Android RK356X TVSettings USB调试开关

平台

RK3568 + Android 11

概述

RK3568 是瑞芯微（Rockchip）推出的一款高性能处理器，支持 USB OTG（On-The-Go）和 USB Host 功能。USB OTG 和 Host 的切换功能是 RK3568 的一项重要特性，允许设备在不同的 USB 角色之间动态切换，从而实现更灵活的应用场景。

USB OTG 和 Host 的切换功能

1. USB OTG（On-The-Go）
   USB OTG 是一种允许设备在主机（Host）和设备（Device）之间动态切换的功能。通过 OTG 功能，RK3568 可以在以下两种模式之间切换：
   • 主机模式（Host Mode）：RK3568 作为主机，连接其他 USB 设备（如 U 盘、键盘、鼠标等），并控制数据传输。

   • 设备模式（Device Mode）：RK3568 作为从设备，连接到主机（如 PC），被主机控制和数据传输。

2. 动态切换
   RK3568 支持在运行时动态切换 USB OTG 和 Host 模式，无需重新启动设备或重新插拔 USB 线缆。这种切换功能依赖于硬件设计和软件驱动的支持。

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应用场景
USB OTG 和 Host 的切换功能在以下场景中有广泛应用：

1. 移动设备
   • 在智能手机、平板电脑等设备中，OTG 功能允许用户通过 USB 连接外部设备（如 U 盘、键盘、鼠标等），扩展设备的功能。

   • 例如，用户可以将手机作为主机，连接 U 盘进行文件传输，或者连接键盘和鼠标进行办公。

2. 嵌入式设备
   • 在嵌入式系统中，RK3568 的 OTG 功能可以用于连接各种 USB 设备，如打印机、摄像头、传感器等。

   • 通过动态切换，设备可以在主机和从机模式之间切换，适应不同的应用需求。

3. 工业控制
   • 在工业自动化领域，RK3568 可以作为主机连接传感器、控制器等设备，也可以作为从机连接到上位机（如 PC）进行数据采集和监控。

   • 动态切换功能使得设备可以根据任务需求灵活调整角色。

4. 车载系统
   • 在车载娱乐系统或导航设备中，OTG 功能可以用于连接外部存储设备（如 U 盘）播放媒体文件，或者连接诊断工具进行系统维护。

   • 动态切换功能使得设备可以同时支持多种连接方式。

5. 物联网设备
   • 在物联网设备中，RK3568 可以通过 OTG 功能连接各种传感器或执行器，实现数据采集和控制。

   • 通过动态切换，设备可以根据网络环境或任务需求调整角色。

6. 调试和开发
   • 在开发阶段，OTG 功能可以用于连接调试工具（如 JTAG 调试器）或烧录固件。

   • 动态切换功能使得开发者可以方便地在不同模式之间切换，提高开发效率。

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技术实现
RK3568 的 USB OTG 和 Host 切换功能依赖于以下硬件和软件支持：
• 硬件支持：RK3568 集成了 USB OTG 控制器，支持动态角色切换。

• 软件驱动：需要操作系统（如 Linux）提供相应的驱动程序和工具，支持 OTG 功能的动态切换。

• 外部电路设计：需要设计合适的 USB 接口电路，支持 OTG 功能（如 ID 引脚检测）。

操作-打开USB调试

设置 > 设备偏好设置 > 开发者选项 > USB 连接状态

实现源码

packages/apps/TvSettings/Settings/src/com/android/tv/settings/system/development/DevelopmentFragment.java

