GPIO值在RK3288中的计算方法为：bank×32+pin，如：

GPIO7A3： 7×32 + 0*8 +3=227

GPIO0B5: 0×32+ 1*8 +5=13

1. 导出

/sys/class/gpio# echo 44 > export

2. 设置方向

/sys/class/gpio/gpio44# echo out > direction

3. 查看方向

/sys/class/gpio/gpio44# cat direction

4. 设置输出

/sys/class/gpio/gpio44# echo 1 > value

5. 查看输出值

/sys/class/gpio/gpio44# cat value

6. 取消导出

/sys/class/gpio# echo 44 > unexport

读引脚的value

getGpioString("/sys/class/gpio/gpio256/value")

读方法，如果找不到引脚，进行导出

//读GPIO

public String getGpioString(String path) {

String defString = "99";// 默认值

try {

@SuppressWarnings("resource")

BufferedReader reader = new BufferedReader(new FileReader(path));

defString = reader.readLine();

} catch (IOException e) {

LogUtils.e(e.getMessage());

RootCommand("echo 256 > /sys/class/gpio/export");

e.printStackTrace();

}

return defString;

}

// 其他的GPIO口都是一样的方法(gpio0、gpio1、gpio2、gpio3)

//下面的是执行的方法

private boolean RootCommand(String command) {

Process process = null;

DataOutputStream os = null;

try {

process = Runtime.getRuntime().exec("su");

os = new DataOutputStream(process.getOutputStream());

os.writeBytes(command + "\n");

os.writeBytes("exit\n");

os.flush();

process.waitFor();

} catch (Exception e) {

return false;

} finally {

try {

if (os != null) {

os.close();

}

process.destroy();

} catch (Exception e) {

}

}

return true;

}