Update esphome/components/bh1750/bh1750.cpp

esphome/components/bh1750/bh1750.cpp

@@ -1,8 +1,8 @@
 #include "bh1750.h"
 #include "esphome/core/log.h"
+#include "esphome/core/application.h"
 
-namespace esphome {
-namespace bh1750 {
+namespace esphome::bh1750 {
 
 static const char *const TAG = "bh1750.sensor";
 
@@ -13,6 +13,31 @@ static const uint8_t BH1750_COMMAND_ONE_TIME_L = 0b00100011;
 static const uint8_t BH1750_COMMAND_ONE_TIME_H = 0b00100000;
 static const uint8_t BH1750_COMMAND_ONE_TIME_H2 = 0b00100001;
 
+static constexpr uint32_t MEASUREMENT_TIMEOUT_MS = 2000;
+static constexpr float HIGH_LIGHT_THRESHOLD_LX = 7000.0f;
+
+// Measurement time constants (datasheet values)
+static constexpr uint16_t MTREG_DEFAULT = 69;
+static constexpr uint16_t MTREG_MIN = 31;
+static constexpr uint16_t MTREG_MAX = 254;
+static constexpr uint16_t MEAS_TIME_L_MS = 24;   // L-resolution max measurement time @ mtreg=69
+static constexpr uint16_t MEAS_TIME_H_MS = 180;  // H/H2-resolution max measurement time @ mtreg=69
+
+// Conversion constants (datasheet formulas)
+static constexpr float RESOLUTION_DIVISOR = 1.2f;  // counts to lux conversion divisor
+static constexpr float MODE_H2_DIVISOR = 2.0f;     // H2 mode has 2x higher resolution
+
+// MTreg calculation constants
+static constexpr int COUNTS_TARGET = 50000;  // Target counts for optimal range (avoid saturation)
+static constexpr int COUNTS_NUMERATOR = 10;
+static constexpr int COUNTS_DENOMINATOR = 12;
+
+// MTreg register bit manipulation constants
+static constexpr uint8_t MTREG_HI_SHIFT = 5;       // High 3 bits start at bit 5
+static constexpr uint8_t MTREG_HI_MASK = 0b111;    // 3-bit mask for high bits
+static constexpr uint8_t MTREG_LO_SHIFT = 0;       // Low 5 bits start at bit 0
+static constexpr uint8_t MTREG_LO_MASK = 0b11111;  // 5-bit mask for low bits
+
 /*
 bh1750 properties:
 
@@ -43,74 +68,7 @@ void BH1750Sensor::setup() {
     this->mark_failed();
     return;
   }
-}
-
-void BH1750Sensor::read_lx_(BH1750Mode mode, uint8_t mtreg, const std::function<void(float)> &f) {
-  // turn on (after one-shot sensor automatically powers down)
-  uint8_t turn_on = BH1750_COMMAND_POWER_ON;
-  if (this->write(&turn_on, 1) != i2c::ERROR_OK) {
-    ESP_LOGW(TAG, "Power on failed");
-    f(NAN);
-    return;
-  }
-
-  if (active_mtreg_ != mtreg) {
-    // set mtreg
-    uint8_t mtreg_hi = BH1750_COMMAND_MT_REG_HI | ((mtreg >> 5) & 0b111);
-    uint8_t mtreg_lo = BH1750_COMMAND_MT_REG_LO | ((mtreg >> 0) & 0b11111);
-    if (this->write(&mtreg_hi, 1) != i2c::ERROR_OK || this->write(&mtreg_lo, 1) != i2c::ERROR_OK) {
-      ESP_LOGW(TAG, "Set measurement time failed");
-      active_mtreg_ = 0;
-      f(NAN);
-      return;
-    }
-    active_mtreg_ = mtreg;
-  }
-
-  uint8_t cmd;
-  uint16_t meas_time;
-  switch (mode) {
-    case BH1750_MODE_L:
-      cmd = BH1750_COMMAND_ONE_TIME_L;
-      meas_time = 24 * mtreg / 69;
-      break;
-    case BH1750_MODE_H:
-      cmd = BH1750_COMMAND_ONE_TIME_H;
-      meas_time = 180 * mtreg / 69;
-      break;
-    case BH1750_MODE_H2:
-      cmd = BH1750_COMMAND_ONE_TIME_H2;
-      meas_time = 180 * mtreg / 69;
-      break;
-    default:
-      f(NAN);
-      return;
-  }
-  if (this->write(&cmd, 1) != i2c::ERROR_OK) {
-    ESP_LOGW(TAG, "Start measurement failed");
-    f(NAN);
-    return;
-  }
-
-  // probably not needed, but adjust for rounding
-  meas_time++;
-
-  this->set_timeout("read", meas_time, [this, mode, mtreg, f]() {
-    uint16_t raw_value;
-    if (this->read(reinterpret_cast<uint8_t *>(&raw_value), 2) != i2c::ERROR_OK) {
-      ESP_LOGW(TAG, "Read data failed");
-      f(NAN);
-      return;
-    }
-    raw_value = i2c::i2ctohs(raw_value);
-
-    float lx = float(raw_value) / 1.2f;
-    lx *= 69.0f / mtreg;
-    if (mode == BH1750_MODE_H2)
-      lx /= 2.0f;
-
-    f(lx);
-  });
+  this->state_ = IDLE;
 }
 
