Update tca6408.cpp

components/TCA6408/tca6408.cpp

@@ -6,46 +6,74 @@ namespace tca6408 {
 
 static const char *const TAG = "tca6408";
 
-static const uint8_t TCA6408_INPUT_PORT    = 0x00;
+// TCA6408 Register Addresses (from datasheet)
-static const uint8_t TCA6408_OUTPUT_PORT   = 0x01;
+static const uint8_t TCA6408_INPUT_PORT    = 0x00;  // Input Port Register
-static const uint8_t TCA6408_POLARITY_PORT = 0x02;
+static const uint8_t TCA6408_OUTPUT_PORT   = 0x01;  // Output Port Register
-static const uint8_t TCA6408_CONFIG_PORT   = 0x03;
+static const uint8_t TCA6408_POLARITY_PORT = 0x02;  // Polarity Inversion Register
+static const uint8_t TCA6408_CONFIG_PORT   = 0x03;  // Configuration Register (1 = input, 0 = output)
 
 void TCA6408Component::setup() {
   ESP_LOGCONFIG(TAG, "Setting up TCA6408 at address 0x%02X...", this->address_);
 
-  if (this->write_register(TCA6408_POLARITY_PORT, 0x00) != i2c::ERROR_OK ||
+  // Initialize chip to a known safe state
-      this->write_register(TCA6408_CONFIG_PORT, this->mode_mask_) != i2c::ERROR_OK ||
+  if (this->write_register(TCA6408_POLARITY_PORT, 0x00) != i2c::ERROR_OK) {
-      !this->read_gpio_outputs_()) {
+    ESP_LOGE(TAG, "Failed to write polarity register");
     this->mark_failed();
     return;
   }
 
+  if (this->write_register(TCA6408_CONFIG_PORT, this->mode_mask_) != i2c::ERROR_OK) {
+    ESP_LOGE(TAG, "Failed to write config register");
+    this->mark_failed();
+    return;
+  }
+
+  if (!this->read_gpio_outputs_()) {
+    ESP_LOGE(TAG, "Failed to read initial output state");
+    this->mark_failed();
+    return;
+  }
+
+  // Configure interrupt mode if requested
   if (this->interrupt_pin_ != nullptr) {
     this->interrupt_pin_->setup();
-    this->interrupt_pin_->pin_mode(gpio::FLAG_INPUT | gpio::FLAG_PULLUP);
+    this->interrupt_pin_->pin_mode(gpio::FLAG_INPUT | gpio::FLAG_PULLUP);  // Required for open-drain INT
-    this->interrupt_pin_->attach_interrupt(&TCA6408Component::gpio_intr, this, gpio::INTERRUPT_FALLING_EDGE);
+    this->interrupt_pin_->attach_interrupt(&TCA6408Component::gpio_intr, this,
-    this->set_invalidate_on_read_(false);
+                                           gpio::INTERRUPT_FALLING_EDGE);
-    ESP_LOGCONFIG(TAG, "  Interrupt mode enabled (active-low)");
+    this->set_invalidate_on_read_(false);  // We manage cache manually for efficiency
+    ESP_LOGCONFIG(TAG, "  Interrupt mode enabled (active-low INT pin)");
   } else {
-    this->enable_loop();
+    this->enable_loop();  // Fallback to polling
     ESP_LOGCONFIG(TAG, "  Polling mode enabled");
   }
+
+  ESP_LOGCONFIG(TAG, "  TCA6408 setup complete");
 }
 
+/** 
+ * Interrupt Service Routine (ISR)
+ * Runs in interrupt context - must be very lightweight
+ */
 void IRAM_ATTR TCA6408Component::gpio_intr(TCA6408Component *arg) {
   arg->interrupt_triggered_ = true;
-  arg->enable_loop_soon_any_context();
+  arg->enable_loop_soon_any_context();  // Schedule loop() to run soon
 }
 
+/**
+ * Main loop - handles interrupt processing
+ * Only runs when an interrupt occurs (in interrupt mode)
+ */
 void TCA6408Component::loop() {
   if (this->interrupt_triggered_) {
     this->interrupt_triggered_ = false;
-    this->digital_read_hw(0);
-    this->reset_pin_cache_();
 
