[dht] Code clean-up (#15271)

esphome/components/dht/dht.cpp

@@ -2,8 +2,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-namespace esphome {
-namespace dht {
+namespace esphome::dht {
 
 static const char *const TAG = "dht";
 
@@ -45,16 +44,13 @@ void DHT::update() {
   }
 
   if (success) {
-    ESP_LOGD(TAG, "Temperature %.1f°C Humidity %.1f%%", temperature, humidity);
-
     if (this->temperature_sensor_ != nullptr)
       this->temperature_sensor_->publish_state(temperature);
     if (this->humidity_sensor_ != nullptr)
       this->humidity_sensor_->publish_state(humidity);
     this->status_clear_warning();
   } else {
-    ESP_LOGW(TAG, "Invalid readings! Check pin number and pull-up resistor%s.",
-             this->is_auto_detect_ ? " and try manually specifying the model" : "");
+    ESP_LOGW(TAG, "Invalid readings");
     if (this->temperature_sensor_ != nullptr)
       this->temperature_sensor_->publish_state(NAN);
     if (this->humidity_sensor_ != nullptr)
@@ -73,8 +69,7 @@ bool HOT IRAM_ATTR DHT::read_sensor_(float *temperature, float *humidity, bool r
   *temperature = NAN;
 
   int error_code = 0;
-  int8_t i = 0;
-  uint8_t data[5] = {0, 0, 0, 0, 0};
+  uint8_t data[5] = {};
 
 #ifndef USE_ESP32
   this->pin_.pin_mode(gpio::FLAG_OUTPUT);
@@ -107,7 +102,9 @@ bool HOT IRAM_ATTR DHT::read_sensor_(float *temperature, float *humidity, bool r
     uint8_t bit = 7;
     uint8_t byte = 0;
 
-    for (i = -1; i < 40; i++) {
+    // On 32-bit Xtensa/RISC-V cores, int8_t would require masking/sign-extension for comparisons
+    // vs. native int. Using int i is native word size — small win in the timing-critical section.
+    for (int i = -1; i < 40; i++) {
       uint32_t start_time = micros();
 
       // Wait for rising edge
@@ -156,11 +153,9 @@ bool HOT IRAM_ATTR DHT::read_sensor_(float *temperature, float *humidity, bool r
       }
     }
   }
-  if (!report_errors && error_code != 0)
-    return false;
-
-  if (error_code) {
-    ESP_LOGW(TAG, ESP_LOG_MSG_COMM_FAIL);
+  if (error_code != 0) {
+    if (report_errors)
+      ESP_LOGW(TAG, ESP_LOG_MSG_COMM_FAIL);
     return false;
   }
 
@@ -177,7 +172,7 @@ bool HOT IRAM_ATTR DHT::read_sensor_(float *temperature, float *humidity, bool r
 
   if (checksum_a != data[4] && checksum_b != data[4]) {
     if (report_errors) {
-      ESP_LOGW(TAG, "Checksum invalid: %u!=%u", checksum_a, data[4]);
+      ESP_LOGW(TAG, "Invalid checksum");
     }
     return false;
   }
@@ -234,5 +229,4 @@ bool HOT IRAM_ATTR DHT::read_sensor_(float *temperature, float *humidity, bool r
   return true;
 }
 
-}  // namespace dht
-}  // namespace esphome
+}  // namespace esphome::dht

esphome/components/dht/dht.h

@@ -4,10 +4,9 @@
 #include "esphome/core/hal.h"
 #include "esphome/components/sensor/sensor.h"
 
-namespace esphome {
-namespace dht {
+namespace esphome::dht {
 
-enum DHTModel {
+enum DHTModel : uint8_t {
   DHT_MODEL_AUTO_DETECT = 0,
   DHT_MODEL_DHT11,
   DHT_MODEL_DHT22,
@@ -42,7 +41,6 @@ class DHT : public PollingComponent {
     this->t_pin_ = pin;
     this->pin_ = pin->to_isr();
   }
-  void set_model(DHTModel model) { model_ = model; }
   void set_temperature_sensor(sensor::Sensor *temperature_sensor) { temperature_sensor_ = temperature_sensor; }
   void set_humidity_sensor(sensor::Sensor *humidity_sensor) { humidity_sensor_ = humidity_sensor; }
 
@@ -55,13 +53,12 @@ class DHT : public PollingComponent {
  protected:
   bool read_sensor_(float *temperature, float *humidity, bool report_errors);
 
+  sensor::Sensor *temperature_sensor_{nullptr};
+  sensor::Sensor *humidity_sensor_{nullptr};
   InternalGPIOPin *t_pin_;
   ISRInternalGPIOPin pin_;
   DHTModel model_{DHT_MODEL_AUTO_DETECT};
   bool is_auto_detect_{false};
-  sensor::Sensor *temperature_sensor_{nullptr};
-  sensor::Sensor *humidity_sensor_{nullptr};
 };
 
-}  // namespace dht
-}  // namespace esphome
+}  // namespace esphome::dht