Does a two stroke engine have only one valve per cylinder?

Some two stroke engines have 4 valves, Detroit Diesel 71 series and 53 series engines for example.

Most small 2 stroke engines have no "Valves" at all in the sense of the "POP" valve used in four stroke engines.

Some people feel these engine has one valve because the piston acts as the valve covering the ports cut into the cylinder walls.