• Rodolfo Giometti's avatar
    LinuxPPS: core support · eae9d2ba
    Rodolfo Giometti authored
    This patch adds the kernel side of the PPS support currently named
    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: default avatarRodolfo 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: default avatarAlan 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: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
sysfs.c 2.67 KB