Thank you for contacting the Intel community.
Did you try the Intel Atom® Processor Z3600 and Z3700 Series Datasheet, Vol. 1?
Please check page 54
Please let me know how it goes.
I have looked into it but it also only describes the states S0 (SCORE) and S5 (SSUS). What bothers me is that ACPI says it's a ValleyView GPNCORE controller but the term "NCORE" is never mentioned in the datasheet (not once in V.2 and not in this context in V.1).
To provide some further information on what I want to do:
I try to write a touch input driver for an Intel Atom tablet on Genode. The touch controller is connected to the I2C4 bus as a slave device but needs to be enabled first. This can be done either via ACPI (which fails with AE_UNINITIALIZED_ARG, but I think this is off topic here) or via GPIO.
I looked again into the datasheet V.2 and in GPSCORE at the offset 0x1a0 (which corresponds to the pin number 0x1a) is indeed the I2C4 Sda Pad.
The value i read out initially after boot is different to the default value in the datasheet (pull_assign is set to Pull Down instead of Pull Up). I can successfully set the correct Func Pin Mux value but setting the Pad Value seems to have no effect. Also since sda is the I2C data line (afaik) I'm not sure that this is the correct pin.