how is convert this code to CodeIgniter code?

[eluser]SaSa[/eluser]
how is convert this code to CodeIgniter code:
search_hotel: -> this is CI_Model

Code:

return mysql_query("select * from hotel_submits where name LIKE '".$searchterm."'")

i try but have error:

Code:

$query = $this->db->order_by("id", "desc")->like('name', '$searchterm')->get('hotel_submits');
        return $query->row();

error:

A PHP Error was encountered
Severity: Warning
Message: mysql_fetch_assoc() expects parameter 1 to be resource, array given
Filename: admin/tour.php
Line Number: 15


A PHP Error was encountered
Severity: Notice
Message: Undefined variable: data
Filename: admin/tour.php
Line Number: 21

code:-> this is CI_Controller

Code:

$searchterm = $this->input->post('search_hotel');
        $result = $this->model_tour->search_hotel($searchterm);
        while ($row = mysql_fetch_assoc($result)) { //this is line 15
        //giving names to the fields
        $data = array (
            'name' => $row->name,            
        );
        }
        echo json_encode($data);  //this is line 21