diff --git a/sensors/common/default/2.X/Android.bp b/sensors/common/default/2.X/Android.bp
new file mode 100644
index 0000000..ea75a10
--- /dev/null
+++ b/sensors/common/default/2.X/Android.bp
@@ -0,0 +1,36 @@
+//
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+cc_library_static {
+    name: "android.hardware.sensors@2.X-shared-impl",
+    vendor: true,
+    export_include_dirs: ["."],
+    srcs: [
+        "Sensor.cpp",
+    ],
+    header_libs: [
+        "android.hardware.sensors@2.X-shared-utils",
+    ],
+    shared_libs: [
+        "android.hardware.sensors@1.0",
+        "android.hardware.sensors@2.0",
+        "libcutils",
+        "libfmq",
+        "libhidlbase",
+        "liblog",
+        "libpower",
+        "libutils",
+    ],
+}
diff --git a/sensors/common/default/2.X/OWNERS b/sensors/common/default/2.X/OWNERS
new file mode 100644
index 0000000..90c2330
--- /dev/null
+++ b/sensors/common/default/2.X/OWNERS
@@ -0,0 +1,3 @@
+arthuri@google.com
+bduddie@google.com
+stange@google.com
diff --git a/sensors/common/default/2.X/Sensor.cpp b/sensors/common/default/2.X/Sensor.cpp
new file mode 100644
index 0000000..4c40d1f
--- /dev/null
+++ b/sensors/common/default/2.X/Sensor.cpp
@@ -0,0 +1,378 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Sensor.h"
+
+#include <utils/SystemClock.h>
+
+#include <cmath>
+
+namespace android {
+namespace hardware {
+namespace sensors {
+namespace V2_X {
+namespace implementation {
+
+using ::android::hardware::sensors::V1_0::Event;
+using ::android::hardware::sensors::V1_0::MetaDataEventType;
+using ::android::hardware::sensors::V1_0::OperationMode;
+using ::android::hardware::sensors::V1_0::Result;
+using ::android::hardware::sensors::V1_0::SensorFlagBits;
+using ::android::hardware::sensors::V1_0::SensorInfo;
+using ::android::hardware::sensors::V1_0::SensorStatus;
+using ::android::hardware::sensors::V1_0::SensorType;
+
+static constexpr float kDefaultMaxDelayUs = 10 * 1000 * 1000;
+
+Sensor::Sensor(ISensorsEventCallback* callback)
+    : mIsEnabled(false),
+      mSamplingPeriodNs(0),
+      mLastSampleTimeNs(0),
+      mCallback(callback),
+      mMode(OperationMode::NORMAL) {
+    mRunThread = std::thread(startThread, this);
+}
+
+Sensor::~Sensor() {
+    std::unique_lock<std::mutex> lock(mRunMutex);
+    mStopThread = true;
+    mIsEnabled = false;
+    mWaitCV.notify_all();
+    lock.release();
+    mRunThread.join();
+}
+
+const SensorInfo& Sensor::getSensorInfo() const {
+    return mSensorInfo;
+}
+
+void Sensor::batch(int32_t samplingPeriodNs) {
+    if (samplingPeriodNs < mSensorInfo.minDelay * 1000) {
+        samplingPeriodNs = mSensorInfo.minDelay * 1000;
+    } else if (samplingPeriodNs > mSensorInfo.maxDelay * 1000) {
+        samplingPeriodNs = mSensorInfo.maxDelay * 1000;
+    }
+
+    if (mSamplingPeriodNs != samplingPeriodNs) {
+        mSamplingPeriodNs = samplingPeriodNs;
+        // Wake up the 'run' thread to check if a new event should be generated now
+        mWaitCV.notify_all();
+    }
+}
+
+void Sensor::activate(bool enable) {
+    if (mIsEnabled != enable) {
+        std::unique_lock<std::mutex> lock(mRunMutex);
+        mIsEnabled = enable;
+        mWaitCV.notify_all();
+    }
+}
+
+Result Sensor::flush() {
+    // Only generate a flush complete event if the sensor is enabled and if the sensor is not a
+    // one-shot sensor.
