[pylontech] Batch UART reads to reduce loop overhead

esphome/components/dlms_meter/dlms_meter.cpp

@@ -28,28 +28,15 @@ void DlmsMeterComponent::dump_config() {
 
 void DlmsMeterComponent::loop() {
   // Read while data is available, netznoe uses two frames so allow 2x max frame length
-  int avail = this->available();
-  if (avail > 0) {
-    size_t remaining = MBUS_MAX_FRAME_LENGTH * 2 - this->receive_buffer_.size();
-    if (remaining == 0) {
+  while (this->available()) {
+    if (this->receive_buffer_.size() >= MBUS_MAX_FRAME_LENGTH * 2) {
       ESP_LOGW(TAG, "Receive buffer full, dropping remaining bytes");
-    } else {
-      // Read all available bytes in batches to reduce UART call overhead.
-      // Cap reads to remaining buffer capacity.
-      if (static_cast<size_t>(avail) > remaining) {
-        avail = remaining;
-      }
-      uint8_t buf[64];
-      while (avail > 0) {
-        size_t to_read = std::min(static_cast<size_t>(avail), sizeof(buf));
-        if (!this->read_array(buf, to_read)) {
-          break;
-        }
-        avail -= to_read;
-        this->receive_buffer_.insert(this->receive_buffer_.end(), buf, buf + to_read);
-        this->last_read_ = millis();
-      }
+      break;
     }
+    uint8_t c;
+    this->read_byte(&c);
+    this->receive_buffer_.push_back(c);
+    this->last_read_ = millis();
   }
 
   if (!this->receive_buffer_.empty() && millis() - this->last_read_ > this->read_timeout_) {

esphome/components/pylontech/pylontech.cpp

@@ -56,17 +56,23 @@ void PylontechComponent::setup() {
 void PylontechComponent::update() { this->write_str("pwr\n"); }
 
 void PylontechComponent::loop() {
-  if (this->available() > 0) {
+  int avail = this->available();
+  if (avail > 0) {
     // pylontech sends a lot of data very suddenly
     // we need to quickly put it all into our own buffer, otherwise the uart's buffer will overflow
-    uint8_t data;
     int recv = 0;
-    while (this->available() > 0) {
-      if (this->read_byte(&data)) {
-        buffer_[buffer_index_write_] += (char) data;
-        recv++;
-        if (buffer_[buffer_index_write_].back() == static_cast<char>(ASCII_LF) ||
-            buffer_[buffer_index_write_].length() >= MAX_DATA_LENGTH_BYTES) {
+    uint8_t buf[64];
+    while (avail > 0) {
+      size_t to_read = std::min(static_cast<size_t>(avail), sizeof(buf));
+      if (!this->read_array(buf, to_read)) {
+        break;
+      }
+      avail -= to_read;
+      recv += to_read;
+
+      for (size_t i = 0; i < to_read; i++) {
+        buffer_[buffer_index_write_] += (char) buf[i];
+        if (buf[i] == ASCII_LF || buffer_[buffer_index_write_].length() >= MAX_DATA_LENGTH_BYTES) {
           // complete line received
           buffer_index_write_ = (buffer_index_write_ + 1) % NUM_BUFFERS;
         }