Commit 580afe4a authored by Rodolfo Giometti's avatar Rodolfo Giometti Committed by Greg Kroah-Hartman
Browse files

drivers pps/generators: add dummy PPS generator 



This dummy PPS generator can be used for debugging and documentation
purposes.

Signed-off-by: default avatarRodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/20241108073115.759039-3-giometti@enneenne.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 86b525be

drivers/pps/generators/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -14,6 +14,15 @@ menuconfig PPS_GENERATOR 


if PPS_GENERATOR



config PPS_GENERATOR_DUMMY

        tristate "Dummy PPS generator (Testing generator, use for debug)"

        help

          If you say yes here you get support for a PPS debugging generator

          (which generates no PPS signal at all).



          This driver can also be built as a module.  If so, the module

          will be called pps_gen-dummy.



config PPS_GENERATOR_PARPORT

	tristate "Parallel port PPS signal generator"

	depends on PARPORT && BROKEN

drivers/pps/generators/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
pps_gen_core-y			:= pps_gen.o sysfs.o

obj-$(CONFIG_PPS_GENERATOR)	:= pps_gen_core.o



obj-$(CONFIG_PPS_GENERATOR_DUMMY)   += pps_gen-dummy.o

obj-$(CONFIG_PPS_GENERATOR_PARPORT) += pps_gen_parport.o



ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG

drivers/pps/generators/pps_gen-dummy.c

0 → 100644
+96 −0
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// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * PPS dummy generator

 *

 * Copyright (C) 2024 Rodolfo Giometti <giometti@enneenne.com>

 */



#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/time.h>

#include <linux/timer.h>

#include <linux/random.h>

#include <linux/pps_gen_kernel.h>



static struct pps_gen_device *pps_gen;

static struct timer_list ktimer;



static unsigned int get_random_delay(void)

{

	unsigned int delay = get_random_u8() & 0x0f;



	return (delay + 1) * HZ;

}



/*

 * The kernel timer

 */



static void pps_gen_ktimer_event(struct timer_list *unused)

{

	pps_gen_event(pps_gen, PPS_GEN_EVENT_MISSEDPULSE, NULL);

}



/*

 * PPS Generator methods

 */



static int pps_gen_dummy_get_time(struct pps_gen_device *pps_gen,

					struct timespec64 *time)

{

	struct system_time_snapshot snap;



	ktime_get_snapshot(&snap);

	*time = ktime_to_timespec64(snap.real);



	return 0;

}



static int pps_gen_dummy_enable(struct pps_gen_device *pps_gen, bool enable)

{

	if (enable)

		mod_timer(&ktimer, jiffies + get_random_delay());

	else

		del_timer_sync(&ktimer);



	return 0;

}



/*

 * The PPS info struct

 */



static struct pps_gen_source_info pps_gen_dummy_info = {

	.use_system_clock	= true,

	.get_time		= pps_gen_dummy_get_time,

	.enable			= pps_gen_dummy_enable,

};



/*

 * Module staff

 */



static void __exit pps_gen_dummy_exit(void)

{

	del_timer_sync(&ktimer);

	pps_gen_unregister_source(pps_gen);

}



static int __init pps_gen_dummy_init(void)

{

	pps_gen = pps_gen_register_source(&pps_gen_dummy_info);

	if (IS_ERR(pps_gen))

		return PTR_ERR(pps_gen);



	timer_setup(&ktimer, pps_gen_ktimer_event, 0);



	return 0;

}



module_init(pps_gen_dummy_init);

module_exit(pps_gen_dummy_exit);



MODULE_AUTHOR("Rodolfo Giometti <giometti@enneenne.com>");

MODULE_DESCRIPTION("LinuxPPS dummy generator");

MODULE_LICENSE("GPL");