This seems like a simple feature that must exist, yet I can't find it in settings or by googling. I want this behavior:
The screen should never lock while I'm on a voice call, no matter how long I'm talking.
After the call is over, it should return to its normal behavior, locking after X minutes of inactivity or when I click the top button to turn the screen off.
Can this be achieved?
Best Answer
To summarize in an actual answer: no, this feature has not been included in iOS - as of iOS 7.
As you are aware, the proximity sensor disables the screen when the phone is close to your ear (to avoid accidentally selecting options on the screen, and reduce battery drain), and you can choose to have the phone auto-lock after X number of minutes, but these two features do not work together at all.
Perhaps a somewhat plausible workaround would be to have your passcode, if applicable, only engage after a set amount of lock-time. That way, at least you wouldn't have to enter in your passcode to resume activity on the device after a phone call.
Otherwise, unfortunately, like many other things on iOS, there is remarkably little "hacking" or workarounds that are available unless you decide to jailbreak your phone.