Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/EFR32BG22C222F352GN32/CMU_NS/PRORTCCLKCTRL#0x0
No Description
Clock Select
1 (LFRCO): LFRCO is clocking PRORTCCLK
2 (LFXO): LFXO is clocking PRORTCCLK
3 (ULFRCO): ULFRCO is clocking PRORTCCLK
https://github.com/cmsis-svd/cmsis-svd-data