MTK LIGHT分析

以MTK 6737源代码分析：

代码路径：

system:

./frameworks/base/services/java/com/android/server/SystemServer.java 启动LightsService
./frameworks/base/services/core/java/com/android/server/SystemServiceManager.java

startService(String className)-->service.onStart()

framework:

封装LightsService
./frameworks/base/services/core/java/com/android/server/lights/LightsService.java
./frameworks/base/services/core/java/com/android/server/lights/LightsManager.java
./frameworks/base/services/core/java/com/android/server/lights/Light.java

JNI

./frameworks/base/services/core/jni/com_android_server_lights_LightsService.cpp

HAL

./vendor/mediatek/proprietary/hardware/liblights/lights.c

kernel
驱动
./kernel-3.18/drivers/misc/mediatek/leds/leds_drv.c
./kernel-3.18/drivers/misc/mediatek/leds/mt6735/leds.c
dts
./kernel-3.18/arch/arm/boot/dts/*.dts
./kernel-3.18/arch/arm64/boot/dts/*.dts

代码分析:
开机kernel -> init进程 –> Zygote进程 –> SystemServer进程 —> LightsService

lightservice start
   mSystemServiceManager.startService(LightsService.class); //SystemServer.java
                       startService(serviceClass)->mServices.add(service)/service.onStart(); //SystemServiceManager.java
                               public void onStart() {
                                   publishLocalService(LightsManager.class, mService); //LightsService.java
                               }
                               private final LightsManager mService = new LightsManager() {
                               public Light getLight(int id) {
                               if (id < LIGHT_ID_COUNT) {
                               return mLights[id];
                               } else {
                               return null;
                               }
                               }
                               };
                               final LightImpl mLights[] = new LightImpl[LightsManager.LIGHT_ID_COUNT]; //LightsService 成员变量

                               private final class LightImpl extends Light{       //继承Light类

                               }
应用使用 lightservice
   final LightsManager lights = getLocalService(LightsManager.class); //publishLocalService(LightsManager.class, mService);
   mNotificationLight = lights.getLight(LightsManager.LIGHT_ID_NOTIFICATIONS); //获取到LightImpl的实例，
   mNotificationLight.setFlashing(ledARGB, Light.LIGHT_FLASH_TIMED,ledOnMS, ledOffMS); //设置亮度

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