diff --git a/camera/common/1.0/default/CameraModule.cpp b/camera/common/1.0/default/CameraModule.cpp
index 08354b3..3e3ef43 100644
--- a/camera/common/1.0/default/CameraModule.cpp
+++ b/camera/common/1.0/default/CameraModule.cpp
@@ -462,6 +462,17 @@
     return res;
 }
 
+void CameraModule::notifyDeviceStateChange(uint64_t deviceState) {
+   if (getModuleApiVersion() >= CAMERA_MODULE_API_VERSION_2_5 &&
+           mModule->notify_device_state_change != NULL) {
+       ATRACE_BEGIN("camera_module->notify_device_state_change");
+       ALOGI("%s: calling notify_device_state_change with state %" PRId64, __FUNCTION__,
+               deviceState);
+       mModule->notify_device_state_change(deviceState);
+       ATRACE_END();
+   }
+}
+
 status_t CameraModule::filterOpenErrorCode(status_t err) {
     switch(err) {
         case NO_ERROR:
diff --git a/camera/common/1.0/default/include/CameraModule.h b/camera/common/1.0/default/include/CameraModule.h
index ee75e72..32c387f 100644
--- a/camera/common/1.0/default/include/CameraModule.h
+++ b/camera/common/1.0/default/include/CameraModule.h
@@ -67,6 +67,7 @@
     void removeCamera(int cameraId);
     int getPhysicalCameraInfo(int physicalCameraId, camera_metadata_t **physicalInfo);
     int isStreamCombinationSupported(int cameraId, camera_stream_combination_t *streams);
+    void notifyDeviceStateChange(uint64_t deviceState);
 
 private:
     // Derive camera characteristics keys defined after HAL device version
diff --git a/camera/metadata/3.4/Android.bp b/camera/metadata/3.4/Android.bp
index 388df68..17a2675 100644
--- a/camera/metadata/3.4/Android.bp
+++ b/camera/metadata/3.4/Android.bp
@@ -15,6 +15,9 @@
     ],
     types: [
         "CameraMetadataEnumAndroidInfoSupportedBufferManagementVersion",
+        "CameraMetadataEnumAndroidScalerAvailableFormats",
+        "CameraMetadataEnumAndroidScalerAvailableRecommendedStreamConfigurations",
+        "CameraMetadataEnumAndroidSensorInfoColorFilterArrangement",
         "CameraMetadataTag",
     ],
     gen_java: true,
diff --git a/camera/provider/2.4/default/Android.bp b/camera/provider/2.4/default/Android.bp
index 81e5738..9d73934 100644
--- a/camera/provider/2.4/default/Android.bp
+++ b/camera/provider/2.4/default/Android.bp
@@ -1,46 +1,126 @@
 cc_library_shared {
-    name: "android.hardware.camera.provider@2.4-impl",
+    name: "android.hardware.camera.provider@2.4-legacy",
     defaults: ["hidl_defaults"],
     proprietary: true,
-    relative_install_path: "hw",
-    srcs: ["CameraProvider.cpp",
-           "ExternalCameraProvider.cpp"],
+    srcs: ["LegacyCameraProviderImpl_2_4.cpp"],
     shared_libs: [
-        "libhidlbase",
-        "libhidltransport",
-        "libutils",
-        "libcutils",
+        "android.hardware.camera.common@1.0",
         "android.hardware.camera.device@1.0",
         "android.hardware.camera.device@3.2",
         "android.hardware.camera.device@3.3",
         "android.hardware.camera.device@3.4",
         "android.hardware.camera.device@3.5",
+        "android.hardware.camera.provider@2.4",
+        "android.hardware.graphics.mapper@2.0",
+        "android.hidl.allocator@1.0",
+        "android.hidl.memory@1.0",
         "camera.device@1.0-impl",
         "camera.device@3.2-impl",
         "camera.device@3.3-impl",
         "camera.device@3.4-impl",
         "camera.device@3.5-impl",
-        "camera.device@3.4-external-impl",
-        "camera.device@3.5-external-impl",
-        "android.hardware.camera.provider@2.4",
-        "android.hardware.camera.common@1.0",
-        "android.hardware.graphics.mapper@2.0",
-        "android.hidl.allocator@1.0",
-        "android.hidl.memory@1.0",
-        "liblog",
-        "libhardware",
         "libcamera_metadata",
-        "libtinyxml2"
-    ],
-    header_libs: [
-        "camera.device@3.4-impl_headers",
-        "camera.device@3.5-impl_headers",
-        "camera.device@3.4-external-impl_headers",
-        "camera.device@3.5-external-impl_headers"
+        "libcutils",
+        "libhardware",
+        "libhidlbase",
+        "libhidltransport",
+        "liblog",
+        "libutils",
     ],
     static_libs: [
         "android.hardware.camera.common@1.0-helper",
     ],
+    header_libs: [
+        "camera.device@3.4-impl_headers",
+        "camera.device@3.5-impl_headers",
+    ],
+    export_include_dirs: ["."],
+}
+
+cc_library_shared {
+    name: "android.hardware.camera.provider@2.4-external",
+    proprietary: true,
+    srcs: ["ExternalCameraProviderImpl_2_4.cpp"],
+    shared_libs: [
+        "android.hardware.camera.common@1.0",
+        "android.hardware.camera.device@1.0",
+        "android.hardware.camera.device@3.2",
+        "android.hardware.camera.device@3.3",
+        "android.hardware.camera.device@3.4",
+        "android.hardware.camera.device@3.5",
+        "android.hardware.camera.provider@2.4",
+        "android.hardware.graphics.mapper@2.0",
+        "android.hidl.allocator@1.0",
+        "android.hidl.memory@1.0",
+        "camera.device@3.3-impl",
+        "camera.device@3.4-external-impl",
+        "camera.device@3.4-impl",
+        "camera.device@3.5-external-impl",
+        "camera.device@3.5-impl",
+        "libcamera_metadata",
+        "libcutils",
+        "libhardware",
+        "libhidlbase",
+        "libhidltransport",
+        "liblog",
+        "libtinyxml2",
+        "libutils",
+    ],
+    static_libs: [
+        "android.hardware.camera.common@1.0-helper",
+    ],
+    header_libs: [
+        "camera.device@3.4-external-impl_headers",
+        "camera.device@3.5-external-impl_headers"
+    ],
+    export_include_dirs: ["."],
+}
+
+cc_library_shared {
+    name: "android.hardware.camera.provider@2.4-impl",
+    defaults: ["hidl_defaults"],
+    proprietary: true,
+    relative_install_path: "hw",
+    srcs: ["CameraProvider_2_4.cpp"],
+    shared_libs: [
+        "android.hardware.camera.common@1.0",
+        "android.hardware.camera.device@1.0",
+        "android.hardware.camera.device@3.2",
+        "android.hardware.camera.device@3.3",
+        "android.hardware.camera.device@3.4",
+        "android.hardware.camera.device@3.5",
+        "android.hardware.camera.provider@2.4",
+        "android.hardware.camera.provider@2.4-external",
+        "android.hardware.camera.provider@2.4-legacy",
+        "android.hardware.graphics.mapper@2.0",
+        "android.hidl.allocator@1.0",
+        "android.hidl.memory@1.0",
+        "camera.device@1.0-impl",
+        "camera.device@3.2-impl",
+        "camera.device@3.3-impl",
+        "camera.device@3.4-external-impl",
+        "camera.device@3.4-impl",
+        "camera.device@3.5-external-impl",
+        "camera.device@3.5-impl",
+        "libcamera_metadata",
+        "libcutils",
+        "libhardware",
+        "libhidlbase",
+        "libhidltransport",
+        "liblog",
+        "libtinyxml2",
+        "libutils",
+    ],
+    header_libs: [
+        "camera.device@3.4-external-impl_headers",
+        "camera.device@3.4-impl_headers",
+        "camera.device@3.5-external-impl_headers",
+        "camera.device@3.5-impl_headers",
+    ],
+    static_libs: [
+        "android.hardware.camera.common@1.0-helper",
+    ],
+    export_include_dirs: ["."],
 }
 
