Personally, I think using 2 digital pins would be more appropriate:
For example D3 and D4,
D3 = 0, D4 = 0 case 1
D3 = 1, D4 = 0 case 2
D3 = 0, D4 = 1 case 3
D3 = 1, D4 = 1 case 4
Now just put switch case in loop() and add your specific coded between the cases and common code before/after the case.