 void BH1750Sensor::dump_config() {
@@ -124,45 +82,189 @@ void BH1750Sensor::dump_config() {
 }
 
 void BH1750Sensor::update() {
-  // first do a quick measurement in L-mode with full range
-  // to find right range
-  this->read_lx_(BH1750_MODE_L, 31, [this](float val) {
-    if (std::isnan(val)) {
-      this->status_set_warning();
-      this->publish_state(NAN);
+  const uint32_t now = millis();
+
+  // Start coarse measurement to determine optimal mode/mtreg
+  if (this->state_ != IDLE) {
+    // Safety timeout: reset if stuck
+    if (now - this->measurement_start_time_ > MEASUREMENT_TIMEOUT_MS) {
+      ESP_LOGW(TAG, "Measurement timeout, resetting state");
+      this->state_ = IDLE;
+    } else {
+      ESP_LOGW(TAG, "Previous measurement not complete, skipping update");
       return;
     }
+  }
 
-    BH1750Mode use_mode;
-    uint8_t use_mtreg;
-    if (val <= 7000) {
-      use_mode = BH1750_MODE_H2;
-      use_mtreg = 254;
-    } else {
-      use_mode = BH1750_MODE_H;
-      // lx = counts / 1.2 * (69 / mtreg)
-      // -> mtreg = counts / 1.2 * (69 / lx)
-      // calculate for counts=50000 (allow some range to not saturate, but maximize mtreg)
-      // -> mtreg = 50000*(10/12)*(69/lx)
-      int ideal_mtreg = 50000 * 10 * 69 / (12 * (int) val);
-      use_mtreg = std::min(254, std::max(31, ideal_mtreg));
-    }
-    ESP_LOGV(TAG, "L result: %f -> Calculated mode=%d, mtreg=%d", val, (int) use_mode, use_mtreg);
+  if (!this->start_measurement_(BH1750_MODE_L, MTREG_MIN, now)) {
+    this->status_set_warning();
+    this->publish_state(NAN);
+    return;
+  }
 
