/*
   * PPS API kernel header
   *
   * Copyright (C) 2009   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.
   */
  
  #ifndef LINUX_PPS_KERNEL_H
  #define LINUX_PPS_KERNEL_H
  
  #include <linux/pps.h>
  
  #include <linux/cdev.h>
  #include <linux/device.h>
  #include <linux/time.h>
  
  /*
   * Global defines
   */
  
  struct pps_device;
  
  /* 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)(struct pps_device *pps,
  			int event, void *data);	/* PPS echo function */
  
  	struct module *owner;
  	struct device *dev;		/* Parent device for device_create */
  };
  
  struct pps_event_time {
  #ifdef CONFIG_NTP_PPS
  	struct timespec ts_raw;
  #endif /* CONFIG_NTP_PPS */
  	struct timespec ts_real;
  };
  
  /* 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 */
  
  	unsigned int last_ev;			/* last PPS event id */
  	wait_queue_head_t queue;		/* PPS event queue */
  
  	unsigned int id;			/* PPS source unique ID */
  	void const *lookup_cookie;		/* pps_lookup_dev only */
  	struct cdev cdev;
  	struct device *dev;
  	struct fasync_struct *async_queue;	/* fasync method */
  	spinlock_t lock;
  };
  
  /*
   * Global variables
   */
  
  extern const struct attribute_group *pps_groups[];
  
  /*
   * Internal functions.
   *
   * These are not actually part of the exported API, but this is a
   * convenient header file to put them in.
   */
  
  extern int pps_register_cdev(struct pps_device *pps);
  extern void pps_unregister_cdev(struct pps_device *pps);
  
  /*
   * Exported functions
   */
  
  extern struct pps_device *pps_register_source(
  		struct pps_source_info *info, int default_params);
  extern void pps_unregister_source(struct pps_device *pps);
  extern void pps_event(struct pps_device *pps,
  		struct pps_event_time *ts, int event, void *data);
  /* Look up a pps device by magic cookie */
  struct pps_device *pps_lookup_dev(void const *cookie);
  
  static inline void timespec_to_pps_ktime(struct pps_ktime *kt,
  		struct timespec ts)
  {
  	kt->sec = ts.tv_sec;
  	kt->nsec = ts.tv_nsec;
  }
  
  #ifdef CONFIG_NTP_PPS
  
  static inline void pps_get_ts(struct pps_event_time *ts)
  {
  	getnstime_raw_and_real(&ts->ts_raw, &ts->ts_real);
  }
  
  #else /* CONFIG_NTP_PPS */
  
  static inline void pps_get_ts(struct pps_event_time *ts)
  {
  	getnstimeofday(&ts->ts_real);
  }
  
  #endif /* CONFIG_NTP_PPS */
  
  /* Subtract known time delay from PPS event time(s) */
  static inline void pps_sub_ts(struct pps_event_time *ts, struct timespec delta)
  {
  	ts->ts_real = timespec_sub(ts->ts_real, delta);
  #ifdef CONFIG_NTP_PPS
  	ts->ts_raw = timespec_sub(ts->ts_raw, delta);
  #endif
  }
  
  #endif /* LINUX_PPS_KERNEL_H */