LED驅動程式設計的文章

LED Class, Triggers and Drivers
new class for led devices

Android Proting 首部曲--- 環境建置與原始碼下載

最近針對Android移植部分做了點練習稍有心得，分享最近 Porting 心得看是否可以增加部落格瀏覽人氣 。 　^_^

Android Porting的方法在網路上已經有很多的教學，本系列文章是針對ARM S3C6410的開發版進行Android 2.1移植，移植流程如下圖:

Android 燈光控制軟體追蹤

Google Android提供完整的開發智慧型手機的原始程式，該程式實際上是由Java及C++或C組合而成。本文我們將說明燈光控制相關的軟體，程式說明如下
1. 燈光硬體抽象層(HAL):

有關LED HAL的定義在android_source\hardware\libhardware\include\hardware\lights.h的檔案中，在該檔案中可以看到定義struct light_state_t的資料結構，來儲存燈光的狀態。另一個資料結構struct light_device_t則定義set_light的函式，其完整的定如下：

struct light_device_t {
    struct hw_device_t common;

    /**
     * Set the provided lights to the provided values.
     *
     * Returns: 0 on succes, error code on failure.
     */
    int (*set_light)(struct light_device_t* dev,
            struct light_state_t const* state);
};

2. 實作燈號系統函式庫(.so)：在android_source\hardware\msm7k\liblights\目錄下可以看到lights.c及Android.mk兩個檔案，前者是實現硬體抽象層的系統檔案，而後者則提供編譯資訊。我們以處理追蹤球燈號為例，其原始程式如下：

static int
handle_trackball_light_locked(struct light_device_t* dev)
{
    int mode = g_attention;

    if (mode == 7 && g_backlight) {
        mode = 0;
    }
    LOGV("%s g_backlight = %d, mode = %d, g_attention = %d\n",
        __func__, g_backlight, mode, g_attention);

    // If the value isn't changing, don't set it, because this
    // can reset the timer on the breathing mode, which looks bad.
    if (g_trackball == mode) {
        return 0;
    }

    return write_int(TRACKBALL_FILE, mode);
}

上述程式中會呼叫write_int函式來和底層驅動溝通，利用open函式來開啟驅動並用write函式來進行控制。

static int
write_int(char const* path, int value)
{
    int fd;
    static int already_warned = 0;

    fd = open(path, O_RDWR);
    if (fd >= 0) {
        char buffer[20];
        int bytes = sprintf(buffer, "%d\n", value);
        int amt = write(fd, buffer, bytes);
        close(fd);
        return amt == -1 ? -errno : 0;
    } else {
        if (already_warned == 0) {
            LOGE("write_int failed to open %s\n", path);
            already_warned = 1;
        }
        return -errno;
    }
}

何時會點亮追蹤球燈號呢？當手機有通知事件要通知使用者時，我們可以用set_light_notifications函式來設定追蹤球燈號。

static int
set_light_notifications(struct light_device_t* dev,
        struct light_state_t const* state)
{
    pthread_mutex_lock(&g_lock);
    g_notification = *state;
    LOGV("set_light_notifications g_trackball=%d color=0x%08x",
            g_trackball, state->color);
    if (g_haveTrackballLight) {
        handle_trackball_light_locked(dev);
    }
    handle_speaker_battery_locked(dev);
    pthread_mutex_unlock(&g_lock);
    return 0;
}

以上的程式是說明定義在硬體抽象層中的set_light如何和系統函式庫相互連結。

static int open_lights(const struct hw_module_t* module, char const* name,
        struct hw_device_t** device)
{
    int (*set_light)(struct light_device_t* dev,
            struct light_state_t const* state);

    if (0 == strcmp(LIGHT_ID_BACKLIGHT, name)) {
        set_light = set_light_backlight;
    }
    else if (0 == strcmp(LIGHT_ID_KEYBOARD, name)) {
        set_light = set_light_keyboard;
    }
    else if (0 == strcmp(LIGHT_ID_BUTTONS, name)) {
        set_light = set_light_buttons;
    }
    else if (0 == strcmp(LIGHT_ID_BATTERY, name)) {
        set_light = set_light_battery;
    }
    else if (0 == strcmp(LIGHT_ID_NOTIFICATIONS, name)) {
        set_light = set_light_notifications;
    }
    else if (0 == strcmp(LIGHT_ID_ATTENTION, name)) {
        set_light = set_light_attention;
    }
    else {
        return -EINVAL;
    }

    pthread_once(&g_init, init_globals);

    struct light_device_t *dev = malloc(sizeof(struct light_device_t));
    memset(dev, 0, sizeof(*dev));

    dev->common.tag = HARDWARE_DEVICE_TAG;
    dev->common.version = 0;
    dev->common.module = (struct hw_module_t*)module;
    dev->common.close = (int (*)(struct hw_device_t*))close_lights;
    dev->set_light = set_light;

