The high school rule (NFHS) has not changed. A player can grasp the ring to prevent injury. Any grasping of the rule other than to prevent injury is a technical foul.
I don't know the exact wording of the collegiate or NBA rules, but I see the application of the rule gets looser the higher you go. In addition to chin-ups on the rim in the NBA, I believe I have seen a Healy in a pike position and a salto with a half-twist (those are gymnastics moves on the high bar.. and yes, I had to look those up in Google I'm proud to say).
Case 10.3.5 D
Z