[adc] Fix 11db deprecation warning (#6749)

esphome/components/adc/sensor.py

@@ -1,3 +1,5 @@
+import logging
+
 import esphome.codegen as cg
 import esphome.config_validation as cv
 import esphome.final_validate as fv
@@ -19,16 +21,29 @@ from . import (
     ATTENUATION_MODES,
     ESP32_VARIANT_ADC1_PIN_TO_CHANNEL,
     ESP32_VARIANT_ADC2_PIN_TO_CHANNEL,
+    adc_ns,
     validate_adc_pin,
 )
 
+_LOGGER = logging.getLogger(__name__)
+
 AUTO_LOAD = ["voltage_sampler"]
 
 
+_attenuation = cv.enum(ATTENUATION_MODES, lower=True)
+
+
 def validate_config(config):
     if config[CONF_RAW] and config.get(CONF_ATTENUATION, None) == "auto":
         raise cv.Invalid("Automatic attenuation cannot be used when raw output is set")
 
+    if config.get(CONF_ATTENUATION) == "11db":
+        _LOGGER.warning(
+            "`attenuation: 11db` is deprecated, use `attenuation: 12db` instead"
+        )
+        # Alter value here so `config` command prints the recommended change
+        config[CONF_ATTENUATION] = _attenuation("12db")
+
     return config
 
 
@@ -47,7 +62,6 @@ def final_validate_config(config):
     return config
 
 
-adc_ns = cg.esphome_ns.namespace("adc")
 ADCSensor = adc_ns.class_(
     "ADCSensor", sensor.Sensor, cg.PollingComponent, voltage_sampler.VoltageSampler
 )
@@ -65,7 +79,7 @@ CONFIG_SCHEMA = cv.All(
             cv.Required(CONF_PIN): validate_adc_pin,
             cv.Optional(CONF_RAW, default=False): cv.boolean,
             cv.SplitDefault(CONF_ATTENUATION, esp32="0db"): cv.All(
-                cv.only_on_esp32, cv.enum(ATTENUATION_MODES, lower=True)
+                cv.only_on_esp32, _attenuation
             ),
         }
     )