 cc_defaults {
@@ -50,18 +130,32 @@
     relative_install_path: "hw",
     srcs: ["service.cpp"],
     shared_libs: [
-        "libhidlbase",
-        "libhidltransport",
-        "libbinder",
-        "liblog",
-        "libutils",
+        "android.hardware.camera.common@1.0",
         "android.hardware.camera.device@1.0",
         "android.hardware.camera.device@3.2",
         "android.hardware.camera.device@3.3",
         "android.hardware.camera.device@3.4",
         "android.hardware.camera.device@3.5",
         "android.hardware.camera.provider@2.4",
-        "android.hardware.camera.common@1.0",
+        "android.hardware.graphics.mapper@2.0",
+        "android.hidl.allocator@1.0",
+        "android.hidl.memory@1.0",
+        "libbinder",
+        "libcamera_metadata",
+        "libhardware",
+        "libhidlbase",
+        "libhidltransport",
+        "liblog",
+        "libutils",
+    ],
+    static_libs: [
+        "android.hardware.camera.common@1.0-helper",
+    ],
+    header_libs: [
+        "camera.device@3.4-external-impl_headers",
+        "camera.device@3.4-impl_headers",
+        "camera.device@3.5-external-impl_headers",
+        "camera.device@3.5-impl_headers",
     ],
 }
 
