include/linux/pps.h

   1 /*
   2  * PPS API header
   3  *
   4  * Copyright (C) 2005-2009   Rodolfo Giometti <giometti@linux.it>
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21
  22 #ifndef _PPS_H_
  23 #define _PPS_H_
  24
  25 #include <linux/types.h>
  26
  27 #define PPS_VERSION             "5.3.6"
  28 #define PPS_MAX_SOURCES         16              /* should be enough... */
  29
  30 /* Implementation note: the logical states ``assert'' and ``clear''
  31  * are implemented in terms of the chip register, i.e. ``assert''
  32  * means the bit is set.  */
  33
  34 /*
  35  * 3.2 New data structures
  36  */
  37
  38 #define PPS_API_VERS_1          1
  39 #define PPS_API_VERS            PPS_API_VERS_1  /* we use API version 1 */
  40 #define PPS_MAX_NAME_LEN        32
  41
  42 /* 32-bit vs. 64-bit compatibility.
  43  *
  44  * 0n i386, the alignment of a uint64_t is only 4 bytes, while on most other
  45  * architectures it's 8 bytes. On i386, there will be no padding between the
  46  * two consecutive 'struct pps_ktime' members of struct pps_kinfo and struct
  47  * pps_kparams. But on most platforms there will be padding to ensure correct
  48  * alignment.
  49  *
  50  * The simple fix is probably to add an explicit padding.
  51  *                                                      [David Woodhouse]
  52  */
  53 struct pps_ktime {
  54         __s64 sec;
  55         __s32 nsec;
  56         __u32 flags;
  57 };
  58 #define PPS_TIME_INVALID        (1<<0)  /* used to specify timeout==NULL */
  59
  60 struct pps_kinfo {
  61         __u32 assert_sequence;          /* seq. num. of assert event */
  62         __u32 clear_sequence;           /* seq. num. of clear event */
  63         struct pps_ktime assert_tu;     /* time of assert event */
  64         struct pps_ktime clear_tu;      /* time of clear event */
  65         int current_mode;               /* current mode bits */
  66 };
  67
  68 struct pps_kparams {
  69         int api_version;                /* API version # */
  70         int mode;                       /* mode bits */
  71         struct pps_ktime assert_off_tu; /* offset compensation for assert */
  72         struct pps_ktime clear_off_tu;  /* offset compensation for clear */
  73 };
  74
  75 /*
  76  * 3.3 Mode bit definitions
  77  */
  78
  79 /* Device/implementation parameters */
  80 #define PPS_CAPTUREASSERT       0x01    /* capture assert events */
  81 #define PPS_CAPTURECLEAR        0x02    /* capture clear events */
  82 #define PPS_CAPTUREBOTH         0x03    /* capture assert and clear events */
  83
  84 #define PPS_OFFSETASSERT        0x10    /* apply compensation for assert ev. */
  85 #define PPS_OFFSETCLEAR         0x20    /* apply compensation for clear ev. */
  86
  87 #define PPS_CANWAIT             0x100   /* can we wait for an event? */
  88 #define PPS_CANPOLL             0x200   /* bit reserved for future use */
  89
  90 /* Kernel actions */
  91 #define PPS_ECHOASSERT          0x40    /* feed back assert event to output */
  92 #define PPS_ECHOCLEAR           0x80    /* feed back clear event to output */
  93
  94 /* Timestamp formats */
  95 #define PPS_TSFMT_TSPEC         0x1000  /* select timespec format */
  96 #define PPS_TSFMT_NTPFP         0x2000  /* select NTP format */
  97
  98 /*
  99  * 3.4.4 New functions: disciplining the kernel timebase
 100  */
 101
 102 /* Kernel consumers */
 103 #define PPS_KC_HARDPPS          0       /* hardpps() (or equivalent) */
 104 #define PPS_KC_HARDPPS_PLL      1       /* hardpps() constrained to
 105                                            use a phase-locked loop */
 106 #define PPS_KC_HARDPPS_FLL      2       /* hardpps() constrained to
 107                                            use a frequency-locked loop */
 108 /*
 109  * Here begins the implementation-specific part!
 110  */
 111
 112 struct pps_fdata {
 113         struct pps_kinfo info;
 114         struct pps_ktime timeout;
 115 };
 116
 117 #include <linux/ioctl.h>
 118
 119 #define PPS_GETPARAMS           _IOR('p', 0xa1, struct pps_kparams *)
 120 #define PPS_SETPARAMS           _IOW('p', 0xa2, struct pps_kparams *)
 121 #define PPS_GETCAP              _IOR('p', 0xa3, int *)
 122 #define PPS_FETCH               _IOWR('p', 0xa4, struct pps_fdata *)
 123
 124 #endif /* _PPS_H_ */