Re: [chrony-dev] [RFC] Support for raw memory mapped clock sources

[Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@xxxxxxxxxxxxxxxxxxxx>]

On 10/21/25 16:14, Josef 'Jeff' Sipek wrote:
> Another option would be to write a kernel module to expose the FPGA's
> registers as a /dev/ptp device.  (I *think* it is possible to expose PTP
> device without it being a NIC, but I'd have to check the code.)  Chrony and
> other timekeeping related software already know how to use those.  Granted,
> writing kernel code is way more effort than a simple mmio <-> SOCK refclock
> user tool.
Thank you very much everyone for your input.

I had a look at the PHC driver possibilities. Turns out their is already 
one in Xilinx's Linux fork! There's a corresponding IP for the FPGA 
programmable logic. The PL should be able to forward NMEA to this IP.

 - 
https://github.com/Xilinx/linux-xlnx/blob/e9aec5f9a14dcfacbd0f839cdae46ec42616ce1c/drivers/ptp/ptp_xilinx.c#L1

--
Cheers,

Enguerrand de Ribaucourt
Savoir-faire Linux

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