+    if (!mIsEnabled || (mSensorInfo.flags & static_cast<uint32_t>(SensorFlagBits::ONE_SHOT_MODE))) {
+        return Result::BAD_VALUE;
+    }
+
+    // Note: If a sensor supports batching, write all of the currently batched events for the sensor
+    // to the Event FMQ prior to writing the flush complete event.
+    Event ev;
+    ev.sensorHandle = mSensorInfo.sensorHandle;
+    ev.sensorType = SensorType::META_DATA;
+    ev.u.meta.what = MetaDataEventType::META_DATA_FLUSH_COMPLETE;
+    std::vector<Event> evs{ev};
+    mCallback->postEvents(evs, isWakeUpSensor());
+
+    return Result::OK;
+}
+
+void Sensor::startThread(Sensor* sensor) {
+    sensor->run();
+}
+
+void Sensor::run() {
+    std::unique_lock<std::mutex> runLock(mRunMutex);
+    constexpr int64_t kNanosecondsInSeconds = 1000 * 1000 * 1000;
+
+    while (!mStopThread) {
+        if (!mIsEnabled || mMode == OperationMode::DATA_INJECTION) {
+            mWaitCV.wait(runLock, [&] {
+                return ((mIsEnabled && mMode == OperationMode::NORMAL) || mStopThread);
+            });
+        } else {
+            timespec curTime;
+            clock_gettime(CLOCK_REALTIME, &curTime);
+            int64_t now = (curTime.tv_sec * kNanosecondsInSeconds) + curTime.tv_nsec;
+            int64_t nextSampleTime = mLastSampleTimeNs + mSamplingPeriodNs;
+
+            if (now >= nextSampleTime) {
+                mLastSampleTimeNs = now;
+                nextSampleTime = mLastSampleTimeNs + mSamplingPeriodNs;
+                mCallback->postEvents(readEvents(), isWakeUpSensor());
+            }
+
+            mWaitCV.wait_for(runLock, std::chrono::nanoseconds(nextSampleTime - now));
+        }
+    }
+}
+
+bool Sensor::isWakeUpSensor() {
+    return mSensorInfo.flags & static_cast<uint32_t>(SensorFlagBits::WAKE_UP);
+}
+
+std::vector<Event> Sensor::readEvents() {
+    std::vector<Event> events;
+    Event event;
+    event.sensorHandle = mSensorInfo.sensorHandle;
+    event.sensorType = mSensorInfo.type;
+    event.timestamp = ::android::elapsedRealtimeNano();
+    event.u.vec3.x = 0;
+    event.u.vec3.y = 0;
+    event.u.vec3.z = 0;
+    event.u.vec3.status = SensorStatus::ACCURACY_HIGH;
+    events.push_back(event);
+    return events;
+}
+
+void Sensor::setOperationMode(OperationMode mode) {
+    if (mMode != mode) {
+        std::unique_lock<std::mutex> lock(mRunMutex);
+        mMode = mode;
+        mWaitCV.notify_all();
+    }
+}
+
+bool Sensor::supportsDataInjection() const {
+    return mSensorInfo.flags & static_cast<uint32_t>(SensorFlagBits::DATA_INJECTION);
+}
+
+Result Sensor::injectEvent(const Event& event) {
+    Result result = Result::OK;
+    if (event.sensorType == SensorType::ADDITIONAL_INFO) {
+        // When in OperationMode::NORMAL, SensorType::ADDITIONAL_INFO is used to push operation
+        // environment data into the device.
