i2c.cpp

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#include "i2c.h"
 
#include "esphome/core/defines.h"
#include "esphome/core/hal.h"
#include "esphome/core/log.h"
#include <memory>
 
namespace esphome::i2c {
 
static const char *const TAG = "i2c";
 
void I2CBus::i2c_scan_() {
  for (uint8_t address = 8; address != 120; address++) {
    auto err = write_readv(address, nullptr, 0, nullptr, 0);
    if (err == ERROR_OK) {
      scan_results_.emplace_back(address, true);
    } else if (err == ERROR_UNKNOWN) {
      scan_results_.emplace_back(address, false);
    }
    // it takes 16sec to scan on nrf52. It prevents board reset.
    arch_feed_wdt();
  }
}
 
ErrorCode I2CDevice::read_register(uint8_t a_register, uint8_t *data, size_t len) {
  return bus_->write_readv(this->address_, &a_register, 1, data, len);
}
 
ErrorCode I2CDevice::read_register16(uint16_t a_register, uint8_t *data, size_t len) {
  a_register = convert_big_endian(a_register);
  return bus_->write_readv(this->address_, reinterpret_cast<const uint8_t *>(&a_register), 2, data, len);
}
 
ErrorCode I2CDevice::write_register(uint8_t a_register, const uint8_t *data, size_t len) const {
  SmallBufferWithHeapFallback<17> buffer_alloc(len + 1);  // Most I2C writes are <= 16 bytes
  uint8_t *buffer = buffer_alloc.get();
 
  buffer[0] = a_register;
  std::copy(data, data + len, buffer + 1);
  return this->bus_->write_readv(this->address_, buffer, len + 1, nullptr, 0);
}
 
ErrorCode I2CDevice::write_register16(uint16_t a_register, const uint8_t *data, size_t len) const {
  SmallBufferWithHeapFallback<18> buffer_alloc(len + 2);  // Most I2C writes are <= 16 bytes + 2 for register
  uint8_t *buffer = buffer_alloc.get();
 
  buffer[0] = a_register >> 8;
  buffer[1] = a_register;
  std::copy(data, data + len, buffer + 2);
  return this->bus_->write_readv(this->address_, buffer, len + 2, nullptr, 0);
}
 
bool I2CDevice::read_bytes_16(uint8_t a_register, uint16_t *data, uint8_t len) {
  if (read_register(a_register, reinterpret_cast<uint8_t *>(data), len * 2) != ERROR_OK)
    return false;
  for (size_t i = 0; i < len; i++)
    data[i] = i2ctohs(data[i]);
  return true;
}
 
bool I2CDevice::write_bytes_16(uint8_t a_register, const uint16_t *data, uint8_t len) const {
  // we have to copy in order to be able to change byte order
  std::unique_ptr<uint16_t[]> temp{new uint16_t[len]};
  for (size_t i = 0; i < len; i++)
    temp[i] = htoi2cs(data[i]);
  return write_register(a_register, reinterpret_cast<const uint8_t *>(temp.get()), len * 2) == ERROR_OK;
}
 
I2CRegister &I2CRegister::operator=(uint8_t value) {
  this->parent_->write_register(this->register_, &value, 1);
  return *this;
}
I2CRegister &I2CRegister::operator&=(uint8_t value) {
  value &= get();
  this->parent_->write_register(this->register_, &value, 1);
  return *this;
}
I2CRegister &I2CRegister::operator|=(uint8_t value) {
  value |= get();
  this->parent_->write_register(this->register_, &value, 1);
  return *this;
}
 
uint8_t I2CRegister::get() const {
  uint8_t value = 0x00;
  this->parent_->read_register(this->register_, &value, 1);
  return value;
}
 
I2CRegister16 &I2CRegister16::operator=(uint8_t value) {
  this->parent_->write_register16(this->register_, &value, 1);
  return *this;
}
I2CRegister16 &I2CRegister16::operator&=(uint8_t value) {
  value &= get();
  this->parent_->write_register16(this->register_, &value, 1);
  return *this;
}
I2CRegister16 &I2CRegister16::operator|=(uint8_t value) {
  value |= get();
  this->parent_->write_register16(this->register_, &value, 1);
  return *this;
}
 
uint8_t I2CRegister16::get() const {
  uint8_t value = 0x00;
  this->parent_->read_register16(this->register_, &value, 1);
  return value;
}
 
}  // namespace esphome::i2c