From: Richard Cochran <richardcochran@gmail.com>
To: Michael Walle <michael@walle.cc>
Cc: Andrew Lunn <andrew@lunn.ch>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Florian Fainelli <f.fainelli@gmail.com>,
Heiner Kallweit <hkallweit1@gmail.com>,
Russell King <linux@armlinux.org.uk>,
"David S . Miller" <davem@davemloft.net>
Subject: Re: [RFC PATCH 0/2] AT8031 PHY timestamping support
Date: Tue, 25 Feb 2020 18:54:41 -0800 [thread overview]
Message-ID: <20200226025441.GB10271@localhost> (raw)
In-Reply-To: <9955C44A-8105-4087-8555-BAC5AE4AF25D@walle.cc>
On Wed, Feb 26, 2020 at 01:07:26AM +0100, Michael Walle wrote:
> Am 26. Februar 2020 00:50:40 MEZ schrieb Andrew Lunn <andrew@lunn.ch>:
> >That sounds fundamentally broken.
Right. It can't work unless the PHY latches the time stamp.
> This might be the case, but the datasheet (some older revision can
> be found on the internet, maybe you find something) doesn't mention
> it. Nor does the PTP "guide" (I don't know the exact name, I'd have
> to check at work) of this PHY. Besides the timestamp there's also
> the sequence number and the source port id which would need to be
> read atomically together with the timestamp.
Maybe the part is not intended to be used at all in this way?
AFAICT, PHYs like this are meant to feed a "PTP frame detected" pulse
into the time stamping unit on the attached MAC. The interrupt serves
to allow the SW to gather the matching fields from the frame.
Thanks,
Richard
next prev parent reply other threads:[~2020-02-26 2:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 23:08 [RFC PATCH 0/2] AT8031 PHY timestamping support Michael Walle
2020-02-25 23:08 ` [RFC PATCH 1/2] net: phy: let the driver register its own IRQ handler Michael Walle
2020-02-26 7:27 ` Heiner Kallweit
2020-02-26 11:12 ` Michael Walle
2020-02-26 21:17 ` Heiner Kallweit
2020-02-26 22:56 ` Michael Walle
2020-02-25 23:08 ` [RFC PATCH 2/2] net: phy: at803x: add PTP support for AR8031 Michael Walle
2020-02-25 23:50 ` [RFC PATCH 0/2] AT8031 PHY timestamping support Andrew Lunn
2020-02-26 0:07 ` Michael Walle
2020-02-26 2:54 ` Richard Cochran [this message]
2020-02-26 11:30 ` Michael Walle
2020-02-26 14:29 ` Richard Cochran
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