+    } else if (!supportsDataInjection()) {
+        result = Result::INVALID_OPERATION;
+    } else if (mMode == OperationMode::DATA_INJECTION) {
+        mCallback->postEvents(std::vector<Event>{event}, isWakeUpSensor());
+    } else {
+        result = Result::BAD_VALUE;
+    }
+    return result;
+}
+
+OnChangeSensor::OnChangeSensor(ISensorsEventCallback* callback)
+    : Sensor(callback), mPreviousEventSet(false) {}
+
+void OnChangeSensor::activate(bool enable) {
+    Sensor::activate(enable);
+    if (!enable) {
+        mPreviousEventSet = false;
+    }
+}
+
+std::vector<Event> OnChangeSensor::readEvents() {
+    std::vector<Event> events = Sensor::readEvents();
+    std::vector<Event> outputEvents;
+
+    for (auto iter = events.begin(); iter != events.end(); ++iter) {
+        Event ev = *iter;
+        if (ev.u.vec3 != mPreviousEvent.u.vec3 || !mPreviousEventSet) {
+            outputEvents.push_back(ev);
+            mPreviousEvent = ev;
+            mPreviousEventSet = true;
+        }
+    }
+    return outputEvents;
+}
+
+AccelSensor::AccelSensor(int32_t sensorHandle, ISensorsEventCallback* callback) : Sensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Accel Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::ACCELEROMETER;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 78.4f;  // +/- 8g
+    mSensorInfo.resolution = 1.52e-5;
+    mSensorInfo.power = 0.001f;        // mA
+    mSensorInfo.minDelay = 20 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = static_cast<uint32_t>(SensorFlagBits::DATA_INJECTION);
+};
+
+PressureSensor::PressureSensor(int32_t sensorHandle, ISensorsEventCallback* callback)
+    : Sensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Pressure Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::PRESSURE;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 1100.0f;     // hPa
+    mSensorInfo.resolution = 0.005f;    // hPa
+    mSensorInfo.power = 0.001f;         // mA
+    mSensorInfo.minDelay = 100 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = 0;
+};
+
+MagnetometerSensor::MagnetometerSensor(int32_t sensorHandle, ISensorsEventCallback* callback)
+    : Sensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Magnetic Field Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::MAGNETIC_FIELD;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 1300.0f;
+    mSensorInfo.resolution = 0.01f;
+    mSensorInfo.power = 0.001f;        // mA
+    mSensorInfo.minDelay = 20 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = 0;
+};
+
+LightSensor::LightSensor(int32_t sensorHandle, ISensorsEventCallback* callback)
+    : OnChangeSensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Light Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::LIGHT;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 43000.0f;
+    mSensorInfo.resolution = 10.0f;
+    mSensorInfo.power = 0.001f;         // mA
+    mSensorInfo.minDelay = 200 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = static_cast<uint32_t>(SensorFlagBits::ON_CHANGE_MODE);
+};
+
+ProximitySensor::ProximitySensor(int32_t sensorHandle, ISensorsEventCallback* callback)
+    : OnChangeSensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Proximity Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::PROXIMITY;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 5.0f;
+    mSensorInfo.resolution = 1.0f;
+    mSensorInfo.power = 0.012f;         // mA
+    mSensorInfo.minDelay = 200 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags =
+            static_cast<uint32_t>(SensorFlagBits::ON_CHANGE_MODE | SensorFlagBits::WAKE_UP);
+};
+
+GyroSensor::GyroSensor(int32_t sensorHandle, ISensorsEventCallback* callback) : Sensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Gyro Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::GYROSCOPE;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 1000.0f * M_PI / 180.0f;
+    mSensorInfo.resolution = 1000.0f * M_PI / (180.0f * 32768.0f);
+    mSensorInfo.power = 0.001f;
+    mSensorInfo.minDelay = 2.5f * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = 0;
+};
+
