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| author | Rodolfo Giometti <giometti@linux.it> | 2009-06-17 16:28:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-18 13:04:04 -0700 |
| commit | eae9d2ba0cfc27a2ad9765f23efb98fb80d80234 (patch) | |
| tree | f4be40ca528b2f23f97fa9cb6ebe91b8d6696d5b /Documentation/ioctl/ioctl-number.txt | |
| parent | 8820f27ad9a5ad2a62cdcdf425d7921c31831800 (diff) | |
| download | lwn-eae9d2ba0cfc27a2ad9765f23efb98fb80d80234.tar.gz lwn-eae9d2ba0cfc27a2ad9765f23efb98fb80d80234.zip | |
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>
Diffstat (limited to 'Documentation/ioctl/ioctl-number.txt')
| -rw-r--r-- | Documentation/ioctl/ioctl-number.txt | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index 1f779a25c703..7bb0d934b6d8 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -149,6 +149,8 @@ Code Seq# Include File Comments 'p' 40-7F linux/nvram.h 'p' 80-9F user-space parport <mailto:tim@cyberelk.net> +'p' a1-a4 linux/pps.h LinuxPPS + <mailto:giometti@linux.it> 'q' 00-1F linux/serio.h 'q' 80-FF Internet PhoneJACK, Internet LineJACK <http://www.quicknet.net> |