From aa097a2fe6ba533a23b1598d44290c677d03ef04 Mon Sep 17 00:00:00 2001
From: Anton Sergunov <setosha@gmail.com>
Date: Mon, 17 Nov 2025 07:25:00 +0600
Subject: [PATCH] [uart] Setup uart pins only if flags are set (#11914)

Co-authored-by: J. Nick Koston <nick+github@koston.org>
---
 .../components/uart/uart_component_esp8266.cpp | 18 +++++++++++++-----
 .../components/uart/uart_component_esp_idf.cpp | 18 +++++++++++++-----
 .../uart/uart_component_libretiny.cpp          |  2 +-
 .../components/uart/uart_component_rp2040.cpp  | 18 +++++++++++++-----
 4 files changed, 40 insertions(+), 16 deletions(-)

diff --git a/esphome/components/uart/uart_component_esp8266.cpp b/esphome/components/uart/uart_component_esp8266.cpp
index 7a453dbb50..c84a877ef4 100644
--- a/esphome/components/uart/uart_component_esp8266.cpp
+++ b/esphome/components/uart/uart_component_esp8266.cpp
@@ -56,11 +56,19 @@ uint32_t ESP8266UartComponent::get_config() {
 }
 
 void ESP8266UartComponent::setup() {
-  if (this->rx_pin_) {
-    this->rx_pin_->setup();
-  }
-  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
-    this->tx_pin_->setup();
+  auto setup_pin_if_needed = [](InternalGPIOPin *pin) {
+    if (!pin) {
+      return;
+    }
+    const auto mask = gpio::Flags::FLAG_OPEN_DRAIN | gpio::Flags::FLAG_PULLUP | gpio::Flags::FLAG_PULLDOWN;
+    if ((pin->get_flags() & mask) != gpio::Flags::FLAG_NONE) {
+      pin->setup();
+    }
+  };
+
+  setup_pin_if_needed(this->rx_pin_);
+  if (this->rx_pin_ != this->tx_pin_) {
+    setup_pin_if_needed(this->tx_pin_);
   }
 
   // Use Arduino HardwareSerial UARTs if all used pins match the ones
diff --git a/esphome/components/uart/uart_component_esp_idf.cpp b/esphome/components/uart/uart_component_esp_idf.cpp
index 70a13c9e37..61ca8c1c0c 100644
--- a/esphome/components/uart/uart_component_esp_idf.cpp
+++ b/esphome/components/uart/uart_component_esp_idf.cpp
@@ -133,11 +133,19 @@ void IDFUARTComponent::load_settings(bool dump_config) {
     return;
   }
 
-  if (this->rx_pin_) {
-    this->rx_pin_->setup();
-  }
-  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
-    this->tx_pin_->setup();
+  auto setup_pin_if_needed = [](InternalGPIOPin *pin) {
+    if (!pin) {
+      return;
+    }
+    const auto mask = gpio::Flags::FLAG_OPEN_DRAIN | gpio::Flags::FLAG_PULLUP | gpio::Flags::FLAG_PULLDOWN;
+    if ((pin->get_flags() & mask) != gpio::Flags::FLAG_NONE) {
+      pin->setup();
+    }
+  };
+
+  setup_pin_if_needed(this->rx_pin_);
+  if (this->rx_pin_ != this->tx_pin_) {
+    setup_pin_if_needed(this->tx_pin_);
   }
 
   int8_t tx = this->tx_pin_ != nullptr ? this->tx_pin_->get_pin() : -1;
diff --git a/esphome/components/uart/uart_component_libretiny.cpp b/esphome/components/uart/uart_component_libretiny.cpp
index 8d1d28fce4..1e408b169b 100644
--- a/esphome/components/uart/uart_component_libretiny.cpp
+++ b/esphome/components/uart/uart_component_libretiny.cpp
@@ -53,7 +53,7 @@ void LibreTinyUARTComponent::setup() {
 
   auto shouldFallbackToSoftwareSerial = [&]() -> bool {
     auto hasFlags = [](InternalGPIOPin *pin, const gpio::Flags mask) -> bool {
-      return pin && pin->get_flags() & mask != gpio::Flags::FLAG_NONE;
+      return pin && (pin->get_flags() & mask) != gpio::Flags::FLAG_NONE;
     };
     if (hasFlags(this->tx_pin_, gpio::Flags::FLAG_OPEN_DRAIN | gpio::Flags::FLAG_PULLUP | gpio::Flags::FLAG_PULLDOWN) ||
         hasFlags(this->rx_pin_, gpio::Flags::FLAG_OPEN_DRAIN | gpio::Flags::FLAG_PULLUP | gpio::Flags::FLAG_PULLDOWN)) {
diff --git a/esphome/components/uart/uart_component_rp2040.cpp b/esphome/components/uart/uart_component_rp2040.cpp
index c78691653d..cd3905b5c1 100644
--- a/esphome/components/uart/uart_component_rp2040.cpp
+++ b/esphome/components/uart/uart_component_rp2040.cpp
@@ -52,11 +52,19 @@ uint16_t RP2040UartComponent::get_config() {
 }
 
 void RP2040UartComponent::setup() {
-  if (this->rx_pin_) {
-    this->rx_pin_->setup();
-  }
-  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
-    this->tx_pin_->setup();
+  auto setup_pin_if_needed = [](InternalGPIOPin *pin) {
+    if (!pin) {
+      return;
+    }
+    const auto mask = gpio::Flags::FLAG_OPEN_DRAIN | gpio::Flags::FLAG_PULLUP | gpio::Flags::FLAG_PULLDOWN;
+    if ((pin->get_flags() & mask) != gpio::Flags::FLAG_NONE) {
+      pin->setup();
+    }
+  };
+
+  setup_pin_if_needed(this->rx_pin_);
+  if (this->rx_pin_ != this->tx_pin_) {
+    setup_pin_if_needed(this->tx_pin_);
   }
 
   uint16_t config = get_config();