-    this->read_lx_(use_mode, use_mtreg, [this](float val) {
-      if (std::isnan(val)) {
-        this->status_set_warning();
-        this->publish_state(NAN);
-        return;
+  this->state_ = WAITING_COARSE_MEASUREMENT;
+  this->enable_loop();  // Enable loop while measurement in progress
+}
+
+void BH1750Sensor::loop() {
+  const uint32_t now = App.get_loop_component_start_time();
+
+  switch (this->state_) {
+    case IDLE:
+      // Disable loop when idle to save cycles
+      this->disable_loop();
+      break;
+
+    case WAITING_COARSE_MEASUREMENT:
+      if (now - this->measurement_start_time_ >= this->measurement_duration_) {
+        this->state_ = READING_COARSE_RESULT;
       }
-      ESP_LOGD(TAG, "'%s': Illuminance=%.1flx", this->get_name().c_str(), val);
+      break;
+
+    case READING_COARSE_RESULT: {
+      float lx;
+      if (!this->read_measurement_(lx)) {
+        this->fail_and_reset_();
+        break;
+      }
+
+      this->process_coarse_result_(lx);
+
+      // Start fine measurement with optimal settings
+      // fetch millis() again since the read can take a bit
+      if (!this->start_measurement_(this->fine_mode_, this->fine_mtreg_, millis())) {
+        this->fail_and_reset_();
+        break;
+      }
+
+      this->state_ = WAITING_FINE_MEASUREMENT;
+      break;
+    }
+
+    case WAITING_FINE_MEASUREMENT:
+      if (now - this->measurement_start_time_ >= this->measurement_duration_) {
+        this->state_ = READING_FINE_RESULT;
+      }
+      break;
+
+    case READING_FINE_RESULT: {
+      float lx;
+      if (!this->read_measurement_(lx)) {
+        this->fail_and_reset_();
+        break;
+      }
+
+      ESP_LOGD(TAG, "'%s': Illuminance=%.1flx", this->get_name().c_str(), lx);
       this->status_clear_warning();
-      this->publish_state(val);
-    });
-  });
+      this->publish_state(lx);
+      this->state_ = IDLE;
+      break;
+    }
+  }
+}
+
+bool BH1750Sensor::start_measurement_(BH1750Mode mode, uint8_t mtreg, uint32_t now) {
+  // Power on
+  uint8_t turn_on = BH1750_COMMAND_POWER_ON;
+  if (this->write(&turn_on, 1) != i2c::ERROR_OK) {
+    ESP_LOGW(TAG, "Power on failed");
+    return false;
+  }
+
+  // Set MTreg if changed
+  if (this->active_mtreg_ != mtreg) {
+    uint8_t mtreg_hi = BH1750_COMMAND_MT_REG_HI | ((mtreg >> MTREG_HI_SHIFT) & MTREG_HI_MASK);
+    uint8_t mtreg_lo = BH1750_COMMAND_MT_REG_LO | ((mtreg >> MTREG_LO_SHIFT) & MTREG_LO_MASK);
+    if (this->write(&mtreg_hi, 1) != i2c::ERROR_OK || this->write(&mtreg_lo, 1) != i2c::ERROR_OK) {
+      ESP_LOGW(TAG, "Set measurement time failed");
+      this->active_mtreg_ = 0;
+      return false;
+    }
+    this->active_mtreg_ = mtreg;
+  }
+
+  // Start measurement
+  uint8_t cmd;
+  uint16_t meas_time;
+  switch (mode) {
+    case BH1750_MODE_L:
+      cmd = BH1750_COMMAND_ONE_TIME_L;
+      meas_time = MEAS_TIME_L_MS * mtreg / MTREG_DEFAULT;
+      break;
+    case BH1750_MODE_H:
+      cmd = BH1750_COMMAND_ONE_TIME_H;
+      meas_time = MEAS_TIME_H_MS * mtreg / MTREG_DEFAULT;
+      break;
+    case BH1750_MODE_H2:
+      cmd = BH1750_COMMAND_ONE_TIME_H2;
+      meas_time = MEAS_TIME_H_MS * mtreg / MTREG_DEFAULT;
+      break;
+    default:
+      return false;
+  }
+
+  if (this->write(&cmd, 1) != i2c::ERROR_OK) {
+    ESP_LOGW(TAG, "Start measurement failed");
+    return false;
+  }
+
+  // Store current measurement parameters
+  this->current_mode_ = mode;
+  this->current_mtreg_ = mtreg;
+  this->measurement_start_time_ = now;
+  this->measurement_duration_ = meas_time + 1;  // Add 1ms for safety
+
+  return true;
+}
+
+bool BH1750Sensor::read_measurement_(float &lx_out) {
+  uint16_t raw_value;
+  if (this->read(reinterpret_cast<uint8_t *>(&raw_value), 2) != i2c::ERROR_OK) {
+    ESP_LOGW(TAG, "Read data failed");
+    return false;
+  }
+  raw_value = i2c::i2ctohs(raw_value);
+
+  float lx = float(raw_value) / RESOLUTION_DIVISOR;
+  lx *= float(MTREG_DEFAULT) / this->current_mtreg_;
+  if (this->current_mode_ == BH1750_MODE_H2) {
+    lx /= MODE_H2_DIVISOR;
+  }
+
+  lx_out = lx;
+  return true;
+}
+
+void BH1750Sensor::process_coarse_result_(float lx) {
+  if (std::isnan(lx)) {
+    // Use defaults if coarse measurement failed
+    this->fine_mode_ = BH1750_MODE_H2;
+    this->fine_mtreg_ = MTREG_MAX;
+    return;
+  }
+
+  if (lx <= HIGH_LIGHT_THRESHOLD_LX) {
+    this->fine_mode_ = BH1750_MODE_H2;
+    this->fine_mtreg_ = MTREG_MAX;
+  } else {
+    this->fine_mode_ = BH1750_MODE_H;
+    // lx = counts / 1.2 * (69 / mtreg)
+    // -> mtreg = counts / 1.2 * (69 / lx)
+    // calculate for counts=50000 (allow some range to not saturate, but maximize mtreg)
+    // -> mtreg = 50000*(10/12)*(69/lx)
+    int ideal_mtreg = COUNTS_TARGET * COUNTS_NUMERATOR * MTREG_DEFAULT / (COUNTS_DENOMINATOR * (int) lx);
+    this->fine_mtreg_ = std::min((int) MTREG_MAX, std::max((int) MTREG_MIN, ideal_mtreg));
+  }
+
+  ESP_LOGV(TAG, "L result: %.1f -> Calculated mode=%d, mtreg=%d", lx, (int) this->fine_mode_, this->fine_mtreg_);
+}
+
+void BH1750Sensor::fail_and_reset_() {
+  this->status_set_warning();
+  this->publish_state(NAN);
+  this->state_ = IDLE;
 }
 
