From eae9d2ba0cfc27a2ad9765f23efb98fb80d80234 Mon Sep 17 00:00:00 2001 From: Rodolfo Giometti Date: Wed, 17 Jun 2009 16:28:37 -0700 Subject: 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 --- Documentation/ioctl/ioctl-number.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation/ioctl') 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 +'p' a1-a4 linux/pps.h LinuxPPS + 'q' 00-1F linux/serio.h 'q' 80-FF Internet PhoneJACK, Internet LineJACK -- cgit