[mirror_ubuntu-hirsute-kernel.git] / drivers / pps / clients / pps-ldisc.c

/*
 * pps-ldisc.c -- PPS line discipline
 *
 *
 * Copyright (C) 2008	Rodolfo Giometti <giometti@linux.it>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/serial_core.h>
#include <linux/tty.h>
#include <linux/pps_kernel.h>

#define PPS_TTY_MAGIC		0x0001

static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
				struct pps_event_time *ts)
{
	struct pps_device *pps = (struct pps_device *)tty->disc_data;
	struct pps_event_time __ts;

	/* First of all we get the time stamp... */
	pps_get_ts(&__ts);

	/* Does caller give us a timestamp? */
	if (!ts)	/* No. Do it ourself! */
		ts = &__ts;

	BUG_ON(pps == NULL);

	/* 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;
	}
	tty->disc_data = pps;

	/* Should open N_TTY ldisc too */
	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:
	tty->disc_data = NULL;
	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 = (struct pps_device *)tty->disc_data;

	alias_n_tty_close(tty);

	tty->disc_data = NULL;
	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");
Commit	Line	Data
a0880df0 RG	1	/*
	2	* pps-ldisc.c -- PPS line discipline
	3	*
	4	*
	5	* Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	20	*/
	21
	22	#include <linux/module.h>
	23	#include <linux/serial_core.h>
	24	#include <linux/tty.h>
	25	#include <linux/pps_kernel.h>
	26
	27	#define PPS_TTY_MAGIC 0x0001
	28
	29	static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status,
6f4229b5	30	struct pps_event_time *ts)
a0880df0	31	{
5e196d34	32	struct pps_device pps = (struct pps_device )tty->disc_data;
6f4229b5	33	struct pps_event_time __ts;
a0880df0 RG	34
a0880df0 RG	35	/* First of all we get the time stamp... */
6f4229b5	36	pps_get_ts(&__ts);
a0880df0 RG	37
a0880df0 RG	38	/* Does caller give us a timestamp? */
6f4229b5 AG	39	if (!ts) /* No. Do it ourself! */
6f4229b5 AG	40	ts = &__ts;
a0880df0	41
5e196d34 AG	42	BUG_ON(pps == NULL);
5e196d34 AG	43
a0880df0	44	/* Now do the PPS event report */
5e196d34 AG	45	pps_event(pps, ts, status ? PPS_CAPTUREASSERT :
5e196d34 AG	46	PPS_CAPTURECLEAR, NULL);
a0880df0	47
5e196d34 AG	48	dev_dbg(pps->dev, "PPS %s at %lu\n",
5e196d34 AG	49	status ? "assert" : "clear", jiffies);
a0880df0 RG	50	}
	51
	52	static int (alias_n_tty_open)(struct tty_struct tty);
	53
	54	static int pps_tty_open(struct tty_struct *tty)
	55	{
	56	struct pps_source_info info;
	57	struct tty_driver *drv = tty->driver;
	58	int index = tty->index + drv->name_base;
5e196d34	59	struct pps_device *pps;
a0880df0 RG	60	int ret;
	61
	62	info.owner = THIS_MODULE;
	63	info.dev = NULL;
	64	snprintf(info.name, PPS_MAX_NAME_LEN, "%s%d", drv->driver_name, index);
	65	snprintf(info.path, PPS_MAX_NAME_LEN, "/dev/%s%d", drv->name, index);
	66	info.mode = PPS_CAPTUREBOTH \| \
	67	PPS_OFFSETASSERT \| PPS_OFFSETCLEAR \| \
	68	PPS_CANWAIT \| PPS_TSFMT_TSPEC;
	69
5e196d34	70	pps = pps_register_source(&info, PPS_CAPTUREBOTH \| \
a0880df0	71	PPS_OFFSETASSERT \| PPS_OFFSETCLEAR);
5e196d34	72	if (pps == NULL) {
a0880df0	73	pr_err("cannot register PPS source \"%s\"\n", info.path);
5e196d34	74	return -ENOMEM;
a0880df0	75	}
5e196d34	76	tty->disc_data = pps;
a0880df0 RG	77
	78	/* Should open N_TTY ldisc too */
	79	ret = alias_n_tty_open(tty);
5e196d34 AG	80	if (ret < 0) {
	81	pr_err("cannot open tty ldisc \"%s\"\n", info.path);
	82	goto err_unregister;
	83	}
a0880df0	84
5e196d34	85	dev_info(pps->dev, "source \"%s\" added\n", info.path);
a0880df0 RG	86
a0880df0 RG	87	return 0;
5e196d34 AG	88
	89	err_unregister:
	90	tty->disc_data = NULL;
	91	pps_unregister_source(pps);
	92	return ret;
a0880df0 RG	93	}
	94
	95	static void (alias_n_tty_close)(struct tty_struct tty);
	96
	97	static void pps_tty_close(struct tty_struct *tty)
	98	{
5e196d34	99	struct pps_device pps = (struct pps_device )tty->disc_data;
a0880df0	100
a0880df0 RG	101	alias_n_tty_close(tty);
a0880df0 RG	102
5e196d34 AG	103	tty->disc_data = NULL;
	104	dev_info(pps->dev, "removed\n");
	105	pps_unregister_source(pps);
a0880df0 RG	106	}
	107
	108	static struct tty_ldisc_ops pps_ldisc_ops;
	109
	110	/*
	111	* Module stuff
	112	*/
	113
	114	static int __init pps_tty_init(void)
	115	{
	116	int err;
	117
	118	/* Inherit the N_TTY's ops */
	119	n_tty_inherit_ops(&pps_ldisc_ops);
	120
	121	/* Save N_TTY's open()/close() methods */
	122	alias_n_tty_open = pps_ldisc_ops.open;
	123	alias_n_tty_close = pps_ldisc_ops.close;
	124
	125	/* Init PPS_TTY data */
	126	pps_ldisc_ops.owner = THIS_MODULE;
	127	pps_ldisc_ops.magic = PPS_TTY_MAGIC;
	128	pps_ldisc_ops.name = "pps_tty";
	129	pps_ldisc_ops.dcd_change = pps_tty_dcd_change;
	130	pps_ldisc_ops.open = pps_tty_open;
	131	pps_ldisc_ops.close = pps_tty_close;
	132
	133	err = tty_register_ldisc(N_PPS, &pps_ldisc_ops);
	134	if (err)
	135	pr_err("can't register PPS line discipline\n");
	136	else
	137	pr_info("PPS line discipline registered\n");
	138
	139	return err;
	140	}
	141
	142	static void __exit pps_tty_cleanup(void)
	143	{
	144	int err;
	145
	146	err = tty_unregister_ldisc(N_PPS);
	147	if (err)
	148	pr_err("can't unregister PPS line discipline\n");
	149	else
	150	pr_info("PPS line discipline removed\n");
	151	}
	152
	153	module_init(pps_tty_init);
	154	module_exit(pps_tty_cleanup);
	155
	156	MODULE_ALIAS_LDISC(N_PPS);
	157	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	158	MODULE_DESCRIPTION("PPS TTY device driver");
	159	MODULE_LICENSE("GPL");