Fixed MTP to work with TWRP

drivers/pps/Kconfig

@@ -0,0 +1,47 @@
+#
+# PPS support configuration
+#
+
+menu "PPS support"
+
+config PPS
+	tristate "PPS support"
+	---help---
+	  PPS (Pulse Per Second) is a special pulse provided by some GPS
+	  antennae. Userland can use it to get a high-precision time
+	  reference.
+
+	  Some antennae's PPS signals are connected with the CD (Carrier
+	  Detect) pin of the serial line they use to communicate with the
+	  host. In this case use the SERIAL_LINE client support.
+
+	  Some antennae's PPS signals are connected with some special host
+	  inputs so you have to enable the corresponding client support.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pps_core.ko.
+if PPS
+
+config PPS_DEBUG
+	bool "PPS debugging messages"
+	help
+	  Say Y here if you want the PPS support to produce a bunch of 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.
+
+config NTP_PPS
+	bool "PPS kernel consumer support"
+	depends on !NO_HZ
+	help
+	  This option adds support for direct in-kernel time
+	  synchronization using an external PPS signal.
+
+	  It doesn't work on tickless systems at the moment.
+
+endif
+
+source drivers/pps/clients/Kconfig
+
+source drivers/pps/generators/Kconfig
+
+endmenu

drivers/pps/Makefile

@@ -0,0 +1,10 @@
+#
+# Makefile for the PPS core.
+#
+
+pps_core-y			:= pps.o kapi.o sysfs.o
+pps_core-$(CONFIG_NTP_PPS)	+= kc.o
+obj-$(CONFIG_PPS)		:= pps_core.o
+obj-y				+= clients/ generators/
+
+ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG

drivers/pps/clients/Kconfig

@@ -0,0 +1,41 @@
+#
+# 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.
+
+config PPS_CLIENT_LDISC
+	tristate "PPS line discipline"
+	depends on PPS && TTY
+	help
+	  If you say yes here you get support for a PPS source connected
+	  with the CD (Carrier Detect) pin of your serial port.
+
+config PPS_CLIENT_PARPORT
+	tristate "Parallel port PPS client"
+	depends on PPS && PARPORT
+	help
+	  If you say yes here you get support for a PPS source connected
+	  with the interrupt pin of your parallel port.
+
+config PPS_CLIENT_GPIO
+	tristate "PPS client using GPIO"
+	depends on PPS
+	help
+	  If you say yes here you get support for a PPS source using
+	  GPIO. To be useful you must also register a platform device
+	  specifying the GPIO pin and other options, usually in your board
+	  setup.
+
+endif

drivers/pps/clients/Makefile

@@ -0,0 +1,10 @@
+#
+# Makefile for PPS clients.
+#
+
+obj-$(CONFIG_PPS_CLIENT_KTIMER)	+= pps-ktimer.o
+obj-$(CONFIG_PPS_CLIENT_LDISC)	+= pps-ldisc.o
+obj-$(CONFIG_PPS_CLIENT_PARPORT) += pps_parport.o
+obj-$(CONFIG_PPS_CLIENT_GPIO)	+= pps-gpio.o
+
+ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG

drivers/pps/clients/pps-gpio.c

@@ -0,0 +1,213 @@
+/*
+ * pps-gpio.c -- PPS client driver using GPIO
+ *
+ *
+ * Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
+ * Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
+ *
+ *   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.
+ */
+
+#define PPS_GPIO_NAME "pps-gpio"
+#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/pps_kernel.h>
+#include <linux/pps-gpio.h>
+#include <linux/gpio.h>
+#include <linux/list.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+
+/* Info for each registered platform device */
+struct pps_gpio_device_data {
+	int irq;			/* IRQ used as PPS source */
+	struct pps_device *pps;		/* PPS source device */
+	struct pps_source_info info;	/* PPS source information */
+	bool assert_falling_edge;
+	bool capture_clear;
+	unsigned int gpio_pin;
+};
+
+/*
+ * Report the PPS event
+ */
+
+static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
+{
+	const struct pps_gpio_device_data *info;
+	struct pps_event_time ts;
+	int rising_edge;
+
+	/* Get the time stamp first */
+	pps_get_ts(&ts);
+
+	info = data;
+
+	rising_edge = gpio_get_value(info->gpio_pin);
+	if ((rising_edge && !info->assert_falling_edge) ||
+			(!rising_edge && info->assert_falling_edge))
+		pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
+	else if (info->capture_clear &&
+			((rising_edge && info->assert_falling_edge) ||
+			 (!rising_edge && !info->assert_falling_edge)))
+		pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
+
+	return IRQ_HANDLED;
+}
+
+static unsigned long
+get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
+{
+	unsigned long flags = data->assert_falling_edge ?
+		IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+
+	if (data->capture_clear) {
+		flags |= ((flags & IRQF_TRIGGER_RISING) ?
+				IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
+	}
+
+	return flags;
+}
+
+static int pps_gpio_probe(struct platform_device *pdev)
+{
+	struct pps_gpio_device_data *data;
+	const char *gpio_label;
+	int ret;
+	int pps_default_params;
+	const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
+	struct device_node *np = pdev->dev.of_node;
+
+	/* allocate space for device info */
+	data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
+			GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	if (pdata) {
+		data->gpio_pin = pdata->gpio_pin;
+		gpio_label = pdata->gpio_label;
+
+		data->assert_falling_edge = pdata->assert_falling_edge;
+		data->capture_clear = pdata->capture_clear;
+	} else {
+		ret = of_get_gpio(np, 0);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "failed to get GPIO from device tree\n");
+			return ret;
+		}
+		data->gpio_pin = ret;
+		gpio_label = PPS_GPIO_NAME;
+
+		if (of_get_property(np, "assert-falling-edge", NULL))
+			data->assert_falling_edge = true;
+	}
+
+	/* GPIO setup */
+	ret = devm_gpio_request(&pdev->dev, data->gpio_pin, gpio_label);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to request GPIO %u\n",
+			data->gpio_pin);
+		return ret;
+	}
+
+	ret = gpio_direction_input(data->gpio_pin);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to set pin direction\n");
+		return -EINVAL;
+	}
+
+	/* IRQ setup */
+	ret = gpio_to_irq(data->gpio_pin);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
+		return -EINVAL;
+	}
+	data->irq = ret;
+
+	/* initialize PPS specific parts of the bookkeeping data structure. */
+	data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
+		PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
+	if (data->capture_clear)
+		data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
+			PPS_ECHOCLEAR;
+	data->info.owner = THIS_MODULE;
+	snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
+		 pdev->name, pdev->id);
+
+	/* register PPS source */
+	pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
+	if (data->capture_clear)
+		pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
+	data->pps = pps_register_source(&data->info, pps_default_params);
+	if (data->pps == NULL) {
+		dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
+			data->irq);
+		return -EINVAL;
+	}
+
+	/* register IRQ interrupt handler */
+	ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
+			get_irqf_trigger_flags(data), data->info.name, data);
+	if (ret) {
+		pps_unregister_source(data->pps);
+		dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
+		return -EINVAL;
+	}
+
+	platform_set_drvdata(pdev, data);
+	dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
+		 data->irq);
+
+	return 0;
+}
+
+static int pps_gpio_remove(struct platform_device *pdev)
+{
+	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
+
+	pps_unregister_source(data->pps);
+	dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
+	return 0;
+}
+
+static const struct of_device_id pps_gpio_dt_ids[] = {
+	{ .compatible = "pps-gpio", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
+
+static struct platform_driver pps_gpio_driver = {
+	.probe		= pps_gpio_probe,
+	.remove		= pps_gpio_remove,
+	.driver		= {
+		.name	= PPS_GPIO_NAME,
+		.owner	= THIS_MODULE,
+		.of_match_table	= pps_gpio_dt_ids,
+	},
+};
+
+module_platform_driver(pps_gpio_driver);
+MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
+MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
+MODULE_DESCRIPTION("Use GPIO pin as PPS source");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0.0");

