Improve return values of LSM6DS33 class's methods by utilizing global error codes

[grantKinsley]

Closes #57

Changed update() method in src/sensors/lsm6ds33.cpp to return error codes defined in src/globals.h

1. Changed function type of update() from bool to int
2. Added new error code ERROR_NO_NEW_DATA to globals.h

[tiffany1618]

I think this should also be returning RESULT_FALSE; having no new data is not necessarily an error.

[grantKinsley]

That makes sense. I'll also get rid of the ERROR_NO_NEW_DATA code since I made it for the sole purpose of reflecting that there was no new data.

[tiffany1618]

Looks good, just need to also change any methods that call update() to check for the error codes, like powerOn() and pollData().

[tiffany1618]

This looks good for now. We should also be implementing a way to handle proper error propagation, but I'll probably open that up in a separate issue.

[harrisonCassar]

I was taking a bit of a deeper look, and realized there's a few other places we could utilize these error codes better:

• First of all, we seem to use the same error code ERROR_ADDR for two different error reasons. Can we separate the two? Perhaps another error code should be added

  SPARTAN/Software/src/sensors/lsm6ds33.cpp

  Lines 130 to 144 in 2286670

  	int spartan::LSM6DS33::powerOn() {
  	if (m_status == STATUS_IDLE)
  	return RESULT_SUCCESS;
  	// set I2C address
  	if (m_i2c.address(lsm6Address) != mraa::SUCCESS) {
  	std::cerr << "Unable to set I2C address." << std::endl;
  	return ERROR_ADDR;
  	}
  	// Update settings for accelerometer and gyroscope
  	if (!updateSettings()) {
  	std::cerr << "Update setting failed" << std::endl;
  	return ERROR_ADDR;
  	}

• Second, since we're doing this for the update method, we should probably do the equivalent changes for the writeReg and both updateSettings methods:
  

  SPARTAN/Software/src/sensors/lsm6ds33.cpp

  Lines 25 to 65 in 2286670

  	bool spartan::LSM6DS33::writeReg(uint8_t* buffer, unsigned short size) {
  	mraa::Result msg = m_i2c.write(buffer, size);
  	// Error handling
  	switch (msg) {
  	case mraa::SUCCESS:
  	return true;
  	case mraa::ERROR_INVALID_PARAMETER:
  	std::cerr << "Invalid parameter." << std::endl;
  	break;
  	case mraa::ERROR_INVALID_HANDLE:
  	std::cerr << "ERROR_INVALID_HANDLE" << std::endl;
  	break;
  	case mraa::ERROR_NO_RESOURCES:
  	std::cerr << "ERROR_NO_RESOURCES" << std::endl;
  	break;
  	case mraa::ERROR_INVALID_RESOURCE:
  	std::cerr << "ERROR_INVALID_RESOURCE" << std::endl;
  	break;
  	case mraa::ERROR_INVALID_QUEUE_TYPE:
  	std::cerr << "ERROR_INVALID_QUEUE_TYPE" << std::endl;
  	break;
  	case mraa::ERROR_NO_DATA_AVAILABLE:
  	std::cerr << "ERROR_NO_DATA_AVAILABLE" << std::endl;
  	break;
  	case mraa::ERROR_INVALID_PLATFORM:
  	std::cerr << "ERROR_INVALID_PLATFORM" << std::endl;
  	break;
  	case mraa::ERROR_PLATFORM_NOT_INITIALISED:
  	std::cerr << "ERROR_PLATFORM_NOT_INITIALISED" << std::endl;
  	break;
  	case mraa::ERROR_UNSPECIFIED:
  	std::cerr << "ERROR_UNSPECIFIED" << std::endl;
  	break;
  	default:
  	break;
  	}
  	return false;
  	}

  
  

  SPARTAN/Software/src/sensors/lsm6ds33.cpp

  Lines 104 to 126 in 2286670

  	bool spartan::LSM6DS33::updateSettings() {
  	// Update multiplier constant
  	setMultipliers();
  	// Accelerometer settings
  	m_buffer[0] = lsm6ds33::CTRL1_XL;
  	m_buffer[1] = (m_settings.accel_odr << 4) | m_settings.accelRange | m_settings.accelAAFreq;
  	if (!writeReg(m_buffer, 2))
  	return false;
  	m_buffer[0] = lsm6ds33::CTRL2_G;
  	m_buffer[1] = (m_settings.gyro_odr << 4) | m_settings.gyroRange;
  	if (!writeReg(m_buffer, 2))
  	return false;
  	return true;
  	}
  	bool spartan::LSM6DS33::updateSettings(spartan::LSM6DS33::lsm6Settings settings) {
  	m_settings = settings;
  	return updateSettings();
  	}

Also, just a few styling issues below... Otherwise, great work Grant!