From: Rodolfo Giometti Date: Wed, 17 Jun 2009 23:28:37 +0000 (-0700) Subject: LinuxPPS: core support X-Git-Tag: v2.6.31-rc1~146 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eae9d2ba0cfc27a2ad9765f23efb98fb80d80234;p=pandora-kernel.git 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 Cc: David Woodhouse Cc: Greg KH Cc: Randy Dunlap Cc: Kay Sievers Acked-by: Alan Cox Cc: Michael Kerrisk Cc: Christoph Hellwig Cc: Roman Zippel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed