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Adds support, by using the PPS line discipline, for the PPS sources connected with the CD (Carrier Detect) pin of a serial port. [[email protected]: fix cast size warnings] Signed-off-by: Rodolfo Giometti <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Greg KH <[email protected]> Cc: Alan Cox <[email protected]> Cc: Alexander Gordeev <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
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/* | ||
* pps-ldisc.c -- PPS line discipline | ||
* | ||
* | ||
* Copyright (C) 2008 Rodolfo Giometti <[email protected]> | ||
* | ||
* 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. | ||
*/ | ||
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#include <linux/module.h> | ||
#include <linux/serial_core.h> | ||
#include <linux/tty.h> | ||
#include <linux/pps_kernel.h> | ||
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#define PPS_TTY_MAGIC 0x0001 | ||
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static void pps_tty_dcd_change(struct tty_struct *tty, unsigned int status, | ||
struct timespec *ts) | ||
{ | ||
int id = (long)tty->disc_data; | ||
struct timespec __ts; | ||
struct pps_ktime pps_ts; | ||
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/* First of all we get the time stamp... */ | ||
getnstimeofday(&__ts); | ||
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/* Does caller give us a timestamp? */ | ||
if (ts) { /* Yes. Let's use it! */ | ||
pps_ts.sec = ts->tv_sec; | ||
pps_ts.nsec = ts->tv_nsec; | ||
} else { /* No. Do it ourself! */ | ||
pps_ts.sec = __ts.tv_sec; | ||
pps_ts.nsec = __ts.tv_nsec; | ||
} | ||
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/* Now do the PPS event report */ | ||
pps_event(id, &pps_ts, status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR, | ||
NULL); | ||
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pr_debug("PPS %s at %lu on source #%d\n", | ||
status ? "assert" : "clear", jiffies, id); | ||
} | ||
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static int (*alias_n_tty_open)(struct tty_struct *tty); | ||
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static int pps_tty_open(struct tty_struct *tty) | ||
{ | ||
struct pps_source_info info; | ||
struct tty_driver *drv = tty->driver; | ||
int index = tty->index + drv->name_base; | ||
int ret; | ||
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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; | ||
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ret = pps_register_source(&info, PPS_CAPTUREBOTH | \ | ||
PPS_OFFSETASSERT | PPS_OFFSETCLEAR); | ||
if (ret < 0) { | ||
pr_err("cannot register PPS source \"%s\"\n", info.path); | ||
return ret; | ||
} | ||
tty->disc_data = (void *)(long)ret; | ||
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/* Should open N_TTY ldisc too */ | ||
ret = alias_n_tty_open(tty); | ||
if (ret < 0) | ||
pps_unregister_source((long)tty->disc_data); | ||
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pr_info("PPS source #%d \"%s\" added\n", ret, info.path); | ||
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return 0; | ||
} | ||
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static void (*alias_n_tty_close)(struct tty_struct *tty); | ||
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static void pps_tty_close(struct tty_struct *tty) | ||
{ | ||
int id = (long)tty->disc_data; | ||
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pps_unregister_source(id); | ||
alias_n_tty_close(tty); | ||
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pr_info("PPS source #%d removed\n", id); | ||
} | ||
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static struct tty_ldisc_ops pps_ldisc_ops; | ||
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/* | ||
* Module stuff | ||
*/ | ||
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static int __init pps_tty_init(void) | ||
{ | ||
int err; | ||
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/* Inherit the N_TTY's ops */ | ||
n_tty_inherit_ops(&pps_ldisc_ops); | ||
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/* Save N_TTY's open()/close() methods */ | ||
alias_n_tty_open = pps_ldisc_ops.open; | ||
alias_n_tty_close = pps_ldisc_ops.close; | ||
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/* 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; | ||
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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"); | ||
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return err; | ||
} | ||
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static void __exit pps_tty_cleanup(void) | ||
{ | ||
int err; | ||
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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"); | ||
} | ||
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module_init(pps_tty_init); | ||
module_exit(pps_tty_cleanup); | ||
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MODULE_ALIAS_LDISC(N_PPS); | ||
MODULE_AUTHOR("Rodolfo Giometti <[email protected]>"); | ||
MODULE_DESCRIPTION("PPS TTY device driver"); | ||
MODULE_LICENSE("GPL"); |
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