Improve config final validation (#1917)

esphome/components/dfplayer/__init__.py

@@ -68,6 +68,9 @@ CONFIG_SCHEMA = cv.All(
         }
     ).extend(uart.UART_DEVICE_SCHEMA)
 )
+FINAL_VALIDATE_SCHEMA = uart.final_validate_device_schema(
+    "dfplayer", baud_rate=9600, require_tx=True
+)
 
 
 async def to_code(config):
@@ -80,12 +83,6 @@ async def to_code(config):
         await automation.build_automation(trigger, [], conf)
 
 
-def validate(config, item_config):
-    uart.validate_device(
-        "dfplayer", config, item_config, baud_rate=9600, require_rx=False
-    )
-
-
 @automation.register_action(
     "dfplayer.play_next",
     NextAction,