drivers/ptp/ptp_clock.c - linux/kernel/git/gregkh/usb - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * PTP 1588 clock support
  *
  * Copyright (C) 2010 OMICRON electronics GmbH
  */
 #include <linux/idr.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/posix-clock.h>
 #include <linux/pps_kernel.h>
 #include <linux/slab.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 #include <uapi/linux/sched/types.h>

 #include "ptp_private.h"

 #define PTP_MAX_ALARMS 4
 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)

 /* private globals */

 static dev_t ptp_devt;
 static struct class *ptp_class;

 static DEFINE_IDA(ptp_clocks_map);

 /* time stamp event queue operations */

 static inline int queue_free(struct timestamp_event_queue *q)
 {
 	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
 }

 static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
 				       struct ptp_clock_event *src)
 {
 	struct ptp_extts_event *dst;
 	unsigned long flags;
 	s64 seconds;
 	u32 remainder;

 	seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);

 	spin_lock_irqsave(&queue->lock, flags);

 	dst = &queue->buf[queue->tail];
 	dst->index = src->index;
 	dst->t.sec = seconds;
 	dst->t.nsec = remainder;

 	if (!queue_free(queue))
 		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;

 	queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;

 	spin_unlock_irqrestore(&queue->lock, flags);
 }

 s32 scaled_ppm_to_ppb(long ppm)
 {
 	/*
 	 * The 'freq' field in the 'struct timex' is in parts per
 	 * million, but with a 16 bit binary fractional field.
 	 *
 	 * We want to calculate
 	 *
 	 *    ppb = scaled_ppm * 1000 / 2^16
 	 *
 	 * which simplifies to
 	 *
 	 *    ppb = scaled_ppm * 125 / 2^13
 	 */
 	s64 ppb = 1 + ppm;
 	ppb *= 125;
 	ppb >>= 13;
 	return (s32) ppb;
 }
 EXPORT_SYMBOL(scaled_ppm_to_ppb);

 /* posix clock implementation */

 static int ptp_clock_getres(struct posix_clock *pc, struct timespec64 *tp)
 {
 	tp->tv_sec = 0;
 	tp->tv_nsec = 1;
 	return 0;
 }

 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp)
 {
 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);

 	return  ptp->info->settime64(ptp->info, tp);
 }

 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp)
 {
 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 	int err;

 	if (ptp->info->gettimex64)
 		err = ptp->info->gettimex64(ptp->info, tp, NULL);
 	else
 		err = ptp->info->gettime64(ptp->info, tp);
 	return err;
 }

 static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
 {
 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 	struct ptp_clock_info *ops;
 	int err = -EOPNOTSUPP;

 	ops = ptp->info;

 	if (tx->modes & ADJ_SETOFFSET) {
 		struct timespec64 ts;
 		ktime_t kt;
 		s64 delta;

 		ts.tv_sec  = tx->time.tv_sec;
 		ts.tv_nsec = tx->time.tv_usec;

 		if (!(tx->modes & ADJ_NANO))
 			ts.tv_nsec *= 1000;

 		if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
 			return -EINVAL;

 		kt = timespec64_to_ktime(ts);
 		delta = ktime_to_ns(kt);
 		err = ops->adjtime(ops, delta);
 	} else if (tx->modes & ADJ_FREQUENCY) {
 		s32 ppb = scaled_ppm_to_ppb(tx->freq);
 		if (ppb > ops->max_adj || ppb < -ops->max_adj)
 			return -ERANGE;
 		if (ops->adjfine)
 			err = ops->adjfine(ops, tx->freq);
 		else
 			err = ops->adjfreq(ops, ppb);
 		ptp->dialed_frequency = tx->freq;
 	} else if (tx->modes == 0) {
 		tx->freq = ptp->dialed_frequency;
 		err = 0;
 	}

