Android GPIO 控制方案

摘要： 此方案實現Android APP控制CPU GPIO，支援設定IO方向、輸出、輸入、按鍵功能。 移植驅動與Framework gpio service 原始碼 API呼叫方法 demo 方法1 依賴Fr...

此方案實現Android APP控制CPU GPIO，支援設定IO方向、輸出、輸入、按鍵功能。

移植驅動與Framework gpio service

原始碼

API呼叫方法

demo

方法1 依賴Framework jar包（不推薦）

1. 引入Android定製後的Framework jar包，out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/classes.jar
   1. 將classes.jar拷貝到app/libs/目錄下
   2. 修改專案根目錄build.gradle，在allprojects段內增加下面程式碼：

   allprojects {
   repositories {
   google()
   jcenter()
   }
   
   gradle.projectsEvaluated {
   tasks.withType(JavaCompile) {
   options.compilerArgs.add('-Xbootclasspath/p:app\\libs\\classes.jar')
   }
   }
   }

   3. 修改app/build.gradle，如下：

   android{
   defaultConfig {
   multiDexEnabled true
   }
   }
   
   dependencies {
   compileOnly files('libs/classes.jar')
   }
   
   preBuild {
   doLast {
   def imlFile = file(project.name + ".iml")
   println('Change ' + project.name + '.iml order')
   try {
   def parsedXml = (new XmlParser()).parse(imlFile)
   def jdkNode = parsedXml.component[1].orderEntry.find { it.'@type' == 'jdk' }
   parsedXml.component[1].remove(jdkNode)
   def sdkString = "Android API " + android.compileSdkVersion.substring("android-".length()) + " Platform"
   new groovy.util.Node(parsedXml.component[1], 'orderEntry', ['type': 'jdk', 'jdkName': sdkString, 'jdkType': 'Android SDK'])
   groovy.xml.XmlUtil.serialize(parsedXml, new FileOutputStream(imlFile))
   } catch (FileNotFoundException e) {
   // nop, iml not found
   }
   }
   }

2. 呼叫

SystemGpio gpioService = (SystemGpio) context.getSystemService("gpio");

方法二 反射呼叫（==推薦==）

1. 在APP原始碼src/main目錄下新建aidl/android/os/這樣的目錄結構
2. 在aidl/android/os/目錄下新建IGpioService.aidl檔案，內容如下：

package android.os;
 
/** {@hide} */
interface IGpioService
{
int gpioWrite(int gpio, int value);
int gpioRead(int gpio);
int gpioDirection(int gpio, int direction, int value);
int gpioRegKeyEvent(int gpio);
int gpioUnregKeyEvent(int gpio);
int gpioGetNumber();
}

3. 反射呼叫

Method method = null;
try {
method = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
IBinder binder = (IBinder) method.invoke(null, new Object[]{"gpio"});
IGpioService gpioService = IGpioService.Stub.asInterface(binder);
} catch (Exception e) {
e.printStackTrace();
}

API使用說明

獲取GPIO數量

在使用GPIO前建議先獲取GPIO數量，當呼叫其它方法需要傳入引數“gpio”時可以使用0~Number之間的值。

如：gpioGetNumber()返回7，說明一共有7個GPIO，那麼傳入引數可以為：0、1、2、3、4、5、6。

/**
 * Get GPIO number
 * @return <0: error other: GPIO number
 */
public int gpioGetNumber() {
if (null != mGpioService) {
return mGpioService.gpioGetNumber();
}
return -1;
}

設定輸入輸出模式

/**
 * GPIO direction
 * @param gpio 0~Number
 * @param direction 0: input 1: output
 * @param value 0: Low 1: High
 */
public void gpioDirection(int gpio, int direction, int value) {
if (null != mGpioService) {
mGpioService.gpioDirection(gpio, direction, value);
}
}

控制GPIO輸出

/**
 * GPIO write
 * @param gpio 0~Number
 * @param value 0: Low 1: High
 */
public void gpioWrite(int gpio, int value) {
if (null != mGpioService) {
mGpioService.gpioWrite(gpio, value);
}
}

控制GPIO輸入

/**
 * GPIO read
 * @param gpio 0~Number
 * @return 0: Low 1: High other：error
 */
public int gpioRead(int gpio) {
if (null != mGpioService) {
return mGpioService.gpioRead(gpio);
}
return -1;
}

設定GPIO為按鍵模式

/**
 * GPIO register key event
 * @param gpio 0~Number
 */
public void gpioRegKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioRegKeyEvent(gpio);
}
}

