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Message-Id: <1266313885-1195-7-git-send-email-giometti@linux.it>
Date: Tue, 16 Feb 2010 10:51:23 +0100
From: Rodolfo Giometti <giometti@...ux.it>
To: linux-kernel@...r.kernel.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
David Woodhouse <dwmw2@...radead.org>,
Dave Jones <davej@...hat.com>, Sam Ravnborg <sam@...nborg.org>,
Greg KH <greg@...ah.com>,
Randy Dunlap <randy.dunlap@...cle.com>,
Kay Sievers <kay.sievers@...y.org>,
Alan Cox <alan@...rguk.ukuu.org.uk>,
"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
Michael Kerrisk <mtk.manpages@...il.com>,
Christoph Hellwig <hch@...radead.org>,
Alexander Gordeev <lasaine@....cs.msu.su>,
Rodolfo Giometti <giometti@...ux.it>
Subject: [PATCH 6/8] 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.
Signed-off-by: Rodolfo Giometti <giometti@...ux.it>
---
drivers/pps/clients/Kconfig | 7 ++
drivers/pps/clients/Makefile | 1 +
drivers/pps/clients/pps-ldisc.c | 154 +++++++++++++++++++++++++++++++++++++++
include/linux/serial_core.h | 11 +++-
4 files changed, 172 insertions(+), 1 deletions(-)
create mode 100644 drivers/pps/clients/pps-ldisc.c
diff --git a/drivers/pps/clients/Kconfig b/drivers/pps/clients/Kconfig
index 60b83be..487c1c8 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 ktimer.ko.
+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 f3c1e39..9f5b988 100644
--- a/drivers/pps/clients/Makefile
+++ b/drivers/pps/clients/Makefile
@@ -3,6 +3,7 @@
#
obj-$(CONFIG_PPS_CLIENT_KTIMER) += ktimer.o
+obj-$(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 0000000..59e6301
--- /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@...ux.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 = (int) 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 (*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 *) ret;
+
+ /* Should open N_TTY ldisc too */
+ ret = n_tty_open(tty);
+ if (ret < 0)
+ pps_unregister_source((int) tty->disc_data);
+
+ pr_info("PPS source #%d \"%s\" added\n", ret, info.path);
+
+ return 0;
+}
+
+static void (*n_tty_close)(struct tty_struct *tty);
+
+static void pps_tty_close(struct tty_struct *tty)
+{
+ int id = (int) tty->disc_data;
+
+ pps_unregister_source(id);
+ 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 */
+ n_tty_open = pps_ldisc_ops.open;
+ 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@...ux.it>");
+MODULE_DESCRIPTION("PPS TTY device driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index db532ce..4bfb046 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -488,9 +488,13 @@ uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
{
struct uart_state *state = uport->state;
struct tty_port *port = &state->port;
+ struct tty_ldisc *ld = tty_ldisc_ref(port->tty);
+ struct timespec ts;
- uport->icount.dcd++;
+ if (ld && ld->ops->dcd_change)
+ getnstimeofday(&ts);
+ uport->icount.dcd++;
#ifdef CONFIG_HARD_PPS
if ((uport->flags & UPF_HARDPPS_CD) && status)
hardpps();
@@ -502,6 +506,11 @@ uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
else if (port->tty)
tty_hangup(port->tty);
}
+
+ if (ld && ld->ops->dcd_change)
+ ld->ops->dcd_change(port->tty, status, &ts);
+ if (ld)
+ tty_ldisc_deref(ld);
}
/**
--
1.6.3.3
--
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