+    // Reading Input Port automatically clears the INT pin on TCA6408
+    this->digital_read_hw(0);   // pin argument is ignored - reads all 8 bits
+    this->reset_pin_cache_();   // Notify ESPHome that inputs may have changed
+
+    // Check if INT line has returned high (no more pending interrupts)
     if (this->interrupt_pin_ && this->interrupt_pin_->digital_read()) {
-      this->disable_loop();
+      this->disable_loop();  // Stop looping until next interrupt
     }
   }
 }
@@ -55,6 +83,8 @@ void TCA6408Component::dump_config() {
   LOG_I2C_DEVICE(this);
   ESP_LOGCONFIG(TAG, "  Address: 0x%02X", this->address_);
   LOG_PIN("  Interrupt Pin: ", this->interrupt_pin_);
+  ESP_LOGCONFIG(TAG, "  Mode Mask: 0x%02X (1 = input)", this->mode_mask_);
+  ESP_LOGCONFIG(TAG, "  Polarity Mask: 0x%02X", this->polarity_mask_);
 }
 
 bool TCA6408Component::read_gpio_outputs_() {
@@ -69,25 +99,31 @@ bool TCA6408Component::read_gpio_outputs_() {
   return true;
 }
 
+/** Read current state of all input pins from hardware */
 bool TCA6408Component::digital_read_hw(uint8_t pin) {
   if (this->is_failed()) return false;
+
   uint8_t data = 0;
   if (this->read_register(TCA6408_INPUT_PORT, &data) != i2c::ERROR_OK) {
     this->status_set_warning();
     return false;
   }
+
   this->input_mask_ = data;
   this->status_clear_warning();
   return true;
 }
 
+/** Write to a specific output pin */
 void TCA6408Component::digital_write_hw(uint8_t pin, bool value) {
   if (this->is_failed()) return;
+
   if (value) {
     this->output_mask_ |= (1U << pin);
   } else {
     this->output_mask_ &= ~(1U << pin);
   }
+
   if (this->write_register(TCA6408_OUTPUT_PORT, this->output_mask_) != i2c::ERROR_OK) {
     this->status_set_warning();
   } else {
@@ -95,16 +131,20 @@ void TCA6408Component::digital_write_hw(uint8_t pin, bool value) {
   }
 }
 
+/** Configure pin direction (input/output) */
 void TCA6408Component::pin_mode(uint8_t pin, gpio::Flags flags) {
   if (flags & gpio::FLAG_OUTPUT) {
-    this->mode_mask_ &= ~(1U << pin);
+    this->mode_mask_ &= ~(1U << pin);   // 0 = output
   } else {
-    this->mode_mask_ |= (1U << pin);
+    this->mode_mask_ |= (1U << pin);    // 1 = input
-    if (this->interrupt_pin_ == nullptr) this->enable_loop();
+    if (this->interrupt_pin_ == nullptr) {
+      this->enable_loop();  // Enable polling if no interrupt pin
+    }
   }
   this->write_register(TCA6408_CONFIG_PORT, this->mode_mask_);
 }
 
+/** Set hardware polarity inversion for inputs */
 void TCA6408Component::set_polarity_inversion(uint8_t pin, bool inverted) {
   if (inverted) {
     this->polarity_mask_ |= (1U << pin);
@@ -114,21 +154,31 @@ void TCA6408Component::set_polarity_inversion(uint8_t pin, bool inverted) {
   this->write_register(TCA6408_POLARITY_PORT, this->polarity_mask_);
 }
 
+/** Read cached value with polarity inversion applied */
 bool TCA6408Component::digital_read_cache(uint8_t pin) {
   bool value = (this->input_mask_ & (1U << pin)) != 0;
-  if (this->polarity_mask_ & (1U << pin)) value = !value;
+
+  // Apply hardware polarity inversion if enabled for this pin
+  if (this->polarity_mask_ & (1U << pin)) {
+    value = !value;
+  }
   return value;
 }
 
-// TCA6408GPIOPin
+// ====================== TCA6408GPIOPin Wrapper ======================
+
 void TCA6408GPIOPin::setup() {
   this->pin_mode(this->flags_);
-  if (this->inverted_) this->parent_->set_polarity_inversion(this->pin_, true);
+  if (this->inverted_) {
+    this->parent_->set_polarity_inversion(this->pin_, true);
+  }
 }
 
 void TCA6408GPIOPin::set_inverted(bool inverted) {
   this->inverted_ = inverted;
-  if (this->parent_) this->parent_->set_polarity_inversion(this->pin_, inverted);
+  if (this->parent_) {
+    this->parent_->set_polarity_inversion(this->pin_, inverted);
+  }
 }
 
 void TCA6408GPIOPin::pin_mode(gpio::Flags flags) {
@@ -137,6 +187,7 @@ void TCA6408GPIOPin::pin_mode(gpio::Flags flags) {
 }
 
 bool TCA6408GPIOPin::digital_read() {
+  // Note: inversion handled in digital_read_cache() for inputs
   return this->parent_->digital_read(this->pin_) != this->inverted_;
 }
 
@@ -149,4 +200,4 @@ size_t TCA6408GPIOPin::dump_summary(char *buffer, size_t len) const {
 }
 
 }  // namespace tca6408
-}  // namespace esphome
+}  // namespace esphome