From b608685c6099786e20dcd42ccbdeafd60ce1ebdf Mon Sep 17 00:00:00 2001
From: brambo123 <bram.grit@mtsgrit.nl>
Date: Fri, 17 Jan 2025 17:06:11 +0100
Subject: [PATCH] [uart] flow control - fix ESP32 Arduino < 2.0.8

---
 esphome/components/uart/__init__.py           | 19 ++++++++++++++++---
 .../uart/uart_component_esp32_arduino.cpp     |  2 ++
 .../uart/uart_component_esp_idf.cpp           |  2 +-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/esphome/components/uart/__init__.py b/esphome/components/uart/__init__.py
index fdc85b40e0..9b6dc65897 100644
--- a/esphome/components/uart/__init__.py
+++ b/esphome/components/uart/__init__.py
@@ -30,6 +30,8 @@ from esphome.const import (
     CONF_DUMMY_RECEIVER_ID,
     CONF_LAMBDA,
     PLATFORM_HOST,
+    KEY_CORE,
+    KEY_FRAMEWORK_VERSION
 )
 from esphome.core import CORE
 
@@ -117,10 +119,21 @@ def validate_rx_pin(value):
         raise cv.Invalid("Pins GPIO16 and GPIO17 cannot be used as RX pins on ESP8266.")
     return value
 
+
 def validate_flow_control_support(config):
-    if CONF_FLOW_CONTROL_PIN in config and not CORE.is_esp32:
-        raise cv.Invalid("Hardware does not support flow control.")
-    return config
+    if CORE.is_esp32 and CORE.using_arduino:
+        if CORE.data[KEY_CORE][
+            KEY_FRAMEWORK_VERSION
+        ] >= cv.Version(2, 0, 8):
+            cg.add_define("USE_UART_FLOW_CONTROL")
+        elif CONF_FLOW_CONTROL_PIN in config:
+            raise cv.Invalid(
+                "ESP32 RS485 UART Flow Control requires Arduino framework version 2.0.8 or higher."
+            )
+    elif CORE.is_esp32:
+        return config
+    else:
+        raise cv.Invalid("Hardware does not support RS485 flow control.")
 
 
 def validate_invert_esp32(config):
diff --git a/esphome/components/uart/uart_component_esp32_arduino.cpp b/esphome/components/uart/uart_component_esp32_arduino.cpp
index 99f0f99f2d..abfd48551b 100644
--- a/esphome/components/uart/uart_component_esp32_arduino.cpp
+++ b/esphome/components/uart/uart_component_esp32_arduino.cpp
@@ -141,10 +141,12 @@ void ESP32ArduinoUARTComponent::load_settings(bool dump_config) {
     invert = true;
   this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
   this->hw_serial_->begin(this->baud_rate_, get_config(), rx, tx, invert);
+#ifdef USE_UART_FLOW_CONTROL
   if (this->flow_control_pin_ != nullptr) {
     this->hw_serial_->setPins(-1, -1, -1, this->flow_control_pin_->get_pin());
     this->hw_serial_->setMode(UART_MODE_RS485_HALF_DUPLEX);
   }
+#endif
   if (dump_config) {
     ESP_LOGCONFIG(TAG, "UART %u was reloaded.", this->number_);
     this->dump_config();
diff --git a/esphome/components/uart/uart_component_esp_idf.cpp b/esphome/components/uart/uart_component_esp_idf.cpp
index 0493bd372a..b6bd08e005 100644
--- a/esphome/components/uart/uart_component_esp_idf.cpp
+++ b/esphome/components/uart/uart_component_esp_idf.cpp
@@ -139,7 +139,7 @@ void IDFUARTComponent::setup() {
     this->mark_failed();
     return;
   }
-  
+ 
   if (this->flow_control_pin_ != nullptr) {
     err = uart_set_mode(this->uart_num_, UART_MODE_RS485_HALF_DUPLEX);
     if (err != ESP_OK) {