+AmbientTempSensor::AmbientTempSensor(int32_t sensorHandle, ISensorsEventCallback* callback)
+    : OnChangeSensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Ambient Temp Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::AMBIENT_TEMPERATURE;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 80.0f;
+    mSensorInfo.resolution = 0.01f;
+    mSensorInfo.power = 0.001f;
+    mSensorInfo.minDelay = 40 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = static_cast<uint32_t>(SensorFlagBits::ON_CHANGE_MODE);
+};
+
+DeviceTempSensor::DeviceTempSensor(int32_t sensorHandle, ISensorsEventCallback* callback)
+    : OnChangeSensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Device Temp Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::TEMPERATURE;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 80.0f;
+    mSensorInfo.resolution = 0.01f;
+    mSensorInfo.power = 0.001f;
+    mSensorInfo.minDelay = 40 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = static_cast<uint32_t>(SensorFlagBits::ON_CHANGE_MODE);
+}
+
+RelativeHumiditySensor::RelativeHumiditySensor(int32_t sensorHandle,
+                                               ISensorsEventCallback* callback)
+    : OnChangeSensor(callback) {
+    mSensorInfo.sensorHandle = sensorHandle;
+    mSensorInfo.name = "Relative Humidity Sensor";
+    mSensorInfo.vendor = "Vendor String";
+    mSensorInfo.version = 1;
+    mSensorInfo.type = SensorType::RELATIVE_HUMIDITY;
+    mSensorInfo.typeAsString = "";
+    mSensorInfo.maxRange = 100.0f;
+    mSensorInfo.resolution = 0.1f;
+    mSensorInfo.power = 0.001f;
+    mSensorInfo.minDelay = 40 * 1000;  // microseconds
+    mSensorInfo.maxDelay = kDefaultMaxDelayUs;
+    mSensorInfo.fifoReservedEventCount = 0;
+    mSensorInfo.fifoMaxEventCount = 0;
+    mSensorInfo.requiredPermission = "";
+    mSensorInfo.flags = static_cast<uint32_t>(SensorFlagBits::ON_CHANGE_MODE);
+}
+
+}  // namespace implementation
+}  // namespace V2_X
+}  // namespace sensors
+}  // namespace hardware
+}  // namespace android
diff --git a/sensors/common/default/2.X/Sensor.h b/sensors/common/default/2.X/Sensor.h
new file mode 100644
index 0000000..8592c41
--- /dev/null
+++ b/sensors/common/default/2.X/Sensor.h
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_SENSORS_V2_X_SENSOR_H
+#define ANDROID_HARDWARE_SENSORS_V2_X_SENSOR_H
+
+#include <android/hardware/sensors/1.0/types.h>
+
+#include <condition_variable>
+#include <memory>
+#include <mutex>
+#include <thread>
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace sensors {
+namespace V2_X {
+namespace implementation {
+
+class ISensorsEventCallback {
+  public:
+    using Event = ::android::hardware::sensors::V1_0::Event;
+
+    virtual ~ISensorsEventCallback(){};
+    virtual void postEvents(const std::vector<Event>& events, bool wakeup) = 0;
+};
+
+class Sensor {
+  public:
+    using Event = ::android::hardware::sensors::V1_0::Event;
+    using OperationMode = ::android::hardware::sensors::V1_0::OperationMode;
+    using Result = ::android::hardware::sensors::V1_0::Result;
+    using SensorInfo = ::android::hardware::sensors::V1_0::SensorInfo;
+    using SensorType = ::android::hardware::sensors::V1_0::SensorType;
+
+    Sensor(ISensorsEventCallback* callback);
+    virtual ~Sensor();
+
+    const SensorInfo& getSensorInfo() const;
+    void batch(int32_t samplingPeriodNs);
+    virtual void activate(bool enable);
+    Result flush();
+
+    void setOperationMode(OperationMode mode);
+    bool supportsDataInjection() const;
+    Result injectEvent(const Event& event);
+
+  protected:
+    void run();
+    virtual std::vector<Event> readEvents();
+    static void startThread(Sensor* sensor);
+
+    bool isWakeUpSensor();
+
+    bool mIsEnabled;
+    int64_t mSamplingPeriodNs;
+    int64_t mLastSampleTimeNs;
+    SensorInfo mSensorInfo;
+
+    std::atomic_bool mStopThread;
+    std::condition_variable mWaitCV;
+    std::mutex mRunMutex;
+    std::thread mRunThread;
+
+    ISensorsEventCallback* mCallback;
+
+    OperationMode mMode;
+};
+
+class OnChangeSensor : public Sensor {
+  public:
+    OnChangeSensor(ISensorsEventCallback* callback);
+
