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 #define PPS_VERSION             "5.3.6"
  26 #define PPS_MAX_SOURCES         16              /* should be enough... */
  27
  28 /* Implementation note: the logical states ``assert'' and ``clear''
  29  * are implemented in terms of the chip register, i.e. ``assert''
  30  * means the bit is set.  */
  31
  32 /*
  33  * 3.2 New data structures
  34  */
  35
  36 #define PPS_API_VERS_1          1
  37 #define PPS_API_VERS            PPS_API_VERS_1  /* we use API version 1 */
  38 #define PPS_MAX_NAME_LEN        32
  39
  40 /* 32-bit vs. 64-bit compatibility.
  41  *
  42  * 0n i386, the alignment of a uint64_t is only 4 bytes, while on most other
  43  * architectures it's 8 bytes. On i386, there will be no padding between the
  44  * two consecutive 'struct pps_ktime' members of struct pps_kinfo and struct
  45  * pps_kparams. But on most platforms there will be padding to ensure correct
  46  * alignment.
  47  *
  48  * The simple fix is probably to add an explicit padding.
  49  *                                                      [David Woodhouse]
  50  */
  51 struct pps_ktime {
  52         __s64 sec;
  53         __s32 nsec;
  54         __u32 flags;
  55 };
  56 #define PPS_TIME_INVALID        (1<<0)  /* used to specify timeout==NULL */
  57
  58 struct pps_kinfo {
  59         __u32 assert_sequence;          /* seq. num. of assert event */
  60         __u32 clear_sequence;           /* seq. num. of clear event */
  61         struct pps_ktime assert_tu;     /* time of assert event */
  62         struct pps_ktime clear_tu;      /* time of clear event */
  63         int current_mode;               /* current mode bits */
  64 };
  65
  66 struct pps_kparams {
  67         int api_version;                /* API version # */
  68         int mode;                       /* mode bits */
  69         struct pps_ktime assert_off_tu; /* offset compensation for assert */
  70         struct pps_ktime clear_off_tu;  /* offset compensation for clear */
  71 };
  72
  73 /*
  74  * 3.3 Mode bit definitions
  75  */
  76
  77 /* Device/implementation parameters */
  78 #define PPS_CAPTUREASSERT       0x01    /* capture assert events */
  79 #define PPS_CAPTURECLEAR        0x02    /* capture clear events */
  80 #define PPS_CAPTUREBOTH         0x03    /* capture assert and clear events */
  81
  82 #define PPS_OFFSETASSERT        0x10    /* apply compensation for assert ev. */
  83 #define PPS_OFFSETCLEAR         0x20    /* apply compensation for clear ev. */
  84
  85 #define PPS_CANWAIT             0x100   /* can we wait for an event? */
  86 #define PPS_CANPOLL             0x200   /* bit reserved for future use */
  87
  88 /* Kernel actions */
  89 #define PPS_ECHOASSERT          0x40    /* feed back assert event to output */
  90 #define PPS_ECHOCLEAR           0x80    /* feed back clear event to output */
  91
  92 /* Timestamp formats */
  93 #define PPS_TSFMT_TSPEC         0x1000  /* select timespec format */
  94 #define PPS_TSFMT_NTPFP         0x2000  /* select NTP format */
  95
  96 /*
  97  * 3.4.4 New functions: disciplining the kernel timebase
  98  */
  99
 100 /* Kernel consumers */
 101 #define PPS_KC_HARDPPS          0       /* hardpps() (or equivalent) */
 102 #define PPS_KC_HARDPPS_PLL      1       /* hardpps() constrained to
 103                                            use a phase-locked loop */
 104 #define PPS_KC_HARDPPS_FLL      2       /* hardpps() constrained to
 105                                            use a frequency-locked loop */
 106 /*
 107  * Here begins the implementation-specific part!
 108  */
 109
 110 struct pps_fdata {
 111         struct pps_kinfo info;
 112         struct pps_ktime timeout;
 113 };
 114
 115 #include <linux/ioctl.h>
 116
 117 #define PPS_GETPARAMS           _IOR('p', 0xa1, struct pps_kparams *)
 118 #define PPS_SETPARAMS           _IOW('p', 0xa2, struct pps_kparams *)
 119 #define PPS_GETCAP              _IOR('p', 0xa3, int *)
 120 #define PPS_FETCH               _IOWR('p', 0xa4, struct pps_fdata *)
 121
 122 #endif /* _PPS_H_ */