diff --git a/camera/provider/default/ExternalCameraProvider.cpp b/camera/provider/default/ExternalCameraProvider.cpp
new file mode 100644
index 0000000..d47ddbf
--- /dev/null
+++ b/camera/provider/default/ExternalCameraProvider.cpp
@@ -0,0 +1,382 @@
+/*
+ * Copyright (C) 2022 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.
+ */
+
+#define LOG_TAG "ExtCamPrvdr"
+// #define LOG_NDEBUG 0
+
+#include "ExternalCameraProvider.h"
+
+#include <ExternalCameraDevice.h>
+#include <aidl/android/hardware/camera/common/Status.h>
+#include <convert.h>
+#include <cutils/properties.h>
+#include <linux/videodev2.h>
+#include <log/log.h>
+#include <sys/inotify.h>
+#include <regex>
+
+namespace android {
+namespace hardware {
+namespace camera {
+namespace provider {
+namespace implementation {
+
+using ::aidl::android::hardware::camera::common::Status;
+using ::android::hardware::camera::device::implementation::ExternalCameraDevice;
+using ::android::hardware::camera::device::implementation::fromStatus;
+using ::android::hardware::camera::external::common::ExternalCameraConfig;
+
+namespace {
+// "device@<version>/external/<id>"
+const std::regex kDeviceNameRE("device@([0-9]+\\.[0-9]+)/external/(.+)");
+const int kMaxDevicePathLen = 256;
+constexpr char kDevicePath[] = "/dev/";
+constexpr char kPrefix[] = "video";
+constexpr int kPrefixLen = sizeof(kPrefix) - 1;
+constexpr int kDevicePrefixLen = sizeof(kDevicePath) + kPrefixLen + 1;
+
+bool matchDeviceName(int cameraIdOffset, const std::string& deviceName, std::string* deviceVersion,
+                     std::string* cameraDevicePath) {
+    std::smatch sm;
+    if (std::regex_match(deviceName, sm, kDeviceNameRE)) {
+        if (deviceVersion != nullptr) {
+            *deviceVersion = sm[1];
+        }
+        if (cameraDevicePath != nullptr) {
+            *cameraDevicePath = "/dev/video" + std::to_string(std::stoi(sm[2]) - cameraIdOffset);
+        }
+        return true;
+    }
+    return false;
+}
+}  // namespace
+
+ExternalCameraProvider::ExternalCameraProvider() : mCfg(ExternalCameraConfig::loadFromCfg()) {
+    mHotPlugThread = std::make_shared<HotplugThread>(this);
+    mHotPlugThread->run();
+}
+
+ExternalCameraProvider::~ExternalCameraProvider() {
+    mHotPlugThread->requestExitAndWait();
+}
+
+ndk::ScopedAStatus ExternalCameraProvider::setCallback(
+        const std::shared_ptr<ICameraProviderCallback>& in_callback) {
+    {
+        Mutex::Autolock _l(mLock);
+        mCallback = in_callback;
+    }
+
+    if (mCallback == nullptr) {
+        return fromStatus(Status::OK);
+    }
+
+    for (const auto& pair : mCameraStatusMap) {
+        mCallback->cameraDeviceStatusChange(pair.first, pair.second);
+    }
+    return fromStatus(Status::OK);
+}
+
+ndk::ScopedAStatus ExternalCameraProvider::getVendorTags(
+        std::vector<VendorTagSection>* _aidl_return) {
+    if (_aidl_return == nullptr) {
+        return fromStatus(Status::ILLEGAL_ARGUMENT);
+    }
+    // No vendor tag support for USB camera
+    *_aidl_return = {};
+    return fromStatus(Status::OK);
+}
+
+ndk::ScopedAStatus ExternalCameraProvider::getCameraIdList(std::vector<std::string>* _aidl_return) {
+    if (_aidl_return == nullptr) {
