[SL-ONLY] Make MQTT Subscribe/Publish QoS configurable via MqttClientConfig (#1190)

* Adding the option for the QoS level selection

* Addressing the review comments

Author: chirag-silabs

examples/thermostat/silabs/src/mqtt_example.cpp

@@ -34,7 +34,6 @@ using chip::ByteSpan;
 using chip::DeviceLayer::Silabs::MqttBroker;
 using chip::DeviceLayer::Silabs::MqttClient;
 using chip::DeviceLayer::Silabs::MqttClientConfig;
-using chip::DeviceLayer::Silabs::MqttQoS;
 
 // Please fill in the details for your own MQTT broker.
 constexpr char kMqttBrokerIp[]       = MQTT_BROKER_IP;    // The IP address of your MQTT broker
@@ -88,6 +87,7 @@ sl_status_t mqtt_client_demo_start(void)
         return SL_STATUS_ALREADY_INITIALIZED;
     }
 
+    // Subscribe/Publish without an explicit QoS use MqttClientConfig::subQoS / pubQoS.
     const MqttClientConfig config = {
         .useTls               = true,
         .clientId             = kMqttClientId,
@@ -137,7 +137,7 @@ sl_status_t mqtt_client_demo_start(void)
     }
 
     gOpDone = false;
-    err     = RunOperation(gMqttsClient.Subscribe(kMqttTopic, MqttQoS::QoS1, OnOperationDone));
+    err     = RunOperation(gMqttsClient.Subscribe(kMqttTopic, OnOperationDone));
     if (err != CHIP_NO_ERROR)
     {
         ChipLogError(DeviceLayer, "MQTT Subscribe failed: %" CHIP_ERROR_FORMAT, err.Format());
@@ -146,7 +146,7 @@ sl_status_t mqtt_client_demo_start(void)
 
     const ByteSpan payload(reinterpret_cast<const uint8_t *>(kMqttPublishMessage), strlen(kMqttPublishMessage));
     gOpDone = false;
-    err     = RunOperation(gMqttsClient.Publish(kMqttTopic, payload, MqttQoS::QoS1, false, OnOperationDone));
+    err     = RunOperation(gMqttsClient.Publish(kMqttTopic, payload, false, OnOperationDone));
     if (err != CHIP_NO_ERROR)
     {
         ChipLogError(DeviceLayer, "MQTT Publish failed: %" CHIP_ERROR_FORMAT, err.Format());

src/platform/silabs/services/mqtt_client.cpp

@@ -600,6 +600,11 @@ CHIP_ERROR MqttClient::Subscribe(const char * topic, MqttQoS qos, MqttOperationC
     return QueueOperation(Operation::Subscribe, callback, context);
 }
 
+CHIP_ERROR MqttClient::Subscribe(const char * topic, MqttOperationCallback callback, void * context)
+{
+    return Subscribe(topic, mConfig.subQoS, callback, context);
+}
+
 CHIP_ERROR MqttClient::Unsubscribe(const char * topic, MqttOperationCallback callback, void * context)
 {
     VerifyOrReturnError(IsRunning(), CHIP_ERROR_INCORRECT_STATE);
@@ -626,6 +631,11 @@ CHIP_ERROR MqttClient::Publish(const char * topic, ByteSpan payload, MqttQoS qos
     return QueueOperation(Operation::Publish, callback, context);
 }
 
+CHIP_ERROR MqttClient::Publish(const char * topic, ByteSpan payload, bool retained, MqttOperationCallback callback, void * context)
+{
+    return Publish(topic, payload, mConfig.pubQoS, retained, callback, context);
+}
+
 CHIP_ERROR MqttClient::Yield(uint32_t timeoutMs, MqttOperationCallback callback, void * context)
 {
     VerifyOrReturnError(IsRunning(), CHIP_ERROR_INCORRECT_STATE);

src/platform/silabs/services/mqtt_client.h

@@ -78,8 +78,11 @@ struct MqttClientConfig
     bool willEnable          = false;
     const char * willTopic   = nullptr;
     const char * willMessage = nullptr;
-    MqttQoS willQoS          = MqttQoS::QoS1;
+    // Defaults used when Subscribe / Publish omit an explicit QoS.
+    MqttQoS willQoS          = MqttQoS::QoS1; ///< Last Will QoS when willEnable is true.
     bool willRetained        = false;
+    MqttQoS pubQoS           = MqttQoS::QoS1; ///< Default Publish QoS.
+    MqttQoS subQoS           = MqttQoS::QoS1; ///< Default Subscribe QoS.
 
     /** PEM bytes for host mbedTLS CA chain. nullptr = skip CA install. */
     const uint8_t * tlsCaCert = nullptr;
@@ -158,6 +161,11 @@ class MqttClient : public MatterService
      */
     CHIP_ERROR Subscribe(const char * topic, MqttQoS qos, MqttOperationCallback callback, void * context = nullptr);
 
+    /**
+     * @brief Subscribe using @ref MqttClientConfig::subQoS from Init.
+     */
+    CHIP_ERROR Subscribe(const char * topic, MqttOperationCallback callback, void * context = nullptr);
+
     CHIP_ERROR Unsubscribe(const char * topic, MqttOperationCallback callback, void * context = nullptr);
 
     /**
@@ -168,6 +176,12 @@ class MqttClient : public MatterService
     CHIP_ERROR Publish(const char * topic, ByteSpan payload, MqttQoS qos, bool retained, MqttOperationCallback callback,
                        void * context = nullptr);
 
+    /**
+     * @brief Publish using @ref MqttClientConfig::pubQoS from Init.
+     */
+    CHIP_ERROR Publish(const char * topic, ByteSpan payload, bool retained, MqttOperationCallback callback,
+                       void * context = nullptr);
+
     /**
      * @brief Queue a one-shot MQTTYield (optional; idle auto-yield covers keepalive/receive).
      */
@@ -228,7 +242,7 @@ class MqttClient : public MatterService
 
     const char * mPendingTopic = nullptr;
     ByteSpan mPendingPayload;
-    MqttQoS mPendingQos             = MqttQoS::QoS1;
+    MqttQoS mPendingQos             = MqttQoS::QoS0;
     bool mPendingRetained           = false;
     uint32_t mPendingYieldTimeoutMs = 0;