[Solved] Regex Check Codeigniter Form Validation

In codeigniter callback form validation

How can I check if $password has at least one upper case letter?

PHP Code:

<?php

class Login extends CI_Controller {

    public function __construct() {
        parent::__construct();
    }

    public function index() {    
        $data['title'] = 'Administration';

        $this->form_validation->set_rules('username', 'Username', 'trim|required');
        $this->form_validation->set_rules('password', 'Password', 'trim|required|callback_regex');

        if ($this->form_validation->run() == FALSE) {

            $this->load->view('common/header.tpl', $data);
            $this->load->view('common/login.tpl', $data);
            $this->load->view('common/footer.tpl');

        } else {

            redirect('common/dashboard');

        }
    }

    public function regex($password) {
        if ($password == FALSE) {
            $this->form_validation->set_message('regex', 'Password must contain at least one upper case letter');
            return false;
        } else {
            return true;
        }
    }
} 


There's only one rule - please don't tell anyone to go and read the manual.  Sometimes the manual just SUCKS!