    *device = (struct hw_device_t*)dev;
    return 0;
}

3. Java/C JNI介面函式:在android_source\frameworks\base\services\jni目錄下，可以找到com_android_server_HardwareService.cpp檔案，您可以發現JNINativeMethod method_table陣列及register_android_server_HardwareService函式，利用此兩項資訊來註冊硬體相關服務。

static JNINativeMethod method_table[] = {
    { "init_native", "()I", (void*)init_native },
    { "finalize_native", "(I)V", (void*)finalize_native },
    { "setLight_native", "(IIIIIII)V", (void*)setLight_native },
    { "vibratorOn", "(J)V", (void*)vibratorOn },
    { "vibratorOff", "()V", (void*)vibratorOff }
};

int register_android_server_HardwareService(JNIEnv *env)
{
    return jniRegisterNativeMethods(env, "com/android/server/HardwareService",
            method_table, NELEM(method_table));
}

在上述資訊中，我們可以看到setLight_native函式，其程式列表如下：

static void setLight_native(JNIEnv *env, jobject clazz, int ptr,
        int light, int colorARGB, int flashMode, int onMS, int offMS, int brightnessMode)
{
    Devices* devices = (Devices*)ptr;
    light_state_t state;

    if (light < 0 || light >= LIGHT_COUNT || devices->lights[light] == NULL) {
        return ;
    }

    memset(&state, 0, sizeof(light_state_t));
    state.color = colorARGB;
    state.flashMode = flashMode;
    state.flashOnMS = onMS;
    state.flashOffMS = offMS;
    state.brightnessMode = brightnessMode;

    devices->lights[light]->set_light(devices->lights[light], &state);
}

上述的set_light就定義在硬體抽象層中。

4. Java服務軟體實作:在android_source\frameworks\base\services\java\com\android\server目錄下，HardwareService.java實作硬體服務的程式，該程式定義HardwareService並繼承IHardwareService.Stub介面，在該程式中可以呼叫setLight_native函式來連結JNI層的軟體。

public class HardwareService extends IHardwareService.Stub {
    private static final String TAG = "HardwareService";
:
:
    private static native int init_native();
    private static native void finalize_native(int ptr);

    private static native void setLight_native(int ptr, int light, int color, int mode,
            int onMS, int offMS, int brightnessMode);
}

以上簡略說明從底層硬體抽象層、系統函式庫層、JNI介面層、及Java服務層，相信您對如何在Google Android平台中控制硬體已有初步的瞭解。

實作IPC COM控制程式

以下程式用於DMA-6410L 開發平台，其步驟如下：
1. 新增新的activity元件。
2. 修改activityMain.java，更換執行元件。
3. 新增AIDL檔案。
4. 新增COM Service程式。
5. 修改activity程式。
6. 修改Manifest檔案。
7. 安裝及測試














UartIPCactivity.java程式列表:

package tw.com.dmatek.dma6410xp.ipc;

import java.util.Timer;
import java.util.TimerTask;

import tw.com.dmatek.dma6410xp.R;
import tw.com.dmatek.dma6410xp.uart.Linuxc;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;

public class UartIPCactivity extends Activity {
 TextView view1,view2,view;
 
 Spinner spinner1;
 
 String receiveMsg;
 String Msg,str="liwei",ReStr;
 EditText editmsg;
 Button myButton0,myButton1,myButton2,myButton3,myButton4;
 public int num=1; 
 public int fd,set,i=-1,ss=0;
 int p;
 private static final String[] countriesStr =
   { "B1200", "B2400", "B4800", "B9600","B19200","B38400","B57600","B115200","B230400","B921600"};
 private Spinner mySpinner;
 private ArrayAdapter adapter;
 private IUartService uartService=null; 

 private Button.OnClickListener myButton0_listener=new Button.OnClickListener()
 {
  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub

  try {
   if(uartService.openUart(1)>=0)
     setTitle("ipc open device sucess!");
    else
     setTitle("ipc open device false!"); 
  } catch (RemoteException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
   view1.setText("The current COM1");
  }
  
 };

 
 private Button.OnClickListener myButton1_listener=new Button.OnClickListener()
 {
  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
   try {
    if(uartService.openUart(2)>=0)
      setTitle("ipc open device sucess!");
     else
      setTitle("ipc open device false!"); 
   } catch (RemoteException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
    view1.setText("The current COM2");   
  }  
 };
 
 private Button.OnClickListener myButton2_listener=new Button.OnClickListener()
 {
  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub   
   view.setText(null);

