Thanks to @Michael_Welling and @Felipe_Balbi for their insights! @Robert_Nelson has merged a fix for the eQEP driver by @Nathaniel_Lewis :
tieqep: add patch to fix unhandled fault on 4.9 kernel
https://github.com/RobertCNelson/ti-linux-kernel-dev/commit/f89418b8f79dea8a843dab279b7c47c5a4b79ef9
(FYI: eQEP is a term by @Texas_Instruments that stands for enhanced Quadature Encoded Pulse decorder. The eQEP peripheral can automatically track the position of a rotary encoder knob or motor encoder without having to bother the ARM core).