Re: [PATCH net-next v5 1/2] ptp: introduce Alibaba CIPU PHC driver

[Wen Gu]

On 2025/11/1 07:58, Jakub Kicinski wrote:
> On Thu, 30 Oct 2025 20:13:13 +0800 Wen Gu wrote:
> > This adds a driver for Alibaba CIPU PTP clock. The CIPU, an underlying
> > infrastructure of Alibaba Cloud, synchronizes time with atomic clocks
> > via the network and provides microsecond or sub-microsecond precision
> > timestamps for VMs and bare metals on cloud.
> >
> > User space processes, such as chrony, running in VMs or on bare metals
> > can get the high precision time through the PTP device exposed by this
> > driver.
>
> As mentioned on previous revisions this is a pure clock device which has
> nothing to do with networking and PTP.

I don't quite agree that this has nothing to do with PTP.

What is the difference between this CIPU PTP driver and other PTP drivers
under drivers/ptp? such as ptp_s390, ptp_vmw, ptp_pch, and others. Most of
these PTP drivers do not directly involve IEEE 1588 or networking as well.

> There should be a separate class
> for "hypervisor clocks", if not a common driver.

'hypervisor clock' is not very accurate. CIPU PTP can be used in VM and
bare metal scenarios, and bare metals do not need hypervisors.

Regards.