  }  
 };

 private Button.OnClickListener myButton3_listener=new Button.OnClickListener()
 {
  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
//   timer.cancel();
   try {
    uartService.closeUart(0);
   } catch (RemoteException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
   finish();
  }  
 };
 
 private Button.OnClickListener myButton4_listener=new Button.OnClickListener()
 {
  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
   Msg=editmsg.getText().toString();
   try {
    uartService.sendMsgUart(Msg);
   } catch (RemoteException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }  
 };

 private ServiceConnection mConnection = new ServiceConnection(){

  @Override
  public void onServiceConnected(ComponentName arg0, IBinder arg1) {
   // TODO Auto-generated method stub
   uartService = IUartService.Stub.asInterface(arg1);
  }

  @Override
  public void onServiceDisconnected(ComponentName arg0) {
   // TODO Auto-generated method stub
   uartService = null;
   
  }
  
 };
 
 Timer timer = new Timer();
 
 TimerTask task = new TimerTask() {
  public void run() {
   runOnUiThread(new Runnable() {
    @Override
    public void run() {
     if (uartService!=null) {

      try {
       ReStr=uartService.receiveMsgUart();
      } catch (RemoteException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
      }
      if(ReStr!=null)
       {
        
        view.append(ReStr);
        view.append("\n");
        ReStr=null;
       }
            
     }
      
    }
   });
  }
 };
 
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  setContentView(R.layout.uart);
  timer.schedule(task, 1000, 1000);
  setTitle("IPC Testing");
        bindService(new Intent(UartIPCactivity.this, UartService.class), mConnection , Context.BIND_AUTO_CREATE);

        view1=(TextView)findViewById(R.id.uart_textview);
        view=(TextView)findViewById(R.id.uart_view);
        editmsg=(EditText)findViewById(R.id.uart_edit);
        editmsg.setWidth(200);
        mySpinner=(Spinner)findViewById(R.id.uart_mode);
        myButton0=(Button)findViewById(R.id.uart_button0);
        myButton1=(Button)findViewById(R.id.uart_button1);
        myButton2=(Button)findViewById(R.id.uart_button2);
        myButton3=(Button)findViewById(R.id.uart_button3);
        myButton4=(Button)findViewById(R.id.uart_button4);       
        
        myButton0.setOnClickListener(myButton0_listener);     
        myButton1.setOnClickListener(myButton1_listener);  
        myButton2.setOnClickListener(myButton2_listener);   
        myButton3.setOnClickListener(myButton3_listener);  
        myButton4.setOnClickListener(myButton4_listener);  
        
        adapter = new ArrayAdapter(this,
        android.R.layout.simple_spinner_item, countriesStr);
           
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

          
        mySpinner.setAdapter(adapter);
            
        mySpinner.setOnItemSelectedListener(new Spinner.OnItemSelectedListener()
         {

            @Override
        public void onItemSelected(AdapterView arg0, View arg1, int arg2,long arg3)
          {                              
             try {
     if(uartService!=null) uartService.setUart(arg2);
    } catch (RemoteException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
              arg0.setVisibility(View.VISIBLE);
          }

              @Override
              public void onNothingSelected(AdapterView arg0)
              {
                // TODO Auto-generated method stub
              }

            });   
 }

}

UartService.java程式列表：

package tw.com.dmatek.dma6410xp.ipc;

import tw.com.dmatek.dma6410xp.uart.Linuxc;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.RemoteException;

public class UartService extends Service {
 int fd = -1;
 int ss = 3;
 
 private final IUartService.Stub mBinder = new IUartService.Stub() {

  @Override
  public int setUart(int buad) throws RemoteException {
   // TODO Auto-generated method stub
   ss=buad;
   return Linuxc.setUart(ss);
  }
  
  @Override
  public int openUart(int port) throws RemoteException {
   // TODO Auto-generated method stub
   if(fd>=0) Linuxc.closeUart(0);
   fd=Linuxc.openUart(port);
   
   if(fd>=0)
       {
    Linuxc.setUart(ss);
       }

   return fd;
  }
  
  @Override
  public void closeUart(int port) throws RemoteException {
   // TODO Auto-generated method stub
   Linuxc.closeUart(port);
  }

  @Override
  public int sendMsgUart(String message) throws RemoteException {
   // TODO Auto-generated method stub
   return Linuxc.sendMsgUart(message);
  
  }

  @Override
  public String receiveMsgUart() throws RemoteException {
   // TODO Auto-generated method stub
   return Linuxc.receiveMsgUart();
  }
 };
 @Override
 public IBinder onBind(Intent arg0) {
  // TODO Auto-generated method stub
  return mBinder;
 }
 
}

IUartService.aidl程式列表如下：

package tw.com.dmatek.dma6410xp.ipc;

interface IUartService{
 int openUart(int buad);
 void closeUart(int port);
 int setUart(int port);
 int sendMsgUart(String message);
 String receiveMsgUart();
}

