On 06/05/2018 04:28 PM, Andrew Lunn wrote:

quoted

I hope you are right - question is always in number of available options
and which one to select - and, most important, explain it to the end user :(

The end customer being ptp4linux? At least for Marvell switches, it is
happy about everything except that the switch is a bit slow, so we
need to modify some of the time outs in the configuration file.

quoted

For example:
phc_index is returned as part of .get_ts_info() = cpsw_get_ts_info(),
so which intf should return phc_index?

It is not a 1:1 relationship. See:

https://elixir.bootlin.com/linux/latest/source/drivers/net/dsa/mv88e6xxx/hwtstamp.c#L61

All interfaces return the same index.

In fact, for a switch, having a PHC per port would be odd. That would
mean you need to sync the PHCs in order to act as a boundary clock.

PHC only one, but hw timestamping blocks are per port.

-- 
regards,
-grygorii