[espnow] Stop polling the Wi-Fi driver every loop and disable loop when idle (#18027)

esphome/components/espnow/__init__.py

@@ -13,7 +13,7 @@ from esphome.const import (
     CONF_TRIGGER_ID,
     CONF_WIFI,
 )
-from esphome.core import HexInt
+from esphome.core import CORE, HexInt
 from esphome.types import ConfigType
 
 CODEOWNERS = ["@jesserockz"]
@@ -151,6 +151,10 @@ async def to_code(config):
 
     cg.add_define("USE_ESPNOW")
     cg.add_define("USE_ESPNOW_MAX_PAYLOAD_SIZE", config[CONF_MAX_PAYLOAD_SIZE])
+
+    if CONF_WIFI in CORE.config:
+        # Track the Wi-Fi channel via connect events instead of polling every loop
+        wifi.request_wifi_connect_state_listener()
     if wifi_channel := config.get(CONF_CHANNEL):
         cg.add(var.set_wifi_channel(wifi_channel))
 

esphome/components/espnow/espnow_component.cpp

@@ -7,7 +7,6 @@
 #include <algorithm>
 #include <cinttypes>
 
-#include "esphome/core/application.h"
 #include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
@@ -75,6 +74,7 @@ void on_send_report(const uint8_t *mac_addr, esp_now_send_status_t status)
   if (packet == nullptr) {
     // No events available - queue is full or we're out of memory
     global_esp_now->receive_packet_queue_.increment_dropped_count();
+    global_esp_now->enable_loop_soon_any_context();
     return;
   }
 
@@ -90,8 +90,8 @@ void on_send_report(const uint8_t *mac_addr, esp_now_send_status_t status)
   // Push always succeeds: pool is sized to queue capacity (SIZE-1), so if
   // allocate() returned non-null, the queue cannot be full.
 
-  // Wake main loop immediately to process ESP-NOW send event
+  // Re-enable and wake the main loop to process the ESP-NOW send event
-  App.wake_loop_threadsafe();
+  global_esp_now->enable_loop_soon_any_context();
 }
 
 void on_data_received(const esp_now_recv_info_t *info, const uint8_t *data, int size) {
@@ -101,6 +101,7 @@ void on_data_received(const esp_now_recv_info_t *info, const uint8_t *data, int
   // larger frame would overflow packet_.receive.data.
   if (size < 0 || size > ESPNOW_MAX_DATA_LEN) {
     global_esp_now->receive_packet_queue_.increment_dropped_count();
+    global_esp_now->enable_loop_soon_any_context();
     return;
   }
 
@@ -109,6 +110,7 @@ void on_data_received(const esp_now_recv_info_t *info, const uint8_t *data, int
   if (packet == nullptr) {
     // No events available - queue is full or we're out of memory
     global_esp_now->receive_packet_queue_.increment_dropped_count();
+    global_esp_now->enable_loop_soon_any_context();
     return;
   }
 
@@ -120,8 +122,8 @@ void on_data_received(const esp_now_recv_info_t *info, const uint8_t *data, int
   // Push always succeeds: pool is sized to queue capacity (SIZE-1), so if
   // allocate() returned non-null, the queue cannot be full.
 
-  // Wake main loop immediately to process ESP-NOW receive event
+  // Re-enable and wake the main loop to process the ESP-NOW receive event
-  App.wake_loop_threadsafe();
+  global_esp_now->enable_loop_soon_any_context();
 }
 
 ESPNowComponent::ESPNowComponent() { global_esp_now = this; }
@@ -156,6 +158,11 @@ bool ESPNowComponent::is_wifi_enabled() {
 }
 
 void ESPNowComponent::setup() {
+#if defined(USE_WIFI) && defined(USE_WIFI_CONNECT_STATE_LISTENERS)
+  if (wifi::global_wifi_component != nullptr) {
+    wifi::global_wifi_component->add_connect_state_listener(this);
+  }
+#endif
   if (this->enable_on_boot_) {
     this->enable_();
   } else {
@@ -163,6 +170,19 @@ void ESPNowComponent::setup() {
   }
 }
 
