I am doing Power Management in my Linux code where the wakeup source is keypad and resistive touch. The touch driver is STMPE811 and basically the touch is working fine. Its a 4-wire touch controller with an interrupt line and no dedicated wakeup line . When I issue the command for suspend, the stmpe suspend function is called and the irq is enabled . The irq number is 275 and the touch interrupt number is also same. I tried adding wakeup-source property under stmpe node in dts file but the touch wakeup is not working and the system is under suspend mode.
When we probed the interrupt line using a multimeter probe, the moment the positive terminal of the multimeter is touched on the interrupt line, the system is resumed . That looked little strange and confusing.
Could anyone help me to find out the solution to configure the touch as wakeup source ?