Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/EFR32BG12P/EFR32BG12P432F1024GL125/I2C1/CLKDIV#0x0
Clock Division Register
Clock Divider
https://github.com/cmsis-svd/cmsis-svd-data