drivers/pps/pps.c - kernel/msm-4.9 - Gitiles

 /*
  * 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");
	/*
	* 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");