xref: /src/sys/dev/i2c/ds1307.c

/*	$NetBSD: ds1307.c,v 1.6 2006/09/04 23:45:30 gdamore Exp $	*/

/*
 * Copyright (c) 2003 Wasabi Systems, Inc.
 * All rights reserved.
 *
 * Written by Steve C. Woodford and Jason R. Thorpe for Wasabi Systems, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed for the NetBSD Project by
 *      Wasabi Systems, Inc.
 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
 *    or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/fcntl.h>
#include <sys/uio.h>
#include <sys/conf.h>
#include <sys/event.h>

#include <dev/clock_subr.h>

#include <dev/i2c/i2cvar.h>
#include <dev/i2c/ds1307reg.h>

struct dsrtc_softc {
	struct device sc_dev;
	i2c_tag_t sc_tag;
	int sc_address;
	int sc_open;
	struct todr_chip_handle sc_todr;
};

static void	dsrtc_attach(struct device *, struct device *, void *);
static int	dsrtc_match(struct device *, struct cfdata *, void *);

CFATTACH_DECL(dsrtc, sizeof(struct dsrtc_softc),
    dsrtc_match, dsrtc_attach, NULL, NULL);
extern struct cfdriver dsrtc_cd;

dev_type_open(dsrtc_open);
dev_type_close(dsrtc_close);
dev_type_read(dsrtc_read);
dev_type_write(dsrtc_write);

const struct cdevsw dsrtc_cdevsw = {
	dsrtc_open, dsrtc_close, dsrtc_read, dsrtc_write, noioctl,
	nostop, notty, nopoll, nommap, nokqfilter
};

static int dsrtc_clock_read(struct dsrtc_softc *, struct clock_ymdhms *);
static int dsrtc_clock_write(struct dsrtc_softc *, struct clock_ymdhms *);
static int dsrtc_gettime(struct todr_chip_handle *, volatile struct timeval *);
static int dsrtc_settime(struct todr_chip_handle *, volatile struct timeval *);

static int
dsrtc_match(struct device *parent, struct cfdata *cf, void *arg)
{
	struct i2c_attach_args *ia = arg;

	if (ia->ia_addr == DS1307_ADDR)
		return (1);

	return (0);
}

static void
dsrtc_attach(struct device *parent, struct device *self, void *arg)
{
	struct dsrtc_softc *sc = device_private(self);
	struct i2c_attach_args *ia = arg;

	aprint_naive(": Real-time Clock/NVRAM\n");
	aprint_normal(": DS1307 Real-time Clock/NVRAM\n");

	sc->sc_tag = ia->ia_tag;
	sc->sc_address = ia->ia_addr;
	sc->sc_open = 0;
	sc->sc_todr.cookie = sc;
	sc->sc_todr.todr_gettime = dsrtc_gettime;
	sc->sc_todr.todr_settime = dsrtc_settime;
	sc->sc_todr.todr_setwen = NULL;

	todr_attach(&sc->sc_todr);
}

/*ARGSUSED*/
int
dsrtc_open(dev_t dev, int flag, int fmt, struct lwp *l)
{
	struct dsrtc_softc *sc;

	if ((sc = device_lookup(&dsrtc_cd, minor(dev))) == NULL)
		return (ENXIO);

	/* XXX: Locking */

	if (sc->sc_open)
		return (EBUSY);

	sc->sc_open = 1;
	return (0);
}

/*ARGSUSED*/
int
dsrtc_close(dev_t dev, int flag, int fmt, struct lwp *l)
{
	struct dsrtc_softc *sc;

	if ((sc = device_lookup(&dsrtc_cd, minor(dev))) == NULL)
		return (ENXIO);

	sc->sc_open = 0;
	return (0);
}

/*ARGSUSED*/
int
dsrtc_read(dev_t dev, struct uio *uio, int flags)
{
	struct dsrtc_softc *sc;
	u_int8_t ch, cmdbuf[1];
	int a, error;

	if ((sc = device_lookup(&dsrtc_cd, minor(dev))) == NULL)
		return (ENXIO);

	if (uio->uio_offset >= DS1307_NVRAM_SIZE)
		return (EINVAL);

