Beaglebone ADC external reference voltage

Hi all,

I am using the ADC channels on a custom board (very similar to beaglebone; in fact a copy with added peripherals) with am33xx. I want to change the ADC reference voltage to external (1.6 v which I have setup on VREFP)

I am digging through the touchscreen driver file in linux kernel. (ti_tscadc.c) I have changed the RFP & RFM registers on IDLECONFIG, CHARGECONFIG, and all the STEPCONFIG and still no luck. Anyone has any ideas? I am attaching my ti_tscadc.c file. I have confirmed that the kernel only executes __devinit tscadc_probe function at the start up. I am able to get ADC readings but still the reference voltage is 1.8 V.

Best regards,

ti_tscadc.c (23.6 KB)