[MQTT] Added Doxygen comments

src/protocols/MQTT.h

@@ -27,19 +27,104 @@
 #define MQTT_CONNECT_WILL_FLAG                        0b00000100
 #define MQTT_CONNECT_CLEAN_SESSION                    0b00000010
 
+/*!
+  \class MQTTClient
+
+  \brief Client for simple MQTT communication.
+*/
 class MQTTClient {
   public:
-    // constructor
+    /*!
+      \brief Default constructor.
+
+      \param tl Pointer to the wireless module providing TransportLayer communication.
+    */
     MQTTClient(TransportLayer* tl, uint16_t port = 1883);
 
     // basic methods
+
+    /*!
+      \brief Connects to MQTT broker (/server).
+
+      \param host URL of the MQTT broker.
+
+      \param clientId ID of the client.
+
+      \param username Username to be used in the connection. Defaults to empty string (no username).
+
+      \param password Password to be used in the connection. Defaults to empty string (no password).
+
+      \param keepAlive Connection keep-alive period in seconds. Defaults to 60.
+
+      \param cleanSession MQTT CleanSession flag. Defaults to true.
+
+      \param willTopic MQTT will topic. Defaults to empty string (no will topic).
+
+      \param willMessage MQTT will message. Defaults to empty string (no will message).
+
+      \returns \ref status_codes
+    */
     int16_t connect(const char* host, const char* clientId, const char* userName = "", const char* password = "", uint16_t keepAlive = 60, bool cleanSession = true, const char* willTopic = "", const char* willMessage = "");
+
+    /*!
+      \brief Disconnect from MQTT broker.
+
+      \returns \ref status_codes
+    */
     int16_t disconnect();
+
+    /*!
+      \brief Publish MQTT message.
+
+      \param topic MQTT topic to which the message will be published.
+
+      \param message Message to be published.
+
+      \returns \ref status_codes
+    */
     int16_t publish(String& topic, String& message);
+
+    /*!
+      \brief Publish MQTT message.
+
+      \param topic MQTT topic to which the message will be published.
+
+      \param message Message to be published.
+
+      \returns \ref status_codes
+    */
     int16_t publish(const char* topic, const char* message);
+
+    /*!
+      \brief Subscribe to MQTT topic.
+
+      \param topicFilter Topic to subscribe to.
+
+      \returns \ref status_codes
+    */
     int16_t subscribe(const char* topicFilter);
+
+    /*!
+      \brief Unsubscribe from MQTT topic.
+
+      \param topicFilter Topic to unsubscribe from.
+
+      \returns \ref status_codes
+    */
     int16_t unsubscribe(const char* topicFilter);
+
+    /*!
+      \brief Ping MQTT broker. This method can be used to keep connection open.
+
+      \returns \ref status_codes
+    */
     int16_t ping();
+
+    /*!
+      \brief Set function to be called when checking new messages in subscribed topics.
+
+      \returns \ref status_codes
+    */
     int16_t check(void (*func)(const char*, const char*));
 
   private: