From 6b8a75d3b8511a3b12199f7419df4e524a0c6100 Mon Sep 17 00:00:00 2001
From: tracestep <16390082+tracestep@users.noreply.github.com>
Date: Wed, 25 Oct 2023 23:36:58 -0300
Subject: [PATCH] SX1509 output debounce fix (resolves esphome/issues#4402)
 (#4672)

---
 esphome/components/sx1509/sx1509.cpp | 14 ++++++++++++--
 esphome/components/sx1509/sx1509.h   |  1 +
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/esphome/components/sx1509/sx1509.cpp b/esphome/components/sx1509/sx1509.cpp
index d0a84b99ffe7..ee90e0e410b5 100644
--- a/esphome/components/sx1509/sx1509.cpp
+++ b/esphome/components/sx1509/sx1509.cpp
@@ -68,9 +68,18 @@ void SX1509Component::digital_write(uint8_t pin, bool bit_value) {
     uint16_t temp_reg_data = 0;
     this->read_byte_16(REG_DATA_B, &temp_reg_data);
     if (bit_value) {
-      temp_reg_data |= (1 << pin);
+      output_state_ |= (1 << pin);  // set bit in shadow register
     } else {
-      temp_reg_data &= ~(1 << pin);
+      output_state_ &= ~(1 << pin);  // reset bit shadow register
+    }
+    for (uint16_t b = 0x8000; b; b >>= 1) {
+      if ((~ddr_mask_) & b) {  // transfer bits of outputs, but don't mess with inputs
+        if (output_state_ & b) {
+          temp_reg_data |= b;
+        } else {
+          temp_reg_data &= ~b;
+        }
+      }
     }
     this->write_byte_16(REG_DATA_B, temp_reg_data);
   }
@@ -134,6 +143,7 @@ void SX1509Component::setup_led_driver(uint8_t pin) {
 
   this->read_byte_16(REG_DATA_B, &temp_word);
   temp_word &= ~(1 << pin);
+  output_state_ &= ~(1 << pin);
   this->write_byte_16(REG_DATA_B, temp_word);
 }
 
diff --git a/esphome/components/sx1509/sx1509.h b/esphome/components/sx1509/sx1509.h
index 8e3b41e233c4..9e4f31aab0d9 100644
--- a/esphome/components/sx1509/sx1509.h
+++ b/esphome/components/sx1509/sx1509.h
@@ -61,6 +61,7 @@ class SX1509Component : public Component, public i2c::I2CDevice {
   uint16_t ddr_mask_ = 0x00;
   uint16_t input_mask_ = 0x00;
   uint16_t port_mask_ = 0x00;
+  uint16_t output_state_ = 0x00;
   bool has_keypad_ = false;
   uint8_t rows_ = 0;
   uint8_t cols_ = 0;