 	return err;
 }

 static struct posix_clock_operations ptp_clock_ops = {
 	.owner		= THIS_MODULE,
 	.clock_adjtime	= ptp_clock_adjtime,
 	.clock_gettime	= ptp_clock_gettime,
 	.clock_getres	= ptp_clock_getres,
 	.clock_settime	= ptp_clock_settime,
 	.ioctl		= ptp_ioctl,
 	.open		= ptp_open,
 	.poll		= ptp_poll,
 	.read		= ptp_read,
 };

 static void ptp_clock_release(struct device *dev)
 {
 	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);

 	mutex_destroy(&ptp->tsevq_mux);
 	mutex_destroy(&ptp->pincfg_mux);
 	ida_simple_remove(&ptp_clocks_map, ptp->index);
 	kfree(ptp);
 }

 static void ptp_aux_kworker(struct kthread_work *work)
 {
 	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
 					     aux_work.work);
 	struct ptp_clock_info *info = ptp->info;
 	long delay;

 	delay = info->do_aux_work(info);

 	if (delay >= 0)
 		kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 }

 /* public interface */

 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 				     struct device *parent)
 {
 	struct ptp_clock *ptp;
 	int err = 0, index, major = MAJOR(ptp_devt);

 	if (info->n_alarm > PTP_MAX_ALARMS)
 		return ERR_PTR(-EINVAL);

 	/* Initialize a clock structure. */
 	err = -ENOMEM;
 	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
 	if (ptp == NULL)
 		goto no_memory;

 	index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
 	if (index < 0) {
 		err = index;
 		goto no_slot;
 	}

 	ptp->clock.ops = ptp_clock_ops;
 	ptp->info = info;
 	ptp->devid = MKDEV(major, index);
 	ptp->index = index;
 	spin_lock_init(&ptp->tsevq.lock);
 	mutex_init(&ptp->tsevq_mux);
 	mutex_init(&ptp->pincfg_mux);
 	init_waitqueue_head(&ptp->tsev_wq);

 	if (ptp->info->do_aux_work) {
 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
 		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
 		if (IS_ERR(ptp->kworker)) {
 			err = PTR_ERR(ptp->kworker);
 			pr_err("failed to create ptp aux_worker %d\n", err);
 			goto kworker_err;
 		}
 	}

 	err = ptp_populate_pin_groups(ptp);
 	if (err)
 		goto no_pin_groups;

 	/* Register a new PPS source. */
 	if (info->pps) {
 		struct pps_source_info pps;
 		memset(&pps, 0, sizeof(pps));
 		snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
 		pps.mode = PTP_PPS_MODE;
 		pps.owner = info->owner;
 		ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
 		if (IS_ERR(ptp->pps_source)) {
 			err = PTR_ERR(ptp->pps_source);
 			pr_err("failed to register pps source\n");
 			goto no_pps;
 		}
 	}

 	/* Initialize a new device of our class in our clock structure. */
 	device_initialize(&ptp->dev);
 	ptp->dev.devt = ptp->devid;
 	ptp->dev.class = ptp_class;
 	ptp->dev.parent = parent;
 	ptp->dev.groups = ptp->pin_attr_groups;
 	ptp->dev.release = ptp_clock_release;
 	dev_set_drvdata(&ptp->dev, ptp);
 	dev_set_name(&ptp->dev, "ptp%d", ptp->index);

 	/* Create a posix clock and link it to the device. */
 	err = posix_clock_register(&ptp->clock, &ptp->dev);
 	if (err) {
 		pr_err("failed to create posix clock\n");
 		goto no_clock;
 	}

 	return ptp;

 no_clock:
 	if (ptp->pps_source)
 		pps_unregister_source(ptp->pps_source);
 no_pps:
 	ptp_cleanup_pin_groups(ptp);
 no_pin_groups:
 	if (ptp->kworker)
 		kthread_destroy_worker(ptp->kworker);
 kworker_err:
 	mutex_destroy(&ptp->tsevq_mux);
 	mutex_destroy(&ptp->pincfg_mux);
 	ida_simple_remove(&ptp_clocks_map, index);
 no_slot:
 	kfree(ptp);
 no_memory:
 	return ERR_PTR(err);
 }
 EXPORT_SYMBOL(ptp_clock_register);