+    virtual void activate(bool enable) override;
+
+  protected:
+    virtual std::vector<Event> readEvents() override;
+
+  protected:
+    Event mPreviousEvent;
+    bool mPreviousEventSet;
+};
+
+class AccelSensor : public Sensor {
+  public:
+    AccelSensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class GyroSensor : public Sensor {
+  public:
+    GyroSensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class AmbientTempSensor : public OnChangeSensor {
+  public:
+    AmbientTempSensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class DeviceTempSensor : public OnChangeSensor {
+  public:
+    DeviceTempSensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class PressureSensor : public Sensor {
+  public:
+    PressureSensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class MagnetometerSensor : public Sensor {
+  public:
+    MagnetometerSensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class LightSensor : public OnChangeSensor {
+  public:
+    LightSensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class ProximitySensor : public OnChangeSensor {
+  public:
+    ProximitySensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+class RelativeHumiditySensor : public OnChangeSensor {
+  public:
+    RelativeHumiditySensor(int32_t sensorHandle, ISensorsEventCallback* callback);
+};
+
+}  // namespace implementation
+}  // namespace V2_X
+}  // namespace sensors
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_SENSORS_V2_X_SENSOR_H
diff --git a/sensors/common/default/2.X/Sensors.h b/sensors/common/default/2.X/Sensors.h
new file mode 100644
index 0000000..de998eb
--- /dev/null
+++ b/sensors/common/default/2.X/Sensors.h
@@ -0,0 +1,376 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_SENSORS_V2_X_SENSORS_H
+#define ANDROID_HARDWARE_SENSORS_V2_X_SENSORS_H
+
+#include "EventMessageQueueWrapper.h"
+#include "Sensor.h"
+
+#include <android/hardware/sensors/2.0/ISensors.h>
+#include <android/hardware/sensors/2.0/types.h>
+#include <fmq/MessageQueue.h>
+#include <hardware_legacy/power.h>
+#include <hidl/MQDescriptor.h>
+#include <hidl/Status.h>
+#include <log/log.h>
+
+#include <atomic>
+#include <memory>
+#include <thread>
+
+namespace android {
+namespace hardware {
+namespace sensors {
+namespace V2_X {
+namespace implementation {
+
+template <class ISensorsInterface>
+struct Sensors : public ISensorsInterface, public ISensorsEventCallback {
+    using Event = ::android::hardware::sensors::V1_0::Event;
+    using OperationMode = ::android::hardware::sensors::V1_0::OperationMode;
+    using RateLevel = ::android::hardware::sensors::V1_0::RateLevel;
+    using Result = ::android::hardware::sensors::V1_0::Result;
+    using SharedMemInfo = ::android::hardware::sensors::V1_0::SharedMemInfo;
+    using EventQueueFlagBits = ::android::hardware::sensors::V2_0::EventQueueFlagBits;
+    using SensorTimeout = ::android::hardware::sensors::V2_0::SensorTimeout;
+    using WakeLockQueueFlagBits = ::android::hardware::sensors::V2_0::WakeLockQueueFlagBits;
+    using ISensorsCallback = ::android::hardware::sensors::V2_0::ISensorsCallback;
+    using EventMessageQueue = MessageQueue<Event, kSynchronizedReadWrite>;
+    using WakeLockMessageQueue = MessageQueue<uint32_t, kSynchronizedReadWrite>;
+
+    static constexpr const char* kWakeLockName = "SensorsHAL_WAKEUP";
+
+    Sensors()
+        : mEventQueueFlag(nullptr),
+          mNextHandle(1),
+          mOutstandingWakeUpEvents(0),
+          mReadWakeLockQueueRun(false),
+          mAutoReleaseWakeLockTime(0),
+          mHasWakeLock(false) {
+        AddSensor<AccelSensor>();
+        AddSensor<GyroSensor>();
+        AddSensor<AmbientTempSensor>();
+        AddSensor<DeviceTempSensor>();
+        AddSensor<PressureSensor>();
+        AddSensor<MagnetometerSensor>();
+        AddSensor<LightSensor>();
+        AddSensor<ProximitySensor>();
+        AddSensor<RelativeHumiditySensor>();
+    }
+
+    virtual ~Sensors() {
+        deleteEventFlag();
+        mReadWakeLockQueueRun = false;
+        mWakeLockThread.join();
+    }
+
+    // Methods from ::android::hardware::sensors::V2_0::ISensors follow.