import com.android.tv.settings.dialog.UsbModeSettings;
/*** Displays preferences for application developers.*/
public class DevelopmentFragment extends SettingsPreferenceFragmentimplements Preference.OnPreferenceChangeListener,EnableDevelopmentDialog.Callback, OemUnlockDialog.Callback, AdbDialog.Callback {private static final String TAG = "DevelopmentSettings";private static final String ENABLE_DEVELOPER = "development_settings_enable";private static final String ENABLE_ADB = "enable_adb";private static final String ENABLE_USB = "enable_usb";//...省略代码...@Overridepublic void onCreatePreferences(Bundle savedInstanceState, String rootKey) {mLogdSizeController = new LogdSizePreferenceController(getActivity());mLogpersistController = new LogpersistPreferenceController(getActivity(), getLifecycle());mUsbModeSetting = new UsbModeSettings(getPreferenceManager().getContext());if (!mUm.isAdminUser()|| mUm.hasUserRestriction(UserManager.DISALLOW_DEBUGGING_FEATURES)|| Settings.Global.getInt(mContentResolver,Settings.Global.DEVICE_PROVISIONED, 0) == 0) {// Block access to developer options if the user is not the owner, if user policy// restricts it, or if the device has not been provisionedmUnavailable = true;addPreferencesFromResource(R.xml.development_prefs_not_available);return;}addPreferencesFromResource(R.xml.development_prefs);final PreferenceScreen preferenceScreen = getPreferenceScreen();// Don't add to prefs lists or it'll disable itself when switched offmEnableDeveloper = (SwitchPreference) findPreference(ENABLE_DEVELOPER);final PreferenceGroup debugDebuggingCategory = (PreferenceGroup)findPreference(DEBUG_DEBUGGING_CATEGORY_KEY);mEnableAdb = findAndInitSwitchPref(ENABLE_ADB);mEnableUsb = findAndInitSwitchPref(ENABLE_USB);mEnableInternetAdb = findAndInitSwitchPref(ENABLE_INTERNET_ADB);mEnableAbc = findAndInitSwitchPref(ENABLE_ABC);mEnableUsb.setChecked(mUsbModeSetting.getDefaultValue());if (mEnableUsb.isChecked()){mEnableUsb.setSummary(R.string.usb_connect_to_computer);} else {mEnableUsb.setSummary(R.string.usb_disconnect_to_computer);}//...省略代码....}

packages/apps/TvSettings/Settings/src/com/android/tv/settings/dialog/UsbModeSettings.java

package com.android.tv.settings.dialog;import com.android.tv.settings.R;import android.content.Context;
import android.os.Handler;
import java.io.File;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import android.os.storage.StorageManager;
import android.os.storage.StorageEventListener;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.SystemProperties;
import android.text.TextUtils;import android.util.Log;public class UsbModeSettings {private static final String TAG = "UsbModeSettings";// 0 otg 1 host 2 peripheralpublic static final String HOST_MODE = new String("host");public static final String SLAVE_MODE = new String("otg");public static final String PROP_FAKE_DATA_ROLE = "persist.fake_data_role";private static final String FILE_NAME_RK3399 = "/sys/kernel/debug/usb@fe800000/rk_usb_force_mode";private static final String FILE_NAME_RK3328 = "/sys/devices/platform/ff450000.syscon/ff450000.syscon:usb2-phy@100/otg_mode";private static final String FILE_NAME_RK3229 = "/sys/devices/platform/11000000.syscon/11000000.syscon:usb2-phy@760/otg_mode";private static final String FILE_NAME_RK356X = "/sys/devices/platform/fe8a0000.usb2-phy/otg_mode";private File file = null;private StorageManager mStorageManager = null;private String mMode = "";private String mSocName = "";private Context mContext;private boolean mLock = false;public UsbModeSettings(Context context) {mContext = context;mSocName = SystemProperties.get("sys.rk.soc");if (TextUtils.isEmpty(mSocName)) {mSocName = SystemProperties.get("ro.board.platform");}if(!TextUtils.isEmpty(mSocName) && mSocName.contains("rk3399")){file = new File(FILE_NAME_RK3399);}else{file = new File(FILE_NAME_RK3328);}file = getFile();mStorageManager = (StorageManager) mContext.getSystemService(Context.STORAGE_SERVICE);boolean ret = checkFile();String mode = ReadFromFile(file);if(ret && !TextUtils.isEmpty(mode)) {mMode = mode;}}private File getFile() {String fileName = FILE_NAME_RK3328;if (!TextUtils.isEmpty(mSocName) && mSocName.contains("rk3399")) {fileName = FILE_NAME_RK3399;} else if (!TextUtils.isEmpty(mSocName) && (mSocName.contains("rk322x") || mSocName.contains("rk3128h"))) {fileName = FILE_NAME_RK3229;} else if (!TextUtils.isEmpty(mSocName) && mSocName.contains("rk356x")) {fileName = FILE_NAME_RK356X;} else {fileName = FILE_NAME_RK3328;}return new File(fileName);}public boolean getDefaultValue() {if (isRk3368()) {//通过prop和init来设置otg模式return getFakeDataRole();}if (checkFile()) {Log.d("UsbModeSelect", "/data/otg.cfg not exist,but temp file exist");if (isRk3368()) {return getFakeDataRole();}if (mMode.equals(HOST_MODE)) {return false;} else {return true;}} else {mMode = HOST_MODE;return false;}}private String ReadFromFile(File file) {if (checkFile()) {try {FileInputStream fin = new FileInputStream(file);BufferedReader reader = new BufferedReader(new InputStreamReader(fin));String config = reader.readLine();fin.close();return config;} catch (IOException e) {Log.i(TAG, "ReadFromFile exception:" + e);e.printStackTrace();}}return null;}private void Write2File(File file, String mode) {if (!checkFile() || (mode == null))return;Log.d("UsbModeSelect", "Write2File,write mode = " + mode);try {FileOutputStream fout = new FileOutputStream(file);PrintWriter pWriter = new PrintWriter(fout);pWriter.println(mode);pWriter.flush();pWriter.close();fout.close();} catch (IOException re) {}}public void onUsbModeClick(String mode) {if (isRk3368()) {setPropFakeDataRole(mode);return;}if (mLock)return;mLock = true;mMode = mode;synchronized (this) {Log.d("UsbModeSettings", "synchronized start");new Thread(mUsbSwitch).start();}}private Runnable mUsbSwitch = new Runnable() {public synchronized void run() {Log.d("UsbModeSettings", "mUsbSwitch Runnable() in*******************");if (mStorageManager != null) {if (mMode == HOST_MODE) {mStorageManager.disableUsbMassStorage();Log.d("UsbModeSettings", "mStorageManager.disableUsbMassStorage()*******************");Write2File(file, mMode);} else {Write2File(file, mMode);Log.d("UsbModeSettings", "mStorageManager.enableUsbMassStorage()  in *******************");mStorageManager.enableUsbMassStorage();Log.d("UsbModeSettings", "mStorageManager.enableUsbMassStorage()   out*******************");}}Log.d("UsbModeSettings", "mUsbSwitch Runnable() out*******************");mLock = false;}};private boolean checkFile() {if (file == null) {Log.e(TAG, "file is null pointer");return false;}String fileName = file.getName();if (!file.exists()) {Log.e(TAG, fileName + " not exist!!!");return false;}if (!file.canRead()) {Log.e(TAG, fileName + " can't read!!!");return false;}if (!file.canWrite()) {Log.e(TAG, fileName + " can't write!!!");return false;}return true;}// 判断是否为3368芯片private boolean isRk3368() {if (!TextUtils.isEmpty(mSocName) && mSocName.contains("rk3368")) {return true;} else {return false;}}private boolean getFakeDataRole() {String fakeDataRole = SystemProperties.get(PROP_FAKE_DATA_ROLE, SLAVE_MODE);Log.d(TAG, "prop fakeDataRole = " + fakeDataRole);if (!TextUtils.isEmpty(fakeDataRole) && fakeDataRole.equals(SLAVE_MODE)) {return true;} else {return false;}}// 将mode转换为Int值，3368的mode为0,1,2private void setPropFakeDataRole(String mode) {Log.d(TAG, "setprop mode = " + mode);SystemProperties.set(PROP_FAKE_DATA_ROLE, mode);}
}