 int ptp_clock_unregister(struct ptp_clock *ptp)
 {
 	ptp->defunct = 1;
 	wake_up_interruptible(&ptp->tsev_wq);

 	if (ptp->kworker) {
 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
 		kthread_destroy_worker(ptp->kworker);
 	}

 	/* Release the clock's resources. */
 	if (ptp->pps_source)
 		pps_unregister_source(ptp->pps_source);

 	ptp_cleanup_pin_groups(ptp);

 	posix_clock_unregister(&ptp->clock);
 	return 0;
 }
 EXPORT_SYMBOL(ptp_clock_unregister);

 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event)
 {
 	struct pps_event_time evt;

 	switch (event->type) {

 	case PTP_CLOCK_ALARM:
 		break;

 	case PTP_CLOCK_EXTTS:
 		enqueue_external_timestamp(&ptp->tsevq, event);
 		wake_up_interruptible(&ptp->tsev_wq);
 		break;

 	case PTP_CLOCK_PPS:
 		pps_get_ts(&evt);
 		pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
 		break;

 	case PTP_CLOCK_PPSUSR:
 		pps_event(ptp->pps_source, &event->pps_times,
 			  PTP_PPS_EVENT, NULL);
 		break;
 	}
 }
 EXPORT_SYMBOL(ptp_clock_event);

 int ptp_clock_index(struct ptp_clock *ptp)
 {
 	return ptp->index;
 }
 EXPORT_SYMBOL(ptp_clock_index);

 int ptp_find_pin(struct ptp_clock *ptp,
 		 enum ptp_pin_function func, unsigned int chan)
 {
 	struct ptp_pin_desc *pin = NULL;
 	int i;

 	mutex_lock(&ptp->pincfg_mux);
 	for (i = 0; i < ptp->info->n_pins; i++) {
 		if (ptp->info->pin_config[i].func == func &&
 		    ptp->info->pin_config[i].chan == chan) {
 			pin = &ptp->info->pin_config[i];
 			break;
 		}
 	}
 	mutex_unlock(&ptp->pincfg_mux);

 	return pin ? i : -1;
 }
 EXPORT_SYMBOL(ptp_find_pin);

 int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
 {
 	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
 }
 EXPORT_SYMBOL(ptp_schedule_worker);

 /* module operations */

 static void __exit ptp_exit(void)
 {
 	class_destroy(ptp_class);
 	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
 	ida_destroy(&ptp_clocks_map);
 }

 static int __init ptp_init(void)
 {
 	int err;

 	ptp_class = class_create(THIS_MODULE, "ptp");
 	if (IS_ERR(ptp_class)) {
 		pr_err("ptp: failed to allocate class\n");
 		return PTR_ERR(ptp_class);
 	}

 	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
 	if (err < 0) {
 		pr_err("ptp: failed to allocate device region\n");
 		goto no_region;
 	}

 	ptp_class->dev_groups = ptp_groups;
 	pr_info("PTP clock support registered\n");
 	return 0;

 no_region:
 	class_destroy(ptp_class);
 	return err;
 }

 subsys_initcall(ptp_init);
 module_exit(ptp_exit);

 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 MODULE_DESCRIPTION("PTP clocks support");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* PTP 1588 clock support
	*
	* Copyright (C) 2010 OMICRON electronics GmbH
	*/
	#include <linux/idr.h>
	#include <linux/device.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/posix-clock.h>
	#include <linux/pps_kernel.h>
	#include <linux/slab.h>
	#include <linux/syscalls.h>
	#include <linux/uaccess.h>
	#include <uapi/linux/sched/types.h>

