[Linuxptp-users] AR8031 (or other 1 GigE) PHC driver availability

[Dave Berg]

Hello,

We have been using LinuxPTP with great success on a system with a
dp83640 PHY and DaVinci MAC running Linux 4.2. We now need to move to
a 1 GigE based system with PHY-based timestamping, but it seems that
no driver exists which supports the PHC of the PHY we're targeting.

The system we're targeting is the TI am335x Starter Kit (TMDSSK3358),
which uses the Qualcomm Atheros ar8031 PHY, and the MAC in the am335x
processor uses the TI CPTS for timestamping.

I found a previous response from Richard on the linuxptp-devel mailing
list (URL: https://sourceforge.net/p/linuxptp/mailman/message/31706496/)
which states "Right now, the dp83640 is only PHY driver in the kernel
with time stamping and PHC supported", but since that was written on
2013-12-02 I am hopeful that there may be more options by now.
However, the mainline ar8031 PHY driver has no PHC support, and I see
no other PHY-based timestamping solutions listed in the Driver Support
Matrix in LinuxPTP's current readme file.

Is there any chance that a driver for the ar8031 with timestamping and
PHC support exists outside of mainline Linux so that we could still
potentially use this platform? Even an in-development driver could be
an option for us.

If not, is this group aware of any alternative 1 GigE PHYs with PHC
Linux driver support of some sort?

Any help or suggestions would be greatly appreciated.
Dave

[Richard Cochran]

Post by Dave Berg
The system we're targeting is the TI am335x Starter Kit (TMDSSK3358),
which uses the Qualcomm Atheros ar8031 PHY, and the MAC in the am335x
processor uses the TI CPTS for timestamping.

Just FYI, we don't have generic support for systems with both a MAC
and a PHY PHC on the same interface. If and when you get a PHY
driver, then you'll have to patch the MAC driver minimally to disable
CPTS support and pass the ioctls through.

Post by Dave Berg
Is there any chance that a driver for the ar8031 with timestamping and
PHC support exists outside of mainline Linux so that we could still
potentially use this platform? Even an in-development driver could be
an option for us.

I am not aware of any.

Post by Dave Berg
If not, is this group aware of any alternative 1 GigE PHYs with PHC
Linux driver support of some sort?

Yeah, a gigabit PHY with PHC would be great, but unfortunately I have
not seen one yet. Too bad NatSemi^W TI didn't produce a GB phyter.

Sorry,
Richard

PS IIRC, there is a technical hurdle to achieve real PHY time stamps
in gigabit devices. Are you sure the Atheros time stamps in the PHY
and not on the MII bus inputs/outputs? (Just curious)

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[Dave Berg]

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