esp32_Adafruit_BusIO/Adafruit_BusIO_Register.cpp

#include <Adafruit_I2CRegister.h>

Adafruit_I2CRegister::Adafruit_I2CRegister(Adafruit_I2CDevice *device, uint16_t reg_addr, uint8_t width, uint8_t bitorder, uint8_t address_width) {
  _device = device;
  _addrwidth = address_width;
  _address = reg_addr;
  _bitorder = bitorder;
  _width = width;
}


bool Adafruit_I2CRegister::write(uint8_t *buffer, uint8_t len) {
  uint8_t addrbuffer[2] = {(uint8_t)(_address & 0xFF), (uint8_t)(_address>>8)};
  if (! _device->write(buffer, len, true, addrbuffer, _addrwidth)) {
    return false;
  }
  return true;
}

bool Adafruit_I2CRegister::write(uint32_t value, uint8_t numbytes) {
  if (numbytes == 0) {
    numbytes = _width;
  }
  if (numbytes > 4) {
    return false;
  }

  for (int i=0; i<numbytes; i++) {
    if (_bitorder == LSBFIRST) {
      _buffer[i] = value & 0xFF;
    } else {
      _buffer[numbytes-i-1] = value & 0xFF;
    }
    value >>= 8;
  }
  return write(_buffer, numbytes);
}

// This does not do any error checking! returns 0xFFFFFFFF on failure
uint32_t Adafruit_I2CRegister::read(void) {
  if (! read(_buffer, _width)) {
    return -1;
  }

  uint32_t value = 0;

   for (int i=0; i < _width; i++) {
     value <<= 8;
     if (_bitorder == LSBFIRST) {
       value |= _buffer[_width-i-1];
     } else {
       value |= _buffer[i];
     }
   }

   return value;
}


bool Adafruit_I2CRegister::read(uint8_t *buffer, uint8_t len) {
  _buffer[0] = _address;
  if (! _device->write_then_read(_buffer, 1, buffer, len)) {
    return false;
  }
  return true;
}

bool Adafruit_I2CRegister::read(uint16_t *value) {
  if (! read(_buffer, 2)) {
    return false;
  }

  if (_bitorder == LSBFIRST) {
    *value = _buffer[1];
    *value <<= 8;
    *value |= _buffer[0];
  } else {
    *value = _buffer[0];
    *value <<= 8;
    *value |= _buffer[1];
  }
  return true;
}

bool Adafruit_I2CRegister::read(uint8_t *value) {
  if (! read(_buffer, 1)) {
    return false;
  }

  *value = _buffer[0];
  return true;
}

void Adafruit_I2CRegister::print(Stream *s) {
  uint32_t val = read();
  s->print("0x"); s->print(val, HEX);
}

void Adafruit_I2CRegister::println(Stream *s) {
  print(s);
  s->println();
}


Adafruit_I2CRegisterBits::Adafruit_I2CRegisterBits(Adafruit_I2CRegister *reg, uint8_t bits, uint8_t shift) {
  _register = reg;
  _bits = bits;
  _shift = shift;
}

uint32_t Adafruit_I2CRegisterBits::read(void) {
  uint32_t val = _register->read();
  val >>= _shift;
  return val & ((1 << (_bits+1)) - 1);
}

void Adafruit_I2CRegisterBits::write(uint32_t data) {
  uint32_t val = _register->read();

  // mask off the data before writing
  uint32_t mask = (1 << (_bits+1)) - 1;
  data &= mask;

  mask <<= _shift;
  val &= ~mask;      // remove the current data at that spot
  val |= data << _shift; // and add in the new data
  
  _register->write(val, _register->width());
}