	#include "ptp_private.h"

	#define PTP_MAX_ALARMS 4
	#define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT \| PPS_OFFSETASSERT)
	#define PTP_PPS_EVENT PPS_CAPTUREASSERT
	#define PTP_PPS_MODE (PTP_PPS_DEFAULTS \| PPS_CANWAIT \| PPS_TSFMT_TSPEC)

	/* private globals */

	static dev_t ptp_devt;
	static struct class *ptp_class;

	static DEFINE_IDA(ptp_clocks_map);

	/* time stamp event queue operations */

	static inline int queue_free(struct timestamp_event_queue *q)
	{
	return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1;
	}

	static void enqueue_external_timestamp(struct timestamp_event_queue *queue,
	struct ptp_clock_event *src)
	{
	struct ptp_extts_event *dst;
	unsigned long flags;
	s64 seconds;
	u32 remainder;

	seconds = div_u64_rem(src->timestamp, 1000000000, &remainder);

	spin_lock_irqsave(&queue->lock, flags);

	dst = &queue->buf[queue->tail];
	dst->index = src->index;
	dst->t.sec = seconds;
	dst->t.nsec = remainder;

	if (!queue_free(queue))
	queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;

	queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS;

	spin_unlock_irqrestore(&queue->lock, flags);
	}

	s32 scaled_ppm_to_ppb(long ppm)
	{
	/*
	* The 'freq' field in the 'struct timex' is in parts per
	* million, but with a 16 bit binary fractional field.
	*
	* We want to calculate
	*
	* ppb = scaled_ppm * 1000 / 2^16
	*
	* which simplifies to
	*
	* ppb = scaled_ppm * 125 / 2^13
	*/
	s64 ppb = 1 + ppm;
	ppb *= 125;
	ppb >>= 13;
	return (s32) ppb;
	}
	EXPORT_SYMBOL(scaled_ppm_to_ppb);

	/* posix clock implementation */

	static int ptp_clock_getres(struct posix_clock pc, struct timespec64 tp)
	{
	tp->tv_sec = 0;
	tp->tv_nsec = 1;
	return 0;
	}

	static int ptp_clock_settime(struct posix_clock pc, const struct timespec64 tp)
	{
	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);

	return ptp->info->settime64(ptp->info, tp);
	}

	static int ptp_clock_gettime(struct posix_clock pc, struct timespec64 tp)
	{
	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
	int err;

	if (ptp->info->gettimex64)
	err = ptp->info->gettimex64(ptp->info, tp, NULL);
	else
	err = ptp->info->gettime64(ptp->info, tp);
	return err;
	}

	static int ptp_clock_adjtime(struct posix_clock pc, struct __kernel_timex tx)
	{
	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
	struct ptp_clock_info *ops;
	int err = -EOPNOTSUPP;

	ops = ptp->info;

	if (tx->modes & ADJ_SETOFFSET) {
	struct timespec64 ts;
	ktime_t kt;
	s64 delta;

	ts.tv_sec = tx->time.tv_sec;
	ts.tv_nsec = tx->time.tv_usec;

	if (!(tx->modes & ADJ_NANO))
	ts.tv_nsec *= 1000;

	if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC)
	return -EINVAL;

	kt = timespec64_to_ktime(ts);
	delta = ktime_to_ns(kt);
	err = ops->adjtime(ops, delta);
	} else if (tx->modes & ADJ_FREQUENCY) {
	s32 ppb = scaled_ppm_to_ppb(tx->freq);
	if (ppb > ops->max_adj \|\| ppb < -ops->max_adj)
	return -ERANGE;
	if (ops->adjfine)
	err = ops->adjfine(ops, tx->freq);
	else
	err = ops->adjfreq(ops, ppb);
	ptp->dialed_frequency = tx->freq;
	} else if (tx->modes == 0) {
	tx->freq = ptp->dialed_frequency;
	err = 0;
	}