 float BH1750Sensor::get_setup_priority() const { return setup_priority::DATA; }
 
-}  // namespace bh1750
-}  // namespace esphome
+}  // namespace esphome::bh1750

esphome/components/bh1750/bh1750.h

@@ -4,10 +4,9 @@
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/i2c/i2c.h"
 
-namespace esphome {
-namespace bh1750 {
+namespace esphome::bh1750 {
 
-enum BH1750Mode {
+enum BH1750Mode : uint8_t {
   BH1750_MODE_L,
   BH1750_MODE_H,
   BH1750_MODE_H2,
@@ -21,13 +20,36 @@ class BH1750Sensor : public sensor::Sensor, public PollingComponent, public i2c:
   void setup() override;
   void dump_config() override;
   void update() override;
+  void loop() override;
   float get_setup_priority() const override;
 
  protected:
-  void read_lx_(BH1750Mode mode, uint8_t mtreg, const std::function<void(float)> &f);
+  // State machine states
+  enum State : uint8_t {
+    IDLE,
+    WAITING_COARSE_MEASUREMENT,
+    READING_COARSE_RESULT,
+    WAITING_FINE_MEASUREMENT,
+    READING_FINE_RESULT,
+  };
 
+  // 4-byte aligned members
+  uint32_t measurement_start_time_{0};
+  uint32_t measurement_duration_{0};
+
+  // 1-byte members grouped together to minimize padding
+  State state_{IDLE};
+  BH1750Mode current_mode_{BH1750_MODE_L};
+  uint8_t current_mtreg_{31};
+  BH1750Mode fine_mode_{BH1750_MODE_H2};
+  uint8_t fine_mtreg_{254};
   uint8_t active_mtreg_{0};
+
+  // Helper methods
+  bool start_measurement_(BH1750Mode mode, uint8_t mtreg, uint32_t now);
+  bool read_measurement_(float &lx_out);
+  void process_coarse_result_(float lx);
+  void fail_and_reset_();
 };
 
-}  // namespace bh1750
-}  // namespace esphome
+}  // namespace esphome::bh1750