+    Return<void> getSensorsList(V2_0::ISensors::getSensorsList_cb _hidl_cb) override {
+        std::vector<V1_0::SensorInfo> sensors;
+        for (const auto& sensor : mSensors) {
+            sensors.push_back(sensor.second->getSensorInfo());
+        }
+
+        // Call the HIDL callback with the SensorInfo
+        _hidl_cb(sensors);
+
+        return Void();
+    }
+
+    Return<Result> setOperationMode(OperationMode mode) override {
+        for (auto sensor : mSensors) {
+            sensor.second->setOperationMode(mode);
+        }
+        return Result::OK;
+    }
+
+    Return<Result> activate(int32_t sensorHandle, bool enabled) override {
+        auto sensor = mSensors.find(sensorHandle);
+        if (sensor != mSensors.end()) {
+            sensor->second->activate(enabled);
+            return Result::OK;
+        }
+        return Result::BAD_VALUE;
+    }
+
+    Return<Result> initialize(
+            const ::android::hardware::MQDescriptorSync<Event>& eventQueueDescriptor,
+            const ::android::hardware::MQDescriptorSync<uint32_t>& wakeLockDescriptor,
+            const sp<ISensorsCallback>& sensorsCallback) override {
+        auto eventQueue =
+                std::make_unique<EventMessageQueue>(eventQueueDescriptor, true /* resetPointers */);
+        std::unique_ptr<V2_1::implementation::EventMessageQueueWrapperBase> wrapper =
+                std::make_unique<V2_1::implementation::EventMessageQueueWrapperV1_0>(eventQueue);
+        return initializeBase(wrapper, wakeLockDescriptor, sensorsCallback);
+    }
+
+    Return<Result> initializeBase(
+            std::unique_ptr<V2_1::implementation::EventMessageQueueWrapperBase>& eventQueue,
+            const ::android::hardware::MQDescriptorSync<uint32_t>& wakeLockDescriptor,
+            const sp<ISensorsCallback>& sensorsCallback) {
+        Result result = Result::OK;
+
+        // Ensure that all sensors are disabled
+        for (auto sensor : mSensors) {
+            sensor.second->activate(false /* enable */);
+        }
+
+        // Stop the Wake Lock thread if it is currently running
+        if (mReadWakeLockQueueRun.load()) {
+            mReadWakeLockQueueRun = false;
+            mWakeLockThread.join();
+        }
+
+        // Save a reference to the callback
+        mCallback = sensorsCallback;
+
+        // Save the event queue.
+        mEventQueue = std::move(eventQueue);
+
+        // Ensure that any existing EventFlag is properly deleted
+        deleteEventFlag();
+
+        // Create the EventFlag that is used to signal to the framework that sensor events have been
+        // written to the Event FMQ
+        if (EventFlag::createEventFlag(mEventQueue->getEventFlagWord(), &mEventQueueFlag) != OK) {
+            result = Result::BAD_VALUE;
+        }
+
+        // Create the Wake Lock FMQ that is used by the framework to communicate whenever WAKE_UP
+        // events have been successfully read and handled by the framework.
