diff options
Diffstat (limited to 'drivers/pps/clients/pps-ldisc.c')
| -rw-r--r-- | drivers/pps/clients/pps-ldisc.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/pps/clients/pps-ldisc.c b/drivers/pps/clients/pps-ldisc.c new file mode 100644 index 000000000000..8e1932d29fd4 --- /dev/null +++ b/drivers/pps/clients/pps-ldisc.c @@ -0,0 +1,154 @@ +/* + * 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 timespec *ts) +{ + int id = (long)tty->disc_data; + struct timespec __ts; + struct pps_ktime pps_ts; + + /* First of all we get the time stamp... */ + getnstimeofday(&__ts); + + /* 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; + } + + /* Now do the PPS event report */ + pps_event(id, &pps_ts, status ? PPS_CAPTUREASSERT : PPS_CAPTURECLEAR, + NULL); + + pr_debug("PPS %s at %lu on source #%d\n", + status ? "assert" : "clear", jiffies, id); +} + +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; + 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; + + 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; + + /* Should open N_TTY ldisc too */ + ret = alias_n_tty_open(tty); + if (ret < 0) + pps_unregister_source((long)tty->disc_data); + + pr_info("PPS source #%d \"%s\" added\n", ret, info.path); + + return 0; +} + +static void (*alias_n_tty_close)(struct tty_struct *tty); + +static void pps_tty_close(struct tty_struct *tty) +{ + int id = (long)tty->disc_data; + + pps_unregister_source(id); + alias_n_tty_close(tty); + + pr_info("PPS source #%d removed\n", id); +} + +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"); |