pps: LinuxPPS clients support

Each PPS source can be registered/deregistered into the system by using
special modules called "clients".  They simply define the PPS sources'
attributes and implement the time signal registration mechanism.

This patch adds a special directory for such clients and adds a dummy
client that can be useful to test system integrity on real systems.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg KH <greg@kroah.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rodolfo Giometti 2010-03-10 15:23:45 -08:00 committed by Linus Torvalds
parent 51e7364ef2
commit 697fb85fcf
5 changed files with 153 additions and 0 deletions

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@ -30,4 +30,6 @@ config PPS_DEBUG
messages to the system log. Select this if you are having a
problem with PPS support and want to see more of what is going on.
source drivers/pps/clients/Kconfig
endmenu

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@ -4,5 +4,6 @@
pps_core-y := pps.o kapi.o sysfs.o
obj-$(CONFIG_PPS) := pps_core.o
obj-y += clients/
ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG

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@ -0,0 +1,18 @@
#
# PPS clients configuration
#
if PPS
comment "PPS clients support"
config PPS_CLIENT_KTIMER
tristate "Kernel timer client (Testing client, use for debug)"
help
If you say yes here you get support for a PPS debugging client
which uses a kernel timer to generate the PPS signal.
This driver can also be built as a module. If so, the module
will be called pps-ktimer.
endif

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@ -0,0 +1,9 @@
#
# Makefile for PPS clients.
#
obj-$(CONFIG_PPS_CLIENT_KTIMER) += pps-ktimer.o
ifeq ($(CONFIG_PPS_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
endif

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@ -0,0 +1,123 @@
/*
* pps-ktimer.c -- kernel timer test client
*
*
* Copyright (C) 2005-2006 Rodolfo Giometti <giometti@linux.it>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/timer.h>
#include <linux/pps_kernel.h>
/*
* Global variables
*/
static int source;
static struct timer_list ktimer;
/*
* The kernel timer
*/
static void pps_ktimer_event(unsigned long ptr)
{
struct timespec __ts;
struct pps_ktime ts;
/* First of all we get the time stamp... */
getnstimeofday(&__ts);
pr_info("PPS event at %lu\n", jiffies);
/* ... and translate it to PPS time data struct */
ts.sec = __ts.tv_sec;
ts.nsec = __ts.tv_nsec;
pps_event(source, &ts, PPS_CAPTUREASSERT, NULL);
mod_timer(&ktimer, jiffies + HZ);
}
/*
* The echo function
*/
static void pps_ktimer_echo(int source, int event, void *data)
{
pr_info("echo %s %s for source %d\n",
event & PPS_CAPTUREASSERT ? "assert" : "",
event & PPS_CAPTURECLEAR ? "clear" : "",
source);
}
/*
* The PPS info struct
*/
static struct pps_source_info pps_ktimer_info = {
.name = "ktimer",
.path = "",
.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
PPS_ECHOASSERT |
PPS_CANWAIT | PPS_TSFMT_TSPEC,
.echo = pps_ktimer_echo,
.owner = THIS_MODULE,
};
/*
* Module staff
*/
static void __exit pps_ktimer_exit(void)
{
del_timer_sync(&ktimer);
pps_unregister_source(source);
pr_info("ktimer PPS source unregistered\n");
}
static int __init pps_ktimer_init(void)
{
int ret;
ret = pps_register_source(&pps_ktimer_info,
PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
if (ret < 0) {
printk(KERN_ERR "cannot register ktimer source\n");
return ret;
}
source = ret;
setup_timer(&ktimer, pps_ktimer_event, 0);
mod_timer(&ktimer, jiffies + HZ);
pr_info("ktimer PPS source registered at %d\n", source);
return 0;
}
module_init(pps_ktimer_init);
module_exit(pps_ktimer_exit);
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("dummy PPS source by using a kernel timer (just for debug)");
MODULE_LICENSE("GPL");