From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: Wei Fang <wei.fang@nxp.com>,
andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, xiaoning.wang@nxp.com,
Frank.Li@nxp.com, yangbo.lu@nxp.com, christophe.leroy@csgroup.eu,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org, imx@lists.linux.dev
Subject: Re: [PATCH net-next 0/3] ptp: add pulse signal loopback support for debugging
Date: Wed, 3 Sep 2025 18:11:38 +0300 [thread overview]
Message-ID: <20250903151138.malmfj53hew7caze@skbuf> (raw)
In-Reply-To: <aLhFiqHoUnsBAVR7@hoboy.vegasvil.org>
On Wed, Sep 03, 2025 at 06:41:30AM -0700, Richard Cochran wrote:
> On Wed, Sep 03, 2025 at 04:37:46PM +0800, Wei Fang wrote:
> > Some PTP devices support looping back the periodic pulse signal for
> > debugging,
>
> What kinds of debugs can be resolved by this loopback feature?
The commit message of patch 2/3 shows that you can record extts events
for the periodic output signal emitted by the device, without this
signal ever being required to be routed in any particular way on the PCB,
through the SoC's pins.
So you can make sure that the pulse intervals and their phase alignment
are correct from the perspective of the emitting PHC's time base.
Or you can use it as a built-in extts event generator when you have no
external equipment which does that, as I did a few years ago to validate
the extts functionality on ptp_qoriq.
> It seems pointless to me...
Well, it's pointless in the same sense that a mirror is pointless.
next prev parent reply other threads:[~2025-09-03 15:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-03 8:37 [PATCH net-next 0/3] ptp: add pulse signal loopback support for debugging Wei Fang
2025-09-03 8:37 ` [PATCH net-next 1/3] ptp: add debugfs interfaces to loop back the periodic output signal Wei Fang
2025-09-04 13:30 ` Vladimir Oltean
2025-09-05 2:25 ` Wei Fang
2025-09-03 8:37 ` [PATCH net-next 2/3] ptp: netc: add the periodic output signal loopback support Wei Fang
2025-09-04 13:31 ` Vladimir Oltean
2025-09-03 8:37 ` [PATCH net-next 3/3] ptp: qoriq: covert to use generic interfaces to set loopback mode Wei Fang
2025-09-04 13:35 ` Vladimir Oltean
2025-09-03 13:41 ` [PATCH net-next 0/3] ptp: add pulse signal loopback support for debugging Richard Cochran
2025-09-03 15:11 ` Vladimir Oltean [this message]
2025-09-04 1:55 ` Wei Fang
2025-09-04 13:05 ` Richard Cochran
2025-09-04 13:37 ` Jakub Kicinski
2025-09-05 2:18 ` Wei Fang
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