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Commit 563558b2 authored by Alexander Gordeev's avatar Alexander Gordeev Committed by Linus Torvalds
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pps: add parallel port PPS signal generator 



Add PPS signal generator which utilizes STROBE pin of a parallel port to
send PPS signals.  It uses parport abstraction layer and hrtimers to
precisely control the signal.

Signed-off-by: default avatarAlexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 46b402a0

drivers/pps/generators/Kconfig

+1 −5
Original line number Original line Diff line number Diff line
@@ -2,16 +2,12 @@ 
# PPS generators configuration

# PPS generators configuration

#

#





if PPS



comment "PPS generators support"

comment "PPS generators support"





config PPS_GENERATOR_PARPORT

config PPS_GENERATOR_PARPORT

	tristate "Parallel port PPS signal generator"

	tristate "Parallel port PPS signal generator"

	depends on PARPORT != n && GENERIC_TIME

	depends on PARPORT

	help

	help

	  If you say yes here you get support for a PPS signal generator which

	  If you say yes here you get support for a PPS signal generator which

	  utilizes STROBE pin of a parallel port to send PPS signals. It uses

	  utilizes STROBE pin of a parallel port to send PPS signals. It uses

	  parport abstraction layer and hrtimers to precisely control the signal.
 
	  parport abstraction layer and hrtimers to precisely control the signal.
 


endif

drivers/pps/generators/pps_gen_parport.c

+9 −2
Original line number Original line Diff line number Diff line
@@ -76,8 +76,15 @@ static enum hrtimer_restart hrtimer_event(struct hrtimer *timer) 
	long lim, delta;

	long lim, delta;

	unsigned long flags;

	unsigned long flags;





	/* NB: approx time with blocked interrupts =

	/* We have to disable interrupts here. The idea is to prevent

	   send_delay + 3 * SAFETY_INTERVAL */

	 * other interrupts on the same processor to introduce random

	 * lags while polling the clock. getnstimeofday() takes <1us on

	 * most machines while other interrupt handlers can take much

	 * more potentially.

	 *

	 * NB: approx time with blocked interrupts =

	 * send_delay + 3 * SAFETY_INTERVAL

	 */

	local_irq_save(flags);

	local_irq_save(flags);





	/* first of all we get the time stamp... */

	/* first of all we get the time stamp... */