Attach pdf file to custom post type

Here this is my code which i used in my wordpress site in custom post type for adding the pdf to the post and its work for me try to change its and use it. Hope it will help

function add_custom_meta_boxes() {  
    add_meta_box('wp_custom_attachment', 'Hotel Brochure', 'wp_custom_attachment', 'hotel_post', 'normal', 'high');  
}
add_action('add_meta_boxes', 'add_custom_meta_boxes');  

function wp_custom_attachment() {  
    wp_nonce_field(plugin_basename(__FILE__), 'wp_custom_attachment_nonce');
    $html="<p class="description">";
    $html .= 'Upload your PDF here.';
    $html .= '</p>';
    $html .= '<input type="file" id="wp_custom_attachment" name="wp_custom_attachment" value="" size="25">';
    echo $html;
}

add_action('save_post', 'save_custom_meta_data');
function save_custom_meta_data($id) {
    if(!empty($_FILES['wp_custom_attachment']['name'])) {
        $supported_types = array('application/pdf');
        $arr_file_type = wp_check_filetype(basename($_FILES['wp_custom_attachment']['name']));
        $uploaded_type = $arr_file_type['type'];

        if(in_array($uploaded_type, $supported_types)) {
            $upload = wp_upload_bits($_FILES['wp_custom_attachment']['name'], null, file_get_contents($_FILES['wp_custom_attachment']['tmp_name']));
            if(isset($upload['error']) && $upload['error'] != 0) {
                wp_die('There was an error uploading your file. The error is: ' . $upload['error']);
            } else {
                update_post_meta($id, 'wp_custom_attachment', $upload);
            }
        }
        else {
            wp_die("The file type that you've uploaded is not a PDF.");
        }
    }
}

function update_edit_form() {
    echo ' enctype="multipart/form-data"';
}
add_action('post_edit_form_tag', 'update_edit_form');

To get the PDF

$hotel_brochure = get_post_meta( $post_id, 'wp_custom_attachment', true );
$hotel_brochure['url']