Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32n6/STM32N645/CSI/CSI_PRCR#0x0
PEN=B_0x0
CSI PHY reset control register
When set to 0, this bit places the digital section of the D-PHY in the reset state.
0 (B_0x0): PHY is disabled (in reset state).
1 (B_0x1): PHY is enabled (out of reset state).
https://github.com/modm-io/cmsis-svd-stm32