android light sensor port

 

基于android 2.2 添加Light Sensor支持：

1) UI部分

2) framework部分

3) HAL 部分

4) Driver 部分

 

下面分别讨论:

1) UI部分

    a) 打开亮度设置菜单的自动调整亮度checkbox

        frameworks/base/core/res/res/values/config.xml :

        -  <bool name="config_automatic_brightness_available">false</bool>

        + <bool name="config_automatic_brightness_available">true</bool>

    b) 同时设置Lux级，亮度级，以5级亮度为例

       <integer-array name="config_autoBrightnessLevels">

 

+    <item>1000</item>

+    <item>2000</item>

+    <item>3000</item>

+    <item>4000</item>    

     </integer-array>

     <integer-array name="config_autoBrightnessLcdBacklightValues">

+    <item>20</item>

+    <item>80</item>  

+    <item>120</item>

+    <item>160</item>   

+    <item>250</item>  

     </integer-array>     

     

     autoBrightnessLevels 随便设，HAL层传上来的数据落在这几个值之间以区分级别

     LcdBacklightValues 是5级亮度的实际值

 2) framework部分

     a) framework层的相关文件

./core/java/android/hardware/SensorEvent.java

./core/java/android/hardware/SensorListener.java

./core/java/android/hardware/ISensorService.aidl

./core/java/android/hardware/Sensor.java

./core/java/android/hardware/SensorEventListener.java

./core/jni/android_hardware_SensorManager.cpp     //SensorManager JNI

./core/java/android/hardware/SensorManager.java    //SensorManager

./services/jni/com_android_server_SensorService.cpp //SensorSersvice JNI

./services/java/com/android/server/SensorService.java //SensorService

        ./services/java/com/android/server/PowerManagerService.java

       Sensor系统相对比较简单，我们需要修改的更少：

       添加Light Sensor只需要修改SensorManager.java, PowerManagerService.java两个文件

      b) SensorManager.java:

      

@@ -582,6 +582,8 @@ public class SensorManager
                 return SENSOR_ORIENTATION_RAW;
             case Sensor.TYPE_TEMPERATURE:
                 return SENSOR_TEMPERATURE;
+            case Sensor.TYPE_LIGHT:
+                return SENSOR_LIGHT;
         }
         return 0;
     }
@@ -606,6 +608,9 @@ public class SensorManager
                     result |= SensorManager.SENSOR_ORIENTATION |
                                     SensorManager.SENSOR_ORIENTATION_RAW;
                     break;
+                case Sensor.TYPE_LIGHT:
+                    result |= SensorManager.SENSOR_LIGHT;
+                    break;
             }
         }
         return result;
@@ -707,6 +712,8 @@ public class SensorManager
                 listener, sensors, rate) || result;
         result = registerLegacyListener(SENSOR_TEMPERATURE, Sensor.TYPE_TEMPERATURE,
                 listener, sensors, rate) || result;
+        result = registerLegacyListener(SENSOR_LIGHT, Sensor.TYPE_LIGHT,
+                listener, sensors, rate) || result;
         return result;
     }

@@ -766,6 +773,8 @@ public class SensorManager
                 listener, sensors);
         unregisterLegacyListener(SENSOR_TEMPERATURE, Sensor.TYPE_TEMPERATURE,
                 listener, sensors);
+        unregisterLegacyListener(SENSOR_LIGHT, Sensor.TYPE_LIGHT,
+                listener, sensors);
     }

@@ -582,6 +582,8 @@ public class SensorManager return SENSOR_ORIENTATION_RAW; case Sensor.TYPE_TEMPERATURE: return SENSOR_TEMPERATURE; + case Sensor.TYPE_LIGHT: + return SENSOR_LIGHT; } return 0; } @@ -606,6 +608,9 @@ public class SensorManager result |= SensorManager.SENSOR_ORIENTATION | SensorManager.SENSOR_ORIENTATION_RAW; break; + case Sensor.TYPE_LIGHT: + result |= SensorManager.SENSOR_LIGHT; + break; } } return result; @@ -707,6 +712,8 @@ public class SensorManager listener, sensors, rate) || result; result = registerLegacyListener(SENSOR_TEMPERATURE, Sensor.TYPE_TEMPERATURE, listener, sensors, rate) || result; + result = registerLegacyListener(SENSOR_LIGHT, Sensor.TYPE_LIGHT, + listener, sensors, rate) || result; return result; } @@ -766,6 +773,8 @@ public class SensorManager listener, sensors); unregisterLegacyListener(SENSOR_TEMPERATURE, Sensor.TYPE_TEMPERATURE, listener, sensors); + unregisterLegacyListener(SENSOR_LIGHT, Sensor.TYPE_LIGHT, + listener, sensors); } 

     c) PowerManagerService.java:

       这里似乎一个系统bug

      

                 int lcdValue = getAutoBrightnessValue(
-                        (mIsDocked ? value : mHighestLightSensorValue),
-                        mLcdBacklightValues);
+                        (true ? value : mHighestLightSensorValue),
+                        mLcdBacklightValues);

int lcdValue = getAutoBrightnessValue( - (mIsDocked ? value : mHighestLightSensorValue), - mLcdBacklightValues); + (true ? value : mHighestLightSensorValue), + mLcdBacklightValues);  

   3) HAL 部分      

      实现hardware/libhardware/include/hardware/sensor.h接口，写一个HAL层，

      这部分请参考我上一篇文章: android sensor HAL范例，那个例子写的好级啦

      需要说明的一点是，android系统的所有sensor公用一个HAL层文件，所以如果你的系统已有其他sensor那么需要在其他

      sensor的HAL实现中添加light sensor

      HAL层最终生成 /system/lib/hw/sensors.xxx.so 

   4) Driver 部分

      不管啥接口的light sensor，请把它写成一个input设备，

      通过/dev/input/eventX来提供数据

      这样在HAL层polling的时候就可以

      nread = read(ls_fd, &event, sizeof(event));

      

if (event->type == EV_ABS) {
    LOGV("light-level type: %d code: %d value: %-5d time: %ds",
         event->type, event->code, event->value,
         (int)event->time.tv_sec);
    if (event->code == EVENT_TYPE_LIGHT) {
        struct input_absinfo absinfo;
        int index;
        if (!ioctl(fd, EVIOCGABS(ABS_DISTANCE), &absinfo)) {
            index = event->value;
            if (index >= 0) {
                new_sensors |= SENSORS_LIGHT;
                if (index >= ARRAY_SIZE(sLuxValues)) {
                    index = ARRAY_SIZE(sLuxValues) - 1;
                }
                dev->sensors[ID_L].light = sLuxValues[index];
            }
        }
    }
}

if (event->type == EV_ABS) { LOGV("light-level type: %d code: %d value: %-5d time: %ds", event->type, event->code, event->value, (int)event->time.tv_sec); if (event->code == EVENT_TYPE_LIGHT) { struct input_absinfo absinfo; int index; if (!ioctl(fd, EVIOCGABS(ABS_DISTANCE), &absinfo)) { index = event->value; if (index >= 0) { new_sensors |= SENSORS_LIGHT; if (index >= ARRAY_SIZE(sLuxValues)) { index = ARRAY_SIZE(sLuxValues) - 1; } dev->sensors[ID_L].light = sLuxValues[index]; } } } } 

      .light 最终传给 PowerManager, PowerManager根据config_autoBrightnessLevels数组

      得到config_autoBrightnessLcdBacklightValues数据具体亮度值，然后调整亮度

      比如 .light = 2500.0

         3000.0  <  2500.0 < 4000.0 对应的LcdBacklightValues 就是160

      -- THE END --