	return err;
	}

	static struct posix_clock_operations ptp_clock_ops = {
	.owner = THIS_MODULE,
	.clock_adjtime = ptp_clock_adjtime,
	.clock_gettime = ptp_clock_gettime,
	.clock_getres = ptp_clock_getres,
	.clock_settime = ptp_clock_settime,
	.ioctl = ptp_ioctl,
	.open = ptp_open,
	.poll = ptp_poll,
	.read = ptp_read,
	};

	static void ptp_clock_release(struct device *dev)
	{
	struct ptp_clock *ptp = container_of(dev, struct ptp_clock, dev);

	mutex_destroy(&ptp->tsevq_mux);
	mutex_destroy(&ptp->pincfg_mux);
	ida_simple_remove(&ptp_clocks_map, ptp->index);
	kfree(ptp);
	}

	static void ptp_aux_kworker(struct kthread_work *work)
	{
	struct ptp_clock *ptp = container_of(work, struct ptp_clock,
	aux_work.work);
	struct ptp_clock_info *info = ptp->info;
	long delay;

	delay = info->do_aux_work(info);

	if (delay >= 0)
	kthread_queue_delayed_work(ptp->kworker, &ptp->aux_work, delay);
	}

	/* public interface */

	struct ptp_clock ptp_clock_register(struct ptp_clock_info info,
	struct device *parent)
	{
	struct ptp_clock *ptp;
	int err = 0, index, major = MAJOR(ptp_devt);

	if (info->n_alarm > PTP_MAX_ALARMS)
	return ERR_PTR(-EINVAL);

	/* Initialize a clock structure. */
	err = -ENOMEM;
	ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
	if (ptp == NULL)
	goto no_memory;

	index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);
	if (index < 0) {
	err = index;
	goto no_slot;
	}

	ptp->clock.ops = ptp_clock_ops;
	ptp->info = info;
	ptp->devid = MKDEV(major, index);
	ptp->index = index;
	spin_lock_init(&ptp->tsevq.lock);
	mutex_init(&ptp->tsevq_mux);
	mutex_init(&ptp->pincfg_mux);
	init_waitqueue_head(&ptp->tsev_wq);

	if (ptp->info->do_aux_work) {
	kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
	ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
	if (IS_ERR(ptp->kworker)) {
	err = PTR_ERR(ptp->kworker);
	pr_err("failed to create ptp aux_worker %d\n", err);
	goto kworker_err;
	}
	}

	err = ptp_populate_pin_groups(ptp);
	if (err)
	goto no_pin_groups;

	/* Register a new PPS source. */
	if (info->pps) {
	struct pps_source_info pps;
	memset(&pps, 0, sizeof(pps));
	snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index);
	pps.mode = PTP_PPS_MODE;
	pps.owner = info->owner;
	ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
	if (IS_ERR(ptp->pps_source)) {
	err = PTR_ERR(ptp->pps_source);
	pr_err("failed to register pps source\n");
	goto no_pps;
	}
	}

	/* Initialize a new device of our class in our clock structure. */
	device_initialize(&ptp->dev);
	ptp->dev.devt = ptp->devid;
	ptp->dev.class = ptp_class;
	ptp->dev.parent = parent;
	ptp->dev.groups = ptp->pin_attr_groups;
	ptp->dev.release = ptp_clock_release;
	dev_set_drvdata(&ptp->dev, ptp);
	dev_set_name(&ptp->dev, "ptp%d", ptp->index);

