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authorRodolfo Giometti <giometti@linux.it>2010-03-10 15:23:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-12 15:52:43 -0800
commita0880df0ccde8d551fc4d88c455acb2ee0801e26 (patch)
tree91153c79484ee379d663f5cc7a490d18bac710f9 /drivers/pps
parent572b9adbd40b5565dc413db04af9cc234f72bf19 (diff)
downloadlinux-2.6.34-ux500-a0880df0ccde8d551fc4d88c455acb2ee0801e26.tar.gz
pps: serial clients support
Adds support, by using the PPS line discipline, for the PPS sources connected with the CD (Carrier Detect) pin of a serial port. [akpm@linux-foundation.org: fix cast size warnings] 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>
Diffstat (limited to 'drivers/pps')
-rw-r--r--drivers/pps/clients/Kconfig7
-rw-r--r--drivers/pps/clients/Makefile1
-rw-r--r--drivers/pps/clients/pps-ldisc.c154
3 files changed, 162 insertions, 0 deletions
diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
index 43ccd3b644f..4e801bd7254 100644
--- a/drivers/pps/clients/Kconfig
+++ b/drivers/pps/clients/Kconfig
@@ -15,4 +15,11 @@ config PPS_CLIENT_KTIMER
This driver can also be built as a module. If so, the module
will be called pps-ktimer.
+config PPS_CLIENT_LDISC
+ tristate "PPS line discipline"
+ depends on PPS
+ help
+ If you say yes here you get support for a PPS source connected
+ with the CD (Carrier Detect) pin of your serial port.
+
endif
diff --git a/drivers/pps/clients/Makefile b/drivers/pps/clients/Makefile
index 115572ae3e9..812c9b19b43 100644
--- a/drivers/pps/clients/Makefile
+++ b/drivers/pps/clients/Makefile
@@ -3,6 +3,7 @@
#
obj-$(CONFIG_PPS_CLIENT_KTIMER) += pps-ktimer.o
+obj-$(CONFIG_PPS_CLIENT_LDISC) += pps-ldisc.o
ifeq ($(CONFIG_PPS_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/pps/clients/pps-ldisc.c b/drivers/pps/clients/pps-ldisc.c
new file mode 100644
index 00000000000..8e1932d29fd
--- /dev/null
+++ b/drivers/pps/clients/pps-ldisc.c
@@ -0,0 +1,154 @@
+/*
+ * pps-ldisc.c -- PPS line discipline
+ *
+ *
+ * Copyright (C) 2008 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/module.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/pps_kernel.h>
+
+#define PPS_TTY_MAGIC 0x0001
+
+static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
+ struct timespec *ts)
+{
+ int id = (long)tty->disc_data;
+ struct timespec __ts;
+ struct pps_ktime pps_ts;
+
+ /* First of all we get the time stamp... */
+ getnstimeofday(&__ts);
+
+ /* Does caller give us a timestamp? */
+ if (ts) { /* Yes. Let's use it! */
+ pps_ts.sec = ts->tv_sec;
+ pps_ts.nsec = ts->tv_nsec;
+ } else { /* No. Do it ourself! */
+ pps_ts.sec = __ts.tv_sec;
+ pps_ts.nsec = __ts.tv_nsec;
+ }
+
+ /* Now do the PPS event report */
+ pps_event(id, &pps_ts, status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR,
+ NULL);
+
+ pr_debug("PPS %s at %lu on source #%d\n",
+ status ? "assert" : "clear", jiffies, id);
+}
+
+static int (*alias_n_tty_open)(struct tty_struct *tty);
+
+static int pps_tty_open(struct tty_struct *tty)
+{
+ struct pps_source_info info;
+ struct tty_driver *drv = tty->driver;
+ int index = tty->index + drv->name_base;
+ int ret;
+
+ info.owner = THIS_MODULE;
+ info.dev = NULL;
+ snprintf(info.name, PPS_MAX_NAME_LEN, "%s%d", drv->driver_name, index);
+ snprintf(info.path, PPS_MAX_NAME_LEN, "/dev/%s%d", drv->name, index);
+ info.mode = PPS_CAPTUREBOTH | \
+ PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
+ PPS_CANWAIT | PPS_TSFMT_TSPEC;
+
+ ret = pps_register_source(&info, PPS_CAPTUREBOTH | \
+ PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
+ if (ret < 0) {
+ pr_err("cannot register PPS source \"%s\"\n", info.path);
+ return ret;
+ }
+ tty->disc_data = (void *)(long)ret;
+
+ /* Should open N_TTY ldisc too */
+ ret = alias_n_tty_open(tty);
+ if (ret < 0)
+ pps_unregister_source((long)tty->disc_data);
+
+ pr_info("PPS source #%d \"%s\" added\n", ret, info.path);
+
+ return 0;
+}
+
+static void (*alias_n_tty_close)(struct tty_struct *tty);
+
+static void pps_tty_close(struct tty_struct *tty)
+{
+ int id = (long)tty->disc_data;
+
+ pps_unregister_source(id);
+ alias_n_tty_close(tty);
+
+ pr_info("PPS source #%d removed\n", id);
+}
+
+static struct tty_ldisc_ops pps_ldisc_ops;
+
+/*
+ * Module stuff
+ */
+
+static int __init pps_tty_init(void)
+{
+ int err;
+
+ /* Inherit the N_TTY's ops */
+ n_tty_inherit_ops(&pps_ldisc_ops);
+
+ /* Save N_TTY's open()/close() methods */
+ alias_n_tty_open = pps_ldisc_ops.open;
+ alias_n_tty_close = pps_ldisc_ops.close;
+
+ /* Init PPS_TTY data */
+ pps_ldisc_ops.owner = THIS_MODULE;
+ pps_ldisc_ops.magic = PPS_TTY_MAGIC;
+ pps_ldisc_ops.name = "pps_tty";
+ pps_ldisc_ops.dcd_change = pps_tty_dcd_change;
+ pps_ldisc_ops.open = pps_tty_open;
+ pps_ldisc_ops.close = pps_tty_close;
+
+ err = tty_register_ldisc(N_PPS, &pps_ldisc_ops);
+ if (err)
+ pr_err("can't register PPS line discipline\n");
+ else
+ pr_info("PPS line discipline registered\n");
+
+ return err;
+}
+
+static void __exit pps_tty_cleanup(void)
+{
+ int err;
+
+ err = tty_unregister_ldisc(N_PPS);
+ if (err)
+ pr_err("can't unregister PPS line discipline\n");
+ else
+ pr_info("PPS line discipline removed\n");
+}
+
+module_init(pps_tty_init);
+module_exit(pps_tty_cleanup);
+
+MODULE_ALIAS_LDISC(N_PPS);
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("PPS TTY device driver");
+MODULE_LICENSE("GPL");