Q. Can I program the MAX9257A from the camera side?
A. No, you cannot. The microcontroller can only attached on MAX9258A side.
In camera application, uC can program MAX9258A local device only in UART interface, MAX9257A remote over the link (in reverse direction) and camera in either I2C or UART through MAX9257 peripheral interface.
If the design requires programming the SERDES chipset from the camera side, use one of the newer GMSL SERDES parts families.
The MAX9275/MAX9276 and MAX9281/MAX9282 are good options to consider for GMSL SerDes solutions.