+        mWakeLockQueue = std::make_unique<WakeLockMessageQueue>(wakeLockDescriptor,
+                                                                true /* resetPointers */);
+
+        if (!mCallback || !mEventQueue || !mWakeLockQueue || mEventQueueFlag == nullptr) {
+            result = Result::BAD_VALUE;
+        }
+
+        // Start the thread to read events from the Wake Lock FMQ
+        mReadWakeLockQueueRun = true;
+        mWakeLockThread = std::thread(startReadWakeLockThread, this);
+
+        return result;
+    }
+
+    Return<Result> batch(int32_t sensorHandle, int64_t samplingPeriodNs,
+                         int64_t /* maxReportLatencyNs */) override {
+        auto sensor = mSensors.find(sensorHandle);
+        if (sensor != mSensors.end()) {
+            sensor->second->batch(samplingPeriodNs);
+            return Result::OK;
+        }
+        return Result::BAD_VALUE;
+    }
+
+    Return<Result> flush(int32_t sensorHandle) override {
+        auto sensor = mSensors.find(sensorHandle);
+        if (sensor != mSensors.end()) {
+            return sensor->second->flush();
+        }
+        return Result::BAD_VALUE;
+    }
+
+    Return<Result> injectSensorData(const Event& event) override {
+        auto sensor = mSensors.find(event.sensorHandle);
+        if (sensor != mSensors.end()) {
+            return sensor->second->injectEvent(event);
+        }
+
+        return Result::BAD_VALUE;
+    }
+
+    Return<void> registerDirectChannel(const SharedMemInfo& /* mem */,
+                                       V2_0::ISensors::registerDirectChannel_cb _hidl_cb) override {
+        _hidl_cb(Result::INVALID_OPERATION, -1 /* channelHandle */);
+        return Return<void>();
+    }
+
+    Return<Result> unregisterDirectChannel(int32_t /* channelHandle */) override {
+        return Result::INVALID_OPERATION;
+    }
+
+    Return<void> configDirectReport(int32_t /* sensorHandle */, int32_t /* channelHandle */,
+                                    RateLevel /* rate */,
+                                    V2_0::ISensors::configDirectReport_cb _hidl_cb) override {
+        _hidl_cb(Result::INVALID_OPERATION, 0 /* reportToken */);
+        return Return<void>();
+    }
+
+    void postEvents(const std::vector<Event>& events, bool wakeup) override {
+        std::lock_guard<std::mutex> lock(mWriteLock);
+        if (mEventQueue->write(V2_1::implementation::convertToNewEvents(events))) {
+            mEventQueueFlag->wake(static_cast<uint32_t>(EventQueueFlagBits::READ_AND_PROCESS));
+
+            if (wakeup) {
+                // Keep track of the number of outstanding WAKE_UP events in order to properly hold
+                // a wake lock until the framework has secured a wake lock
+                updateWakeLock(events.size(), 0 /* eventsHandled */);
+            }
+        }
+    }
+
+  protected:
+    /**
+     * Add a new sensor
+     */
+    template <class SensorType>
+    void AddSensor() {
+        std::shared_ptr<SensorType> sensor =
+                std::make_shared<SensorType>(mNextHandle++ /* sensorHandle */, this /* callback */);
+        mSensors[sensor->getSensorInfo().sensorHandle] = sensor;
+    }
+
+    /**
+     * Utility function to delete the Event Flag
+     */
+    void deleteEventFlag() {
+        status_t status = EventFlag::deleteEventFlag(&mEventQueueFlag);
+        if (status != OK) {
+            ALOGI("Failed to delete event flag: %d", status);
+        }
+    }
+
+    static void startReadWakeLockThread(Sensors* sensors) { sensors->readWakeLockFMQ(); }
+
+    /**
+     * Function to read the Wake Lock FMQ and release the wake lock when appropriate
+     */
+    void readWakeLockFMQ() {
+        while (mReadWakeLockQueueRun.load()) {
+            constexpr int64_t kReadTimeoutNs = 500 * 1000 * 1000;  // 500 ms
+            uint32_t eventsHandled = 0;
+
+            // Read events from the Wake Lock FMQ. Timeout after a reasonable amount of time to
+            // ensure that any held wake lock is able to be released if it is held for too long.