@@ -106,17 +200,24 @@
     compile_multilib: "32",
     init_rc: ["android.hardware.camera.provider@2.4-external-service.rc"],
     shared_libs: [
-        "libhidlbase",
-        "libhidltransport",
-        "libbinder",
-        "liblog",
-        "libutils",
+        "android.hardware.camera.common@1.0",
         "android.hardware.camera.device@1.0",
         "android.hardware.camera.device@3.2",
         "android.hardware.camera.device@3.3",
         "android.hardware.camera.device@3.4",
         "android.hardware.camera.device@3.5",
         "android.hardware.camera.provider@2.4",
-        "android.hardware.camera.common@1.0",
+        "libbinder",
+        "libhidlbase",
+        "libhidltransport",
+        "liblog",
+        "libtinyxml2",
+        "libutils",
+    ],
+    header_libs: [
+        "camera.device@3.4-external-impl_headers",
+        "camera.device@3.4-impl_headers",
+        "camera.device@3.5-external-impl_headers",
+        "camera.device@3.5-impl_headers",
     ],
 }
diff --git a/camera/provider/2.4/default/CameraProvider_2_4.cpp b/camera/provider/2.4/default/CameraProvider_2_4.cpp
new file mode 100644
index 0000000..15fc702
--- /dev/null
+++ b/camera/provider/2.4/default/CameraProvider_2_4.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2019 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 "CameraProvider_2_4.h"
+#include "LegacyCameraProviderImpl_2_4.h"
+#include "ExternalCameraProviderImpl_2_4.h"
+
+const char *kLegacyProviderName = "legacy/0";
+const char *kExternalProviderName = "external/0";
+
+namespace android {
+namespace hardware {
+namespace camera {
+namespace provider {
+namespace V2_4 {
+namespace implementation {
+
+using android::hardware::camera::provider::V2_4::ICameraProvider;
+
+extern "C" ICameraProvider* HIDL_FETCH_ICameraProvider(const char* name);
+
+template<typename IMPL>
+CameraProvider<IMPL>* getProviderImpl() {
+    CameraProvider<IMPL> *provider = new CameraProvider<IMPL>();
+    if (provider == nullptr) {
+        ALOGE("%s: cannot allocate camera provider!", __FUNCTION__);
+        return nullptr;
+    }
+    if (provider->isInitFailed()) {
+        ALOGE("%s: camera provider init failed!", __FUNCTION__);
+        delete provider;
+        return nullptr;
+    }
+    return provider;
+}
+
+ICameraProvider* HIDL_FETCH_ICameraProvider(const char* name) {
+    using namespace android::hardware::camera::provider::V2_4::implementation;
+    ICameraProvider* provider = nullptr;
+    if (strcmp(name, kLegacyProviderName) == 0) {
+        provider = getProviderImpl<LegacyCameraProviderImpl_2_4>();
+    } else if (strcmp(name, kExternalProviderName) == 0) {
+        provider = getProviderImpl<ExternalCameraProviderImpl_2_4>();
+    } else {
+        ALOGE("%s: unknown instance name: %s", __FUNCTION__, name);
+    }
+
+    return provider;
+}
+
+}  // namespace implementation
+}  // namespace V2_4
+}  // namespace provider
+}  // namespace camera
+}  // namespace hardware
+}  // namespace android
diff --git a/camera/provider/2.4/default/CameraProvider_2_4.h b/camera/provider/2.4/default/CameraProvider_2_4.h
new file mode 100644
index 0000000..d2e5b94
--- /dev/null
+++ b/camera/provider/2.4/default/CameraProvider_2_4.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2016 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_CAMERA_PROVIDER_V2_4_CAMERAPROVIDER_H
+#define ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_CAMERAPROVIDER_H
+
+#include <android/hardware/camera/provider/2.4/ICameraProvider.h>
+#include <hidl/Status.h>
+#include <hidl/MQDescriptor.h>
+
+namespace android {
+namespace hardware {
+namespace camera {
+namespace provider {
+namespace V2_4 {
+namespace implementation {
+
+using ::android::hardware::camera::common::V1_0::Status;
+using ::android::hardware::camera::provider::V2_4::ICameraProvider;
+using ::android::hardware::camera::provider::V2_4::ICameraProviderCallback;
+using ::android::hardware::Return;
+using ::android::hardware::hidl_string;
+using ::android::sp;
+
+template<typename IMPL>
+struct CameraProvider : public ICameraProvider {
+    CameraProvider() : impl() {}
+    ~CameraProvider() {}
+
+    // Caller must use this method to check if CameraProvider ctor failed
+    bool isInitFailed() { return impl.isInitFailed(); }
+
+    // Methods from ::android::hardware::camera::provider::V2_4::ICameraProvider follow.
+    Return<Status> setCallback(const sp<ICameraProviderCallback>& callback) override {
+        return impl.setCallback(callback);
+    }
+
+    Return<void> getVendorTags(getVendorTags_cb _hidl_cb) override {
+        return impl.getVendorTags(_hidl_cb);
+    }
+
+    Return<void> getCameraIdList(getCameraIdList_cb _hidl_cb) override {
+        return impl.getCameraIdList(_hidl_cb);
+    }
+
+    Return<void> isSetTorchModeSupported(isSetTorchModeSupported_cb _hidl_cb) override {
+        return impl.isSetTorchModeSupported(_hidl_cb);
+    }
+
+    Return<void> getCameraDeviceInterface_V1_x(
+            const hidl_string& cameraDeviceName,
+            getCameraDeviceInterface_V1_x_cb _hidl_cb) override {
+        return impl.getCameraDeviceInterface_V1_x(cameraDeviceName, _hidl_cb);
+    }
+
+    Return<void> getCameraDeviceInterface_V3_x(
+            const hidl_string& cameraDeviceName,
+            getCameraDeviceInterface_V3_x_cb _hidl_cb) override {
+        return impl.getCameraDeviceInterface_V3_x(cameraDeviceName, _hidl_cb);
+    }
+
+private:
+    IMPL impl;
+};
+
+}  // namespace implementation
+}  // namespace V2_4
+}  // namespace provider
+}  // namespace camera
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_CAMERAPROVIDER_H
diff --git a/camera/provider/2.4/default/ExternalCameraProvider.cpp b/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
similarity index 87%
rename from camera/provider/2.4/default/ExternalCameraProvider.cpp
rename to camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
index 604df5c..a6fd288 100644
--- a/camera/provider/2.4/default/ExternalCameraProvider.cpp
+++ b/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.cpp
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#define LOG_TAG "CamPvdr@2.4-external"
+#define LOG_TAG "CamPrvdr@2.4-external"
 //#define LOG_NDEBUG 0
 #include <log/log.h>
 
