excel upload in codeigniter

form.php : 

 <form id="productadd" method="post" action="" enctype="multipart/form-data">
<input type="file"  name="excelfile" />
 <input type="submit">
</form>

//excel upload in controller

if( isset($_FILES['excelfile']['name']) && $_FILES['excelfile']['name']!='') { $fileExtension2 = explode(".", $_FILES['excelfile']['name']); $fileExt = array_pop( $fileExtension2 ); $filename = time().'-'.md5($_FILES['dfile']['name']).".".$fileExt; $config['upload_path'] = DEVICE_FILE_PATH; $config['allowed_types'] = 'xls|xlsx'; $config['file_name'] = $filename; $file = $filename; $this->load->library('upload', $config); if (!$this->upload->do_upload('excelfile')) { $error = array('error' => $this->upload->display_errors()); } }