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From: Jakub Kicinski <kuba@kernel.org>
To: Horatiu Vultur <horatiu.vultur@microchip.com>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<andrew@lunn.ch>, <hkallweit1@gmail.com>, <linux@armlinux.org.uk>,
	<davem@davemloft.net>, <edumazet@google.com>, <pabeni@redhat.com>,
	<richardcochran@gmail.com>
Subject: Re: [PATCH net-next v3] net: phy: micrel: Add support for PTP_PF_PEROUT for lan8841
Date: Fri, 10 Mar 2023 16:38:24 -0800	[thread overview]
Message-ID: <20230310163824.5f5f653e@kernel.org> (raw)
In-Reply-To: <20230307214402.793057-1-horatiu.vultur@microchip.com>

On Tue, 7 Mar 2023 22:44:02 +0100 Horatiu Vultur wrote:
> Lan8841 has 10 GPIOs and it has 2 events(EVENT_A and EVENT_B). It is
> possible to assigned the 2 events to any of the GPIOs, but a GPIO can
> have only 1 event at a time.
> These events are used to generate periodic signals. It is possible to
> configure the length, the start time and the period of the signal by
> configuring the event.
> Currently the SW uses only EVENT_A to generate the perout.
> 
> These events are generated by comparing the target time with the PHC
> time. In case the PHC time is changed to a value bigger than the target
> time + reload time, then it would generate only 1 event and then it
> would stop because target time + reload time is small than PHC time.
> Therefore it is required to change also the target time every time when
> the PHC is changed. The same will apply also when the PHC time is
> changed to a smaller value.
> 
> This was tested using:
> testptp -L 6,2
> testptp -p 1000000000 -w 200000000

AFAICT enabling a new output will steal the event from the previous one.
Is this normal / expected? Should you be checking if any output is
active and refuse to enable another GPIO if so?

Richard, does the patch look good to you?

  reply	other threads:[~2023-03-11  0:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-07 21:44 [PATCH net-next v3] net: phy: micrel: Add support for PTP_PF_PEROUT for lan8841 Horatiu Vultur
2023-03-11  0:38 ` Jakub Kicinski [this message]
2023-03-13  2:31   ` Richard Cochran
2023-03-13 22:35     ` Jakub Kicinski
2023-03-13 22:40 ` patchwork-bot+netdevbpf

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