Excel upload and store data in database in codeigniter

if($this->input->server('REQUEST_METHOD')=='POST')
{
$this->form_validation->set_rules('org_name','Organization Name','trim|required|min_length[2]|max_length[80]|callback_check_unique_orgname');

$org_id = $_POST['org_name'];
$status = $_POST['status'];

if (isset($_FILES['dfile']['name'])){

if( isset($_FILES['dfile']['name']) && $_FILES['dfile']['name']!='')
{
$fileExtension2 = explode(".", $_FILES['dfile']['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('dfile'))
{
$error = array('error' => $this->upload->display_errors());
}

}
elseif (isset($_POST['dfile']))
{
$filename=$_POST['dfile'];

}
else
{
$filename='';
}
$fileExt = 'xlsx';
$file = DEVICE_FILE_PATH.$filename;
$this->load->library('excel');

//read file from path
$objPHPExcel = PHPExcel_IOFactory::load($file);
$cell_collection = $objPHPExcel->getActiveSheet()->getCellCollection();
$sheetData = $objPHPExcel->getActiveSheet()->toArray(null, true, true, true);

$sheetData = array_filter($sheetData);

$j=0;
foreach($sheetData as $headerkeyarray=>$headerkeyvalues)
{
$k=0;

foreach($headerkeyvalues as $eheaderkeyarray=>$eheaderkeyvalues)
{
if($eheaderkeyvalues !='')
{
if($eheaderkeyarray == 'A')
{
$d_name[$headerkeyarray] = $eheaderkeyvalues;
}
}
$k++;
}
$j++;
}


for($row=3;$row<$j;$row++)
{
$dev_id = $this->device_model->device_unique_check( $d_name[$row], $org_id);
if ( $dev_id == '' ){
$device_detail = array(
"device_id"=> isset($d_name[$row])?$d_name[$row]:'',
"org_id"=> $org_id,
"status"=> $status
);
$result = $this->device_model->add_device($device_detail);
}
}

if( isset($result))
{
$this->session->set_flashdata('SucMessage',DEVICE_ADDED_SUS);
redirect(base_url().'device/','refresh');
}
}

}