From cb56f9a9bfd3705ab350e2c19d9e5f387b35ca09 Mon Sep 17 00:00:00 2001
From: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>
Date: Tue, 21 Apr 2026 07:47:16 -0400
Subject: [PATCH] [qmc5883l] Use GPIO interrupt when DRDY pin is configured
 (#15876)

---
 esphome/components/qmc5883l/qmc5883l.cpp | 36 ++++++++++++++++++++----
 esphome/components/qmc5883l/qmc5883l.h   |  5 ++++
 2 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/esphome/components/qmc5883l/qmc5883l.cpp b/esphome/components/qmc5883l/qmc5883l.cpp
index d0488d0c9f..44bd006c1a 100644
--- a/esphome/components/qmc5883l/qmc5883l.cpp
+++ b/esphome/components/qmc5883l/qmc5883l.cpp
@@ -24,6 +24,8 @@ static const uint8_t QMC5883L_REGISTER_CONTROL_1 = 0x09;
 static const uint8_t QMC5883L_REGISTER_CONTROL_2 = 0x0A;
 static const uint8_t QMC5883L_REGISTER_PERIOD = 0x0B;
 
+void IRAM_ATTR QMC5883LComponent::gpio_intr(QMC5883LComponent *arg) { arg->enable_loop_soon_any_context(); }
+
 void QMC5883LComponent::setup() {
   // Soft Reset
   if (!this->write_byte(QMC5883L_REGISTER_CONTROL_2, 1 << 7)) {
@@ -35,6 +37,12 @@ void QMC5883LComponent::setup() {
 
   if (this->drdy_pin_) {
     this->drdy_pin_->setup();
+    if (this->drdy_pin_->is_internal()) {
+      static_cast<InternalGPIOPin *>(this->drdy_pin_)
+          ->attach_interrupt(&QMC5883LComponent::gpio_intr, this, gpio::INTERRUPT_RISING_EDGE);
+      this->drdy_use_isr_ = true;
+      this->stop_poller();
+    }
   }
 
   uint8_t control_1 = 0;
@@ -65,8 +73,8 @@ void QMC5883LComponent::setup() {
     return;
   }
 
-  if (this->get_update_interval() < App.get_loop_interval()) {
-    high_freq_.start();
+  if (!this->drdy_use_isr_ && this->get_update_interval() < App.get_loop_interval()) {
+    this->high_freq_.start();
   }
 }
 
@@ -84,16 +92,32 @@ void QMC5883LComponent::dump_config() {
   LOG_SENSOR("  ", "Heading", this->heading_sensor_);
   LOG_SENSOR("  ", "Temperature", this->temperature_sensor_);
   LOG_PIN("  DRDY Pin: ", this->drdy_pin_);
+  if (this->drdy_pin_ != nullptr) {
+    ESP_LOGCONFIG(TAG, "  DRDY mode: %s",
+                  this->drdy_use_isr_ ? LOG_STR_LITERAL("interrupt") : LOG_STR_LITERAL("polling"));
+  }
 }
 
 void QMC5883LComponent::update() {
-  i2c::ErrorCode err;
-  uint8_t status = false;
-
-  // If DRDY pin is configured and the data is not ready return.
+  // If DRDY is on an external expander we keep the polling path and early-return
+  // if data is not ready yet. Internal DRDY pins take the ISR path via loop().
   if (this->drdy_pin_ && !this->drdy_pin_->digital_read()) {
     return;
   }
+  this->read_sensor_();
+}
+
+void QMC5883LComponent::loop() {
+  this->disable_loop();
+  if (!this->drdy_use_isr_ || !this->drdy_pin_->digital_read()) {
+    return;
+  }
+  this->read_sensor_();
+}
+
+void QMC5883LComponent::read_sensor_() {
+  i2c::ErrorCode err;
+  uint8_t status = false;
 
   // Status byte gets cleared when data is read, so we have to read this first.
   // If status and two axes are desired, it's possible to save one byte of traffic by enabling
diff --git a/esphome/components/qmc5883l/qmc5883l.h b/esphome/components/qmc5883l/qmc5883l.h
index 21ef9c2a17..2ab6aa3e9f 100644
--- a/esphome/components/qmc5883l/qmc5883l.h
+++ b/esphome/components/qmc5883l/qmc5883l.h
@@ -32,6 +32,7 @@ class QMC5883LComponent : public PollingComponent, public i2c::I2CDevice {
   void setup() override;
   void dump_config() override;
   void update() override;
+  void loop() override;
 
   void set_drdy_pin(GPIOPin *pin) { drdy_pin_ = pin; }
   void set_datarate(QMC5883LDatarate datarate) { datarate_ = datarate; }
@@ -44,6 +45,9 @@ class QMC5883LComponent : public PollingComponent, public i2c::I2CDevice {
   void set_temperature_sensor(sensor::Sensor *temperature_sensor) { temperature_sensor_ = temperature_sensor; }
 
  protected:
+  static void IRAM_ATTR gpio_intr(QMC5883LComponent *arg);
+  void read_sensor_();
+
   QMC5883LDatarate datarate_{QMC5883L_DATARATE_10_HZ};
   QMC5883LRange range_{QMC5883L_RANGE_200_UT};
   QMC5883LOversampling oversampling_{QMC5883L_SAMPLING_512};
@@ -53,6 +57,7 @@ class QMC5883LComponent : public PollingComponent, public i2c::I2CDevice {
   sensor::Sensor *heading_sensor_{nullptr};
   sensor::Sensor *temperature_sensor_{nullptr};
   GPIOPin *drdy_pin_{nullptr};
+  bool drdy_use_isr_{false};
   enum ErrorCode {
     NONE = 0,
     COMMUNICATION_FAILED,