Add support for multiple devices in bme680_bsec (#3550)

* Add initial support for multiple devices

Re-introduce support for multiple I2C devices (it was suppressed in https://github.com/trvrnrth/esphome-bsec-bme680/commit/df37a7635f6acc3f7520f257d2645eda10b863a5). Devices are identified by their I2C address, and the BME680 can only have the 0x76 or 0x77 address, so this adds support for a maximum of two devices.

* Reintegrate commit ebf13a0b

Reintegrate commit https://github.com/esphome/esphome/commit/ebf13a0ba0a48453c2cc80bfc942d6a588859233 which was lost in my changes (I were working on old files)

* wrong commit

* wrong commit

* Reintegrate commit ebf13a0b

Reintegrate commit https://github.com/esphome/esphome/commit/ebf13a0ba0a48453c2cc80bfc942d6a588859233 which was lost due to me working on old files

* Reintroduce newlines at end of files

* Reintroduce newlines at end of files

* Adhere to codebase standards

Obey the "All uses of class members and member functions should be prefixed with this-> to distinguish them from global functions in code review" rule of the Codebase Standards

* Fix formatting according to clang-format

* Perform the BSEC library reinitialization+snapshot only when more than one device is present

* Fix formatting according to clang-format

* Degrade abort message in restore_state_() from warning to verbose

This always happen at initial setup, so it's not a really useful message; when some real problems arise, we'll have a more useful warning from snapshot_state_()

Co-authored-by: Trevor North <trevor@freedisc.co.uk>

* Reduce peak stack usage to avoid bootloops on ESP8266

Achieved mainly by moving the work_buffer needed by the BSEC library to the heap, as a single global work buffer shared by all instances.
::set_config_ has been reverted to a code path similar to the original, as that reduces peak stack usage enough to be OK on ESP8266 even without moving the work_buffer to the heap.

* Fix formatting according to clang-format

* Add support for devices with the same i2c address

Devices are now identified using their index in the BME680BSECComponent::instances member, which became a vector. This allows adding two devices with the same i2c address (which should be placed on different i2c buses). Since a BME680 can only have an address of 0x76 or 0x77, a maximum of 2 devices could be added before this commit. Now there is no theoretical limit on the number of devices which could be added.

* Fix formatting according to clang-format

* Fix formatting according to clang-format

---------

Co-authored-by: Trevor North <trevor@freedisc.co.uk>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/bme680_bsec/bme680_bsec.h

@@ -31,6 +31,7 @@ enum SampleRate {
 
 class BME680BSECComponent : public Component, public i2c::I2CDevice {
  public:
+  void set_device_id(const std::string &devid) { this->device_id_.assign(devid); }
   void set_temperature_offset(float offset) { this->temperature_offset_ = offset; }
   void set_iaq_mode(IAQMode iaq_mode) { this->iaq_mode_ = iaq_mode; }
   void set_state_save_interval(uint32_t interval) { this->state_save_interval_ms_ = interval; }
@@ -50,9 +51,9 @@ class BME680BSECComponent : public Component, public i2c::I2CDevice {
   void set_co2_equivalent_sensor(sensor::Sensor *sensor) { this->co2_equivalent_sensor_ = sensor; }
   void set_breath_voc_equivalent_sensor(sensor::Sensor *sensor) { this->breath_voc_equivalent_sensor_ = sensor; }
 
-  static BME680BSECComponent *instance;
-  static int8_t read_bytes_wrapper(uint8_t address, uint8_t a_register, uint8_t *data, uint16_t len);
-  static int8_t write_bytes_wrapper(uint8_t address, uint8_t a_register, uint8_t *data, uint16_t len);
+  static std::vector<BME680BSECComponent *> instances;
+  static int8_t read_bytes_wrapper(uint8_t devid, uint8_t a_register, uint8_t *data, uint16_t len);
+  static int8_t write_bytes_wrapper(uint8_t devid, uint8_t a_register, uint8_t *data, uint16_t len);
   static void delay_ms(uint32_t period);
 
   void setup() override;
@@ -61,23 +62,33 @@ class BME680BSECComponent : public Component, public i2c::I2CDevice {
   void loop() override;
 
  protected:
-  void set_config_(const uint8_t *config);
+  void set_config_();
   float calc_sensor_sample_rate_(SampleRate sample_rate);
   void update_subscription_();
 
   void run_();
-  void read_(int64_t trigger_time_ns, bsec_bme_settings_t bme680_settings);
+  void read_();
   void publish_(const bsec_output_t *outputs, uint8_t num_outputs);
   int64_t get_time_ns_();
 
   void publish_sensor_(sensor::Sensor *sensor, float value, bool change_only = false);
   void publish_sensor_(text_sensor::TextSensor *sensor, const std::string &value);
 
-  void load_state_();
-  void save_state_(uint8_t accuracy);
+  void snapshot_state_();  // Fetch the current BSEC library state and save it in the bsec_state_data_ member (volatile
+                           // memory)
+  void restore_state_();   // Push the state contained in the bsec_state_data_ member (volatile memory) to the BSEC
+                           // library
+  int reinit_bsec_lib_();  // Prepare the BSEC library to be used again after this object returns active
+                           // (as the library may have been used by other objects)
+  void load_state_();      // Initialize the ESP preferences object; retrieve the BSEC library state from the ESP
+                           // preferences (storage); then save it in the bsec_state_data_ member (volatile memory) and
+                           // push it to the BSEC library
+  void save_state_(
+      uint8_t accuracy);  // Save the bsec_state_data_ member (volatile memory) to the ESP preferences (storage)
 
   void queue_push_(std::function<void()> &&f) { this->queue_.push(std::move(f)); }
 
+  static uint8_t work_buffer_[BSEC_MAX_WORKBUFFER_SIZE];
   struct bme680_dev bme680_;
   bsec_library_return_t bsec_status_{BSEC_OK};
   int8_t bme680_status_{BME680_OK};
@@ -88,10 +99,14 @@ class BME680BSECComponent : public Component, public i2c::I2CDevice {
 
   std::queue<std::function<void()>> queue_;
 
+  bool bsec_state_data_valid_;
+  uint8_t bsec_state_data_[BSEC_MAX_STATE_BLOB_SIZE];  // This is the current snapshot of the BSEC library state
   ESPPreferenceObject bsec_state_;
   uint32_t state_save_interval_ms_{21600000};  // 6 hours - 4 times a day
   uint32_t last_state_save_ms_ = 0;
+  bsec_bme_settings_t bme680_settings_;
 
+  std::string device_id_;
   float temperature_offset_{0};
   IAQMode iaq_mode_{IAQ_MODE_STATIC};