SensorDevice.h revision 724d91d778e71c8186399f4955de14b54812b3ed 
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#ifndef ANDROID_SENSOR_DEVICE_H
18#define ANDROID_SENSOR_DEVICE_H
19
20#include <stdint.h>
21#include <sys/types.h>
22
23#include <utils/KeyedVector.h>
24#include <utils/Singleton.h>
25#include <utils/String8.h>
26
27#include <gui/Sensor.h>
28
29// ---------------------------------------------------------------------------
30
31namespace android {
32// ---------------------------------------------------------------------------
33
34class SensorDevice : public Singleton<SensorDevice> {
35    friend class Singleton<SensorDevice>;
36    sensors_poll_device_1_t* mSensorDevice;
37    struct sensors_module_t* mSensorModule;
38    static const nsecs_t MINIMUM_EVENTS_PERIOD =   1000000; // 1000 Hz
39    mutable Mutex mLock; // protect mActivationCount[].batchParams
40    // fixed-size array after construction
41
42    // Struct to store all the parameters(samplingPeriod, maxBatchReportLatency and flags) from
43    // batch call. For continous mode clients, maxBatchReportLatency is set to zero.
44    struct BatchParams {
45      int flags;
46      nsecs_t batchDelay, batchTimeout;
47      BatchParams() : flags(0), batchDelay(0), batchTimeout(0) {}
48      BatchParams(int flag, nsecs_t delay, nsecs_t timeout): flags(flag), batchDelay(delay),
49          batchTimeout(timeout) { }
50      bool operator != (const BatchParams& other) {
51          return other.batchDelay != batchDelay || other.batchTimeout != batchTimeout ||
52                 other.flags != flags;
53      }
54    };
55
56    // Store batch parameters in the KeyedVector and the optimal batch_rate and timeout in
57    // bestBatchParams. For every batch() call corresponding params are stored in batchParams
58    // vector. A continuous mode request is batch(... timeout=0 ..) followed by activate(). A batch
59    // mode request is batch(... timeout > 0 ...) followed by activate().
60    // Info is a per-sensor data structure which contains the batch parameters for each client that
61    // has registered for this sensor.
62    struct Info {
63        BatchParams bestBatchParams;
64        // Key is the unique identifier(ident) for each client, value is the batch parameters
65        // requested by the client.
66        KeyedVector<void*, BatchParams> batchParams;
67
68        Info() : bestBatchParams(-1, -1, -1) {}
69        // Sets batch parameters for this ident. Returns error if this ident is not already present
70        // in the KeyedVector above.
71        status_t setBatchParamsForIdent(void* ident, int flags, int64_t samplingPeriodNs,
72                                        int64_t maxBatchReportLatencyNs);
73        // Finds the optimal parameters for batching and stores them in bestBatchParams variable.
74        void selectBatchParams();
75        // Removes batchParams for an ident and re-computes bestBatchParams. Returns the index of
76        // the removed ident. If index >=0, ident is present and successfully removed.
77        ssize_t removeBatchParamsForIdent(void* ident);
78    };
79    DefaultKeyedVector<int, Info> mActivationCount;
80
81    SensorDevice();
82public:
83    ssize_t getSensorList(sensor_t const** list);
84    status_t initCheck() const;
85    int getHalDeviceVersion() const;
86    ssize_t poll(sensors_event_t* buffer, size_t count);
87    status_t activate(void* ident, int handle, int enabled);
88    status_t batch(void* ident, int handle, int flags, int64_t samplingPeriodNs,
89                   int64_t maxBatchReportLatencyNs);
90    // Call batch with timeout zero instead of calling setDelay() for newer devices.
91    status_t setDelay(void* ident, int handle, int64_t ns);
92    status_t flush(void* ident, int handle);
93    void autoDisable(void *ident, int handle);
94    void dump(String8& result);
95};
96
97// ---------------------------------------------------------------------------
98}; // namespace android
99
100#endif // ANDROID_SENSOR_DEVICE_H
101