uart_mux.h

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#pragma once
#if defined(USE_ESP32_VARIANT_ESP32P4) || defined(USE_ESP32_VARIANT_ESP32S2) || defined(USE_ESP32_VARIANT_ESP32S3)
#include "esphome/components/uart/uart_component.h"
#include "esphome/components/uart/uart_component_esp_idf.h"
#include "esphome/components/cdc_acm_uart/bridge/cdc_acm_uart_bridge.h"
#include "esphome/core/component.h"
 
namespace esphome::uart_mux {
 
class UARTMux final : public uart::UARTComponent, public Component {
 public:
  explicit UARTMux(cdc_acm_uart::CDCACMUARTBridge *bridge) : uart_(bridge->get_uart_parent()), bridge_(bridge) {}
 
  void setup() override;
  void loop() override;
  void dump_config() override;
  // Between the hardware UART (BUS) and its consumers (modbus is BUS - 1): the
  // mirrored framing must exist before anything reads it from us.
  float get_setup_priority() const override { return setup_priority::BUS - 0.5f; }
 
  void set_start_local(bool start_local) { this->start_local_ = start_local; }
 
  void select_local();
  void select_bridge();
  bool is_local() const { return this->route_ == Route::ROUTE_LOCAL; }
 
  // uart::UARTComponent: forwarded while routed locally, inert otherwise.
  void write_array(const uint8_t *data, size_t len) override;
  bool peek_byte(uint8_t *data) override { return this->is_local() && this->uart_->peek_byte(data); }
  bool read_array(uint8_t *data, size_t len) override { return this->is_local() && this->uart_->read_array(data, len); }
  size_t available() override { return this->is_local() ? this->uart_->available() : 0; }
  uart::UARTFlushResult flush() override {
    return this->is_local() ? this->uart_->flush() : uart::UARTFlushResult::UART_FLUSH_RESULT_ASSUMED_SUCCESS;
  }
  bool is_connected() override { return this->is_local(); }
  // Ignored: the bridge's tasks block inside the driver, and reinstalling it would
  // pull it out from under them. The framing is the hardware UART's to change.
  void load_settings(bool dump_config) override;
  using UARTComponent::load_settings;
 
 protected:
  enum class Route : uint8_t {
    ROUTE_BRIDGE,
    ROUTE_PENDING_LOCAL,  // pause() requested; the bridge may still be on the bus
    ROUTE_LOCAL,
  };
 
  // The hardware UART's settings as configured. Taken once at setup, before the
  // bridge can overwrite the live fields with a host's line coding.
  struct Settings {
    uint32_t baud_rate;
    size_t rx_full_threshold;
    size_t rx_timeout;
    size_t rx_buffer_size;
    uint8_t data_bits;
    uint8_t stop_bits;
    uart::UARTParityOptions parity;
  };
 
  void check_logger_conflict() override {}
  // Publish settings_ through the UARTComponent getters.
  void apply_settings_();
 
  uart::IDFUARTComponent *uart_;
  cdc_acm_uart::CDCACMUARTBridge *bridge_;
  Settings settings_{};
  Route route_{Route::ROUTE_BRIDGE};
  bool start_local_{false};
  bool load_settings_warned_{false};
};
 
}  // namespace esphome::uart_mux
#endif