@@ -22,10 +22,10 @@
 #include <sys/inotify.h>
 #include <errno.h>
 #include <linux/videodev2.h>
-#include "ExternalCameraProvider.h"
+#include <cutils/properties.h>
+#include "ExternalCameraProviderImpl_2_4.h"
 #include "ExternalCameraDevice_3_4.h"
 #include "ExternalCameraDevice_3_5.h"
-#include <cutils/properties.h>
 
 namespace android {
 namespace hardware {
@@ -34,6 +34,8 @@
 namespace V2_4 {
 namespace implementation {
 
+template struct CameraProvider<ExternalCameraProviderImpl_2_4>;
+
 namespace {
 // "device@<version>/external/<id>"
 const std::regex kDeviceNameRE("device@([0-9]+\\.[0-9]+)/external/(.+)");
@@ -60,7 +62,7 @@
 
 } // anonymous namespace
 
-ExternalCameraProvider::ExternalCameraProvider() :
+ExternalCameraProviderImpl_2_4::ExternalCameraProviderImpl_2_4() :
         mCfg(ExternalCameraConfig::loadFromCfg()),
         mHotPlugThread(this) {
     mHotPlugThread.run("ExtCamHotPlug", PRIORITY_BACKGROUND);
@@ -81,12 +83,12 @@
     }
 }
 
-ExternalCameraProvider::~ExternalCameraProvider() {
+ExternalCameraProviderImpl_2_4::~ExternalCameraProviderImpl_2_4() {
     mHotPlugThread.requestExit();
 }
 
 
-Return<Status> ExternalCameraProvider::setCallback(
+Return<Status> ExternalCameraProviderImpl_2_4::setCallback(
         const sp<ICameraProviderCallback>& callback) {
     {
         Mutex::Autolock _l(mLock);
@@ -105,14 +107,16 @@
     return Status::OK;
 }
 
-Return<void> ExternalCameraProvider::getVendorTags(getVendorTags_cb _hidl_cb) {
+Return<void> ExternalCameraProviderImpl_2_4::getVendorTags(
+        ICameraProvider::getVendorTags_cb _hidl_cb) {
     // No vendor tag support for USB camera
     hidl_vec<VendorTagSection> zeroSections;
     _hidl_cb(Status::OK, zeroSections);
     return Void();
 }
 
-Return<void> ExternalCameraProvider::getCameraIdList(getCameraIdList_cb _hidl_cb) {
+Return<void> ExternalCameraProviderImpl_2_4::getCameraIdList(
+        ICameraProvider::getCameraIdList_cb _hidl_cb) {
     // External camera HAL always report 0 camera, and extra cameras
     // are just reported via cameraDeviceStatusChange callbacks
     hidl_vec<hidl_string> hidlDeviceNameList;
@@ -120,25 +124,25 @@
     return Void();
 }
 
-Return<void> ExternalCameraProvider::isSetTorchModeSupported(
-        isSetTorchModeSupported_cb _hidl_cb) {
+Return<void> ExternalCameraProviderImpl_2_4::isSetTorchModeSupported(
+        ICameraProvider::isSetTorchModeSupported_cb _hidl_cb) {
     // setTorchMode API is supported, though right now no external camera device
     // has a flash unit.
     _hidl_cb (Status::OK, true);
     return Void();
 }
 
-Return<void> ExternalCameraProvider::getCameraDeviceInterface_V1_x(
+Return<void> ExternalCameraProviderImpl_2_4::getCameraDeviceInterface_V1_x(
         const hidl_string&,
-        getCameraDeviceInterface_V1_x_cb _hidl_cb) {
+        ICameraProvider::getCameraDeviceInterface_V1_x_cb _hidl_cb) {
     // External Camera HAL does not support HAL1
     _hidl_cb(Status::OPERATION_NOT_SUPPORTED, nullptr);
     return Void();
 }
 
-Return<void> ExternalCameraProvider::getCameraDeviceInterface_V3_x(
+Return<void> ExternalCameraProviderImpl_2_4::getCameraDeviceInterface_V3_x(
         const hidl_string& cameraDeviceName,
-        getCameraDeviceInterface_V3_x_cb _hidl_cb) {
+        ICameraProvider::getCameraDeviceInterface_V3_x_cb _hidl_cb) {
 
     std::string cameraId, deviceVersion;
     bool match = matchDeviceName(cameraDeviceName, &deviceVersion, &cameraId);
@@ -194,7 +198,7 @@
     return Void();
 }
 
-void ExternalCameraProvider::addExternalCamera(const char* devName) {
+void ExternalCameraProviderImpl_2_4::addExternalCamera(const char* devName) {
     ALOGI("ExtCam: adding %s to External Camera HAL!", devName);
     Mutex::Autolock _l(mLock);
     std::string deviceName;
@@ -209,7 +213,7 @@
     }
 }
 
-void ExternalCameraProvider::deviceAdded(const char* devName) {
+void ExternalCameraProviderImpl_2_4::deviceAdded(const char* devName) {
     {
         base::unique_fd fd(::open(devName, O_RDWR));
         if (fd.get() < 0) {
@@ -242,7 +246,7 @@
     return;
 }
 