+        return fromStatus(Status::ILLEGAL_ARGUMENT);
+    }
+    // External camera HAL always report 0 camera, and extra cameras
+    // are just reported via cameraDeviceStatusChange callbacks
+    *_aidl_return = {};
+    return fromStatus(Status::OK);
+}
+
+ndk::ScopedAStatus ExternalCameraProvider::getCameraDeviceInterface(
+        const std::string& in_cameraDeviceName, std::shared_ptr<ICameraDevice>* _aidl_return) {
+    if (_aidl_return == nullptr) {
+        return fromStatus(Status::ILLEGAL_ARGUMENT);
+    }
+    std::string cameraDevicePath, deviceVersion;
+    bool match = matchDeviceName(mCfg.cameraIdOffset, in_cameraDeviceName, &deviceVersion,
+                                 &cameraDevicePath);
+
+    if (!match) {
+        *_aidl_return = nullptr;
+        return fromStatus(Status::ILLEGAL_ARGUMENT);
+    }
+
+    if (mCameraStatusMap.count(in_cameraDeviceName) == 0 ||
+        mCameraStatusMap[in_cameraDeviceName] != CameraDeviceStatus::PRESENT) {
+        *_aidl_return = nullptr;
+        return fromStatus(Status::ILLEGAL_ARGUMENT);
+    }
+
+    ALOGV("Constructing external camera device");
+    std::shared_ptr<ExternalCameraDevice> deviceImpl =
+            ndk::SharedRefBase::make<ExternalCameraDevice>(cameraDevicePath, mCfg);
+    if (deviceImpl == nullptr || deviceImpl->isInitFailed()) {
+        ALOGE("%s: camera device %s init failed!", __FUNCTION__, cameraDevicePath.c_str());
+        *_aidl_return = nullptr;
+        return fromStatus(Status::INTERNAL_ERROR);
+    }
+
+    IF_ALOGV() {
+        int interfaceVersion;
+        deviceImpl->getInterfaceVersion(&interfaceVersion);
+        ALOGV("%s: device interface version: %d", __FUNCTION__, interfaceVersion);
+    }
+
+    *_aidl_return = deviceImpl;
+    return fromStatus(Status::OK);
+}
+
+ndk::ScopedAStatus ExternalCameraProvider::notifyDeviceStateChange(int64_t) {
+    return fromStatus(Status::OK);
+}
+
+ndk::ScopedAStatus ExternalCameraProvider::getConcurrentCameraIds(
+        std::vector<ConcurrentCameraIdCombination>* _aidl_return) {
+    if (_aidl_return == nullptr) {
+        return fromStatus(Status::ILLEGAL_ARGUMENT);
+    }
+    *_aidl_return = {};
+    return fromStatus(Status::OK);
+}
+
+ndk::ScopedAStatus ExternalCameraProvider::isConcurrentStreamCombinationSupported(
+        const std::vector<CameraIdAndStreamCombination>&, bool* _aidl_return) {
+    if (_aidl_return == nullptr) {
+        return fromStatus(Status::ILLEGAL_ARGUMENT);
+    }
+    // No concurrent stream combinations are supported
+    *_aidl_return = false;
+    return fromStatus(Status::OK);
+}
+
+void ExternalCameraProvider::addExternalCamera(const char* devName) {
+    ALOGV("%s: ExtCam: adding %s to External Camera HAL!", __FUNCTION__, devName);
+    Mutex::Autolock _l(mLock);
+    std::string deviceName;
+    std::string cameraId =
+            std::to_string(mCfg.cameraIdOffset + std::atoi(devName + kDevicePrefixLen));
+    deviceName =
+            std::string("device@") + ExternalCameraDevice::kDeviceVersion + "/external/" + cameraId;
+    mCameraStatusMap[deviceName] = CameraDeviceStatus::PRESENT;
+    if (mCallback != nullptr) {
+        mCallback->cameraDeviceStatusChange(deviceName, CameraDeviceStatus::PRESENT);
+    }
+}
+
