spi_zephyr.h

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#pragma once
 
#ifdef USE_ZEPHYR
 
#include "spi.h"
#include <zephyr/drivers/spi.h>
 
namespace esphome::spi {
 
class ZephyrSPIDelegate;
 
class ZephyrSPIBus : public SPIBus {
  friend class ZephyrSPIDelegate;
 
 public:
  explicit ZephyrSPIBus(const device *dev) : dev_(dev) {
    this->idle_cfg_.frequency = IDLE_FREQUENCY;
    this->idle_cfg_.operation = SPI_OP_MODE_MASTER | SPI_WORD_SET(8);
  }
 
  bool is_hw() override { return true; }
 
  SPIDelegate *get_delegate(uint32_t data_rate, SPIBitOrder bit_order, SPIMode mode, GPIOPin *cs_pin,
                            bool release_device, bool write_only) override;
 
 protected:
  // The lowest rate the SPIM driver accepts; only ever applied with no device selected
  static constexpr uint32_t IDLE_FREQUENCY = 125000;
 
  const device *dev_;
  // Delegate whose mode and frequency the driver last applied
  const ZephyrSPIDelegate *active_{nullptr};
  // Applied when the active delegate is deleted, so the driver never keeps a pointer to a freed config
  spi_config idle_cfg_{};
};
 
class ZephyrSPIDelegate : public SPIDelegate {
 public:
  ZephyrSPIDelegate(ZephyrSPIBus *bus, uint32_t data_rate, SPIBitOrder bit_order, SPIMode mode, GPIOPin *cs_pin);
  ~ZephyrSPIDelegate() override;
 
  void begin_transaction() override;
 
  uint8_t transfer(uint8_t data) override;
  void transfer(const uint8_t *txbuf, uint8_t *rxbuf, size_t length) override;
  void write_array(const uint8_t *ptr, size_t length) override;
  void write_array16(const uint16_t *data, size_t length) override;
  void read_array(uint8_t *ptr, size_t length) override;
 
 protected:
  void transceive_(const uint8_t *tx, uint8_t *rx, size_t length);
 
  ZephyrSPIBus *bus_;
  // CS is driven by ESPHome via SPIDelegate::cs_pin_; cfg_.cs stays unset so
  // the Zephyr driver never touches a devicetree cs-gpios pin itself.
  spi_config cfg_{};
};
 
}  // namespace esphome::spi
 
#endif  // USE_ZEPHYR