[mqtt] Add rp2040 support

MQTT portion of skilau's pull request https://github.com/esphome/esphome/pull/5305

esphome/components/mqtt/__init__.py

@@ -48,6 +48,7 @@ from esphome.const import (
     PLATFORM_ESP32,
     PLATFORM_ESP8266,
     PLATFORM_BK72XX,
+    PLATFORM_RP2040,
 )
 from esphome.core import coroutine_with_priority, CORE
 from esphome.components.esp32 import add_idf_sdkconfig_option
@@ -287,7 +288,7 @@ CONFIG_SCHEMA = cv.All(
         }
     ),
     validate_config,
-    cv.only_on([PLATFORM_ESP32, PLATFORM_ESP8266, PLATFORM_BK72XX]),
+    cv.only_on([PLATFORM_ESP32, PLATFORM_ESP8266, PLATFORM_BK72XX, PLATFORM_RP2040]),
 )
 
 
@@ -309,9 +310,12 @@ async def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
     # Add required libraries for ESP8266 and LibreTiny
-    if CORE.is_esp8266 or CORE.is_libretiny:
+    if CORE.is_esp8266 or CORE.is_libretiny or CORE.is_rp2040:
         # https://github.com/heman/async-mqtt-client/blob/master/library.json
         cg.add_library("heman/AsyncMqttClient-esphome", "2.0.0")
+    if CORE.is_rp2040:
+        # https://github.com/khoih-prog/AsyncTCP_RP2040W
+        cg.add_library("khoih-prog/AsyncTCP_RP2040W", "1.2.0")
 
     cg.add_define("USE_MQTT")
     cg.add_global(mqtt_ns.using)

esphome/components/mqtt/mqtt_backend_rp2040.h

@@ -0,0 +1,72 @@
+#pragma once
+
+#ifdef USE_RP2040
+
+#include "mqtt_backend.h"
+#include <AsyncMqttClient.h>
+
+namespace esphome {
+namespace mqtt {
+
+class MQTTBackendRP2040 final : public MQTTBackend {
+ public:
+  void set_keep_alive(uint16_t keep_alive) final { mqtt_client_.setKeepAlive(keep_alive); }
+  void set_client_id(const char *client_id) final { mqtt_client_.setClientId(client_id); }
+  void set_clean_session(bool clean_session) final { mqtt_client_.setCleanSession(clean_session); }
+  void set_credentials(const char *username, const char *password) final {
+    mqtt_client_.setCredentials(username, password);
+  }
+  void set_will(const char *topic, uint8_t qos, bool retain, const char *payload) final {
+    mqtt_client_.setWill(topic, qos, retain, payload);
+  }
+  void set_server(network::IPAddress ip, uint16_t port) final { mqtt_client_.setServer(IPAddress(ip), port); }
+  void set_server(const char *host, uint16_t port) final { mqtt_client_.setServer(host, port); }
+#if ASYNC_TCP_SSL_ENABLED
+  void set_secure(bool secure) { mqtt_client.setSecure(secure); }
+  void add_server_fingerprint(const uint8_t *fingerprint) { mqtt_client.addServerFingerprint(fingerprint); }
+#endif
+
+  void set_on_connect(std::function<on_connect_callback_t> &&callback) final {
+    this->mqtt_client_.onConnect(std::move(callback));
+  }
+  void set_on_disconnect(std::function<on_disconnect_callback_t> &&callback) final {
+    auto async_callback = [callback](AsyncMqttClientDisconnectReason reason) {
+      // int based enum so casting isn't a problem
+      callback(static_cast<MQTTClientDisconnectReason>(reason));
+    };
+    this->mqtt_client_.onDisconnect(std::move(async_callback));
+  }
+  void set_on_subscribe(std::function<on_subscribe_callback_t> &&callback) final {
+    this->mqtt_client_.onSubscribe(std::move(callback));
+  }
+  void set_on_unsubscribe(std::function<on_unsubscribe_callback_t> &&callback) final {
+    this->mqtt_client_.onUnsubscribe(std::move(callback));
+  }
+  void set_on_message(std::function<on_message_callback_t> &&callback) final {
+    auto async_callback = [callback](const char *topic, const char *payload,
+                                     AsyncMqttClientMessageProperties async_properties, size_t len, size_t index,
+                                     size_t total) { callback(topic, payload, len, index, total); };
+    mqtt_client_.onMessage(std::move(async_callback));
+  }
+  void set_on_publish(std::function<on_publish_user_callback_t> &&callback) final {
+    this->mqtt_client_.onPublish(std::move(callback));
+  }
+
+  bool connected() const final { return mqtt_client_.connected(); }
+  void connect() final { mqtt_client_.connect(); }
+  void disconnect() final { mqtt_client_.disconnect(true); }
+  bool subscribe(const char *topic, uint8_t qos) final { return mqtt_client_.subscribe(topic, qos) != 0; }
+  bool unsubscribe(const char *topic) final { return mqtt_client_.unsubscribe(topic) != 0; }
+  bool publish(const char *topic, const char *payload, size_t length, uint8_t qos, bool retain) final {
+    return mqtt_client_.publish(topic, qos, retain, payload, length, false, 0) != 0;
+  }
+  using MQTTBackend::publish;
+
+ protected:
+  AsyncMqttClient mqtt_client_;
+};
+
+}  // namespace mqtt
+}  // namespace esphome
+
+#endif  // defined(USE_RP2040)

esphome/components/mqtt/mqtt_client.cpp

@@ -114,6 +114,9 @@ void MQTTClientComponent::send_device_info_() {
 #ifdef USE_LIBRETINY
         root["platform"] = lt_cpu_get_model_name();
 #endif
+#ifdef USE_RP2040
+        root["platform"] = "RP2040";
+#endif
 
         root["board"] = ESPHOME_BOARD;
 #if defined(USE_WIFI)

esphome/components/mqtt/mqtt_client.h

@@ -15,6 +15,8 @@
 #include "mqtt_backend_esp8266.h"
 #elif defined(USE_LIBRETINY)
 #include "mqtt_backend_libretiny.h"
+#elif defined(USE_RP2040)
+#include "mqtt_backend_rp2040.h"
 #endif
 #include "lwip/ip_addr.h"
 
@@ -304,6 +306,8 @@ class MQTTClientComponent : public Component {
   MQTTBackendESP32 mqtt_backend_;
 #elif defined(USE_ESP8266)
   MQTTBackendESP8266 mqtt_backend_;
+#elif defined(USE_RP2040)
+  MQTTBackendRP2040 mqtt_backend_;
 #elif defined(USE_LIBRETINY)
   MQTTBackendLibreTiny mqtt_backend_;
 #endif