Commit graph

10 commits

Author SHA1 Message Date
Robert P. J. Day
a2d8180301 drivers/pps: aesthetic tweaks to PPS-related content
Collection of aesthetic adjustments to various PPS-related files,
directories and Documentation, some quite minor just for the sake of
consistency, including:

 * Updated example of pps device tree node (courtesy Rodolfo G.)
 * "PPS-API" -> "PPS API"
 * "pps_source_info_s" -> "pps_source_info"
 * "ktimer driver" -> "pps-ktimer driver"
 * "ppstest /dev/pps0" -> "ppstest /dev/pps1" to match example
 * Add missing PPS-related entries to MAINTAINERS file
 * Other trivialities

Link: http://lkml.kernel.org/r/alpine.LFD.2.20.1708261048220.8106@localhost.localdomain
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:51 -07:00
Sanjeev
f2c1a053ce Doc: clarify source of jitter in USB1.1, and USB2.0
Even though the jitter due to USB1.1 may be 1ms,
NTP can reduce its effect significantly.  And
USB2.0 reduces this anyway.

Signed-off-by: Sanjeev Gupta <ghane0@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-01-04 14:40:52 -07:00
Sanjeev
fe4c56c98c Doc: Typos in documentation
No semantic changes.  The next patch in this series will
do the actual changes to sync with NTP current
best practices

Signed-off-by: Sanjeev Gupta <ghane0@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-01-04 14:39:42 -07:00
Sanjeev
e1235e18b5 Doc: Correct PPS doc to reflect code location
timepps.h , as well as PPS sample test utilities, are
no longer in the kernel tree.  Update documentation
to point to new locations.

Signed-off-by: Sanjeev Gupta <ghane0@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-01-04 14:39:26 -07:00
Eric Engestrom
c0270efc51 Documentation: pps: fix spelling mistake
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-04-28 07:23:59 -06:00
Masanari Iida
5d250eeb9d Doc: pps: Fix file name in pps.txt
This patch fix a file name of example code.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-07-14 12:35:42 -06:00
Masanari Iida
ce9ae951d4 Doc:pps: Fix typo in pps.txt
This patch fix a spelling typo in Documentation/pps/pps.txt

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
[jc: did s/into/in the/ on the same line while we were there]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-06-22 09:59:28 -06:00
Paul Chavent
833efc0ed1 USB: serial: invoke dcd_change ldisc's handler.
The DCD pin of the serial port can receive a PPS signal. By calling
the port line discipline dcd handle, this patch allow to monitor PPS
through USB serial devices.

However the performance aren't as good as the uart drivers, so
document this point too.

Signed-off-by: Paul Chavent <paul.chavent@onera.fr>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-26 09:45:40 -07:00
Alexander Gordeev
46b402a0e5 pps: add parallel port PPS signal generator
Add PPS signal generator which utilizes STROBE pin of a parallel port to
send PPS signals.  It uses parport abstraction layer and hrtimers to
precisely control the signal.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 08:03:21 -08:00
Rodolfo Giometti
eae9d2ba0c LinuxPPS: core support
This patch adds the kernel side of the PPS support currently named
"LinuxPPS".

PPS means "pulse per second" and a PPS source is just a device which
provides a high precision signal each second so that an application can
use it to adjust system clock time.

Common use is the combination of the NTPD as userland program with a GPS
receiver as PPS source to obtain a wallclock-time with sub-millisecond
synchronisation to UTC.

To obtain this goal the userland programs shoud use the PPS API
specification (RFC 2783 - Pulse-Per-Second API for UNIX-like Operating
Systems, Version 1.0) which in part is implemented by this patch.  It
provides a set of chars devices, one per PPS source, which can be used to
get the time signal.  The RFC's functions can be implemented by accessing
to these char devices.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg KH <greg@kroah.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:04:04 -07:00