Proud moment: catching the kid up at midnight reading. I can verify it's actually impossible to tell a child off for something you both did and totally approve of.
Serious passion for reading, though we did end up having to 'bring the hammer down' and shake him down for lights before bed, alas.
These days I mostly read serial online fiction, because it comes comes in metered doses; e.g. http://pactwebserial.wordpress.com/
My parents quickly realized that "go to your room" was totally a non-punishment for me, and they couldn't reasonably do anything to stop me from reading after they'd gone to bed.
I'd suggest working with your son on flexible solutions -- it could work to ask him to always read more advanced stuff (with more challenging vocabulary, plot, etc.) at bedtime so that it takes more brain-work... that makes it a bit more likely that he'll put it down when he's really tired.
The main thing (I think -- my oldest is only 5) is to see if he himself thinks there's a problem, and (if so) help him hack his own lifestyle, acknowledging that you don't know the answer, but you can help experiment & track the results.
It's pretty much a solved problem. We talked about it, over the course of several years.
Mostly, for him, it's about self moderation/regulation. He's mildly autistic, so it's super easy for him to get 'stuck' on many types of tasks/actions.
He is now able to grasp and internalize the consequences of staying up all night reading. :)