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TODR(9)                  BSD Kernel Developer's Manual                 TODR(9)

NAME
     todr_attach, todr_gettime, todr_settime, todr_getcal, todr_setcal,
     clock_ymdhms_to_secs, clock_secs_to_ymdhms -- time-of-day clock support

SYNOPSIS
     #include <&lt;dev/clock_subr.h>&gt;

     void
     todr_attach(todr_chip_handle_t);

     int
     todr_gettime(todr_chip_handle_t, struct timeval *);

     int
     todr_settime(todr_chip_handle_t, struct timeval *);

     int
     todr_getcal(todr_chip_handle_t, int *);

     int
     todr_setcal(todr_chip_handle_t, int);

     void
     clock_secs_to_ymdhms(int, struct clock_ymdhms *);

     time_t
     clock_ymdhms_to_secs(struct clock_ymdhms *);

DESCRIPTION
     The todr_*() functions provide an interface to read, set and control
     'time-of-day' devices.  A driver for a 'time-of-day' device registers its
     todr_chip_handle_t with machine-dependent code using the todr_attach()
     function.  Alternatively, a machine-dependent front-end to a
     'time-of-day' device driver may obtain the todr_chip_handle_t directly.

     The todr_gettime() retrieves the current data and time from the TODR
     device and returns it in the struct timeval storage provided by the call-
     er.  todr_settime() sets the date and time in the TODR device represented
     by todr_chip_handle_t according to the struct timeval argument.

     todr_setcal() specifies a calibration value in PPM units to be programmed
     in the TODR device.  Positive values shall speed up the TODR clock, nega-
     tive values shall slow it down.  If the device in not capable of handling
     calibration, this function shall return EOPNOTSUPP.  The measurement and
     calculations necessary to use this method is expected to be provided by
     higher-level software modules.  todr_getcal() returns the current cali-
     bration (in PPM units) in effect on the TODR device.

     The utilities clock_secs_to_ymdhms() and clock_ymdhms_to_secs() are pro-
     vided to convert a time value in seconds to and from a structure repre-
     senting the date and time as a
     <year,month,day,weekday,hour,minute,seconds> tuple.  This structure is
     defined as follows:

     struct clock_ymdhms {
             u_short dt_year;        /* Year */
             u_char dt_mon;          /* Month (1-12) */
             u_char dt_day;          /* Day (0-365) */
             u_char dt_wday;         /* Day of week (0-6) */
             u_char dt_hour;         /* Hour (0-23) */
             u_char dt_min;          /* Minute (0-59) */
             u_char dt_sec;          /* Second (0-59) */
     };

     Note: leap years are recognised by these conversion routines.

RETURN VALUES
     The todr_*() functions return 0 if the requested operation was success-
     ful; otherwise an error code from <sys/errno.h> shall be returned.  How-
     ever, behaviour is undefined if an invalid todr_chip_handle_t is passed
     to any of these functions.  The clock_secs_to_ymdhms() and
     clock_ymdhms_to_secs() functions never fail.

SEE ALSO
     intersil7170(4), mk48txx(4), inittodr(9), resettodr(9), time(9)

BSD                              July 18, 2003                             BSD