Re: [PATCH spi for-5.4 0/5] Deterministic SPI latency with NXP DSPI driver

On Tue, Aug 20, 2019 at 09:38:45PM -0700, Richard Cochran wrote:

Overall, the PTP switch use case is well supported by Linux.  The
synchronization of the management CPU to the PTP, while nice to have,
is not required to implement a Transparent Clock.  Your specific
application might require it, but honestly, if the management CPU
needs good synchronization, then you really aught to feed a PPS from
the switch into a gpio (for example) on the CPU.

Another way to achieve this is to have a second MAC interface on the
management CPU connected to a spare port on the switch.  Then time
stamping, PHC, ptp4l, and phc2sys work as expected.

Thanks,
Richard