-void ExternalCameraProvider::deviceRemoved(const char* devName) {
+void ExternalCameraProviderImpl_2_4::deviceRemoved(const char* devName) {
     Mutex::Autolock _l(mLock);
     std::string deviceName;
     if (mPreferredHal3MinorVersion == 5) {
@@ -260,14 +264,15 @@
     }
 }
 
-ExternalCameraProvider::HotplugThread::HotplugThread(ExternalCameraProvider* parent) :
+ExternalCameraProviderImpl_2_4::HotplugThread::HotplugThread(
+        ExternalCameraProviderImpl_2_4* parent) :
         Thread(/*canCallJava*/false),
         mParent(parent),
         mInternalDevices(parent->mCfg.mInternalDevices) {}
 
-ExternalCameraProvider::HotplugThread::~HotplugThread() {}
+ExternalCameraProviderImpl_2_4::HotplugThread::~HotplugThread() {}
 
-bool ExternalCameraProvider::HotplugThread::threadLoop() {
+bool ExternalCameraProviderImpl_2_4::HotplugThread::threadLoop() {
     // Find existing /dev/video* devices
     DIR* devdir = opendir(kDevicePath);
     if(devdir == 0) {
diff --git a/camera/provider/2.4/default/ExternalCameraProvider.h b/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.h
similarity index 72%
rename from camera/provider/2.4/default/ExternalCameraProvider.h
rename to camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.h
index a69cf8b..8c79f68 100644
--- a/camera/provider/2.4/default/ExternalCameraProvider.h
+++ b/camera/provider/2.4/default/ExternalCameraProviderImpl_2_4.h
@@ -20,13 +20,14 @@
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
-#include "utils/Mutex.h"
-#include "utils/Thread.h"
-#include <android/hardware/camera/provider/2.4/ICameraProvider.h>
+#include <utils/Mutex.h>
+#include <utils/Thread.h>
 #include <hidl/Status.h>
 #include <hidl/MQDescriptor.h>
 #include "ExternalCameraUtils.h"
 
+#include "CameraProvider_2_4.h"
+
 namespace android {
 namespace hardware {
 namespace camera {
@@ -47,25 +48,32 @@
 using ::android::sp;
 using ::android::Mutex;
 
-struct ExternalCameraProvider : public ICameraProvider {
-    ExternalCameraProvider();
-    ~ExternalCameraProvider();
+/**
+ * The implementation of external webcam CameraProvider 2.4, separated
+ * from the HIDL interface layer to allow for implementation reuse by later
+ * provider versions.
+ *
+ * This camera provider supports standard UVC webcameras via the Linux V4L2
+ * UVC driver.
+ */
+struct ExternalCameraProviderImpl_2_4 {
+    ExternalCameraProviderImpl_2_4();
+    ~ExternalCameraProviderImpl_2_4();
+
+    // Caller must use this method to check if CameraProvider ctor failed
+    bool isInitFailed() { return false;}
 
     // Methods from ::android::hardware::camera::provider::V2_4::ICameraProvider follow.
-    Return<Status> setCallback(const sp<ICameraProviderCallback>& callback) override;
-
-    Return<void> getVendorTags(getVendorTags_cb _hidl_cb) override;
-
-    Return<void> getCameraIdList(getCameraIdList_cb _hidl_cb) override;
-
-    Return<void> isSetTorchModeSupported(isSetTorchModeSupported_cb _hidl_cb) override;
-
+    Return<Status> setCallback(const sp<ICameraProviderCallback>& callback);
+    Return<void> getVendorTags(ICameraProvider::getVendorTags_cb _hidl_cb);
+    Return<void> getCameraIdList(ICameraProvider::getCameraIdList_cb _hidl_cb);
+    Return<void> isSetTorchModeSupported(ICameraProvider::isSetTorchModeSupported_cb _hidl_cb);
     Return<void> getCameraDeviceInterface_V1_x(
             const hidl_string&,
-            getCameraDeviceInterface_V1_x_cb) override;
+            ICameraProvider::getCameraDeviceInterface_V1_x_cb);
     Return<void> getCameraDeviceInterface_V3_x(
             const hidl_string&,
-            getCameraDeviceInterface_V3_x_cb) override;
+            ICameraProvider::getCameraDeviceInterface_V3_x_cb);
 
 private:
 
@@ -77,13 +85,13 @@
 
     class HotplugThread : public android::Thread {
     public:
-        HotplugThread(ExternalCameraProvider* parent);
+        HotplugThread(ExternalCameraProviderImpl_2_4* parent);
         ~HotplugThread();
 
         virtual bool threadLoop() override;
 
     private:
-        ExternalCameraProvider* mParent = nullptr;
+        ExternalCameraProviderImpl_2_4* mParent = nullptr;
         const std::unordered_set<std::string> mInternalDevices;
 
         int mINotifyFD = -1;
diff --git a/camera/provider/2.4/default/CameraProvider.cpp b/camera/provider/2.4/default/LegacyCameraProviderImpl_2_4.cpp
similarity index 89%
rename from camera/provider/2.4/default/CameraProvider.cpp
rename to camera/provider/2.4/default/LegacyCameraProviderImpl_2_4.cpp
index e02cc7e..4cff1b7 100644
--- a/camera/provider/2.4/default/CameraProvider.cpp
+++ b/camera/provider/2.4/default/LegacyCameraProviderImpl_2_4.cpp
@@ -14,21 +14,21 @@
  * limitations under the License.
  */
 
