How can I get userid from procedure?

See more:

SQL

PHP

MySQL

hi,
i wrote a mysql query(procedure) for insert to user(userID,Role) and userID is auto increament. it works true. i want to get the userID with out parameters but i dont know how?!
my procedure query :

CREATE DEFINER=`root`@`localhost` PROCEDURE `Insert_User`(IN `Role` INT(1))
BEGIN
INSERT INTO user(UserID, Role)VALUES(null, Role);
END

i called it by php code:

if(isset($_POST['sbm']))
	{
		$pass = '1050585712';
		$role = $_POST['user'];
		switch($role)
		{
			case 0 :$role = 0;break;
			case 1 :$role = 1;break;
			case 2 :$role = 2;break;
			case 3 :$role = 3;break;
			case 4 :$role = 4;break;
			default:$role = 3;break;
		}
		if($con = mysqli_connect("localhost", "root", $pass))
		{
			mysqli_select_db($con, "toggery");
			mysqli_set_charset($con, "utf8");
			$p = $con -> prepare("CALL Insert_User(?)");
			$p -> bind_param('i', $role);
			$p -> execute();
		}
		else
		{
			echo 'db connection error!';
		}
	}

What I have tried:

how can i get UserID by php?
and how should i change the procedure query for do this?