設定為按鍵模式後，當GPIO有電平翻轉時會上報按鍵事件，GPIO與KeyCode對應關係如下：

GPIO_0KeyEvent.KEYCODE_GPIO_0
GPIO_1KeyEvent.KEYCODE_GPIO_1
GPIO_2KeyEvent.KEYCODE_GPIO_2
GPIO_3KeyEvent.KEYCODE_GPIO_3
GPIO_4KeyEvent.KEYCODE_GPIO_4
GPIO_5KeyEvent.KEYCODE_GPIO_5
GPIO_6KeyEvent.KEYCODE_GPIO_6
GPIO_7KeyEvent.KEYCODE_GPIO_7
GPIO_8KeyEvent.KEYCODE_GPIO_8
GPIO_9KeyEvent.KEYCODE_GPIO_9

• 當GPIO變為低電平將上報：KeyEvent.ACTION_DOWN
• 當GPIO變為高電平將上報：KeyEvent.ACTION_UP

如果要取消按鍵模式則呼叫如下方法：

/**
 * GPIO unregister key event
 * @param gpio 0~Number
 */
public void gpioUnregKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioUnregKeyEvent(gpio);
}
}

例

依賴Framework jar方式參考原始碼：

package com.ayst.item;

import android.annotation.SuppressLint;
import android.content.Context;
import android.os.SystemGpio;

/**
 * Created by Administrator on 2018/11/6.
 */

public class GpioTest {
private SystemGpio mGpioService;

@SuppressLint("WrongConstant")
public GpioTest(Context context) {
mGpioService = (SystemGpio) context.getSystemService("gpio");
}

/**
* GPIO write
* @param gpio 0~Number
* @param value 0: Low 1: High
*/
public void gpioWrite(int gpio, int value) {
if (null != mGpioService) {
mGpioService.gpioWrite(gpio, value);
}
}

/**
* GPIO read
* @param gpio 0~Number
* @return 0: Low 1: High other：error
*/
public int gpioRead(int gpio) {
if (null != mGpioService) {
return mGpioService.gpioRead(gpio);
}
return -1;
}

/**
* GPIO direction
* @param gpio 0~Number
* @param direction 0: input 1: output
* @param value 0: Low 1: High
*/
public void gpioDirection(int gpio, int direction, int value) {
if (null != mGpioService) {
mGpioService.gpioDirection(gpio, direction, value);
}
}

/**
* GPIO register key event
* @param gpio 0~Number
*/
public void gpioRegKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioRegKeyEvent(gpio);
}
}

/**
* GPIO unregister key event
* @param gpio 0~Number
*/
public void gpioUnregKeyEvent(int gpio) {
if (null != mGpioService) {
mGpioService.gpioUnregKeyEvent(gpio);
}
}

/**
* Get GPIO number
* @return <0: error other: GPIO number
*/
public int gpioGetNumber() {
if (null != mGpioService) {
return mGpioService.gpioGetNumber();
}
return -1;
}
}

反射方式參考原始碼：

package com.ayst.item;

import android.annotation.SuppressLint;
import android.content.Context;
import android.os.IBinder;
import android.os.IGpioService;
import android.os.RemoteException;

import java.lang.reflect.Method;

/**
 * Created by Administrator on 2018/11/6.
 */

public class GpioTest {
private IGpioService mGpioService;

@SuppressLint("WrongConstant")
public GpioTest(Context context) {
Method method = null;
try {
method = Class.forName("android.os.ServiceManager").getMethod("getService", String.class);
IBinder binder = (IBinder) method.invoke(null, new Object[]{"gpio"});
mGpioService = IGpioService.Stub.asInterface(binder);
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* GPIO write
*
* @param gpio0~Number
* @param value 0: Low 1: High
*/
public void gpioWrite(int gpio, int value) {
if (null != mGpioService) {
try {
mGpioService.gpioWrite(gpio, value);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}

/**
* GPIO read
*
* @param gpio 0~Number
* @return 0: Low 1: High other：error
*/
public int gpioRead(int gpio) {
if (null != mGpioService) {
try {
return mGpioService.gpioRead(gpio);
} catch (RemoteException e) {
e.printStackTrace();
}
}
return -1;
}

/**
* GPIO direction
*
* @param gpio0~Number
* @param direction 0: input 1: output
* @param value0: Low 1: High
*/
public void gpioDirection(int gpio, int direction, int value) {
if (null != mGpioService) {
try {
mGpioService.gpioDirection(gpio, direction, value);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}

/**
* GPIO register key event
*
* @param gpio 0~Number
*/
public void gpioRegKeyEvent(int gpio) {
if (null != mGpioService) {
try {
mGpioService.gpioRegKeyEvent(gpio);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}

/**
* GPIO unregister key event
*
* @param gpio 0~Number
*/
public void gpioUnregKeyEvent(int gpio) {
if (null != mGpioService) {
try {
mGpioService.gpioUnregKeyEvent(gpio);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}

/**
* Get GPIO number
*
* @return <0: error other: GPIO number
*/
public int gpioGetNumber() {
if (null != mGpioService) {
try {
return mGpioService.gpioGetNumber();
} catch (RemoteException e) {
e.printStackTrace();
}
}
return -1;
}
}