Time Restriction

HI,

I want to know if there is a way to set up the phone so it is un useable after a certain time. So it needs parent permission to continue to use it or is that a service provider question?

For Example:

The kids come home they are playing on the phone. I want them to not be able to use the phone except to call me after 4:00pm when they are suppose to be doing their homework. And then I can simply enter a passcode that allows them in after their hwk is done or the day passes into the next (but then resets to do it again the next day.)

I want to make sure my kids are focusing on their hwk and less on their friends latest instagram photo. Please help. Thank You.