From 48858198818e0712b56069f6ca073e04bc88ad50 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 4 Sep 2025 12:21:48 -0500
Subject: [PATCH] use helper

---
 esphome/components/pcf8574/__init__.py |  1 +
 esphome/components/pcf8574/pcf8574.cpp | 22 +++++++++++-----------
 esphome/components/pcf8574/pcf8574.h   | 16 ++++++++++------
 3 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/esphome/components/pcf8574/__init__.py b/esphome/components/pcf8574/__init__.py
index ff7c314bcd..f387d0a610 100644
--- a/esphome/components/pcf8574/__init__.py
+++ b/esphome/components/pcf8574/__init__.py
@@ -11,6 +11,7 @@ from esphome.const import (
     CONF_OUTPUT,
 )
 
+AUTO_LOAD = ["gpio_expander"]
 DEPENDENCIES = ["i2c"]
 MULTI_CONF = True
 
diff --git a/esphome/components/pcf8574/pcf8574.cpp b/esphome/components/pcf8574/pcf8574.cpp
index a75f4f2256..67e84d6629 100644
--- a/esphome/components/pcf8574/pcf8574.cpp
+++ b/esphome/components/pcf8574/pcf8574.cpp
@@ -17,9 +17,8 @@ void PCF8574Component::setup() {
   this->read_gpio_();
 }
 void PCF8574Component::loop() {
-  // Invalidate the cache at the start of each loop.
-  // The actual read will happen on demand in digital_read()
-  this->cache_valid_ = false;
+  // Invalidate the cache at the start of each loop
+  this->reset_pin_cache_();
 }
 void PCF8574Component::dump_config() {
   ESP_LOGCONFIG(TAG, "PCF8574:");
@@ -29,20 +28,21 @@ void PCF8574Component::dump_config() {
     ESP_LOGE(TAG, ESP_LOG_MSG_COMM_FAIL);
   }
 }
-bool PCF8574Component::digital_read(uint8_t pin) {
-  // Read the inputs once per loop on demand and cache the result
-  if (!this->cache_valid_ && this->read_gpio_()) {
-    this->cache_valid_ = true;
-  }
-  return this->input_mask_ & (1 << pin);
+bool PCF8574Component::digital_read(uint8_t pin) { return this->get_pin_value_(pin); }
+
+bool PCF8574Component::digital_read_hw(uint8_t pin) {
+  return this->read_gpio_() ? (this->input_mask_ & (1 << pin)) : false;
 }
-void PCF8574Component::digital_write(uint8_t pin, bool value) {
+
+bool PCF8574Component::digital_read_cache(uint8_t pin) { return this->input_mask_ & (1 << pin); }
+void PCF8574Component::digital_write(uint8_t pin, bool value) { this->set_pin_value_(pin, value); }
+
+void PCF8574Component::digital_write_hw(uint8_t pin, bool value) {
   if (value) {
     this->output_mask_ |= (1 << pin);
   } else {
     this->output_mask_ &= ~(1 << pin);
   }
-
   this->write_gpio_();
 }
 void PCF8574Component::pin_mode(uint8_t pin, gpio::Flags flags) {
diff --git a/esphome/components/pcf8574/pcf8574.h b/esphome/components/pcf8574/pcf8574.h
index 41cb411f28..cb848060aa 100644
--- a/esphome/components/pcf8574/pcf8574.h
+++ b/esphome/components/pcf8574/pcf8574.h
@@ -3,11 +3,16 @@
 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"
 #include "esphome/components/i2c/i2c.h"
+#include "esphome/components/gpio_expander/cached_gpio.h"
 
 namespace esphome {
 namespace pcf8574 {
 
-class PCF8574Component : public Component, public i2c::I2CDevice {
+// PCF8574(8 pins)/PCF8575(16 pins) always read/write all pins in a single I2C transaction
+// so we use uint16_t as bank type to ensure all pins are in one bank and cached together
+class PCF8574Component : public Component,
+                         public i2c::I2CDevice,
+                         public gpio_expander::CachedGpioExpander<uint16_t, 16> {
  public:
   PCF8574Component() = default;
 
@@ -17,8 +22,6 @@ class PCF8574Component : public Component, public i2c::I2CDevice {
   void setup() override;
   /// Invalidate cache at start of each loop
   void loop() override;
-  /// Helper function to read the value of a pin.
-  bool digital_read(uint8_t pin);
   /// Helper function to write the value of a pin.
   void digital_write(uint8_t pin, bool value);
   /// Helper function to set the pin mode of a pin.
@@ -30,8 +33,11 @@ class PCF8574Component : public Component, public i2c::I2CDevice {
   void dump_config() override;
 
  protected:
-  bool read_gpio_();
+  bool digital_read_hw(uint8_t pin) override;
+  bool digital_read_cache(uint8_t pin) override;
+  void digital_write_hw(uint8_t pin, bool value) override;
 
+  bool read_gpio_();
   bool write_gpio_();
 
   /// Mask for the pin mode - 1 means output, 0 means input
@@ -40,8 +46,6 @@ class PCF8574Component : public Component, public i2c::I2CDevice {
   uint16_t output_mask_{0x00};
   /// The state read in read_gpio_ - 1 means HIGH, 0 means LOW
   uint16_t input_mask_{0x00};
-  /// Cache validity flag - true if we've read inputs this loop cycle
-  bool cache_valid_{false};
   bool pcf8575_;  ///< TRUE->16-channel PCF8575, FALSE->8-channel PCF8574
 };