From 9373ebe3530660aecac3854cdaaf3d368209d5a7 Mon Sep 17 00:00:00 2001
From: Greg Gibeling <gdgib@outlook.com>
Date: Mon, 22 Jan 2024 17:14:47 -0800
Subject: [PATCH] SN74HC595 support for inverted & restore modes without relay
 pulsing

---
 esphome/components/sn74hc595/sn74hc595.cpp | 41 +++++++++++++++++-----
 esphome/components/sn74hc595/sn74hc595.h   | 10 +++---
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/esphome/components/sn74hc595/sn74hc595.cpp b/esphome/components/sn74hc595/sn74hc595.cpp
index 8a37c3bece..08325b5662 100644
--- a/esphome/components/sn74hc595/sn74hc595.cpp
+++ b/esphome/components/sn74hc595/sn74hc595.cpp
@@ -48,31 +48,53 @@ void SN74HC595Component::digital_write_(uint16_t pin, bool value) {
     return;
   }
   if (value) {
-    this->output_bytes_[pin / 8] |= (1 << (pin % 8));
+    this->value_bytes_[pin / 8] |= (1 << (pin % 8));
   } else {
-    this->output_bytes_[pin / 8] &= ~(1 << (pin % 8));
+    this->value_bytes_[pin / 8] &= ~(1 << (pin % 8));
   }
   this->write_gpio();
 }
+void SN74HC595Component::set_inverted_(uint16_t pin, bool inverted) {
+  if (pin >= this->sr_count_ * 8) {
+    ESP_LOGE(TAG, "Pin %u is out of range! Maximum pin number with %u chips in series is %u", pin, this->sr_count_,
+             (this->sr_count_ * 8) - 1);
+    return;
+  }
+  if (inverted) {
+    this->inverted_bytes_[pin / 8] |= (1 << (pin % 8));
+  } else {
+    this->inverted_bytes_[pin / 8] &= ~(1 << (pin % 8));
+  }
+}
 
 void SN74HC595GPIOComponent::write_gpio() {
-  for (auto byte = this->output_bytes_.rbegin(); byte != this->output_bytes_.rend(); byte++) {
+  auto value = this->value_bytes_.rbegin();
+  auto inverted = this->inverted_bytes_.rbegin();
+  while (value != this->value_bytes_.rend() && inverted != this->inverted_bytes_.rend()) {
     for (int8_t i = 7; i >= 0; i--) {
-      bool bit = (*byte >> i) & 1;
-      this->data_pin_->digital_write(bit);
+      bool value_bit = (*value >> i) & 1;
+      bool value_inverted = (*inverted >> i) & 1;
+      this->data_pin_->digital_write(value_bit != value_inverted);
       this->clock_pin_->digital_write(true);
       this->clock_pin_->digital_write(false);
     }
+    value++;
+    inverted++;
   }
   SN74HC595Component::write_gpio();
 }
 
 #ifdef USE_SPI
 void SN74HC595SPIComponent::write_gpio() {
-  for (auto byte = this->output_bytes_.rbegin(); byte != this->output_bytes_.rend(); byte++) {
+  auto value = this->value_bytes_.rbegin();
+  auto inverted = this->inverted_bytes_.rbegin();
+  while (value != this->value_bytes_.rend() && inverted != this->inverted_bytes_.rend()) {
     this->enable();
-    this->transfer_byte(*byte);
+    this->transfer_byte((*byte) ^ (*inverted));
     this->disable();
+    
+    value++;
+    inverted++;
   }
   SN74HC595Component::write_gpio();
 }
@@ -92,7 +114,10 @@ void SN74HC595Component::write_gpio() {
 float SN74HC595Component::get_setup_priority() const { return setup_priority::IO; }
 
 void SN74HC595GPIOPin::digital_write(bool value) {
-  this->parent_->digital_write_(this->pin_, value != this->inverted_);
+  this->parent_->digital_write_(this->pin_, value);
+}
+void SN74HC595GPIOPin::set_inverted(bool inverted) {
+  this->parent_->set_inverted_(this->pin_, inverted);
 }
 std::string SN74HC595GPIOPin::dump_summary() const { return str_snprintf("%u via SN74HC595", 18, pin_); }
 
diff --git a/esphome/components/sn74hc595/sn74hc595.h b/esphome/components/sn74hc595/sn74hc595.h
index cb9d7bf140..0855a80f4a 100644
--- a/esphome/components/sn74hc595/sn74hc595.h
+++ b/esphome/components/sn74hc595/sn74hc595.h
@@ -29,12 +29,14 @@ class SN74HC595Component : public Component {
   }
   void set_sr_count(uint8_t count) {
     this->sr_count_ = count;
-    this->output_bytes_.resize(count);
+    this->value_bytes_.resize(count);
+    this->inverted_bytes_.resize(count);
   }
 
  protected:
   friend class SN74HC595GPIOPin;
   void digital_write_(uint16_t pin, bool value);
+  void set_inverted_(uint16_t pin, bool inverted);
   virtual void write_gpio();
 
   void pre_setup_();
@@ -44,7 +46,8 @@ class SN74HC595Component : public Component {
   GPIOPin *oe_pin_;
   uint8_t sr_count_;
   bool have_oe_pin_{false};
-  std::vector<uint8_t> output_bytes_;
+  std::vector<uint8_t> value_bytes_;
+  std::vector<uint8_t> inverted_bytes_;
 };
 
 /// Helper class to expose a SC74HC595 pin as an internal output GPIO pin.
@@ -57,11 +60,10 @@ class SN74HC595GPIOPin : public GPIOPin, public Parented<SN74HC595Component> {
   std::string dump_summary() const override;
 
   void set_pin(uint16_t pin) { pin_ = pin; }
-  void set_inverted(bool inverted) { inverted_ = inverted; }
+  void set_inverted(bool inverted);
 
  protected:
   uint16_t pin_;
-  bool inverted_;
 };
 
 class SN74HC595GPIOComponent : public SN74HC595Component {