配置设备节点权限：

 // android/device/qcom/***/init.target.rc 
 // 该目录下添加对应设备节点的配置
 # Add /dev/sys
 chmod  0660  /dev/sys
 

 // android/device/qcom/common/rootdir/etc/uevented.qcon.rc
 // 该目录下添加对应设备节点的配置
 # Add /dev/sys
 /dev/sys  0666  system  system
 

 // android/device/qcom/sepolicy/private/platform_app.te 
 // 该目录下添加对应设备节点的配置
 # Add /dev/sys
 allow platform_app device:chr_file { open read write ioctl };
 

 // android/system/sepolicy/private/system_server.te
 // android/system/sepolicy/prebuilts/api/28.0/private/system_server.te
 // 该目录下添加对应设备节点的配置,两个目录需保持一致
 #Add /dev/sys
 allow system_server device:chr_file {open read write getattr };
 

 // android/system/sepolicy/public/domain.te
 // android/system/sepolicy/prebuilts/api/28.0/public/domain.te
 // 该目录下添加对应设备节点的配置,两个目录需保持一致
 # Don't allow raw read/write/open access to generic device.
 # Rather force a relabel to a more specific type.
 # 注释掉
 # neverallow domain device:chr_file { open read write };

  

写入设备节点

    final String FILE_PATH = "/sys/dev";

    private void writeSysFile(){
        final File file = new File(PATH_REPORT) ;
        String cmd = "1";
        FileOutputStream fos = null;
        try{
            fos = new FileOutputStream(file);
            fos.write(cmd.getBytes()); 
            fos.flush();
            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
           if (fos != null){
               try {
                   fos.close();
               }catch (IOException e){
                    e.printStackTrace();
               }
           }
        }
    }