def tls_params(mqtt_config):
    """Return the TLS configuration parameters from a :class:`.MQTTConfig`
    object.

    Args:
        mqtt_config (:class:`.MQTTConfig`): The MQTT connection settings.

    Returns:
        dict: A dict {'ca_certs': ca_certs, 'certfile': certfile,
        'keyfile': keyfile} with the TLS configuration parameters, or None if
        no TLS connection is used.

    .. versionadded:: 0.6.0
    """
    if mqtt_config.tls.hostname:
        return {'ca_certs': mqtt_config.tls.ca_file, 'certfile':
            mqtt_config.tls.client_cert, 'keyfile': mqtt_config.tls.client_key}
    else:
        return None
