From: Christian Riesch <christian@riesch•at>
To: Alan Cox <alan@lxorguk•ukuu.org.uk>
Cc: Rodolfo Giometti <giometti@linux•it>,
Arnd Bergmann <arnd@arndb•de>, john stultz <johnstul@us•ibm.com>,
Richard Cochran <richardcochran@gmail•com>,
linux-kernel@vger•kernel.org,
Christian Riesch <christian.riesch@omicron•at>,
netdev@vger•kernel.org, linuxppc-dev@lists•ozlabs.org,
devicetree-discuss@lists•ozlabs.org,
linux-arm-kernel@lists•infradead.org,
Krzysztof Halasa <khc@pm•waw.pl>
Subject: Re: [PATCH 1/5] ptp: Added a brand new class driver for ptp clocks.
Date: Sun, 29 Aug 2010 15:32:20 +0200 [thread overview]
Message-ID: <4C7A6164.60208@riesch.at> (raw)
In-Reply-To: <20100827134154.50eef56c@lxorguk.ukuu.org.uk>
Alan Cox wrote:
>> The master node in a PTP network probably takes its time from a
>> precise external time source, like GPS. The GPS provides a 1 PPS
>> directly to the PTP clock hardware, which latches the PTP hardware
>> clock time on the PPS edge. This provides one sample as input to a
>> clock servo (in the PTPd) that, in turn, regulates the PTP clock
>> hardware.
>
> A PTP clock is TAI, Unix time is UTC.
Not necessarily. AFAIK, the time distributed by IEEE1588v2 can either be
based on the "PTP epoch" (timePropertiesDS.ptpTimescale=TRUE) and thus
represent TAI or be based on an implementation specific arbitrary epoch
(timePropertiesDS.ptpTimescale=FALSE) and represent time on some
arbitrary time scale.
Christian
next prev parent reply other threads:[~2010-08-29 13:32 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-16 11:17 [PATCH v5 0/5] ptp: IEEE 1588 clock support Richard Cochran
2010-08-16 11:17 ` [PATCH 1/5] ptp: Added a brand new class driver for ptp clocks Richard Cochran
[not found] ` <363bd749a38d0b785d8431e591bf54c38db4c2d7.1281956490.git.richard.cochran-3mrvs1K0uXizZXS1Dc/lvw@public.gmane.org>
2010-08-16 14:26 ` Arnd Bergmann
2010-08-16 19:00 ` Richard Cochran
2010-08-16 19:59 ` Arnd Bergmann
2010-08-17 8:32 ` Richard Cochran
2010-08-17 9:25 ` Arnd Bergmann
[not found] ` <201008170925.55592.arnd-r2nGTMty4D4@public.gmane.org>
2010-08-17 10:52 ` Richard Cochran
[not found] ` <20100817105232.GA9079-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-08-17 11:36 ` Arnd Bergmann
2010-08-18 0:40 ` john stultz
[not found] ` <201008171336.29375.arnd-r2nGTMty4D4@public.gmane.org>
2010-08-18 14:04 ` Richard Cochran
2010-08-18 15:02 ` Arnd Bergmann
[not found] ` <201008181702.03384.arnd-r2nGTMty4D4@public.gmane.org>
2010-08-19 9:22 ` Richard Cochran
2010-08-19 12:29 ` Arnd Bergmann
2010-08-19 15:23 ` Ira W. Snyder
2010-08-19 15:48 ` Arnd Bergmann
2010-08-16 19:24 ` john stultz
2010-08-16 19:38 ` john stultz
[not found] ` <AANLkTik_2MKMhOuDGOmu8Kzyq-ipLe+Bxrb3FaD+Tv4U-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-08-17 8:53 ` Richard Cochran
2010-08-18 0:22 ` john stultz
2010-08-18 7:19 ` Richard Cochran
2010-08-19 0:12 ` john stultz
[not found] ` <1282176776.2865.100.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-08-19 5:55 ` Richard Cochran
2010-08-19 12:28 ` Arnd Bergmann
2010-08-19 15:38 ` Richard Cochran
2010-08-23 20:21 ` john stultz
[not found] ` <1282594899.3111.358.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-08-27 11:08 ` Richard Cochran
[not found] ` <20100827110855.GA11657-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-08-27 12:03 ` Arnd Bergmann
2010-08-27 20:56 ` John Stultz
2010-08-27 12:45 ` Alan Cox
2010-08-27 20:14 ` John Stultz
2010-08-23 20:08 ` john stultz
2010-08-24 18:30 ` Stephan Gatzka
2010-08-25 9:40 ` Christian Riesch
2010-08-27 1:57 ` john stultz
[not found] ` <1282874269.4371.74.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-08-27 7:57 ` Richard Cochran
2010-08-27 12:41 ` Alan Cox
[not found] ` <20100827134154.50eef56c-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
2010-08-27 14:02 ` Richard Cochran
[not found] ` <20100827140205.GA3293-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-08-27 14:50 ` Alan Cox
2010-08-27 15:35 ` M. Warner Losh
2010-08-29 13:32 ` Christian Riesch [this message]
[not found] ` <1282594125.3111.344.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-08-27 12:38 ` Richard Cochran
[not found] ` <20100827123849.GC11657-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-08-27 13:38 ` Alan Cox
[not found] ` <20100827143844.646eccf6-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>
2010-08-27 14:34 ` Richard Cochran
[not found] ` <20100827143437.GB3293-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-08-27 15:06 ` Alan Cox
2010-08-27 15:21 ` Patrick Loschmidt
2010-08-27 16:17 ` Jacob Keller
2010-08-27 22:30 ` John Stultz
2010-09-06 6:33 ` Richard Cochran
[not found] ` <20100906063327.GA4549-7KxsofuKt4IfAd9E5cN8NEzG7cXyKsk/@public.gmane.org>
2010-09-21 16:54 ` Stephan Gatzka
2010-09-21 20:47 ` Kyle Moffett
[not found] ` <AANLkTinRM3_kBc5S3wV=_S6P8+x7A43kz0qSYbixJYnq-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-09-22 10:14 ` Richard Cochran
2010-08-16 11:18 ` [PATCH 2/5] ptp: Added a clock that uses the Linux system time Richard Cochran
2010-08-16 11:18 ` [PATCH 3/5] ptp: Added a clock that uses the eTSEC found on the MPC85xx Richard Cochran
2010-08-16 11:18 ` [PATCH 4/5] ptp: Added a clock driver for the IXP46x Richard Cochran
2010-08-16 11:19 ` [PATCH 5/5] ptp: Added a clock driver for the National Semiconductor PHYTER Richard Cochran
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