+            mWakeLockQueue->readBlocking(&eventsHandled, 1 /* count */, 0 /* readNotification */,
+                                         static_cast<uint32_t>(WakeLockQueueFlagBits::DATA_WRITTEN),
+                                         kReadTimeoutNs);
+            updateWakeLock(0 /* eventsWritten */, eventsHandled);
+        }
+    }
+
+    /**
+     * Responsible for acquiring and releasing a wake lock when there are unhandled WAKE_UP events
+     */
+    void updateWakeLock(int32_t eventsWritten, int32_t eventsHandled) {
+        std::lock_guard<std::mutex> lock(mWakeLockLock);
+        int32_t newVal = mOutstandingWakeUpEvents + eventsWritten - eventsHandled;
+        if (newVal < 0) {
+            mOutstandingWakeUpEvents = 0;
+        } else {
+            mOutstandingWakeUpEvents = newVal;
+        }
+
+        if (eventsWritten > 0) {
+            // Update the time at which the last WAKE_UP event was sent
+            mAutoReleaseWakeLockTime =
+                    ::android::uptimeMillis() +
+                    static_cast<uint32_t>(SensorTimeout::WAKE_LOCK_SECONDS) * 1000;
+        }
+
+        if (!mHasWakeLock && mOutstandingWakeUpEvents > 0 &&
+            acquire_wake_lock(PARTIAL_WAKE_LOCK, kWakeLockName) == 0) {
+            mHasWakeLock = true;
+        } else if (mHasWakeLock) {
+            // Check if the wake lock should be released automatically if
+            // SensorTimeout::WAKE_LOCK_SECONDS has elapsed since the last WAKE_UP event was written
+            // to the Wake Lock FMQ.
+            if (::android::uptimeMillis() > mAutoReleaseWakeLockTime) {
+                ALOGD("No events read from wake lock FMQ for %d seconds, auto releasing wake lock",
+                      SensorTimeout::WAKE_LOCK_SECONDS);
+                mOutstandingWakeUpEvents = 0;
+            }
+
+            if (mOutstandingWakeUpEvents == 0 && release_wake_lock(kWakeLockName) == 0) {
+                mHasWakeLock = false;
+            }
+        }
+    }
+
+    /**
+     * The Event FMQ where sensor events are written
+     */
+    std::unique_ptr<V2_1::implementation::EventMessageQueueWrapperBase> mEventQueue;
+
+    /**
+     * The Wake Lock FMQ that is read to determine when the framework has handled WAKE_UP events
+     */
+    std::unique_ptr<WakeLockMessageQueue> mWakeLockQueue;
+
+    /**
+     * Event Flag to signal to the framework when sensor events are available to be read
+     */
+    EventFlag* mEventQueueFlag;
+
+    /**
+     * Callback for asynchronous events, such as dynamic sensor connections.
+     */
+    sp<ISensorsCallback> mCallback;
+
+    /**
+     * A map of the available sensors
+     */
+    std::map<int32_t, std::shared_ptr<Sensor>> mSensors;
+
+    /**
+     * The next available sensor handle
+     */
+    int32_t mNextHandle;
+
+    /**
+     * Lock to protect writes to the FMQs
+     */
+    std::mutex mWriteLock;
+
+    /**
+     * Lock to protect acquiring and releasing the wake lock
+     */
+    std::mutex mWakeLockLock;
+
+    /**
+     * Track the number of WAKE_UP events that have not been handled by the framework
+     */
+    uint32_t mOutstandingWakeUpEvents;
+
+    /**
+     * A thread to read the Wake Lock FMQ
+     */
+    std::thread mWakeLockThread;
+
+    /**
+     * Flag to indicate that the Wake Lock Thread should continue to run
+     */
+    std::atomic_bool mReadWakeLockQueueRun;
+
+    /**
+     * Track the time when the wake lock should automatically be released
+     */
+    int64_t mAutoReleaseWakeLockTime;
+
+    /**
+     * Flag to indicate if a wake lock has been acquired
+     */
+    bool mHasWakeLock;
+};
+
+}  // namespace implementation
+}  // namespace V2_X
+}  // namespace sensors
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_SENSORS_V2_X_SENSORS_H