pps.h

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/*
 * PPS API header
 *
 * Copyright (C) 2005-2009   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.
 */


#ifndef _PPS_H_
#define _PPS_H_

#include <linux/types.h>

#define PPS_VERSION     "5.3.6"
#define PPS_MAX_SOURCES     16      /* should be enough... */

/* Implementation note: the logical states ``assert'' and ``clear''
 * are implemented in terms of the chip register, i.e. ``assert''
 * means the bit is set.  */

/*
 * 3.2 New data structures
 */

#define PPS_API_VERS_1      1
#define PPS_API_VERS        PPS_API_VERS_1  /* we use API version 1 */
#define PPS_MAX_NAME_LEN    32

/* 32-bit vs. 64-bit compatibility.
 *
 * 0n i386, the alignment of a uint64_t is only 4 bytes, while on most other
 * architectures it's 8 bytes. On i386, there will be no padding between the
 * two consecutive 'struct pps_ktime' members of struct pps_kinfo and struct
 * pps_kparams. But on most platforms there will be padding to ensure correct
 * alignment.
 *
 * The simple fix is probably to add an explicit padding.
 *                          [David Woodhouse]
 */
struct pps_ktime {
    __s64 sec;
    __s32 nsec;
    __u32 flags;
};
#define PPS_TIME_INVALID    (1<<0)  /* used to specify timeout==NULL */

struct pps_kinfo {
    __u32 assert_sequence;      /* seq. num. of assert event */
    __u32 clear_sequence;       /* seq. num. of clear event */
    struct pps_ktime assert_tu; /* time of assert event */
    struct pps_ktime clear_tu;  /* time of clear event */
    int current_mode;       /* current mode bits */
};

struct pps_kparams {
    int api_version;        /* API version # */
    int mode;           /* mode bits */
    struct pps_ktime assert_off_tu; /* offset compensation for assert */
    struct pps_ktime clear_off_tu;  /* offset compensation for clear */
};

/*
 * 3.3 Mode bit definitions
 */

/* Device/implementation parameters */
#define PPS_CAPTUREASSERT   0x01    /* capture assert events */
#define PPS_CAPTURECLEAR    0x02    /* capture clear events */
#define PPS_CAPTUREBOTH     0x03    /* capture assert and clear events */

#define PPS_OFFSETASSERT    0x10    /* apply compensation for assert ev. */
#define PPS_OFFSETCLEAR     0x20    /* apply compensation for clear ev. */

#define PPS_CANWAIT     0x100   /* can we wait for an event? */
#define PPS_CANPOLL     0x200   /* bit reserved for future use */

/* Kernel actions */
#define PPS_ECHOASSERT      0x40    /* feed back assert event to output */
#define PPS_ECHOCLEAR       0x80    /* feed back clear event to output */

/* Timestamp formats */
#define PPS_TSFMT_TSPEC     0x1000  /* select timespec format */
#define PPS_TSFMT_NTPFP     0x2000  /* select NTP format */

/*
 * 3.4.4 New functions: disciplining the kernel timebase
 */

/* Kernel consumers */
#define PPS_KC_HARDPPS      0   /* hardpps() (or equivalent) */
#define PPS_KC_HARDPPS_PLL  1   /* hardpps() constrained to
                       use a phase-locked loop */
#define PPS_KC_HARDPPS_FLL  2   /* hardpps() constrained to
                       use a frequency-locked loop */
/*
 * Here begins the implementation-specific part!
 */

struct pps_fdata {
    struct pps_kinfo info;
    struct pps_ktime timeout;
};

struct pps_bind_args {
    int tsformat;   /* format of time stamps */
    int edge;   /* selected event type */
    int consumer;   /* selected kernel consumer */
};

#include <linux/ioctl.h>

#define PPS_GETPARAMS       _IOR('p', 0xa1, struct pps_kparams *)
#define PPS_SETPARAMS       _IOW('p', 0xa2, struct pps_kparams *)
#define PPS_GETCAP      _IOR('p', 0xa3, int *)
#define PPS_FETCH       _IOWR('p', 0xa4, struct pps_fdata *)
#define PPS_KC_BIND     _IOW('p', 0xa5, struct pps_bind_args *)

#endif /* _PPS_H_ */