實作IPC LED控制程式

以下程式用於DMA-6410L 開發平台，其步驟如下：
1.新增新的activity元件。
2.修改activityMain.java，更換執行元件。
3.新增AIDL檔案。
4. 新增LED Service程式。
5. 修改LED Activity程式。
6. 修改Manifest檔案。
7. 安裝與測試













LedIPCactivity.java程式列表

package tw.com.dmatek.dma6410xp.ipc;

import tw.com.dmatek.dma6410xp.R;
import tw.com.dmatek.dma6410xp.led.Linuxc;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.view.View;
import android.widget.Button;

public class LedIPCactivity extends Activity {
    /** Called when the activity is first created. */
    
    private Button mButton1; 
    private Button mButton2;
    private Button mButton3;
    private Button mButton4;
    private Button mButton5;

        public  int state1=0,state2=0;      
       public  int led_on = 1; 
     public  int led_off = 2;
 public  int fd = 0;
   
 
 private Button.OnClickListener button1_listener= new Button.OnClickListener()
 {
  public void onClick(View v)
        {
          
          
           
         //Linuxc.send(2, led_on);
   try {
    ledService.TurnOn(2);
   } catch (RemoteException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
         
         
        }
 };
 
 private Button.OnClickListener button4_listener= new Button.OnClickListener()
 {
  public void onClick(View v)
        {
          
          
         // Linuxc.send(2, led_off);
   try {
    ledService.TurnOff(2);
   } catch (RemoteException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
          
        }
 };
 
 private Button.OnClickListener button5_listener= new Button.OnClickListener()
 {
  public void onClick(View v)
  {
         
          
          //Linuxc.send(1, led_off);
   try {
    ledService.TurnOff(1);
   } catch (RemoteException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
  }   
 };
 
 
 
 private Button.OnClickListener button2_listener= new Button.OnClickListener(){
    public void onClick(View v)
          {
           
           //Linuxc.send(1, led_on);
     try {
    ledService.TurnOn(1);
   } catch (RemoteException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   }
              
            }
 };
 private Button.OnClickListener button3_listener= new Button.OnClickListener(){
   public void onClick(View v)
         {
 
           finish();
           }
 };
 private ILedService ledService=null;
 private ServiceConnection mConnection = new ServiceConnection(){

  @Override
  public void onServiceConnected(ComponentName arg0, IBinder arg1) {
   // TODO Auto-generated method stub
   ledService=ILedService.Stub.asInterface(arg1);
  }

  @Override
  public void onServiceDisconnected(ComponentName arg0) {
   // TODO Auto-generated method stub
   
  }
  
 };
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.led);
        
        mButton1=(Button)findViewById(R.id.led_myButton1);
        mButton2 =(Button) findViewById(R.id.led_myButton2);
        mButton3 =(Button) findViewById(R.id.led_myButton3);
        mButton4 =(Button) findViewById(R.id.led_myButton1_1);
        mButton5 =(Button) findViewById(R.id.led_myButton2_1);
        

  bindService(new Intent(LedIPCactivity.this, LedService.class), mConnection , Context.BIND_AUTO_CREATE);
        
         
        mButton1.setOnClickListener(button1_listener);
        
        mButton2.setOnClickListener(button2_listener);
        
        
        mButton3.setOnClickListener(button3_listener);
        mButton4.setOnClickListener(button4_listener);
        mButton5.setOnClickListener(button5_listener);
   
    }
}

LedService.java列表

package tw.com.dmatek.dma6410xp.ipc;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.os.RemoteException;
import tw.com.dmatek.dma6410xp.led.Linuxc;;

public class LedService extends Service {
    public  int led_on = 1; 
    public  int led_off = 2;
    public  int fd = -1;
 private ILedService.Stub mbinder=new ILedService.Stub(){

  @Override
  public void TurnOff(int port) throws RemoteException {
   // TODO Auto-generated method stub
   if(fd>=0) Linuxc.send(port, led_off);
  }

  @Override
  public void TurnOn(int port) throws RemoteException {
   // TODO Auto-generated method stub
   if(fd>=0) Linuxc.send(port, led_on);
  }
  
 };
 @Override
 public IBinder onBind(Intent arg0) {
  // TODO Auto-generated method stub
  fd=Linuxc.openled();
  return mbinder;
 }
 @Override
 public boolean onUnbind(Intent intent) {
  // TODO Auto-generated method stub
  Linuxc.closeled();
  return super.onUnbind(intent);
  
 }

}

虛擬Android Market

Android Market可以使用在模擬器上了，教學網址連結在下面有興趣可以試試看喔。

網址連結

優化Eclipse 開發工具

一般我們進行Android程式的開發所使用的Eclipse工具，
如果使用在多核心的系統上，可以在eclipse.ini中加入如下的一行讓Eclipse支援雙核心。
-XX:+UseParallelGC