-#define LOG_TAG "CamProvider@2.4-impl"
+#define LOG_TAG "CamPrvdr@2.4-legacy"
 //#define LOG_NDEBUG 0
 #include <android/log.h>
 
-#include "CameraProvider.h"
-#include "ExternalCameraProvider.h"
+#include "LegacyCameraProviderImpl_2_4.h"
 #include "CameraDevice_1_0.h"
 #include "CameraDevice_3_3.h"
 #include "CameraDevice_3_4.h"
 #include "CameraDevice_3_5.h"
+#include "CameraProvider_2_4.h"
 #include <cutils/properties.h>
+#include <regex>
 #include <string.h>
 #include <utils/Trace.h>
 
-
 namespace android {
 namespace hardware {
 namespace camera {
@@ -36,9 +36,9 @@
 namespace V2_4 {
 namespace implementation {
 
+template struct CameraProvider<LegacyCameraProviderImpl_2_4>;
+
 namespace {
-const char *kLegacyProviderName = "legacy/0";
-const char *kExternalProviderName = "external/0";
 // "device@<version>/legacy/<id>"
 const std::regex kDeviceNameRE("device@([0-9]+\\.[0-9]+)/legacy/(.+)");
 const char *kHAL3_4 = "3.4";
@@ -67,7 +67,7 @@
 using ::android::hardware::camera::common::V1_0::CameraMetadataType;
 using ::android::hardware::camera::common::V1_0::Status;
 
-void CameraProvider::addDeviceNames(int camera_id, CameraDeviceStatus status, bool cam_new)
+void LegacyCameraProviderImpl_2_4::addDeviceNames(int camera_id, CameraDeviceStatus status, bool cam_new)
 {
     char cameraId[kMaxCameraIdLen];
     snprintf(cameraId, sizeof(cameraId), "%d", camera_id);
@@ -107,7 +107,7 @@
     }
 }
 
-void CameraProvider::removeDeviceNames(int camera_id)
+void LegacyCameraProviderImpl_2_4::removeDeviceNames(int camera_id)
 {
     std::string cameraIdStr = std::to_string(camera_id);
 
@@ -134,13 +134,12 @@
 /**
  * static callback forwarding methods from HAL to instance
  */
-void CameraProvider::sCameraDeviceStatusChange(
+void LegacyCameraProviderImpl_2_4::sCameraDeviceStatusChange(
         const struct camera_module_callbacks* callbacks,
         int camera_id,
         int new_status) {
-    CameraProvider* cp = const_cast<CameraProvider*>(
-            static_cast<const CameraProvider*>(callbacks));
-
+    LegacyCameraProviderImpl_2_4* cp = const_cast<LegacyCameraProviderImpl_2_4*>(
+            static_cast<const LegacyCameraProviderImpl_2_4*>(callbacks));
     if (cp == nullptr) {
         ALOGE("%s: callback ops is null", __FUNCTION__);
         return;
@@ -181,12 +180,12 @@
     }
 }
 
-void CameraProvider::sTorchModeStatusChange(
+void LegacyCameraProviderImpl_2_4::sTorchModeStatusChange(
         const struct camera_module_callbacks* callbacks,
         const char* camera_id,
         int new_status) {
-    CameraProvider* cp = const_cast<CameraProvider*>(
-            static_cast<const CameraProvider*>(callbacks));
+    LegacyCameraProviderImpl_2_4* cp = const_cast<LegacyCameraProviderImpl_2_4*>(
+            static_cast<const LegacyCameraProviderImpl_2_4*>(callbacks));
 
     if (cp == nullptr) {
         ALOGE("%s: callback ops is null", __FUNCTION__);
@@ -206,7 +205,7 @@
     }
 }
 
-Status CameraProvider::getHidlStatus(int status) {
+Status LegacyCameraProviderImpl_2_4::getHidlStatus(int status) {
     switch (status) {
         case 0: return Status::OK;
         case -ENODEV: return Status::INTERNAL_ERROR;
@@ -217,13 +216,13 @@
     }
 }
 
-std::string CameraProvider::getLegacyCameraId(const hidl_string& deviceName) {
+std::string LegacyCameraProviderImpl_2_4::getLegacyCameraId(const hidl_string& deviceName) {
     std::string cameraId;
     matchDeviceName(deviceName, nullptr, &cameraId);
     return cameraId;
 }
 
-std::string CameraProvider::getHidlDeviceName(
+std::string LegacyCameraProviderImpl_2_4::getHidlDeviceName(
         std::string cameraId, int deviceVersion) {
     // Maybe consider create a version check method and SortedVec to speed up?
     if (deviceVersion != CAMERA_DEVICE_API_VERSION_1_0 &&
@@ -258,15 +257,15 @@
     return deviceName;
 }
 
-CameraProvider::CameraProvider() :
+LegacyCameraProviderImpl_2_4::LegacyCameraProviderImpl_2_4() :
         camera_module_callbacks_t({sCameraDeviceStatusChange,
                                    sTorchModeStatusChange}) {
     mInitFailed = initialize();
 }
 