drivers/pps/clients/pps-ktimer.c

@@ -0,0 +1,101 @@
+/*
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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 struct pps_device *pps;
+static struct timer_list ktimer;
+
+/*
+ * The kernel timer
+ */
+
+static void pps_ktimer_event(unsigned long ptr)
+{
+	struct pps_event_time ts;
+
+	/* First of all we get the time stamp... */
+	pps_get_ts(&ts);
+
+	pps_event(pps, &ts, PPS_CAPTUREASSERT, NULL);
+
+	mod_timer(&ktimer, jiffies + HZ);
+}
+
+/*
+ * 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,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Module staff
+ */
+
+static void __exit pps_ktimer_exit(void)
+{
+	dev_info(pps->dev, "ktimer PPS source unregistered\n");
+
+	del_timer_sync(&ktimer);
+	pps_unregister_source(pps);
+}
+
+static int __init pps_ktimer_init(void)
+{
+	pps = pps_register_source(&pps_ktimer_info,
+				PPS_CAPTUREASSERT | PPS_OFFSETASSERT);
+	if (pps == NULL) {
+		pr_err("cannot register PPS source\n");
+		return -ENOMEM;
+	}
+
+	setup_timer(&ktimer, pps_ktimer_event, 0);
+	mod_timer(&ktimer, jiffies + HZ);
+
+	dev_info(pps->dev, "ktimer PPS source registered\n");
+
+	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");

drivers/pps/clients/pps-ldisc.c

@@ -0,0 +1,163 @@
+/*
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/pps_kernel.h>
+#include <linux/bug.h>
+
+#define PPS_TTY_MAGIC		0x0001
+
+static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status)
+{
+	struct pps_device *pps;
+	struct pps_event_time ts;
+
+	pps_get_ts(&ts);
+
+	pps = pps_lookup_dev(tty);
+	/*
+	 * This should never fail, but the ldisc locking is very
+	 * convoluted, so don't crash just in case.
+	 */
+	if (WARN_ON_ONCE(pps == NULL))
+		return;
+
+	/* Now do the PPS event report */
+	pps_event(pps, &ts, status ? PPS_CAPTUREASSERT :
+			PPS_CAPTURECLEAR, NULL);
+
+	dev_dbg(pps->dev, "PPS %s at %lu\n",
+			status ? "assert" : "clear", jiffies);
+}
+
+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;
+	struct pps_device *pps;
+	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;
+
+	pps = pps_register_source(&info, PPS_CAPTUREBOTH | \
+				PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
+	if (pps == NULL) {
+		pr_err("cannot register PPS source \"%s\"\n", info.path);
+		return -ENOMEM;
+	}
+	pps->lookup_cookie = tty;
+
+	/* Now open the base class N_TTY ldisc */
+	ret = alias_n_tty_open(tty);
+	if (ret < 0) {
+		pr_err("cannot open tty ldisc \"%s\"\n", info.path);
+		goto err_unregister;
+	}
+
+	dev_info(pps->dev, "source \"%s\" added\n", info.path);
+
+	return 0;
+
+err_unregister:
+	pps_unregister_source(pps);
+	return ret;
+}
+
+static void (*alias_n_tty_close)(struct tty_struct *tty);
+
+static void pps_tty_close(struct tty_struct *tty)
+{
+	struct pps_device *pps = pps_lookup_dev(tty);
+
+	alias_n_tty_close(tty);
+
+	if (WARN_ON(!pps))
+		return;
+
+	dev_info(pps->dev, "removed\n");
+	pps_unregister_source(pps);
+}
+
+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");

