Question: Linux changes required for off control board RTC

[Tracy Smith]

Hi, not sure if this is the correct venue to post a question, so
please forgive and direct me to the correct board or list if not.

A custom board implementation using a ARM-8 Cortex A53 NXP LS1043ardb
is considering moving the RTC from the control board to an FPGA.
Reason is for accuracy of time/date and efficiency for their FPGA/DSP
application.

1) What kernel changes would be required to support such an
implementation and these would need to be pushed to the community
under the GPL?

2) Is it a trivial task to make such changes in the kernel to support
an RTC not located on the control board/SoC itself?

3) What is the expected behavior of the kernel with no changes added
to accommodate such an architecture?

4) Is there a configurable kernel option to allow for such a change,
or have these or similar changes already been added to the kernel?

thx,
Tracy