I am working on a custom system with the i.MX515 and MC13892 PMIC. We have a touch screen set up in the system (we are using a separate device, not the controller in the PMIC) and have a need to suspend the system to RAM and wakeup on a touch event. While we can do a fast bootup (~2s till graphics) that is not enough for this particular end device. From what I can tell the suspend functionality is working in 22.214.171.124 (this is a freescale kernel, unsure about mainline) but I cant get it to wake up.
The MC13892 documentation calls out that the internal ADC can be put in to a mode to correctly trigger a wakeup on a touch event. This is done by the PMIC putting voltage on one plane, and ground on the other. When both planes are at ground potential the PMIC causes a TSI interrupt and should wake up the whole system. Is there a linux mechanism in place to put the ADC in to this interrupt mode? I can wire in some hardware to generate the touch event (not using the PMIC touchscreen controller, remember) but the actual pins involved in this interrupt state (TSX2 to be exact) all have ground potential and do not show a voltage. Because of this there is no way for me to trigger this interrupt.
Anyone know how to put the PMIC ADC in the state to allow wakeup from suspend to RAM?