drivers/pps/clients/pps_parport.c

@@ -0,0 +1,250 @@
+/*
+ * pps_parport.c -- kernel parallel port PPS client
+ *
+ *
+ * Copyright (C) 2009   Alexander Gordeev <lasaine@lvk.cs.msu.su>
+ *
+ * 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.
+ */
+
+
+/*
+ * TODO:
+ * implement echo over SEL pin
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/irqnr.h>
+#include <linux/time.h>
+#include <linux/slab.h>
+#include <linux/parport.h>
+#include <linux/pps_kernel.h>
+
+#define DRVDESC "parallel port PPS client"
+
+/* module parameters */
+
+#define CLEAR_WAIT_MAX		100
+#define CLEAR_WAIT_MAX_ERRORS	5
+
+static unsigned int clear_wait = 100;
+MODULE_PARM_DESC(clear_wait,
+	"Maximum number of port reads when polling for signal clear,"
+	" zero turns clear edge capture off entirely");
+module_param(clear_wait, uint, 0);
+
+
+/* internal per port structure */
+struct pps_client_pp {
+	struct pardevice *pardev;	/* parport device */
+	struct pps_device *pps;		/* PPS device */
+	unsigned int cw;		/* port clear timeout */
+	unsigned int cw_err;		/* number of timeouts */
+};
+
+static inline int signal_is_set(struct parport *port)
+{
+	return (port->ops->read_status(port) & PARPORT_STATUS_ACK) != 0;
+}
+
+/* parport interrupt handler */
+static void parport_irq(void *handle)
+{
+	struct pps_event_time ts_assert, ts_clear;
+	struct pps_client_pp *dev = handle;
+	struct parport *port = dev->pardev->port;
+	unsigned int i;
+	unsigned long flags;
+
+	/* first of all we get the time stamp... */
+	pps_get_ts(&ts_assert);
+
+	if (dev->cw == 0)
+		/* clear edge capture disabled */
+		goto out_assert;
+
+	/* try capture the clear edge */
+
+	/* We have to disable interrupts here. The idea is to prevent
+	 * other interrupts on the same processor to introduce random
+	 * lags while polling the port. Reading from IO port is known
+	 * to take approximately 1us while other interrupt handlers can
+	 * take much more potentially.
+	 *
+	 * Interrupts won't be disabled for a long time because the
+	 * number of polls is limited by clear_wait parameter which is
+	 * kept rather low. So it should never be an issue.
+	 */
+	local_irq_save(flags);
+	/* check the signal (no signal means the pulse is lost this time) */
+	if (!signal_is_set(port)) {
+		local_irq_restore(flags);
+		dev_err(dev->pps->dev, "lost the signal\n");
+		goto out_assert;
+	}
+
+	/* poll the port until the signal is unset */
+	for (i = dev->cw; i; i--)
+		if (!signal_is_set(port)) {
+			pps_get_ts(&ts_clear);
+			local_irq_restore(flags);
+			dev->cw_err = 0;
+			goto out_both;
+		}
+	local_irq_restore(flags);
+
+	/* timeout */
+	dev->cw_err++;
+	if (dev->cw_err >= CLEAR_WAIT_MAX_ERRORS) {
+		dev_err(dev->pps->dev, "disabled clear edge capture after %d"
+				" timeouts\n", dev->cw_err);
+		dev->cw = 0;
+		dev->cw_err = 0;
+	}
+
+out_assert:
+	/* fire assert event */
+	pps_event(dev->pps, &ts_assert,
+			PPS_CAPTUREASSERT, NULL);
+	return;
+
+out_both:
+	/* fire assert event */
+	pps_event(dev->pps, &ts_assert,
+			PPS_CAPTUREASSERT, NULL);
+	/* fire clear event */
+	pps_event(dev->pps, &ts_clear,
+			PPS_CAPTURECLEAR, NULL);
+	return;
+}
+
+static void parport_attach(struct parport *port)
+{
+	struct pps_client_pp *device;
+	struct pps_source_info info = {
+		.name		= KBUILD_MODNAME,
+		.path		= "",
+		.mode		= PPS_CAPTUREBOTH | \
+				  PPS_OFFSETASSERT | PPS_OFFSETCLEAR | \
+				  PPS_ECHOASSERT | PPS_ECHOCLEAR | \
+				  PPS_CANWAIT | PPS_TSFMT_TSPEC,
+		.owner		= THIS_MODULE,
+		.dev		= NULL
+	};
+
+	device = kzalloc(sizeof(struct pps_client_pp), GFP_KERNEL);
+	if (!device) {
+		pr_err("memory allocation failed, not attaching\n");
+		return;
+	}
+
+	device->pardev = parport_register_device(port, KBUILD_MODNAME,
+			NULL, NULL, parport_irq, PARPORT_FLAG_EXCL, device);
+	if (!device->pardev) {
+		pr_err("couldn't register with %s\n", port->name);
+		goto err_free;
+	}
+
+	if (parport_claim_or_block(device->pardev) < 0) {
+		pr_err("couldn't claim %s\n", port->name);
+		goto err_unregister_dev;
+	}
+
+	device->pps = pps_register_source(&info,
+			PPS_CAPTUREBOTH | PPS_OFFSETASSERT | PPS_OFFSETCLEAR);
+	if (device->pps == NULL) {
+		pr_err("couldn't register PPS source\n");
+		goto err_release_dev;
+	}
+
+	device->cw = clear_wait;
+
+	port->ops->enable_irq(port);
+
+	pr_info("attached to %s\n", port->name);
+
+	return;
+
+err_release_dev:
+	parport_release(device->pardev);
+err_unregister_dev:
+	parport_unregister_device(device->pardev);
+err_free:
+	kfree(device);
+}
+
+static void parport_detach(struct parport *port)
+{
+	struct pardevice *pardev = port->cad;
+	struct pps_client_pp *device;
+
+	/* FIXME: oooh, this is ugly! */
+	if (strcmp(pardev->name, KBUILD_MODNAME))
+		/* not our port */
+		return;
+
+	device = pardev->private;
+
+	port->ops->disable_irq(port);
+	pps_unregister_source(device->pps);
+	parport_release(pardev);
+	parport_unregister_device(pardev);
+	kfree(device);
+}
+
+static struct parport_driver pps_parport_driver = {
+	.name = KBUILD_MODNAME,
+	.attach = parport_attach,
+	.detach = parport_detach,
+};
+
+/* module staff */
+
+static int __init pps_parport_init(void)
+{
+	int ret;
+
+	pr_info(DRVDESC "\n");
+
+	if (clear_wait > CLEAR_WAIT_MAX) {
+		pr_err("clear_wait value should be not greater"
+				" then %d\n", CLEAR_WAIT_MAX);
+		return -EINVAL;
+	}
+
+	ret = parport_register_driver(&pps_parport_driver);
+	if (ret) {
+		pr_err("unable to register with parport\n");
+		return ret;
+	}
+
+	return  0;
+}
+
+static void __exit pps_parport_exit(void)
+{
+	parport_unregister_driver(&pps_parport_driver);
+}
+
+module_init(pps_parport_init);
+module_exit(pps_parport_exit);
+
+MODULE_AUTHOR("Alexander Gordeev <lasaine@lvk.cs.msu.su>");
+MODULE_DESCRIPTION(DRVDESC);
+MODULE_LICENSE("GPL");

drivers/pps/generators/Kconfig

@@ -0,0 +1,13 @@
+#
+# PPS generators configuration
+#
+
+comment "PPS generators support"
+
+config PPS_GENERATOR_PARPORT
+	tristate "Parallel port PPS signal generator"
+	depends on PARPORT && BROKEN
+	help
+	  If you say yes here you get support for a PPS signal generator which
+	  utilizes STROBE pin of a parallel port to send PPS signals. It uses
+	  parport abstraction layer and hrtimers to precisely control the signal.

