Alexander Gordeev a10203c691 pps: add parallel port PPS client ... Add parallel port PPS client. It uses a standard method for capturing timestamps for assert edge transitions: getting a timestamp soon after an interrupt has happened. This is not a very precise source of time information due to interrupt handling delays. However, timestamps for clear edge transitions are much more precise because the interrupt handler continuously polls hardware port until the transition is done. Hardware port operations require only about 1us so the maximum error should not exceed this value. This was my primary goal when developing this client. Clear edge capture could be disabled using clear_wait parameter. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> 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
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clients	pps: add parallel port PPS client	2011-01-13 08:03:21 -08:00
kapi.c	pps: add kernel consumer support	2011-01-13 08:03:21 -08:00
kc.c	pps: add kernel consumer support	2011-01-13 08:03:21 -08:00
kc.h	pps: add kernel consumer support	2011-01-13 08:03:21 -08:00
Kconfig	ntp: add hardpps implementation	2011-01-13 08:03:20 -08:00
Makefile	pps: add kernel consumer support	2011-01-13 08:03:21 -08:00
pps.c	pps: add kernel consumer support	2011-01-13 08:03:21 -08:00
sysfs.c	LinuxPPS: core support	2009-06-18 13:04:04 -07:00