The best person to ask about what exercises are safe is your PT or your surgeon. They will know how much damage there was, and how the repair was performed. That information should be in your operative report, you will want a copy for your records.
The surgeon or PT will be able to give you an idea when you can return to lifting weights, how much, and which activities to avoid.
Since you are a couple of weeks out of your rotator cuff repair, I suggest you concentrate on your early rehabilitation. Lifting weights will have to wait until your shoulder has returned to where it is safe to return to previous activities.