-CameraProvider::~CameraProvider() {}
+LegacyCameraProviderImpl_2_4::~LegacyCameraProviderImpl_2_4() {}
 
-bool CameraProvider::initialize() {
+bool LegacyCameraProviderImpl_2_4::initialize() {
     camera_module_t *rawModule;
     int err = hw_get_module(CAMERA_HARDWARE_MODULE_ID,
             (const hw_module_t **)&rawModule);
@@ -343,7 +342,7 @@
 /**
  * Check that the device HAL version is still in supported.
  */
-int CameraProvider::checkCameraVersion(int id, camera_info info) {
+int LegacyCameraProviderImpl_2_4::checkCameraVersion(int id, camera_info info) {
     if (mModule == nullptr) {
         return NO_INIT;
     }
@@ -390,7 +389,7 @@
     return OK;
 }
 
-bool CameraProvider::setUpVendorTags() {
+bool LegacyCameraProviderImpl_2_4::setUpVendorTags() {
     ATRACE_CALL();
     vendor_tag_ops_t vOps = vendor_tag_ops_t();
 
@@ -447,11 +446,8 @@
 }
 
 // Methods from ::android::hardware::camera::provider::V2_4::ICameraProvider follow.
-Return<Status> CameraProvider::setCallback(const sp<ICameraProviderCallback>& callback)  {
-    if (callback == nullptr) {
-        return Status::ILLEGAL_ARGUMENT;
-    }
-
+Return<Status> LegacyCameraProviderImpl_2_4::setCallback(
+        const sp<ICameraProviderCallback>& callback) {
     Mutex::Autolock _l(mCbLock);
     mCallbacks = callback;
 
@@ -467,12 +463,14 @@
     return Status::OK;
 }
 
-Return<void> CameraProvider::getVendorTags(getVendorTags_cb _hidl_cb)  {
+Return<void> LegacyCameraProviderImpl_2_4::getVendorTags(
+        ICameraProvider::getVendorTags_cb _hidl_cb) {
     _hidl_cb(Status::OK, mVendorTagSections);
     return Void();
 }
 
-Return<void> CameraProvider::getCameraIdList(getCameraIdList_cb _hidl_cb)  {
+Return<void> LegacyCameraProviderImpl_2_4::getCameraIdList(
+        ICameraProvider::getCameraIdList_cb _hidl_cb) {
     std::vector<hidl_string> deviceNameList;
     for (auto const& deviceNamePair : mCameraDeviceNames) {
         if (std::stoi(deviceNamePair.first) >= mNumberOfLegacyCameras) {
@@ -489,14 +487,16 @@
     return Void();
 }
 
-Return<void> CameraProvider::isSetTorchModeSupported(isSetTorchModeSupported_cb _hidl_cb) {
+Return<void> LegacyCameraProviderImpl_2_4::isSetTorchModeSupported(
+        ICameraProvider::isSetTorchModeSupported_cb _hidl_cb) {
     bool support = mModule->isSetTorchModeSupported();
     _hidl_cb (Status::OK, support);
     return Void();
 }
 
-Return<void> CameraProvider::getCameraDeviceInterface_V1_x(
-        const hidl_string& cameraDeviceName, getCameraDeviceInterface_V1_x_cb _hidl_cb)  {
+Return<void> LegacyCameraProviderImpl_2_4::getCameraDeviceInterface_V1_x(
+        const hidl_string& cameraDeviceName,
+        ICameraProvider::getCameraDeviceInterface_V1_x_cb _hidl_cb)  {
     std::string cameraId, deviceVersion;
     bool match = matchDeviceName(cameraDeviceName, &deviceVersion, &cameraId);
     if (!match) {
@@ -548,8 +548,9 @@
     return Void();
 }
 
-Return<void> CameraProvider::getCameraDeviceInterface_V3_x(
-        const hidl_string& cameraDeviceName, getCameraDeviceInterface_V3_x_cb _hidl_cb)  {
+Return<void> LegacyCameraProviderImpl_2_4::getCameraDeviceInterface_V3_x(
+        const hidl_string& cameraDeviceName,
+        ICameraProvider::getCameraDeviceInterface_V3_x_cb _hidl_cb)  {
     std::string cameraId, deviceVersion;
     bool match = matchDeviceName(cameraDeviceName, &deviceVersion, &cameraId);
     if (!match) {
@@ -647,27 +648,6 @@
     return Void();
 }
 
-ICameraProvider* HIDL_FETCH_ICameraProvider(const char* name) {
-    if (strcmp(name, kLegacyProviderName) == 0) {
-        CameraProvider* provider = new CameraProvider();
-        if (provider == nullptr) {
-            ALOGE("%s: cannot allocate camera provider!", __FUNCTION__);
-            return nullptr;
-        }
-        if (provider->isInitFailed()) {
-            ALOGE("%s: camera provider init failed!", __FUNCTION__);
-            delete provider;
-            return nullptr;
-        }
-        return provider;
-    } else if (strcmp(name, kExternalProviderName) == 0) {
-        ExternalCameraProvider* provider = new ExternalCameraProvider();
-        return provider;
-    }
-    ALOGE("%s: unknown instance name: %s", __FUNCTION__, name);
-    return nullptr;
-}
-
 } // namespace implementation
 }  // namespace V2_4
 }  // namespace provider
diff --git a/camera/provider/2.4/default/CameraProvider.h b/camera/provider/2.4/default/LegacyCameraProviderImpl_2_4.h
similarity index 79%
rename from camera/provider/2.4/default/CameraProvider.h
rename to camera/provider/2.4/default/LegacyCameraProviderImpl_2_4.h
index 10e9b0d..b4914b3 100644
--- a/camera/provider/2.4/default/CameraProvider.h
+++ b/camera/provider/2.4/default/LegacyCameraProviderImpl_2_4.h
@@ -14,16 +14,14 @@
  * limitations under the License.
  */
 
