[esp8266_pwm] Skip the frequency setter when it matches the default (#19224)

esphome/components/esp8266_pwm/esp8266_pwm.h

@@ -29,7 +29,7 @@ class ESP8266PWM final : public output::FloatOutput, public Component {
   void write_state(float state) override;
 
   InternalGPIOPin *pin_;
-  float frequency_{1000.0};
+  float frequency_{1000.0};  // Keep in sync with DEFAULT_FREQUENCY in output.py
   /// Cache last output level for dynamic frequency updating
   float last_output_{0.0};
 };

esphome/components/esp8266_pwm/output.py

@@ -22,6 +22,10 @@ ESP8266PWM = esp8266_pwm_ns.class_("ESP8266PWM", output.FloatOutput, cg.Componen
 SetFrequencyAction = esp8266_pwm_ns.class_("SetFrequencyAction", automation.Action)
 validate_frequency = cv.All(cv.frequency, cv.float_range(min=1.0e-6))
 
+# Schema default that also matches the C++ initializer in esp8266_pwm.h; codegen
+# skips the setter when the config equals it.
+DEFAULT_FREQUENCY = 1000.0
+
 CONFIG_SCHEMA = cv.All(
     output.FLOAT_OUTPUT_SCHEMA.extend(
         {
@@ -29,7 +33,7 @@ CONFIG_SCHEMA = cv.All(
             cv.Required(CONF_PIN): cv.All(
                 pins.internal_gpio_output_pin_schema, valid_pwm_pin
             ),
-            cv.Optional(CONF_FREQUENCY, default="1kHz"): validate_frequency,
+            cv.Optional(CONF_FREQUENCY, default=DEFAULT_FREQUENCY): validate_frequency,
         }
     ).extend(cv.COMPONENT_SCHEMA),
     cv.require_framework_version(
@@ -48,7 +52,9 @@ async def to_code(config: ConfigType) -> None:
     pin = await cg.gpio_pin_expression(config[CONF_PIN])
     cg.add(var.set_pin(pin))
 
-    cg.add(var.set_frequency(config[CONF_FREQUENCY]))
+    # Skip the setter when the config matches the C++ initializer (DEFAULT_FREQUENCY).
+    if (frequency := config[CONF_FREQUENCY]) != DEFAULT_FREQUENCY:
+        cg.add(var.set_frequency(frequency))
 
 
 @automation.register_action(

tests/component_tests/esp8266_pwm/config/frequency.yaml

@@ -0,0 +1,19 @@
+---
+esphome:
+  name: test
+
+esp8266:
+  board: d1_mini
+
+output:
+  - platform: esp8266_pwm
+    id: default_frequency
+    pin: GPIO4
+    frequency: 1kHz
+  - platform: esp8266_pwm
+    id: custom_frequency
+    pin: GPIO5
+    frequency: 2kHz
+  - platform: esp8266_pwm
+    id: schema_default_frequency
+    pin: GPIO12

tests/component_tests/esp8266_pwm/test_esp8266_pwm.py

@@ -0,0 +1,16 @@
+"""Tests for the esp8266_pwm output codegen."""
+
+from collections.abc import Callable
+from pathlib import Path
+
+
+def test_default_frequency_is_not_emitted(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+) -> None:
+    """The 1 kHz default already lives in the C++ initializer."""
+    main_cpp = generate_main(component_config_path("frequency.yaml"))
+
+    assert "default_frequency->set_frequency(" not in main_cpp
+    assert "schema_default_frequency->set_frequency(" not in main_cpp
+    assert "custom_frequency->set_frequency(2000.0f);" in main_cpp