Lemme quickly answer that last question: no.



How this works? irq_wake.



How does your phone switch on when your phone is in deep sleep and you press the power button? It's because though there is deep sleep, there's still power being routed to those buttons since you want to get those 'interrupt's (viz: key presses).



Similarly, that's what we do with the touch panel: in your device's case, cyttsp3. We don't allow the touch panel to 'sleep', viz. Power is always routed to the touch panel. So, battery drains because the touch panel is always turned on, and not because the phone doesn't go to deep sleep.



P.S. if your touch panel has a 'low power mode' of sorts, that could be used to slightly lower power consumption, thus 'slightly' reducing battery consumption.