Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32l4+/STM32L4P5/SDMMC1/POWER#0x0
power control register
SDMMC state control bits
Voltage switch sequence start
Voltage switch procedure enable
Data and command direction signals polarity selection
https://github.com/modm-io/cmsis-svd-stm32