+void ExternalCameraProvider::deviceAdded(const char* devName) {
+    {
+        base::unique_fd fd(::open(devName, O_RDWR));
+        if (fd.get() < 0) {
+            ALOGE("%s open v4l2 device %s failed:%s", __FUNCTION__, devName, strerror(errno));
+            return;
+        }
+
+        struct v4l2_capability capability;
+        int ret = ioctl(fd.get(), VIDIOC_QUERYCAP, &capability);
+        if (ret < 0) {
+            ALOGE("%s v4l2 QUERYCAP %s failed", __FUNCTION__, devName);
+            return;
+        }
+
+        if (!(capability.device_caps & V4L2_CAP_VIDEO_CAPTURE)) {
+            ALOGW("%s device %s does not support VIDEO_CAPTURE", __FUNCTION__, devName);
+            return;
+        }
+    }
+
+    // See if we can initialize ExternalCameraDevice correctly
+    std::shared_ptr<ExternalCameraDevice> deviceImpl =
+            ndk::SharedRefBase::make<ExternalCameraDevice>(devName, mCfg);
+    if (deviceImpl == nullptr || deviceImpl->isInitFailed()) {
+        ALOGW("%s: Attempt to init camera device %s failed!", __FUNCTION__, devName);
+        return;
+    }
+    deviceImpl.reset();
+    addExternalCamera(devName);
+}
+
+void ExternalCameraProvider::deviceRemoved(const char* devName) {
+    Mutex::Autolock _l(mLock);
+    std::string deviceName;
+    std::string cameraId =
+            std::to_string(mCfg.cameraIdOffset + std::atoi(devName + kDevicePrefixLen));
+
+    deviceName =
+            std::string("device@") + ExternalCameraDevice::kDeviceVersion + "/external/" + cameraId;
+
+    if (mCameraStatusMap.erase(deviceName) == 0) {
+        // Unknown device, do not fire callback
+        ALOGE("%s: cannot find camera device to remove %s", __FUNCTION__, devName);
+        return;
+    }
+
+    if (mCallback != nullptr) {
+        mCallback->cameraDeviceStatusChange(deviceName, CameraDeviceStatus::NOT_PRESENT);
+    }
+}
+
+void ExternalCameraProvider::updateAttachedCameras() {
+    ALOGV("%s start scanning for existing V4L2 devices", __FUNCTION__);
+
+    // Find existing /dev/video* devices
+    DIR* devdir = opendir(kDevicePath);
+    if (devdir == nullptr) {
+        ALOGE("%s: cannot open %s! Exiting threadloop", __FUNCTION__, kDevicePath);
+        return;
+    }
+
+    struct dirent* de;
+    while ((de = readdir(devdir)) != nullptr) {
+        // Find external v4l devices that's existing before we start watching and add them
+        if (!strncmp(kPrefix, de->d_name, kPrefixLen)) {
+            std::string deviceId(de->d_name + kPrefixLen);
+            if (mCfg.mInternalDevices.count(deviceId) == 0) {
+                ALOGV("Non-internal v4l device %s found", de->d_name);
+                char v4l2DevicePath[kMaxDevicePathLen];
+                snprintf(v4l2DevicePath, kMaxDevicePathLen, "%s%s", kDevicePath, de->d_name);
+                deviceAdded(v4l2DevicePath);
+            }
+        }
+    }
+    closedir(devdir);
+}
+
+// Start ExternalCameraProvider::HotplugThread functions
+
+ExternalCameraProvider::HotplugThread::HotplugThread(ExternalCameraProvider* parent)
+    : mParent(parent), mInternalDevices(parent->mCfg.mInternalDevices) {}
+
+ExternalCameraProvider::HotplugThread::~HotplugThread() {
+    // Clean up inotify descriptor if needed.
