ti,vref-delay-usecs vref supply delay in usecs, 0 for
external vref (u16).
ti,vref-mv The VREF voltage, in millivolts (u16).
- Set to 0 to use internal refernce
+ Set to 0 to use internal references
(ADS7846).
ti,keep-vref-on set to keep vref on for differential
measurements as well