	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
		return (error);

	while (uio->uio_resid && uio->uio_offset < DS1307_NVRAM_SIZE) {
		a = (int)uio->uio_offset;
		cmdbuf[0] = a + DS1307_NVRAM_START;
		if ((error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
				      sc->sc_address, cmdbuf, 1,
				      &ch, 1, 0)) != 0) {
			iic_release_bus(sc->sc_tag, 0);
			printf("%s: dsrtc_read: read failed at 0x%x\n",
			    sc->sc_dev.dv_xname, a);
			return (error);
		}
		if ((error = uiomove(&ch, 1, uio)) != 0) {
			iic_release_bus(sc->sc_tag, 0);
			return (error);
		}
	}

	iic_release_bus(sc->sc_tag, 0);

	return (0);
}

/*ARGSUSED*/
int
dsrtc_write(dev_t dev, struct uio *uio, int flags)
{
	struct dsrtc_softc *sc;
	u_int8_t cmdbuf[2];
	int a, error;

	if ((sc = device_lookup(&dsrtc_cd, minor(dev))) == NULL)
		return (ENXIO);

	if (uio->uio_offset >= DS1307_NVRAM_SIZE)
		return (EINVAL);

	if ((error = iic_acquire_bus(sc->sc_tag, 0)) != 0)
		return (error);

	while (uio->uio_resid && uio->uio_offset < DS1307_NVRAM_SIZE) {
		a = (int)uio->uio_offset;
		cmdbuf[0] = a + DS1307_NVRAM_START;
		if ((error = uiomove(&cmdbuf[1], 1, uio)) != 0)
			break;

		if ((error = iic_exec(sc->sc_tag,
		    uio->uio_resid ? I2C_OP_WRITE : I2C_OP_WRITE_WITH_STOP,
		    sc->sc_address, cmdbuf, 1, &cmdbuf[1], 1, 0)) != 0) {
			printf("%s: dsrtc_write: write failed at 0x%x\n",
			    sc->sc_dev.dv_xname, a);
			break;
		}
	}

	iic_release_bus(sc->sc_tag, 0);

	return (error);
}

static int
dsrtc_gettime(struct todr_chip_handle *ch, volatile struct timeval *tv)
{
	struct dsrtc_softc *sc = ch->cookie;
	struct clock_ymdhms dt, check;
	int retries;

	memset(&dt, 0, sizeof(dt));
	memset(&check, 0, sizeof(check));

	/*
	 * Since we don't support Burst Read, we have to read the clock twice
	 * until we get two consecutive identical results.
	 */
	retries = 5;
	do {
		dsrtc_clock_read(sc, &dt);
		dsrtc_clock_read(sc, &check);
	} while (memcmp(&dt, &check, sizeof(check)) != 0 && --retries);

	tv->tv_sec = clock_ymdhms_to_secs(&dt);
	tv->tv_usec = 0;

	return (0);
}

static int
dsrtc_settime(struct todr_chip_handle *ch, volatile struct timeval *tv)
{
	struct dsrtc_softc *sc = ch->cookie;
	struct clock_ymdhms dt;

	clock_secs_to_ymdhms(tv->tv_sec, &dt);

	if (dsrtc_clock_write(sc, &dt) == 0)
		return (-1);

	return (0);
}

static int
dsrtc_clock_read(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
{
	u_int8_t bcd[DS1307_NRTC_REGS], cmdbuf[1];
	int i;

	if (iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) {
		printf("%s: dsrtc_clock_read: failed to acquire I2C bus\n",
		    sc->sc_dev.dv_xname);
		return (0);
	}

	/* Read each RTC register in order. */
	for (i = DS1307_SECONDS; i < DS1307_NRTC_REGS; i++) {
		cmdbuf[0] = i;

		if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP,
			     sc->sc_address, cmdbuf, 1,
			     &bcd[i], 1, I2C_F_POLL)) {
			iic_release_bus(sc->sc_tag, I2C_F_POLL);
			printf("%s: dsrtc_clock_read: failed to read rtc "
			    "at 0x%x\n", sc->sc_dev.dv_xname, i);
			return (0);
		}
	}