-#ifndef ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_CAMERAPROVIDER_H
-#define ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_CAMERAPROVIDER_H
+#ifndef ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_LEGACYCAMERAPROVIDER_H
+#define ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_LEGACYCAMERAPROVIDER_H
 
-#include <regex>
+#include <android/hardware/camera/provider/2.4/ICameraProvider.h>
 #include "hardware/camera_common.h"
 #include "utils/Mutex.h"
 #include "utils/SortedVector.h"
-#include <android/hardware/camera/provider/2.4/ICameraProvider.h>
-#include <hidl/Status.h>
-#include <hidl/MQDescriptor.h>
+
 #include "CameraModule.h"
 #include "VendorTagDescriptor.h"
 
@@ -50,26 +48,34 @@
 using ::android::sp;
 using ::android::Mutex;
 
-struct CameraProvider : public ICameraProvider, public camera_module_callbacks_t {
-    CameraProvider();
-    ~CameraProvider();
+/**
+ * The implementation of legacy wrapper CameraProvider 2.4, separated
+ * from the HIDL interface layer to allow for implementation reuse by later
+ * provider versions.
+ *
+ * This implementation supports cameras implemented via the legacy libhardware
+ * camera HAL definitions.
+ */
+struct LegacyCameraProviderImpl_2_4 : public camera_module_callbacks_t {
+    LegacyCameraProviderImpl_2_4();
+    ~LegacyCameraProviderImpl_2_4();
 
     // Caller must use this method to check if CameraProvider ctor failed
     bool isInitFailed() { return mInitFailed; }
 
     // Methods from ::android::hardware::camera::provider::V2_4::ICameraProvider follow.
-    Return<Status> setCallback(const sp<ICameraProviderCallback>& callback) override;
-    Return<void> getVendorTags(getVendorTags_cb _hidl_cb) override;
-    Return<void> getCameraIdList(getCameraIdList_cb _hidl_cb) override;
-    Return<void> isSetTorchModeSupported(isSetTorchModeSupported_cb _hidl_cb) override;
+    Return<Status> setCallback(const sp<ICameraProviderCallback>& callback);
+    Return<void> getVendorTags(ICameraProvider::getVendorTags_cb _hidl_cb);
+    Return<void> getCameraIdList(ICameraProvider::getCameraIdList_cb _hidl_cb);
+    Return<void> isSetTorchModeSupported(ICameraProvider::isSetTorchModeSupported_cb _hidl_cb);
     Return<void> getCameraDeviceInterface_V1_x(
             const hidl_string& cameraDeviceName,
-            getCameraDeviceInterface_V1_x_cb _hidl_cb) override;
+            ICameraProvider::getCameraDeviceInterface_V1_x_cb _hidl_cb);
     Return<void> getCameraDeviceInterface_V3_x(
             const hidl_string& cameraDeviceName,
-            getCameraDeviceInterface_V3_x_cb _hidl_cb) override;
+            ICameraProvider::getCameraDeviceInterface_V3_x_cb _hidl_cb);
 
-private:
+protected:
     Mutex mCbLock;
     sp<ICameraProviderCallback> mCallbacks = nullptr;
 
@@ -115,9 +121,8 @@
     void addDeviceNames(int camera_id, CameraDeviceStatus status = CameraDeviceStatus::PRESENT,
                         bool cam_new = false);
     void removeDeviceNames(int camera_id);
-};
 
-extern "C" ICameraProvider* HIDL_FETCH_ICameraProvider(const char* name);
+};
 
 }  // namespace implementation
 }  // namespace V2_4
@@ -126,4 +131,4 @@
 }  // namespace hardware
 }  // namespace android
 
-#endif  // ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_CAMERAPROVIDER_H
+#endif  // ANDROID_HARDWARE_CAMERA_PROVIDER_V2_4_LEGACYCAMERAPROVIDER_H
diff --git a/camera/provider/2.4/default/service.cpp b/camera/provider/2.4/default/service.cpp
index 15d0ea6..4475f7d 100644
--- a/camera/provider/2.4/default/service.cpp
+++ b/camera/provider/2.4/default/service.cpp
@@ -21,9 +21,8 @@
 #endif
 
 #include <android/hardware/camera/provider/2.4/ICameraProvider.h>
-#include <hidl/LegacySupport.h>
-
 #include <binder/ProcessState.h>
+#include <hidl/LegacySupport.h>
 
 using android::status_t;
 using android::hardware::defaultLazyPassthroughServiceImplementation;
@@ -38,7 +37,7 @@
 
 int main()
 {
-    ALOGI("Camera provider Service is starting.");
+    ALOGI("CameraProvider@2.4 legacy service is starting.");
     // The camera HAL may communicate to other vendor components via
     // /dev/vndbinder
     android::ProcessState::initWithDriver("/dev/vndbinder");