Create custom field for display suite

workshop_helper.module

/**
 * Implements hook_ctools_plugin_api().
 */
function workshop_helper_ctools_plugin_api($module, $api) {
  if ($module == "ds" && $api == "ds") {
    return array("version" => "1");
  }
  return NULL;
}

/**
 * Implements hook_ds_fields_info().
 */
function workshop_helper_ds_fields_info($entity_type) {
  $fields = array();

  $fields['node']['ds_prefix'] = array(
    'title' => t('Prefix'),
    'field_type' => DS_FIELD_TYPE_FUNCTION,
    'function' => 'workshop_helper_ds_field__ds_prefix',
    // settings & default: optional if you have a settings form for your field.
    'properties' => array(
      'settings' => array(
        'wrapper' => array(
          'type' => 'textfield',
          'description' => t('Eg: div, h1, h2, p, span'),
        ),
        'css_class' => array(
          'type' => 'textfield',
          'description' => t('Put a class on the wrapper. Eg: block-title'),
        ),
      ),
      'default' => array(
        'wrapper'            => 'div',
        'css_class'          => '',
      ),
    )
  );
  $fields['node']['ds_suffix'] = array(
    'title' => t('Suffix'),
    'field_type' => DS_FIELD_TYPE_FUNCTION,
    'function' => 'workshop_helper_ds_field__ds_suffix',
    // settings & default: optional if you have a settings form for your field.
    'properties' => array(
      'settings' => array(
        'wrapper' => array(
          'type' => 'textfield',
          'description' => t('Eg: h1, h2, p, must same with Prefix settingX'),
        )
      ),
      'default' => array(
        'wrapper'            => 'div',
      ),
    )
  );
  if (isset($fields[$entity_type])) {
    return array($entity_type => $fields[$entity_type]);
  }
  return;
}

/**
 * Implements hook_ds_field_settings_form().
 */
function workshop_helper_ds_field_settings_form($field) {
  return ds_ds_field_settings_form($field);
}

/**
 * Implements hook_ds_field_format_summary().
 */
function workshop_helper_ds_field_format_summary($field) {
  return ds_ds_field_format_summary($field);
}

/**
 * Implements hook_ds_field_settings_alter().
 */
function workshop_helper_ds_field_settings_alter(&$field_settings, $form, &$form_state) {
  if (isset($field_settings['ds_prefix']) || isset($field_settings['ds_suffix'])) {
    $field_settings['ds_prefix']['formatter_settings']['ft']['func'] = 'theme_ds_field_reset';
    $field_settings['ds_suffix']['formatter_settings']['ft']['func'] = 'theme_ds_field_reset';
  }
}

/**
 * Render the ds_suffix field.
 */
function workshop_helper_ds_field__ds_suffix($field) {
  $wrapper = isset($field['formatter_settings']['wrapper']) ? check_plain($field['formatter_settings']['wrapper']) : 'div';
  $content = '</' . $wrapper . '>';

  return $content;
}


/**
 * Render the ds_prefix field.
 */
function workshop_helper_ds_field__ds_prefix($field) {
  $wrapper = isset($field['formatter_settings']['wrapper']) ? check_plain($field['formatter_settings']['wrapper']) : 'div';
  $css_class = empty($field['formatter_settings']['css_class']) ? '' : ' class="' . check_plain($field['formatter_settings']['css_class']) . '"';
  $content = '<' . $wrapper . $css_class . '>';

  return $content;
}