	/* Done with I2C */
	iic_release_bus(sc->sc_tag, I2C_F_POLL);

	/*
	 * Convert the DS1307's register values into something useable
	 */
	dt->dt_sec = FROMBCD(bcd[DS1307_SECONDS] & DS1307_SECONDS_MASK);
	dt->dt_min = FROMBCD(bcd[DS1307_MINUTES] & DS1307_MINUTES_MASK);

	if ((bcd[DS1307_HOURS] & DS1307_HOURS_24HRS) == 0) {
		dt->dt_hour = FROMBCD(bcd[DS1307_HOURS] &
		    DS1307_HOURS_12MASK);
		if (bcd[DS1307_HOURS] & DS1307_HOURS_12HRS_PM)
			dt->dt_hour += 12;
	} else {
		dt->dt_hour = FROMBCD(bcd[DS1307_HOURS] &
		    DS1307_HOURS_24MASK);
	}

	dt->dt_day = FROMBCD(bcd[DS1307_DATE] & DS1307_DATE_MASK);
	dt->dt_mon = FROMBCD(bcd[DS1307_MONTH] & DS1307_MONTH_MASK);

	/* XXX: Should be an MD way to specify EPOCH used by BIOS/Firmware */
	dt->dt_year = FROMBCD(bcd[DS1307_YEAR]) + POSIX_BASE_YEAR;

	return (1);
}

static int
dsrtc_clock_write(struct dsrtc_softc *sc, struct clock_ymdhms *dt)
{
	uint8_t bcd[DS1307_NRTC_REGS], cmdbuf[2];
	int i;

	/*
	 * Convert our time representation into something the DS1307
	 * can understand.
	 */
	bcd[DS1307_SECONDS] = TOBCD(dt->dt_sec);
	bcd[DS1307_MINUTES] = TOBCD(dt->dt_min);
	bcd[DS1307_HOURS] = TOBCD(dt->dt_hour) | DS1307_HOURS_24HRS;
	bcd[DS1307_DATE] = TOBCD(dt->dt_day);
	bcd[DS1307_DAY] = TOBCD(dt->dt_wday);
	bcd[DS1307_MONTH] = TOBCD(dt->dt_mon);
	bcd[DS1307_YEAR] = TOBCD((dt->dt_year - POSIX_BASE_YEAR) % 100);

	if (iic_acquire_bus(sc->sc_tag, I2C_F_POLL)) {
		printf("%s: dsrtc_clock_write: failed to acquire I2C bus\n",
		    sc->sc_dev.dv_xname);
		return (0);
	}

	/* Stop the clock */
	cmdbuf[0] = DS1307_SECONDS;
	cmdbuf[1] = DS1307_SECONDS_CH;

	if (iic_exec(sc->sc_tag, I2C_OP_WRITE, sc->sc_address,
		     cmdbuf, 1, &cmdbuf[1], 1, I2C_F_POLL)) {
		iic_release_bus(sc->sc_tag, I2C_F_POLL);
		printf("%s: dsrtc_clock_write: failed to Hold Clock\n",
		    sc->sc_dev.dv_xname);
		return (0);
	}

	/*
	 * Write registers in reverse order. The last write (to the Seconds
	 * register) will undo the Clock Hold, above.
	 */
	for (i = DS1307_NRTC_REGS - 1; i >= 0; i--) {
		cmdbuf[0] = i;
		if (iic_exec(sc->sc_tag,
			     i ? I2C_OP_WRITE : I2C_OP_WRITE_WITH_STOP,
			     sc->sc_address, cmdbuf, 1, &bcd[i], 1,
			     I2C_F_POLL)) {
			iic_release_bus(sc->sc_tag, I2C_F_POLL);
			printf("%s: dsrtc_clock_write: failed to write rtc "
			    " at 0x%x\n", sc->sc_dev.dv_xname, i);
			/* XXX: Clock Hold is likely still asserted! */
			return (0);
		}
	}

	iic_release_bus(sc->sc_tag, I2C_F_POLL);

	return (1);
}