drivers/pps/generators/Makefile

@@ -0,0 +1,9 @@
+#
+# Makefile for PPS generators.
+#
+
+obj-$(CONFIG_PPS_GENERATOR_PARPORT) += pps_gen_parport.o
+
+ifeq ($(CONFIG_PPS_DEBUG),y)
+EXTRA_CFLAGS += -DDEBUG
+endif

drivers/pps/generators/pps_gen_parport.c

@@ -0,0 +1,277 @@
+/*
+ * pps_gen_parport.c -- kernel parallel port PPS signal generator
+ *
+ *
+ * Copyright (C) 2009   Alexander Gordeev <lasaine@lvk.cs.msu.su>
+ *
+ * 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.
+ */
+
+
+/*
+ * TODO:
+ * fix issues when realtime clock is adjusted in a leap
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/hrtimer.h>
+#include <linux/parport.h>
+
+#define DRVDESC "parallel port PPS signal generator"
+
+#define SIGNAL		0
+#define NO_SIGNAL	PARPORT_CONTROL_STROBE
+
+/* module parameters */
+
+#define SEND_DELAY_MAX		100000
+
+static unsigned int send_delay = 30000;
+MODULE_PARM_DESC(delay,
+	"Delay between setting and dropping the signal (ns)");
+module_param_named(delay, send_delay, uint, 0);
+
+
+#define SAFETY_INTERVAL	3000	/* set the hrtimer earlier for safety (ns) */
+
+/* internal per port structure */
+struct pps_generator_pp {
+	struct pardevice *pardev;	/* parport device */
+	struct hrtimer timer;
+	long port_write_time;		/* calibrated port write time (ns) */
+};
+
+static struct pps_generator_pp device = {
+	.pardev = NULL,
+};
+
+static int attached;
+
+/* calibrated time between a hrtimer event and the reaction */
+static long hrtimer_error = SAFETY_INTERVAL;
+
+/* the kernel hrtimer event */
+static enum hrtimer_restart hrtimer_event(struct hrtimer *timer)
+{
+	struct timespec expire_time, ts1, ts2, ts3, dts;
+	struct pps_generator_pp *dev;
+	struct parport *port;
+	long lim, delta;
+	unsigned long flags;
+
+	/* We have to disable interrupts here. The idea is to prevent
+	 * other interrupts on the same processor to introduce random
+	 * lags while polling the clock. getnstimeofday() takes <1us on
+	 * most machines while other interrupt handlers can take much
+	 * more potentially.
+	 *
+	 * NB: approx time with blocked interrupts =
+	 * send_delay + 3 * SAFETY_INTERVAL
+	 */
+	local_irq_save(flags);
+
+	/* first of all we get the time stamp... */
+	getnstimeofday(&ts1);
+	expire_time = ktime_to_timespec(hrtimer_get_softexpires(timer));
+	dev = container_of(timer, struct pps_generator_pp, timer);
+	lim = NSEC_PER_SEC - send_delay - dev->port_write_time;
+
+	/* check if we are late */
+	if (expire_time.tv_sec != ts1.tv_sec || ts1.tv_nsec > lim) {
+		local_irq_restore(flags);
+		pr_err("we are late this time %ld.%09ld\n",
+				ts1.tv_sec, ts1.tv_nsec);
+		goto done;
+	}
+
+	/* busy loop until the time is right for an assert edge */
+	do {
+		getnstimeofday(&ts2);
+	} while (expire_time.tv_sec == ts2.tv_sec && ts2.tv_nsec < lim);
+
+	/* set the signal */
+	port = dev->pardev->port;
+	port->ops->write_control(port, SIGNAL);
+
+	/* busy loop until the time is right for a clear edge */
+	lim = NSEC_PER_SEC - dev->port_write_time;
+	do {
+		getnstimeofday(&ts2);
+	} while (expire_time.tv_sec == ts2.tv_sec && ts2.tv_nsec < lim);
+
+	/* unset the signal */
+	port->ops->write_control(port, NO_SIGNAL);
+
+	getnstimeofday(&ts3);
+
+	local_irq_restore(flags);
+
+	/* update calibrated port write time */
+	dts = timespec_sub(ts3, ts2);
+	dev->port_write_time =
+		(dev->port_write_time + timespec_to_ns(&dts)) >> 1;
+
+done:
+	/* update calibrated hrtimer error */
+	dts = timespec_sub(ts1, expire_time);
+	delta = timespec_to_ns(&dts);
+	/* If the new error value is bigger then the old, use the new
+	 * value, if not then slowly move towards the new value. This
+	 * way it should be safe in bad conditions and efficient in
+	 * good conditions.
+	 */
+	if (delta >= hrtimer_error)
+		hrtimer_error = delta;
+	else
+		hrtimer_error = (3 * hrtimer_error + delta) >> 2;
+
+	/* update the hrtimer expire time */
+	hrtimer_set_expires(timer,
+			ktime_set(expire_time.tv_sec + 1,
+				NSEC_PER_SEC - (send_delay +
+				dev->port_write_time + SAFETY_INTERVAL +
+				2 * hrtimer_error)));
+
+	return HRTIMER_RESTART;
+}
+
+/* calibrate port write time */
+#define PORT_NTESTS_SHIFT	5
+static void calibrate_port(struct pps_generator_pp *dev)
+{
+	struct parport *port = dev->pardev->port;
+	int i;
+	long acc = 0;
+
+	for (i = 0; i < (1 << PORT_NTESTS_SHIFT); i++) {
+		struct timespec a, b;
+		unsigned long irq_flags;
+
+		local_irq_save(irq_flags);
+		getnstimeofday(&a);
+		port->ops->write_control(port, NO_SIGNAL);
+		getnstimeofday(&b);
+		local_irq_restore(irq_flags);
+
+		b = timespec_sub(b, a);
+		acc += timespec_to_ns(&b);
+	}
+
+	dev->port_write_time = acc >> PORT_NTESTS_SHIFT;
+	pr_info("port write takes %ldns\n", dev->port_write_time);
+}
+
+static inline ktime_t next_intr_time(struct pps_generator_pp *dev)
+{
+	struct timespec ts;
+
+	getnstimeofday(&ts);
+
+	return ktime_set(ts.tv_sec +
+			((ts.tv_nsec > 990 * NSEC_PER_MSEC) ? 1 : 0),
+			NSEC_PER_SEC - (send_delay +
+			dev->port_write_time + 3 * SAFETY_INTERVAL));
+}
+
+static void parport_attach(struct parport *port)
+{
+	if (attached) {
+		/* we already have a port */
+		return;
+	}
+
+	device.pardev = parport_register_device(port, KBUILD_MODNAME,
+			NULL, NULL, NULL, PARPORT_FLAG_EXCL, &device);
+	if (!device.pardev) {
+		pr_err("couldn't register with %s\n", port->name);
+		return;
+	}
+
+	if (parport_claim_or_block(device.pardev) < 0) {
+		pr_err("couldn't claim %s\n", port->name);
+		goto err_unregister_dev;
+	}
+
+	pr_info("attached to %s\n", port->name);
+	attached = 1;
+
+	calibrate_port(&device);
+
+	hrtimer_init(&device.timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+	device.timer.function = hrtimer_event;
+	hrtimer_start(&device.timer, next_intr_time(&device), HRTIMER_MODE_ABS);
+
+	return;
+
+err_unregister_dev:
+	parport_unregister_device(device.pardev);
+}
+
+static void parport_detach(struct parport *port)
+{
+	if (port->cad != device.pardev)
+		return;	/* not our port */
+
+	hrtimer_cancel(&device.timer);
+	parport_release(device.pardev);
+	parport_unregister_device(device.pardev);
+}
+
+static struct parport_driver pps_gen_parport_driver = {
+	.name = KBUILD_MODNAME,
+	.attach = parport_attach,
+	.detach = parport_detach,
+};
+
+/* module staff */
+
+static int __init pps_gen_parport_init(void)
+{
+	int ret;
+
+	pr_info(DRVDESC "\n");
+
+	if (send_delay > SEND_DELAY_MAX) {
+		pr_err("delay value should be not greater"
+				" then %d\n", SEND_DELAY_MAX);
+		return -EINVAL;
+	}
+
+	ret = parport_register_driver(&pps_gen_parport_driver);
+	if (ret) {
+		pr_err("unable to register with parport\n");
+		return ret;
+	}
+
+	return  0;
+}
+
+static void __exit pps_gen_parport_exit(void)
+{
+	parport_unregister_driver(&pps_gen_parport_driver);
+	pr_info("hrtimer avg error is %ldns\n", hrtimer_error);
+}
+
+module_init(pps_gen_parport_init);
+module_exit(pps_gen_parport_exit);
+
+MODULE_AUTHOR("Alexander Gordeev <lasaine@lvk.cs.msu.su>");
+MODULE_DESCRIPTION(DRVDESC);
+MODULE_LICENSE("GPL");

