Update the doxygen comment.

src/codec/adau1361lower.hpp

@@ -27,9 +27,8 @@ namespace rpp_driver {
  * method. This function is depend on the signal routing of
  * the CODEC and it is depend on the circuit board.
  * User must derive a subclass of this class to implement
- * that function for his/her board.
- *
- * As an example of sub-class, UmbAdau1361Lower class is provided.
+ * that function for his/her board. As an example of sub-class, UmbAdau1361Lower
+ * class is provided.
  *
  * To initialize codec, follow the sequence. This is done by the Adau1361 class.
  * @li InitializeCore()

src/codec/umbadau1361lower.hpp

@@ -18,10 +18,9 @@ namespace rpp_driver {
 /**
  * @brief lower part of the Adau1361 CODEC controller class.
  * @details
- * This is dedicated class for UMB-ADAU1361-A board.
- * All signal routings are configured for this board.
- *
- * http://dsps.shop-pro.jp/?pid=82798273
+ * This is dedicated class for
+ * [UMB-ADAU1361-A](http://dsps.shop-pro.jp/?pid=82798273) board. All signal
+ * routings are configured for this board.
  *
  */
 class UmbAdau1361Lower : public Adau1361Lower {

src/gpio/gpiobasic.hpp

@@ -27,7 +27,8 @@ namespace rpp_driver {
  * @details
  * This class provides the handy way to control GPIO. To use
  * this class, pass a GPIO pin# through the constructor.
- * So, this class initialize that pin in the constructor.
+ * So, this class initialize and deinitialize that pin in the constructor and
+ * destructor, respectively.
  */
 class GpioBasic {
  public:
@@ -36,12 +37,12 @@ class GpioBasic {
    * @param pin GPIO pin number.
    * @details
    * Receive the GPIO pin.
-   * And then, init it as GPIO.
+   * And then, init it by ::rpp_driver::gpio_init().
    */
   GpioBasic(SdkWrapper &sdk, uint pin);
   GpioBasic() = delete;
   /**
-   * @brief deinit the I2C by sdk.i2c_deinit();
+   * @brief deinit the GPIO by ::rpp_driver::gpio_deinit();
    */
   virtual ~GpioBasic();
   /**

src/i2c/i2cmaster.hpp

@@ -33,6 +33,9 @@ namespace rpp_driver {
  * master controller. Everything operation in this class is polling based and
  * blocking.
  *
+ * The constructor and destructor initializes and finalize the given I2C
+ * controller, respectively.
+ *
  * The ReadBlocking() and WriteBlocking() functions has nostop parameter. To use
  * the restart condition, set this parameter to true.
  *
@@ -48,14 +51,14 @@ class I2cMaster : public I2cMasterInterface {
    * @param sda_pin GPIO pin #
    * @details
    * Receive the uninitialized I2C hardware by parameter i2c, and initialize
-   * it by sdk.i2c_init().
+   * it by ::rpp_driver::i2c_init().
    * And then, set given pins to I2C function, and pull them up.
    */
   I2cMaster(SdkWrapper &sdk, i2c_inst_t &i2c, uint clock_freq, uint scl_pin,
             uint sda_pin);
   I2cMaster() = delete;
   /**
-   * @brief deinit the I2C by sdk.i2c_deinit();
+   * @brief deinit the I2C by ::rpp_driver::i2c_deinit();
    */
   virtual ~I2cMaster();
   /**

src/i2s/i2sslaveduplex.hpp

@@ -65,7 +65,7 @@ class I2sSlaveDuplex {
  public:
   I2sSlaveDuplex(/* args */) = delete;
   /**
-   * @brief Construct a new Duplex Slave I 2 S object
+   * @brief Construct a new Duplex Slave I2S object
    *
    * @param sdk SDK wrapper class injection.
    * @param pio PIO to use.
@@ -74,22 +74,28 @@ class I2sSlaveDuplex {
    * The state machine number is not specified in this constructor.
    * Internally, the state machine will be allocate from the unused one.
    *
+   * This constructor just registers the given parameters and allocated state
+   * machine to the internal parameters. And then, claim the state machine. No
+   * other processing will be done.
    */
   I2sSlaveDuplex(::rpp_driver::SdkWrapper &sdk, PIO pio, uint pin_base);
   /**
-   * @brief Construct a new Duplex Slave I 2 S object
+   * @brief Construct a new Duplex Slave I2S object
    *
    * @param sdk SDK wrapper class injection.
    * @param pio PIO to use.
    * @param sm State machine to use.
    * @param pin_base The GPIO pin number of SDOUT signal.
    * @details
+   * This constructor just registers the given parameters to the internal
+   * parameters. And then, claim the state machine. No other processing will be
+   * done.
    */
   I2sSlaveDuplex(::rpp_driver::SdkWrapper &sdk, PIO pio, uint32_t sm,
                  uint pin_base);
 
   /**
-   * @brief Stop the state machine and make FIFO empty.
+   * @brief Unclaim the state machine. No actual processing.
    */
   ~I2sSlaveDuplex();