From eae9d2ba0cfc27a2ad9765f23efb98fb80d80234 Mon Sep 17 00:00:00 2001 From: Rodolfo Giometti Date: Wed, 17 Jun 2009 16:28:37 -0700 Subject: LinuxPPS: core support This patch adds the kernel side of the PPS support currently named "LinuxPPS". PPS means "pulse per second" and a PPS source is just a device which provides a high precision signal each second so that an application can use it to adjust system clock time. Common use is the combination of the NTPD as userland program with a GPS receiver as PPS source to obtain a wallclock-time with sub-millisecond synchronisation to UTC. To obtain this goal the userland programs shoud use the PPS API specification (RFC 2783 - Pulse-Per-Second API for UNIX-like Operating Systems, Version 1.0) which in part is implemented by this patch. It provides a set of chars devices, one per PPS source, which can be used to get the time signal. The RFC's functions can be implemented by accessing to these char devices. Signed-off-by: Rodolfo Giometti Cc: David Woodhouse Cc: Greg KH Cc: Randy Dunlap Cc: Kay Sievers Acked-by: Alan Cox Cc: Michael Kerrisk Cc: Christoph Hellwig Cc: Roman Zippel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/pps_kernel.h | 89 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 include/linux/pps_kernel.h (limited to 'include/linux/pps_kernel.h') diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h new file mode 100644 index 00000000000..e0a193f830e --- /dev/null +++ b/include/linux/pps_kernel.h @@ -0,0 +1,89 @@ +/* + * PPS API kernel header + * + * Copyright (C) 2009 Rodolfo Giometti + * + * 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 + +#include +#include +#include + +/* + * Global defines + */ + +/* The specific PPS source info */ +struct pps_source_info { + char name[PPS_MAX_NAME_LEN]; /* simbolic name */ + char path[PPS_MAX_NAME_LEN]; /* path of connected device */ + int mode; /* PPS's allowed mode */ + + void (*echo)(int source, int event, void *data); /* PPS echo function */ + + struct module *owner; + struct device *dev; +}; + +/* The main struct */ +struct pps_device { + struct pps_source_info info; /* PSS source info */ + + struct pps_kparams params; /* PPS's current params */ + + __u32 assert_sequence; /* PPS' assert event seq # */ + __u32 clear_sequence; /* PPS' clear event seq # */ + struct pps_ktime assert_tu; + struct pps_ktime clear_tu; + int current_mode; /* PPS mode at event time */ + + int go; /* PPS event is arrived? */ + wait_queue_head_t queue; /* PPS event queue */ + + unsigned int id; /* PPS source unique ID */ + struct cdev cdev; + struct device *dev; + int devno; + struct fasync_struct *async_queue; /* fasync method */ + spinlock_t lock; + + atomic_t usage; /* usage count */ +}; + +/* + * Global variables + */ + +extern spinlock_t pps_idr_lock; +extern struct idr pps_idr; +extern struct timespec pps_irq_ts[]; + +extern struct device_attribute pps_attrs[]; + +/* + * Exported functions + */ + +struct pps_device *pps_get_source(int source); +extern void pps_put_source(struct pps_device *pps); +extern int pps_register_source(struct pps_source_info *info, + int default_params); +extern void pps_unregister_source(int source); +extern int pps_register_cdev(struct pps_device *pps); +extern void pps_unregister_cdev(struct pps_device *pps); +extern void pps_event(int source, struct pps_ktime *ts, int event, void *data); -- cgit v1.2.3