drivers/pps/kapi.c

@@ -0,0 +1,236 @@
+/*
+ * kernel API
+ *
+ *
+ * Copyright (C) 2005-2009   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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+#include <linux/spinlock.h>
+#include <linux/fs.h>
+#include <linux/pps_kernel.h>
+#include <linux/slab.h>
+
+#include "kc.h"
+
+/*
+ * Local functions
+ */
+
+static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
+{
+	ts->nsec += offset->nsec;
+	while (ts->nsec >= NSEC_PER_SEC) {
+		ts->nsec -= NSEC_PER_SEC;
+		ts->sec++;
+	}
+	while (ts->nsec < 0) {
+		ts->nsec += NSEC_PER_SEC;
+		ts->sec--;
+	}
+	ts->sec += offset->sec;
+}
+
+static void pps_echo_client_default(struct pps_device *pps, int event,
+		void *data)
+{
+	dev_info(pps->dev, "echo %s %s\n",
+		event & PPS_CAPTUREASSERT ? "assert" : "",
+		event & PPS_CAPTURECLEAR ? "clear" : "");
+}
+
+/*
+ * Exported functions
+ */
+
+/* pps_register_source - add a PPS source in the system
+ * @info: the PPS info struct
+ * @default_params: the default PPS parameters of the new source
+ *
+ * This function is used to add a new PPS source in the system. The new
+ * source is described by info's fields and it will have, as default PPS
+ * parameters, the ones specified into default_params.
+ *
+ * The function returns, in case of success, the PPS device. Otherwise NULL.
+ */
+
+struct pps_device *pps_register_source(struct pps_source_info *info,
+		int default_params)
+{
+	struct pps_device *pps;
+	int err;
+
+	/* Sanity checks */
+	if ((info->mode & default_params) != default_params) {
+		pr_err("%s: unsupported default parameters\n",
+					info->name);
+		err = -EINVAL;
+		goto pps_register_source_exit;
+	}
+	if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
+		pr_err("%s: unspecified time format\n",
+					info->name);
+		err = -EINVAL;
+		goto pps_register_source_exit;
+	}
+
+	/* Allocate memory for the new PPS source struct */
+	pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL);
+	if (pps == NULL) {
+		err = -ENOMEM;
+		goto pps_register_source_exit;
+	}
+
+	/* These initializations must be done before calling idr_alloc()
+	 * in order to avoid reces into pps_event().
+	 */
+	pps->params.api_version = PPS_API_VERS;
+	pps->params.mode = default_params;
+	pps->info = *info;
+
+	/* check for default echo function */
+	if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) &&
+			pps->info.echo == NULL)
+		pps->info.echo = pps_echo_client_default;
+
+	init_waitqueue_head(&pps->queue);
+	spin_lock_init(&pps->lock);
+
+	/* Create the char device */
+	err = pps_register_cdev(pps);
+	if (err < 0) {
+		pr_err("%s: unable to create char device\n",
+					info->name);
+		goto kfree_pps;
+	}
+
+	dev_info(pps->dev, "new PPS source %s\n", info->name);
+
+	return pps;
+
+kfree_pps:
+	kfree(pps);
+
+pps_register_source_exit:
+	pr_err("%s: unable to register source\n", info->name);
+
+	return NULL;
+}
+EXPORT_SYMBOL(pps_register_source);
+
+/* pps_unregister_source - remove a PPS source from the system
+ * @pps: the PPS source
+ *
+ * This function is used to remove a previously registered PPS source from
+ * the system.
+ */
+
+void pps_unregister_source(struct pps_device *pps)
+{
+	pps_kc_remove(pps);
+	pps_unregister_cdev(pps);
+
+	/* don't have to kfree(pps) here because it will be done on
+	 * device destruction */
+}
+EXPORT_SYMBOL(pps_unregister_source);
+
+/* pps_event - register a PPS event into the system
+ * @pps: the PPS device
+ * @ts: the event timestamp
+ * @event: the event type
+ * @data: userdef pointer
+ *
+ * This function is used by each PPS client in order to register a new
+ * PPS event into the system (it's usually called inside an IRQ handler).
+ *
+ * If an echo function is associated with the PPS device it will be called
+ * as:
+ *	pps->info.echo(pps, event, data);
+ */
+void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
+		void *data)
+{
+	unsigned long flags;
+	int captured = 0;
+	struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 };
+
+	/* check event type */
+	BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0);
+
+	dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
+			ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
+
+	timespec_to_pps_ktime(&ts_real, ts->ts_real);
+
+	spin_lock_irqsave(&pps->lock, flags);
+
+	/* Must call the echo function? */
+	if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
+		pps->info.echo(pps, event, data);
+
+	/* Check the event */
+	pps->current_mode = pps->params.mode;
+	if (event & pps->params.mode & PPS_CAPTUREASSERT) {
+		/* We have to add an offset? */
+		if (pps->params.mode & PPS_OFFSETASSERT)
+			pps_add_offset(&ts_real,
+					&pps->params.assert_off_tu);
+
+		/* Save the time stamp */
+		pps->assert_tu = ts_real;
+		pps->assert_sequence++;
+		dev_dbg(pps->dev, "capture assert seq #%u\n",
+			pps->assert_sequence);
+
+		captured = ~0;
+	}
+	if (event & pps->params.mode & PPS_CAPTURECLEAR) {
+		/* We have to add an offset? */
+		if (pps->params.mode & PPS_OFFSETCLEAR)
+			pps_add_offset(&ts_real,
+					&pps->params.clear_off_tu);
+
+		/* Save the time stamp */
+		pps->clear_tu = ts_real;
+		pps->clear_sequence++;
+		dev_dbg(pps->dev, "capture clear seq #%u\n",
+			pps->clear_sequence);
+
+		captured = ~0;
+	}
+
+	pps_kc_event(pps, ts, event);
+
+	/* Wake up if captured something */
+	if (captured) {
+		pps->last_ev++;
+		wake_up_interruptible_all(&pps->queue);
+
+		kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
+	}
+
+	spin_unlock_irqrestore(&pps->lock, flags);
+}
+EXPORT_SYMBOL(pps_event);

