Added function description.

Adafruit_I2CDevice.h

@@ -1,3 +1,6 @@
+/*!
+ * @file Adafruit_I2CDevice.h
+ */
 #include <Wire.h>
 
 #ifndef Adafruit_I2CDevice_h
@@ -12,8 +15,53 @@ public:
   bool detected(void);
 
   bool read(uint8_t *buffer, size_t len, bool stop = true);
+  /**************************************************************************/
+  /*!
+   * @brief  Writes to a I2C device register.
+   *
+   * @param  buffer
+   *         A pointer to a buffer containing data bytes.
+   *         
+   * @param  len
+   *         Number of bytes to write from the previous buffer.
+   *
+   * @param  stop
+   *         If a stop bit needs to be sent at the end of the transmission.
+   *
+   * @param  prefix_buffer
+   *         A pointer to a buffer containing bytes that needs to be send
+   *         before data bytes (e.g. register address).
+   *
+   * @param  prefix_len
+   *         Number of bytes to write from prefix_buffer.
+   *
+   * @return True if the event read was successful, otherwise false.
+   */
+  /**************************************************************************/
   bool write(const uint8_t *buffer, size_t len, bool stop = true,
              const uint8_t *prefix_buffer = NULL, size_t prefix_len = 0);
+  /**************************************************************************/
+  /*!
+   * @brief  Writes to and then read from a I2C device register.
+   *
+   * @param  write_buffer
+   *         A pointer to a buffer containing write bytes.
+   *         
+   * @param  write_len
+   *         Number of bytes to write from the previous buffer.
+   *
+   * @param  read_buffer
+   *         A pointer to a buffer to store bytes from the read operation.
+   *
+   * @param  read_len
+   *         Number of bytes to read.
+   *
+   * @param  stop
+   *         If a stop bit needs to be sent at the end of the transmission.
+   *
+   * @return True if the event read was successful, otherwise false.
+   */
+  /**************************************************************************/
   bool write_then_read(const uint8_t *write_buffer, size_t write_len,
                        uint8_t *read_buffer, size_t read_len,
                        bool stop = false);