+    if (mINotifyFD >= 0) {
+        close(mINotifyFD);
+    }
+}
+
+bool ExternalCameraProvider::HotplugThread::initialize() {
+    // Update existing cameras
+    mParent->updateAttachedCameras();
+
+    // Set up non-blocking fd. The threadLoop will be responsible for polling read at the
+    // desired frequency
+    mINotifyFD = inotify_init();
+    if (mINotifyFD < 0) {
+        ALOGE("%s: inotify init failed! Exiting threadloop", __FUNCTION__);
+        return false;
+    }
+
+    // Start watching /dev/ directory for created and deleted files
+    mWd = inotify_add_watch(mINotifyFD, kDevicePath, IN_CREATE | IN_DELETE);
+    if (mWd < 0) {
+        ALOGE("%s: inotify add watch failed! Exiting threadloop", __FUNCTION__);
+        return false;
+    }
+
+    mPollFd = {.fd = mINotifyFD, .events = POLLIN};
+
+    mIsInitialized = true;
+    return true;
+}
+
+bool ExternalCameraProvider::HotplugThread::threadLoop() {
+    // Initialize inotify descriptors if needed.
+    if (!mIsInitialized && !initialize()) {
+        return true;
+    }
+
+    // poll /dev/* and handle timeouts and error
+    int pollRet = poll(&mPollFd, /* fd_count= */ 1, /* timeout= */ 250);
+    if (pollRet == 0) {
+        // no read event in 100ms
+        mPollFd.revents = 0;
+        return true;
+    } else if (pollRet < 0) {
+        ALOGE("%s: error while polling for /dev/*: %d", __FUNCTION__, errno);
+        mPollFd.revents = 0;
+        return true;
+    } else if (mPollFd.revents & POLLERR) {
+        ALOGE("%s: polling /dev/ returned POLLERR", __FUNCTION__);
+        mPollFd.revents = 0;
+        return true;
+    } else if (mPollFd.revents & POLLHUP) {
+        ALOGE("%s: polling /dev/ returned POLLHUP", __FUNCTION__);
+        mPollFd.revents = 0;
+        return true;
+    } else if (mPollFd.revents & POLLNVAL) {
+        ALOGE("%s: polling /dev/ returned POLLNVAL", __FUNCTION__);
+        mPollFd.revents = 0;
+        return true;
+    }
+    // mPollFd.revents must contain POLLIN, so safe to reset it before reading
+    mPollFd.revents = 0;
+
+    uint64_t offset = 0;
+    ssize_t ret = read(mINotifyFD, mEventBuf, sizeof(mEventBuf));
+    if (ret < sizeof(struct inotify_event)) {
+        // invalid event. skip
+        return true;
+    }
+
+    while (offset < ret) {
+        struct inotify_event* event = (struct inotify_event*)&mEventBuf[offset];
+        offset += sizeof(struct inotify_event) + event->len;
+
+        if (event->wd != mWd) {
+            // event for an unrelated descriptor. ignore.
+            continue;
+        }
+
+        ALOGV("%s inotify_event %s", __FUNCTION__, event->name);
+        if (strncmp(kPrefix, event->name, kPrefixLen) != 0) {
+            // event not for /dev/video*. ignore.
+            continue;
+        }
+
+        std::string deviceId = event->name + kPrefixLen;
+        if (mInternalDevices.count(deviceId) != 0) {
+            // update to an internal device. ignore.
+            continue;
+        }
+
+        char v4l2DevicePath[kMaxDevicePathLen];
+        snprintf(v4l2DevicePath, kMaxDevicePathLen, "%s%s", kDevicePath, event->name);
+
+        if (event->mask & IN_CREATE) {
+            mParent->deviceAdded(v4l2DevicePath);
+        } else if (event->mask & IN_DELETE) {
+            mParent->deviceRemoved(v4l2DevicePath);
+        }
+    }
+    return true;
+}
+
+// End ExternalCameraProvider::HotplugThread functions
+
+}  // namespace implementation
+}  // namespace provider
+}  // namespace camera
+}  // namespace hardware
+}  // namespace android
\ No newline at end of file