There is a generic ADV728X driver inside linux kernel which you may see here.
In that driver, CSI registers [0x01..0x08] are written different values, according to I2P enablement.
enabled = 0x20, 0x28, 0x38, 0x30, 0x30, 0x80, 0x70, 0x50
disabled = 0x18, 0x18, 0x30, 0x20, 0x28, 0x40, 0x58, 0x30 default values listed in UG-637.
also writing 0x80 to register 0x1D of CSI Map if I2P is enabled.
These are looking like fine-tuning CSI-2 timing to adjust cooperation with the CSI-2 receiver.
Are any of these necessary with a different type of CSI-2 receiver?