| MK48TXX(4) | Device Drivers Manual | MK48TXX(4) | 
mk48txx —
#include <dev/ic/mk48txxreg.h>
#include <dev/ic/mk48txxvar.h>
define mk48txx
  
  file dev/ic/mk48txx.c mk48txx
mk48txx driver provides access to several models of
  Mostek time-of-day clock chips. Access methods to retrieve and set date and
  time are provided through the TODR interface defined in
  todr(9).
To tie an instance of this device to the system, use the
    mk48txx_attach() function and the mk48txx_softc
    structure defined as follows:
void
    mk48txx_attach(struct mk48txx_softc
    *)
typedef uint8_t (*mk48txx_nvrd_t)(struct mk48txx_softc *, int off);
typedef void (*mk48txx_nvwr_t)(struct mk48txx_softc *, int off,
    uint8_t datum);
struct mk48txx_softc {
	struct device   sc_dev;
	bus_space_tag_t sc_bst;
	bus_space_handle_t sc_bsh;
	struct todr_chip_handle sc_handle;
	const char	*sc_model;
	bus_size_t	sc_nvramsz;
	bus_size_t	sc_clkoffset;
	u_int		sc_year0;
	u_int		sc_flag;
	mk48txx_nvrd_t	sc_nvrd;
	mk48txx_nvwr_t	sc_nvwr;
};
todr_attach() function
      to register todr(9)
    interface.mk48txx_attach().mk48txx_attach().NULL is passed as an
      access method, is to access the chip memory (and clock registers) as if
      they were direct-mapped with using the specified bus space.
    Otherwise, the driver will call the respective function to perform the access, passing it the specified bus space and the offset off of the chip memory (or clock register) location to be read from or written to, respectively.
Note that if the resulting date retrieved with the todr_gettime() method is earlier that January 1, 1970, the driver will assume that the chip's year counter actually represents a year in the 21st century. This behaviour can be overridden by setting the MK48TXX_NO_CENT_ADJUST flag in sc_flag.
mk48txx driver first appeared in
  NetBSD 1.5.
mk48txx driver was written by Paul
  Kranenburg ⟨pk@NetBSD.org⟩.
| October 1, 2006 | NetBSD 9.4 |