2] * GRAVITY_EARTH;
57
58        *outEvent = event;
59        outEvent->data[0] = g.x;
60        outEvent->data[1] = g.y;
61        outEvent->data[2] = g.z;
62        outEvent->sensor = '_grv';
63        outEvent->type = SENSOR_TYPE_GRAVITY;
64        return true;
65    }
66    return false;
67}
68
69status_t GravitySensor::activate(void* ident, bool enabled) {
70    return mSensorFusion.activate(this, enabled);
71}
72
73status_t GravitySensor::setDelay(void* ident, int handle, int64_t ns) {
74    return mSensorFusion.setDelay(this, ns);
75}
76
77Sensor GravitySensor::getSensor() const {
78    sensor_t hwSensor;
79    hwSensor.name       = "Gravity Sensor";
80    hwSensor.vendor     = "Google Inc.";
81    hwSensor.version    = 3;
82    hwSensor.handle     = '_grv';
83    hwSensor.type       = SENSOR_TYPE_GRAVITY;
84    hwSensor.maxRange   = GRAVITY_EARTH * 2;
85    hwSensor.resolution = mAccelerometer.getResolution();
86    hwSensor.power      = mSensorFusion.getPowerUsage();
87    hwSensor.minDelay   = mSensorFusion.getMinDelay();
88    Sensor sensor(&hwSensor);
89    return sensor;
90}
91
92// ---------------------------------------------------------------------------
93}; // namespace android
94
95