--- /dev/null
+/**
+ * Implements hook_field_settings_form().
+ */
+function {{ machine_name }}_field_settings_form($field, $instance, $has_data) {
+ $settings = $field['settings'];
+ $form['max_length'] = array(
+ '#type' => 'textfield',
+ '#title' => t('Maximum length'),
+ '#default_value' => $settings['max_length'],
+ '#required' => FALSE,
+ '#element_validate' => array('element_validate_integer_positive'),
+ '#description' => t('The maximum length of the field in characters. Leave blank for an unlimited size.'),
+ );
+ return $form;
+}