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From:   Vincent MAILHOL <mailhol.vincent@wanadoo.fr>
Date:   Tue, 12 Jan 2021 15:38:33 +0900
Message-ID: <CAMZ6RqKY-QiNi_=H_J3QpwPfy7KUSNHRD5ok_MqnWgR-bou2hQ@mail.gmail.com>
Subject: Re: [PATCH v3 1/1] can: dev: add software tx timestamps
To:     Richard Cochran <richardcochran@gmail.com>
Cc:     Marc Kleine-Budde <mkl@pengutronix.de>,
        linux-can <linux-can@vger.kernel.org>,
        Jeroen Hofstee <jhofstee@victronenergy.com>,
        Wolfgang Grandegger <wg@grandegger.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        "open list:NETWORKING DRIVERS" <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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On Tue. 12 Jan 2021 at 11:14, Richard Cochran <richardcochran@gmail.com> wrote:
>
> On Tue, Jan 12, 2021 at 09:00:33AM +0900, Vincent MAILHOL wrote:
> > Out of curiosity, which programs do you use? I guess wireshark
> > but please let me know if you use any other programs (I just use
> > to write a small C program to do the stuff).
>
> I was thinking of PTP over DeviceNET (which, in turn, is over CAN).
> This is specified in Annex G of IEEE 1588.
>
> The linuxptp stack has modular design and could one day support
> DeviceNET.  It would be much easier for linuxptp if CAN interfaces
> support hardware time stamping in the same way as other network
> interfaces.

I actually also thought of implementing PTP but for a slightly
different goal: synchronise the clock of the different CAN
controllers connected to a same Linux host. But so far, it is
just a rough idea and I never looked really deep into the
technical details of linuxptp.

However, I did not know about DeviceNET. I am not really aware of
the use cases for industrial automation applications.

Glad to have asked, learnt something :)


Yours sincerely,
Vincent