Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/Infineon/XMC4300/CAN/MCR#0x0
CLKSEL=value1
Module Control Register
Baud Rate Logic Clock Select
0 (value1): No clock supplied
1 (value2): fPERIPH
2 (value3): fOHP
4 (value4): hard wired to 0
8 (value5): hard wired to 0
Message Pending Selector
https://github.com/cmsis-svd/cmsis-svd-data