From 0cc0979674566d3a1ca2db86ec364ccbfdbb9823 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 7 Sep 2025 17:59:23 -0500
Subject: [PATCH] [pca6416a] Migrate to CachedGpioExpander to reduce I2C bus
 usage (#10587)

---
 esphome/components/pca6416a/__init__.py  |  1 +
 esphome/components/pca6416a/pca6416a.cpp | 25 +++++++++++++++++++-----
 esphome/components/pca6416a/pca6416a.h   | 17 +++++++++++-----
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/esphome/components/pca6416a/__init__.py b/esphome/components/pca6416a/__init__.py
index da6c4623c9..e540edb91f 100644
--- a/esphome/components/pca6416a/__init__.py
+++ b/esphome/components/pca6416a/__init__.py
@@ -14,6 +14,7 @@ from esphome.const import (
 
 CODEOWNERS = ["@Mat931"]
 DEPENDENCIES = ["i2c"]
+AUTO_LOAD = ["gpio_expander"]
 MULTI_CONF = True
 pca6416a_ns = cg.esphome_ns.namespace("pca6416a")
 
diff --git a/esphome/components/pca6416a/pca6416a.cpp b/esphome/components/pca6416a/pca6416a.cpp
index 730c494e34..c0056e780b 100644
--- a/esphome/components/pca6416a/pca6416a.cpp
+++ b/esphome/components/pca6416a/pca6416a.cpp
@@ -51,6 +51,11 @@ void PCA6416AComponent::setup() {
            this->status_has_error());
 }
 
+void PCA6416AComponent::loop() {
+  // Invalidate cache at the start of each loop
+  this->reset_pin_cache_();
+}
+
 void PCA6416AComponent::dump_config() {
   if (this->has_pullup_) {
     ESP_LOGCONFIG(TAG, "PCAL6416A:");
@@ -63,15 +68,25 @@ void PCA6416AComponent::dump_config() {
   }
 }
 
-bool PCA6416AComponent::digital_read(uint8_t pin) {
-  uint8_t bit = pin % 8;
+bool PCA6416AComponent::digital_read_hw(uint8_t pin) {
   uint8_t reg_addr = pin < 8 ? PCA6416A_INPUT0 : PCA6416A_INPUT1;
   uint8_t value = 0;
-  this->read_register_(reg_addr, &value);
-  return value & (1 << bit);
+  if (!this->read_register_(reg_addr, &value)) {
+    return false;
+  }
+
+  // Update the appropriate part of input_mask_
+  if (pin < 8) {
+    this->input_mask_ = (this->input_mask_ & 0xFF00) | value;
+  } else {
+    this->input_mask_ = (this->input_mask_ & 0x00FF) | (uint16_t(value) << 8);
+  }
+  return true;
 }
 
-void PCA6416AComponent::digital_write(uint8_t pin, bool value) {
+bool PCA6416AComponent::digital_read_cache(uint8_t pin) { return this->input_mask_ & (1 << pin); }
+
+void PCA6416AComponent::digital_write_hw(uint8_t pin, bool value) {
   uint8_t reg_addr = pin < 8 ? PCA6416A_OUTPUT0 : PCA6416A_OUTPUT1;
   this->update_register_(pin, value, reg_addr);
 }
diff --git a/esphome/components/pca6416a/pca6416a.h b/esphome/components/pca6416a/pca6416a.h
index 1e8015c40a..10a4a64e9b 100644
--- a/esphome/components/pca6416a/pca6416a.h
+++ b/esphome/components/pca6416a/pca6416a.h
@@ -3,20 +3,20 @@
 #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 pca6416a {
 
-class PCA6416AComponent : public Component, public i2c::I2CDevice {
+class PCA6416AComponent : public Component,
+                          public i2c::I2CDevice,
+                          public gpio_expander::CachedGpioExpander<uint8_t, 16> {
  public:
   PCA6416AComponent() = default;
 
   /// Check i2c availability and setup masks
   void setup() 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);
+  void loop() override;
   /// Helper function to set the pin mode of a pin.
   void pin_mode(uint8_t pin, gpio::Flags flags);
 
@@ -25,6 +25,11 @@ class PCA6416AComponent : public Component, public i2c::I2CDevice {
   void dump_config() override;
 
  protected:
+  // Virtual methods from CachedGpioExpander
+  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_register_(uint8_t reg, uint8_t *value);
   bool write_register_(uint8_t reg, uint8_t value);
   void update_register_(uint8_t pin, bool pin_value, uint8_t reg_addr);
@@ -32,6 +37,8 @@ class PCA6416AComponent : public Component, public i2c::I2CDevice {
   /// The mask to write as output state - 1 means HIGH, 0 means LOW
   uint8_t output_0_{0x00};
   uint8_t output_1_{0x00};
+  /// Cache for input values (16-bit combined for both banks)
+  uint16_t input_mask_{0x00};
   /// Storage for last I2C error seen
   esphome::i2c::ErrorCode last_error_;
   /// Only the PCAL6416A has pull-up resistors