drivers/pps/kc.c

@@ -0,0 +1,122 @@
+/*
+ * PPS kernel consumer API
+ *
+ * Copyright (C) 2009-2010   Alexander Gordeev <lasaine@lvk.cs.msu.su>
+ *
+ *   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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/pps_kernel.h>
+
+#include "kc.h"
+
+/*
+ * Global variables
+ */
+
+/* state variables to bind kernel consumer */
+static DEFINE_SPINLOCK(pps_kc_hardpps_lock);
+/* PPS API (RFC 2783): current source and mode for kernel consumer */
+static struct pps_device *pps_kc_hardpps_dev;	/* unique pointer to device */
+static int pps_kc_hardpps_mode;		/* mode bits for kernel consumer */
+
+/* pps_kc_bind - control PPS kernel consumer binding
+ * @pps: the PPS source
+ * @bind_args: kernel consumer bind parameters
+ *
+ * This function is used to bind or unbind PPS kernel consumer according to
+ * supplied parameters. Should not be called in interrupt context.
+ */
+int pps_kc_bind(struct pps_device *pps, struct pps_bind_args *bind_args)
+{
+	/* Check if another consumer is already bound */
+	spin_lock_irq(&pps_kc_hardpps_lock);
+
+	if (bind_args->edge == 0)
+		if (pps_kc_hardpps_dev == pps) {
+			pps_kc_hardpps_mode = 0;
+			pps_kc_hardpps_dev = NULL;
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_info(pps->dev, "unbound kernel"
+					" consumer\n");
+		} else {
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_err(pps->dev, "selected kernel consumer"
+					" is not bound\n");
+			return -EINVAL;
+		}
+	else
+		if (pps_kc_hardpps_dev == NULL ||
+				pps_kc_hardpps_dev == pps) {
+			pps_kc_hardpps_mode = bind_args->edge;
+			pps_kc_hardpps_dev = pps;
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_info(pps->dev, "bound kernel consumer: "
+				"edge=0x%x\n", bind_args->edge);
+		} else {
+			spin_unlock_irq(&pps_kc_hardpps_lock);
+			dev_err(pps->dev, "another kernel consumer"
+					" is already bound\n");
+			return -EINVAL;
+		}
+
+	return 0;
+}
+
+/* pps_kc_remove - unbind kernel consumer on PPS source removal
+ * @pps: the PPS source
+ *
+ * This function is used to disable kernel consumer on PPS source removal
+ * if this source was bound to PPS kernel consumer. Can be called on any
+ * source safely. Should not be called in interrupt context.
+ */
+void pps_kc_remove(struct pps_device *pps)
+{
+	spin_lock_irq(&pps_kc_hardpps_lock);
+	if (pps == pps_kc_hardpps_dev) {
+		pps_kc_hardpps_mode = 0;
+		pps_kc_hardpps_dev = NULL;
+		spin_unlock_irq(&pps_kc_hardpps_lock);
+		dev_info(pps->dev, "unbound kernel consumer"
+				" on device removal\n");
+	} else
+		spin_unlock_irq(&pps_kc_hardpps_lock);
+}
+
+/* pps_kc_event - call hardpps() on PPS event
+ * @pps: the PPS source
+ * @ts: PPS event timestamp
+ * @event: PPS event edge
+ *
+ * This function calls hardpps() when an event from bound PPS source occurs.
+ */
+void pps_kc_event(struct pps_device *pps, struct pps_event_time *ts,
+		int event)
+{
+	unsigned long flags;
+
+	/* Pass some events to kernel consumer if activated */
+	spin_lock_irqsave(&pps_kc_hardpps_lock, flags);
+	if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode)
+		hardpps(&ts->ts_real, &ts->ts_raw);
+	spin_unlock_irqrestore(&pps_kc_hardpps_lock, flags);
+}

drivers/pps/kc.h

@@ -0,0 +1,46 @@
+/*
+ * PPS kernel consumer API header
+ *
+ * Copyright (C) 2009-2010   Alexander Gordeev <lasaine@lvk.cs.msu.su>
+ *
+ *   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.
+ */
+
+#ifndef LINUX_PPS_KC_H
+#define LINUX_PPS_KC_H
+
+#include <linux/errno.h>
+#include <linux/pps_kernel.h>
+
+#ifdef CONFIG_NTP_PPS
+
+extern int pps_kc_bind(struct pps_device *pps,
+		struct pps_bind_args *bind_args);
+extern void pps_kc_remove(struct pps_device *pps);
+extern void pps_kc_event(struct pps_device *pps,
+		struct pps_event_time *ts, int event);
+
+
+#else /* CONFIG_NTP_PPS */
+
+static inline int pps_kc_bind(struct pps_device *pps,
+		struct pps_bind_args *bind_args) { return -EOPNOTSUPP; }
+static inline void pps_kc_remove(struct pps_device *pps) {}
+static inline void pps_kc_event(struct pps_device *pps,
+		struct pps_event_time *ts, int event) {}
+
+#endif /* CONFIG_NTP_PPS */
+
+#endif /* LINUX_PPS_KC_H */

