Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series1/EFM32GG11B/EFM32GG11B520F2048IL120/I2C2/TXDOUBLE#0x0
Transmit Buffer Double Data Register
TX Data
https://github.com/cmsis-svd/cmsis-svd-data