Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/EFR32BG22C224F512GM32/GPIO_S/PRS0_SYNCH3ROUTE#0x0
SYNCH3 port/pin select
SYNCH3 port select register
SYNCH3 pin select register
https://github.com/cmsis-svd/cmsis-svd-data