drivers/pps/pps.c

@@ -0,0 +1,434 @@
+/*
+ * PPS core file
+ *
+ *
+ * Copyright (C) 2005-2009   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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <linux/idr.h>
+#include <linux/mutex.h>
+#include <linux/cdev.h>
+#include <linux/poll.h>
+#include <linux/pps_kernel.h>
+#include <linux/slab.h>
+
+#include "kc.h"
+
+/*
+ * Local variables
+ */
+
+static dev_t pps_devt;
+static struct class *pps_class;
+
+static DEFINE_MUTEX(pps_idr_lock);
+static DEFINE_IDR(pps_idr);
+
+/*
+ * Char device methods
+ */
+
+static unsigned int pps_cdev_poll(struct file *file, poll_table *wait)
+{
+	struct pps_device *pps = file->private_data;
+
+	poll_wait(file, &pps->queue, wait);
+
+	return POLLIN | POLLRDNORM;
+}
+
+static int pps_cdev_fasync(int fd, struct file *file, int on)
+{
+	struct pps_device *pps = file->private_data;
+	return fasync_helper(fd, file, on, &pps->async_queue);
+}
+
+static long pps_cdev_ioctl(struct file *file,
+		unsigned int cmd, unsigned long arg)
+{
+	struct pps_device *pps = file->private_data;
+	struct pps_kparams params;
+	void __user *uarg = (void __user *) arg;
+	int __user *iuarg = (int __user *) arg;
+	int err;
+
+	switch (cmd) {
+	case PPS_GETPARAMS:
+		dev_dbg(pps->dev, "PPS_GETPARAMS\n");
+
+		spin_lock_irq(&pps->lock);
+
+		/* Get the current parameters */
+		params = pps->params;
+
+		spin_unlock_irq(&pps->lock);
+
+		err = copy_to_user(uarg, &params, sizeof(struct pps_kparams));
+		if (err)
+			return -EFAULT;
+
+		break;
+
+	case PPS_SETPARAMS:
+		dev_dbg(pps->dev, "PPS_SETPARAMS\n");
+
+		/* Check the capabilities */
+		if (!capable(CAP_SYS_TIME))
+			return -EPERM;
+
+		err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
+		if (err)
+			return -EFAULT;
+		if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
+			dev_dbg(pps->dev, "capture mode unspecified (%x)\n",
+								params.mode);
+			return -EINVAL;
+		}
+
+		/* Check for supported capabilities */
+		if ((params.mode & ~pps->info.mode) != 0) {
+			dev_dbg(pps->dev, "unsupported capabilities (%x)\n",
+								params.mode);
+			return -EINVAL;
+		}
+
+		spin_lock_irq(&pps->lock);
+
+		/* Save the new parameters */
+		pps->params = params;
+
+		/* Restore the read only parameters */
+		if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
+			/* section 3.3 of RFC 2783 interpreted */
+			dev_dbg(pps->dev, "time format unspecified (%x)\n",
+								params.mode);
+			pps->params.mode |= PPS_TSFMT_TSPEC;
+		}
+		if (pps->info.mode & PPS_CANWAIT)
+			pps->params.mode |= PPS_CANWAIT;
+		pps->params.api_version = PPS_API_VERS;
+
+		spin_unlock_irq(&pps->lock);
+
+		break;
+
+	case PPS_GETCAP:
+		dev_dbg(pps->dev, "PPS_GETCAP\n");
+
+		err = put_user(pps->info.mode, iuarg);
+		if (err)
+			return -EFAULT;
+
+		break;
+
+	case PPS_FETCH: {
+		struct pps_fdata fdata;
+		unsigned int ev;
+
+		dev_dbg(pps->dev, "PPS_FETCH\n");
+
+		err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
+		if (err)
+			return -EFAULT;
+
+		ev = pps->last_ev;
+
+		/* Manage the timeout */
+		if (fdata.timeout.flags & PPS_TIME_INVALID)
+			err = wait_event_interruptible(pps->queue,
+					ev != pps->last_ev);
+		else {
+			unsigned long ticks;
+
+			dev_dbg(pps->dev, "timeout %lld.%09d\n",
+					(long long) fdata.timeout.sec,
+					fdata.timeout.nsec);
+			ticks = fdata.timeout.sec * HZ;
+			ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
+
+			if (ticks != 0) {
+				err = wait_event_interruptible_timeout(
+						pps->queue,
+						ev != pps->last_ev,
+						ticks);
+				if (err == 0)
+					return -ETIMEDOUT;
+			}
+		}
+
+		/* Check for pending signals */
+		if (err == -ERESTARTSYS) {
+			dev_dbg(pps->dev, "pending signal caught\n");
+			return -EINTR;
+		}
+
+		/* Return the fetched timestamp */
+		spin_lock_irq(&pps->lock);
+
+		fdata.info.assert_sequence = pps->assert_sequence;
+		fdata.info.clear_sequence = pps->clear_sequence;
+		fdata.info.assert_tu = pps->assert_tu;
+		fdata.info.clear_tu = pps->clear_tu;
+		fdata.info.current_mode = pps->current_mode;
+
+		spin_unlock_irq(&pps->lock);
+
+		err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
+		if (err)
+			return -EFAULT;
+
+		break;
+	}
+	case PPS_KC_BIND: {
+		struct pps_bind_args bind_args;
+
+		dev_dbg(pps->dev, "PPS_KC_BIND\n");
+
+		/* Check the capabilities */
+		if (!capable(CAP_SYS_TIME))
+			return -EPERM;
+
+		if (copy_from_user(&bind_args, uarg,
+					sizeof(struct pps_bind_args)))
+			return -EFAULT;
+
+		/* Check for supported capabilities */
+		if ((bind_args.edge & ~pps->info.mode) != 0) {
+			dev_err(pps->dev, "unsupported capabilities (%x)\n",
+					bind_args.edge);
+			return -EINVAL;
+		}
+
+		/* Validate parameters roughly */
+		if (bind_args.tsformat != PPS_TSFMT_TSPEC ||
+				(bind_args.edge & ~PPS_CAPTUREBOTH) != 0 ||
+				bind_args.consumer != PPS_KC_HARDPPS) {
+			dev_err(pps->dev, "invalid kernel consumer bind"
+					" parameters (%x)\n", bind_args.edge);
+			return -EINVAL;
+		}
+
+		err = pps_kc_bind(pps, &bind_args);
+		if (err < 0)
+			return err;
+
+		break;
+	}
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static int pps_cdev_open(struct inode *inode, struct file *file)
+{
+	struct pps_device *pps = container_of(inode->i_cdev,
+						struct pps_device, cdev);
+	file->private_data = pps;
+	kobject_get(&pps->dev->kobj);
+	return 0;
+}
+
+static int pps_cdev_release(struct inode *inode, struct file *file)
+{
+	struct pps_device *pps = container_of(inode->i_cdev,
+						struct pps_device, cdev);
+	kobject_put(&pps->dev->kobj);
+	return 0;
+}
+
+/*
+ * Char device stuff
+ */
+
+static const struct file_operations pps_cdev_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.poll		= pps_cdev_poll,
+	.fasync		= pps_cdev_fasync,
+	.unlocked_ioctl	= pps_cdev_ioctl,
+	.open		= pps_cdev_open,
+	.release	= pps_cdev_release,
+};
+
+static void pps_device_destruct(struct device *dev)
+{
+	struct pps_device *pps = dev_get_drvdata(dev);
+
+	cdev_del(&pps->cdev);
+
+	/* Now we can release the ID for re-use */
+	pr_debug("deallocating pps%d\n", pps->id);
+	mutex_lock(&pps_idr_lock);
+	idr_remove(&pps_idr, pps->id);
+	mutex_unlock(&pps_idr_lock);
+
+	kfree(dev);
+	kfree(pps);
+}
+
+int pps_register_cdev(struct pps_device *pps)
+{
+	int err;
+	dev_t devt;
+
+	mutex_lock(&pps_idr_lock);
+	/*
+	 * Get new ID for the new PPS source.  After idr_alloc() calling
+	 * the new source will be freely available into the kernel.
+	 */
+	err = idr_alloc(&pps_idr, pps, 0, PPS_MAX_SOURCES, GFP_KERNEL);
+	if (err < 0) {
+		if (err == -ENOSPC) {
+			pr_err("%s: too many PPS sources in the system\n",
+			       pps->info.name);
+			err = -EBUSY;
+		}
+		goto out_unlock;
+	}
+	pps->id = err;
+	mutex_unlock(&pps_idr_lock);
+
+	devt = MKDEV(MAJOR(pps_devt), pps->id);
+
+	cdev_init(&pps->cdev, &pps_cdev_fops);
+	pps->cdev.owner = pps->info.owner;
+
+	err = cdev_add(&pps->cdev, devt, 1);
+	if (err) {
+		pr_err("%s: failed to add char device %d:%d\n",
+				pps->info.name, MAJOR(pps_devt), pps->id);
+		goto free_idr;
+	}
+	pps->dev = device_create(pps_class, pps->info.dev, devt, pps,
+							"pps%d", pps->id);
+	if (IS_ERR(pps->dev)) {
+		err = PTR_ERR(pps->dev);
+		goto del_cdev;
+	}
+
+	/* Override the release function with our own */
+	pps->dev->release = pps_device_destruct;
+
+	pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
+			MAJOR(pps_devt), pps->id);
+
+	return 0;
+
+del_cdev:
+	cdev_del(&pps->cdev);
+
+free_idr:
+	mutex_lock(&pps_idr_lock);
+	idr_remove(&pps_idr, pps->id);
+out_unlock:
+	mutex_unlock(&pps_idr_lock);
+	return err;
+}
+
+void pps_unregister_cdev(struct pps_device *pps)
+{
+	pr_debug("unregistering pps%d\n", pps->id);
+	pps->lookup_cookie = NULL;
+	device_destroy(pps_class, pps->dev->devt);
+}
+
+/*
+ * Look up a pps device by magic cookie.
+ * The cookie is usually a pointer to some enclosing device, but this
+ * code doesn't care; you should never be dereferencing it.
+ *
+ * This is a bit of a kludge that is currently used only by the PPS
+ * serial line discipline.  It may need to be tweaked when a second user
+ * is found.
+ *
+ * There is no function interface for setting the lookup_cookie field.
+ * It's initialized to NULL when the pps device is created, and if a
+ * client wants to use it, just fill it in afterward.
+ *
+ * The cookie is automatically set to NULL in pps_unregister_source()
+ * so that it will not be used again, even if the pps device cannot
+ * be removed from the idr due to pending references holding the minor
+ * number in use.
+ */
+struct pps_device *pps_lookup_dev(void const *cookie)
+{
+	struct pps_device *pps;
+	unsigned id;
+
+	rcu_read_lock();
+	idr_for_each_entry(&pps_idr, pps, id)
+		if (cookie == pps->lookup_cookie)
+			break;
+	rcu_read_unlock();
+	return pps;
+}
+EXPORT_SYMBOL(pps_lookup_dev);
+
+/*
+ * Module stuff
+ */
+
+static void __exit pps_exit(void)
+{
+	class_destroy(pps_class);
+	unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
+}
+
+static int __init pps_init(void)
+{
+	int err;
+
+	pps_class = class_create(THIS_MODULE, "pps");
+	if (IS_ERR(pps_class)) {
+		pr_err("failed to allocate class\n");
+		return PTR_ERR(pps_class);
+	}
+	pps_class->dev_groups = pps_groups;
+
+	err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
+	if (err < 0) {
+		pr_err("failed to allocate char device region\n");
+		goto remove_class;
+	}
+
+	pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
+	pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
+		"<giometti@linux.it>\n", PPS_VERSION);
+
+	return 0;
+
+remove_class:
+	class_destroy(pps_class);
+
+	return err;
+}
+
+subsys_initcall(pps_init);
+module_exit(pps_exit);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
+MODULE_LICENSE("GPL");