补充说明

1. 以上源码接口需要system及以上权限
2. StorageManager部分接口可以通过反射获得.

提取关键代码:

    @Overridepublic void onClick(View v) {StorageManager mStorageManager = (StorageManager) getSystemService(Context.STORAGE_SERVICE);File file = new File(FILE_NAME_RK356X);//切换为 OTG (USB 调试)if(R.id.btOtg == v.getId()) {Write2File(file, SLAVE_MODE);Log.d("UsbModeSettings", "mStorageManager.enableUsbMassStorage()  in *******************");enableUsbMassStorage(mStorageManager);Log.d("UsbModeSettings", "mStorageManager.enableUsbMassStorage()   out*******************");} else if(R.id.btHost == v.getId()) {//切换为HOSTdisableUsbMassStorage(mStorageManager);Log.d("UsbModeSettings", "mStorageManager.disableUsbMassStorage()*******************");Write2File(file, HOST_MODE);}}//写入 USB的模式: otg 或 hostprivate void Write2File(File file, String mode) {if (!new File(FILE_NAME_RK356X).exists() || (mode == null))return;Log.d("UsbModeSelect", "Write2File,write mode = " + mode);try {FileOutputStream fout = new FileOutputStream(file);PrintWriter pWriter = new PrintWriter(fout);pWriter.println(mode);pWriter.flush();pWriter.close();fout.close();} catch (IOException re) {}}//反射接口void enableUsbMassStorage(StorageManager sm){try {Method enableUsbMassStorage = sm.getClass().getMethod("enableUsbMassStorage");enableUsbMassStorage.invoke(sm);} catch (Exception e){e.printStackTrace();}}void disableUsbMassStorage(StorageManager sm){try {Method disableUsbMassStorage = sm.getClass().getMethod("disableUsbMassStorage");disableUsbMassStorage.invoke(sm);} catch (Exception e){e.printStackTrace();}}