From 155657f1ccda9d6529ce07a4ffb41996e3641f7a Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 5 Apr 2026 13:26:55 -1000
Subject: [PATCH] [mcp23xxx][pi4ioe5v6408] Disable loop when all pins are
 outputs (#15460)

---
 esphome/components/mcp23x08_base/mcp23x08_base.cpp |  5 +++++
 esphome/components/mcp23x17_base/mcp23x17_base.cpp |  5 +++++
 esphome/components/mcp23xxx_base/mcp23xxx_base.h   |  5 ++++-
 esphome/components/pi4ioe5v6408/pi4ioe5v6408.cpp   | 10 +++++++++-
 4 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/esphome/components/mcp23x08_base/mcp23x08_base.cpp b/esphome/components/mcp23x08_base/mcp23x08_base.cpp
index e4f4d50aae..197b739204 100644
--- a/esphome/components/mcp23x08_base/mcp23x08_base.cpp
+++ b/esphome/components/mcp23x08_base/mcp23x08_base.cpp
@@ -37,6 +37,11 @@ void MCP23X08Base::pin_mode(uint8_t pin, gpio::Flags flags) {
   if (this->interrupt_pin_ != nullptr && (flags & gpio::FLAG_INPUT)) {
     this->pin_interrupt_mode(pin, mcp23xxx_base::MCP23XXX_CHANGE);
   }
+  // Enable polling loop for input pins (not needed for interrupt-driven mode
+  // where the ISR handles re-enabling loop)
+  if (this->interrupt_pin_ == nullptr && (flags & gpio::FLAG_INPUT)) {
+    this->enable_loop();
+  }
 }
 
 void MCP23X08Base::pin_interrupt_mode(uint8_t pin, mcp23xxx_base::MCP23XXXInterruptMode interrupt_mode) {
diff --git a/esphome/components/mcp23x17_base/mcp23x17_base.cpp b/esphome/components/mcp23x17_base/mcp23x17_base.cpp
index 42613053de..efed7f5f17 100644
--- a/esphome/components/mcp23x17_base/mcp23x17_base.cpp
+++ b/esphome/components/mcp23x17_base/mcp23x17_base.cpp
@@ -49,6 +49,11 @@ void MCP23X17Base::pin_mode(uint8_t pin, gpio::Flags flags) {
   if (this->interrupt_pin_ != nullptr && (flags & gpio::FLAG_INPUT)) {
     this->pin_interrupt_mode(pin, mcp23xxx_base::MCP23XXX_CHANGE);
   }
+  // Enable polling loop for input pins (not needed for interrupt-driven mode
+  // where the ISR handles re-enabling loop)
+  if (this->interrupt_pin_ == nullptr && (flags & gpio::FLAG_INPUT)) {
+    this->enable_loop();
+  }
 }
 
 void MCP23X17Base::pin_interrupt_mode(uint8_t pin, mcp23xxx_base::MCP23XXXInterruptMode interrupt_mode) {
diff --git a/esphome/components/mcp23xxx_base/mcp23xxx_base.h b/esphome/components/mcp23xxx_base/mcp23xxx_base.h
index e77eac87e7..6efd04e246 100644
--- a/esphome/components/mcp23xxx_base/mcp23xxx_base.h
+++ b/esphome/components/mcp23xxx_base/mcp23xxx_base.h
@@ -35,8 +35,11 @@ template<uint8_t N> class MCP23XXXBase : public Component, public gpio_expander:
       this->interrupt_pin_->setup();
       this->interrupt_pin_->attach_interrupt(&MCP23XXXBase::gpio_intr, this, gpio::INTERRUPT_FALLING_EDGE);
       this->set_invalidate_on_read_(false);
-      this->disable_loop();
     }
+    // Disable loop until an input pin is configured via pin_mode()
+    // For interrupt-driven mode, loop is re-enabled by the ISR
+    // For polling mode, loop is re-enabled when pin_mode() registers an input pin
+    this->disable_loop();
   }
   static void IRAM_ATTR gpio_intr(MCP23XXXBase *arg) { arg->enable_loop_soon_any_context(); }
 
diff --git a/esphome/components/pi4ioe5v6408/pi4ioe5v6408.cpp b/esphome/components/pi4ioe5v6408/pi4ioe5v6408.cpp
index 8e38e7fa1d..6e8631022a 100644
--- a/esphome/components/pi4ioe5v6408/pi4ioe5v6408.cpp
+++ b/esphome/components/pi4ioe5v6408/pi4ioe5v6408.cpp
@@ -41,8 +41,11 @@ void PI4IOE5V6408Component::setup() {
     this->interrupt_pin_->setup();
     this->interrupt_pin_->attach_interrupt(&PI4IOE5V6408Component::gpio_intr, this, gpio::INTERRUPT_FALLING_EDGE);
     this->set_invalidate_on_read_(false);
-    this->disable_loop();
   }
+  // Disable loop until an input pin is configured via pin_mode()
+  // For interrupt-driven mode, loop is re-enabled by the ISR
+  // For polling mode, loop is re-enabled when pin_mode() registers an input pin
+  this->disable_loop();
 }
 void IRAM_ATTR PI4IOE5V6408Component::gpio_intr(PI4IOE5V6408Component *arg) { arg->enable_loop_soon_any_context(); }
 void PI4IOE5V6408Component::dump_config() {
@@ -67,6 +70,11 @@ void PI4IOE5V6408Component::pin_mode(uint8_t pin, gpio::Flags flags) {
       this->pull_up_down_mask_ &= ~(1 << pin);
       this->pull_enable_mask_ |= 1 << pin;
     }
+    // Enable polling loop for input pins (not needed for interrupt-driven mode
+    // where the ISR handles re-enabling loop)
+    if (this->interrupt_pin_ == nullptr) {
+      this->enable_loop();
+    }
   }
   // Write GPIO to enable input mode
   this->write_gpio_modes_();