Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Spansion/MB9AF31xK/DS/WIFSR#0x0
Deep Standby Return Cause Register 2
RTC interrupt return bit
LVD interrupt return bit
WKUP pin input return bit 0
WKUP pin input return bit 1
WKUP pin input return bit 2
WKUP pin input return bit 3
https://github.com/cmsis-svd/cmsis-svd-data