	/* Create a posix clock and link it to the device. */
	err = posix_clock_register(&ptp->clock, &ptp->dev);
	if (err) {
	pr_err("failed to create posix clock\n");
	goto no_clock;
	}

	return ptp;

	no_clock:
	if (ptp->pps_source)
	pps_unregister_source(ptp->pps_source);
	no_pps:
	ptp_cleanup_pin_groups(ptp);
	no_pin_groups:
	if (ptp->kworker)
	kthread_destroy_worker(ptp->kworker);
	kworker_err:
	mutex_destroy(&ptp->tsevq_mux);
	mutex_destroy(&ptp->pincfg_mux);
	ida_simple_remove(&ptp_clocks_map, index);
	no_slot:
	kfree(ptp);
	no_memory:
	return ERR_PTR(err);
	}
	EXPORT_SYMBOL(ptp_clock_register);

	int ptp_clock_unregister(struct ptp_clock *ptp)
	{
	ptp->defunct = 1;
	wake_up_interruptible(&ptp->tsev_wq);

	if (ptp->kworker) {
	kthread_cancel_delayed_work_sync(&ptp->aux_work);
	kthread_destroy_worker(ptp->kworker);
	}

	/* Release the clock's resources. */
	if (ptp->pps_source)
	pps_unregister_source(ptp->pps_source);

	ptp_cleanup_pin_groups(ptp);

	posix_clock_unregister(&ptp->clock);
	return 0;
	}
	EXPORT_SYMBOL(ptp_clock_unregister);

	void ptp_clock_event(struct ptp_clock ptp, struct ptp_clock_event event)
	{
	struct pps_event_time evt;

	switch (event->type) {

	case PTP_CLOCK_ALARM:
	break;

	case PTP_CLOCK_EXTTS:
	enqueue_external_timestamp(&ptp->tsevq, event);
	wake_up_interruptible(&ptp->tsev_wq);
	break;

	case PTP_CLOCK_PPS:
	pps_get_ts(&evt);
	pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL);
	break;

	case PTP_CLOCK_PPSUSR:
	pps_event(ptp->pps_source, &event->pps_times,
	PTP_PPS_EVENT, NULL);
	break;
	}
	}
	EXPORT_SYMBOL(ptp_clock_event);

	int ptp_clock_index(struct ptp_clock *ptp)
	{
	return ptp->index;
	}
	EXPORT_SYMBOL(ptp_clock_index);

	int ptp_find_pin(struct ptp_clock *ptp,
	enum ptp_pin_function func, unsigned int chan)
	{
	struct ptp_pin_desc *pin = NULL;
	int i;

	mutex_lock(&ptp->pincfg_mux);
	for (i = 0; i < ptp->info->n_pins; i++) {
	if (ptp->info->pin_config[i].func == func &&
	ptp->info->pin_config[i].chan == chan) {
	pin = &ptp->info->pin_config[i];
	break;
	}
	}
	mutex_unlock(&ptp->pincfg_mux);

	return pin ? i : -1;
	}
	EXPORT_SYMBOL(ptp_find_pin);

	int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay)
	{
	return kthread_mod_delayed_work(ptp->kworker, &ptp->aux_work, delay);
	}
	EXPORT_SYMBOL(ptp_schedule_worker);

	/* module operations */

	static void __exit ptp_exit(void)
	{
	class_destroy(ptp_class);
	unregister_chrdev_region(ptp_devt, MINORMASK + 1);
	ida_destroy(&ptp_clocks_map);
	}

	static int __init ptp_init(void)
	{
	int err;

	ptp_class = class_create(THIS_MODULE, "ptp");
	if (IS_ERR(ptp_class)) {
	pr_err("ptp: failed to allocate class\n");
	return PTR_ERR(ptp_class);
	}

	err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
	if (err < 0) {
	pr_err("ptp: failed to allocate device region\n");
	goto no_region;
	}

	ptp_class->dev_groups = ptp_groups;
	pr_info("PTP clock support registered\n");
	return 0;

	no_region:
	class_destroy(ptp_class);
	return err;
	}

	subsys_initcall(ptp_init);
	module_exit(ptp_exit);

	MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
	MODULE_DESCRIPTION("PTP clocks support");
	MODULE_LICENSE("GPL");