+#if defined(USE_WIFI) && defined(USE_WIFI_CONNECT_STATE_LISTENERS)
+void ESPNowComponent::on_wifi_connect_state(StringRef ssid, std::span<const uint8_t, 6> bssid) {
+  if (ssid.empty()) {
+    return;  // Disconnected; the channel is only meaningful while associated
+  }
+  uint8_t old_channel = this->wifi_channel_;
+  this->get_wifi_channel();
+  if (this->wifi_channel_ != old_channel) {
+    ESP_LOGI(TAG, "WiFi channel changed from %d to %d", old_channel, this->wifi_channel_);
+  }
+}
+#endif
+
 void ESPNowComponent::enable() {
   if (this->state_ == ESPNOW_STATE_ENABLED)
     return;
@@ -254,15 +274,6 @@ void ESPNowComponent::apply_wifi_channel() {
 }
 
 void ESPNowComponent::loop() {
-#ifdef USE_WIFI
-  if (wifi::global_wifi_component != nullptr && wifi::global_wifi_component->is_connected()) {
-    int32_t new_channel = wifi::global_wifi_component->get_wifi_channel();
-    if (new_channel != this->wifi_channel_) {
-      ESP_LOGI(TAG, "Wifi Channel is changed from %d to %" PRId32 ".", this->wifi_channel_, new_channel);
-      this->wifi_channel_ = new_channel;
-    }
-  }
-#endif
   // Process received packets
   ESPNowPacket *packet = this->receive_packet_queue_.pop();
   while (packet != nullptr) {
@@ -348,6 +359,15 @@ void ESPNowComponent::loop() {
   if (send_dropped > 0) {
     ESP_LOGW(TAG, "Dropped %u send packets (queue full)", send_dropped);
   }
+
+  // Nothing left to do; sleep until a callback or send() re-enables the loop.
+  // A packet in flight (current_send_packet_) needs no loop time even when more
+  // packets are queued behind it: the send callback re-enables the loop when
+  // the result arrives, and the SENT event handler above starts the next send.
+  if (this->receive_packet_queue_.empty() &&
+      (this->current_send_packet_ != nullptr || this->send_packet_queue_.empty())) {
+    this->disable_loop();
+  }
 }
 
 uint8_t ESPNowComponent::get_wifi_channel() {
@@ -390,6 +410,9 @@ esp_err_t ESPNowComponent::send(const uint8_t *peer_address, const uint8_t *payl
   packet->load_data(peer_address, payload, size, callback);
   // Push the packet to the send queue
   this->send_packet_queue_.push(packet);
+  // Loop may be disabled while idle; re-enable it to send the packet
+  // (any-context variant so callers off the main loop are safe too)
+  this->enable_loop_soon_any_context();
   return ESP_OK;
 }
 

esphome/components/espnow/espnow_component.h

@@ -2,6 +2,7 @@
 
 #include "esphome/core/automation.h"
 #include "esphome/core/component.h"
+#include "esphome/core/defines.h"
 
 #ifdef USE_ESP32
 
@@ -9,6 +10,10 @@
 #include "esphome/core/lock_free_queue.h"
 #include "espnow_packet.h"
 
+#if defined(USE_WIFI) && defined(USE_WIFI_CONNECT_STATE_LISTENERS)
+#include "esphome/components/wifi/wifi_component.h"
+#endif
+
 #include <esp_idf_version.h>
 
 #include <esp_mac.h>
@@ -88,7 +93,11 @@ class ESPNowBroadcastHandler {
   virtual bool on_broadcast(const ESPNowRecvInfo &info, const uint8_t *data, uint16_t size) = 0;
 };
 
+#if defined(USE_WIFI) && defined(USE_WIFI_CONNECT_STATE_LISTENERS)
+class ESPNowComponent final : public Component, public wifi::WiFiConnectStateListener {
+#else
 class ESPNowComponent final : public Component {
+#endif
  public:
   ESPNowComponent();
   void setup() override;
@@ -114,6 +123,11 @@ class ESPNowComponent final : public Component {
 
   void set_auto_add_peer(bool value) { this->auto_add_peer_ = value; }
 
+#if defined(USE_WIFI) && defined(USE_WIFI_CONNECT_STATE_LISTENERS)
+  // WiFiConnectStateListener interface: refresh the cached channel after each (re)connect
+  void on_wifi_connect_state(StringRef ssid, std::span<const uint8_t, 6> bssid) override;
+#endif
+
   void enable();
   void disable();
   bool is_disabled() const { return this->state_ == ESPNOW_STATE_DISABLED; };

tests/components/espnow/common-wifi.yaml

@@ -0,0 +1,9 @@
+wifi:
+  ssid: MySSID
+  password: password1
+
+espnow:
+  id: espnow_component
+  auto_add_peer: true
+  peers:
+    - 11:22:33:44:55:66

tests/components/espnow/test-wifi.esp32-idf.yaml

@@ -0,0 +1,2 @@
+packages:
+  espnow: !include common-wifi.yaml