Processing multiple input fields with codeigniter?

Variant Title:<input type="text" name="variant_title"><br>
Variant Option: <input type="text" name="variant_option[]"><br>
Variant Option: <input type="text" name="variant_option[]"><br>
Variant Option: <input type="text" name="variant_option[]"><br>

if (is_array($this->input->post('variant_option')):
   foreach ($this->input->post('variant_option') as $value):
       $variant_options[] = $value; // loop through...
   endforeach;
endif;
    public function add_banner_image($banner_id = 0) {
            foreach ($this->input->post('link') as $link) {
            $data = array(
                'banner_id' => $banner_id,
                'link' => $link,
            );
            foreach($_FILES as $field => $file) {
                if (!empty($file)) {
                    if ($this->upload->do_upload($field)) {
                        $file_data = $this->upload->data();
                        $data['image'] = $file_data['file_name'];
                    }
                }
            }
            $this->db->insert_id();
            $this->db->insert('banner_image', $data);
            }
        }
https://www.daniweb.com/programming/web-development/threads/490296/inserting-multiple-data-php-codeigniter