drivers/pps/sysfs.c

@@ -0,0 +1,113 @@
+/*
+ * PPS sysfs support
+ *
+ *
+ * Copyright (C) 2007-2009   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/device.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/pps_kernel.h>
+
+/*
+ * Attribute functions
+ */
+
+static ssize_t assert_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct pps_device *pps = dev_get_drvdata(dev);
+
+	if (!(pps->info.mode & PPS_CAPTUREASSERT))
+		return 0;
+
+	return sprintf(buf, "%lld.%09d#%d\n",
+			(long long) pps->assert_tu.sec, pps->assert_tu.nsec,
+			pps->assert_sequence);
+}
+static DEVICE_ATTR_RO(assert);
+
+static ssize_t clear_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct pps_device *pps = dev_get_drvdata(dev);
+
+	if (!(pps->info.mode & PPS_CAPTURECLEAR))
+		return 0;
+
+	return sprintf(buf, "%lld.%09d#%d\n",
+			(long long) pps->clear_tu.sec, pps->clear_tu.nsec,
+			pps->clear_sequence);
+}
+static DEVICE_ATTR_RO(clear);
+
+static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct pps_device *pps = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%4x\n", pps->info.mode);
+}
+static DEVICE_ATTR_RO(mode);
+
+static ssize_t echo_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct pps_device *pps = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", !!pps->info.echo);
+}
+static DEVICE_ATTR_RO(echo);
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct pps_device *pps = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", pps->info.name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t path_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct pps_device *pps = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", pps->info.path);
+}
+static DEVICE_ATTR_RO(path);
+
+static struct attribute *pps_attrs[] = {
+	&dev_attr_assert.attr,
+	&dev_attr_clear.attr,
+	&dev_attr_mode.attr,
+	&dev_attr_echo.attr,
+	&dev_attr_name.attr,
+	&dev_attr_path.attr,
+	NULL,
+};
+
+static const struct attribute_group pps_group = {
+	.attrs = pps_attrs,
+};
+
+const struct attribute_group *pps_groups[] = {
+	&pps_group,
+	NULL,
+};