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>

1 files changed, 123 insertions, 0 deletions

diff --git a/drivers/pps/clients/pps-ktimer.c b/drivers/pps/clients/pps-ktimer.c
new file mode 100644
index 000000000000..e7ef5b8186d0
--- /dev/null
+++ b/drivers/pps/clients/pps-ktimer.c
@@ -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");