Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Silicon Labs/Series0/EZR32HG/EZR32HG320F64R61/USB/DIEP2_TXFSTS#0x0
Device IN Endpoint x+1 Transmit FIFO Status Register
TxFIFO Space Available
https://github.com/cmsis-svd/cmsis-svd-data