TODR(9)

TODR(9) | NetBSD Kernel Developer's Manual | TODR(9)

# NAME

todr_attach, todr_gettime, todr_settime, clock_ymdhms_to_secs, clock_secs_to_ymdhms — time-of-day clock support

# SYNOPSIS

#include <dev/clock_subr.h>

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 *);

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 caller. todr_settime() sets the date and time in the TODR device represented by todr_chip_handle_t according to the struct timeval argument.

The utilities clock_secs_to_ymdhms() and clock_ymdhms_to_secs() are provided to convert a time value in seconds to and from a structure representing 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 (1-31) */
    	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 successful; otherwise an error code from <sys/errno.h> shall be returned. However, behaviour is undefined if an invalid todr_chip_handle_t is passed to any of these functions.

The clock_ymdhms_to_secs() function returns -1 if the time in seconds would be less that zero or too large to fit in a time_t. The clock_secs_to_ymdhms() function never fails.

# SEE ALSO

intersil7170(4), mk48txx(4), inittodr(9), resettodr(9), time_second(9)

September 6, 2006 | NetBSD 5.99