Newbie: Convert strings in nested dict to tuples

[KP]

I now know how to convert a string cont. coordinates to a tuple, but hwo can I do this?

Given

cfg = {'canvas': ('3840', '1024'),
      'panel1': {'gpio': '1', 'id': '4', 'co': '0,0,1280,1024'}, 
      'panel2': {'gpio': '2', 'id': '5', 'co': '1280,0,2560,1024'},
      'panel3': {'gpio': '3', 'id': '6', 'co': '2560,0,3840,1024'}}

how can I transform cfg to 

cfg = {'canvas': ('3840', '1024'),
      'panel1': {'gpio': '1', 'id': '4', 'co': ('0','0','1280','1024')}, 
      'panel2': {'gpio': '2', 'id': '5', 'co': ('1280','0','2560','1024')},
      'panel3': {'gpio': '3', 'id': '6', 'co': ('2560','0','3840','1024')}}

Again, thanks for all help!