/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 Sam Leffler.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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/cdefs.h>
/*
 * Dallas Semiconductor DS1672 RTC sitting on the I2C bus.
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/clock.h>
#include <sys/time.h>
#include <sys/bus.h>
#include <sys/resource.h>
#include <sys/rman.h>

#include <dev/iicbus/iiconf.h>

#include "iicbus_if.h"
#include "clock_if.h"

#define IIC_M_WR        0       /* write operation */

#define DS1672_ADDR     0xd0    /* slave address */

#define DS1672_COUNTER  0       /* counter (bytes 0-3) */
#define DS1672_CTRL     4       /* control (1 byte) */
#define DS1672_TRICKLE  5       /* trickle charger (1 byte) */

#define DS1672_CTRL_EOSC        (1 << 7)        /* Stop/start flag. */

#define MAX_IIC_DATA_SIZE       4

struct ds1672_softc {
        device_t                sc_dev;
};

static int
ds1672_probe(device_t dev)
{
        /* XXX really probe? */
        device_set_desc(dev, "Dallas Semiconductor DS1672 RTC");
        return (BUS_PROBE_NOWILDCARD);
}

static int
ds1672_read(device_t dev, uint8_t addr, uint8_t *data, uint8_t size)
{
        struct iic_msg msgs[2] = {
             { DS1672_ADDR, IIC_M_WR, 1, &addr },
             { DS1672_ADDR, IIC_M_RD, size, data }
        };

        return (iicbus_transfer(dev, msgs, 2));
}

static int
ds1672_write(device_t dev, uint8_t addr, uint8_t *data, uint8_t size)
{
        uint8_t buffer[MAX_IIC_DATA_SIZE + 1];
        struct iic_msg msgs[1] = {
             { DS1672_ADDR, IIC_M_WR, size + 1, buffer },
        };
        
        if (size > MAX_IIC_DATA_SIZE)
                return (ENOMEM);
        /* NB: register pointer precedes actual data */
        buffer[0] = addr;
        memcpy(buffer + 1, data, size);
        return (iicbus_transfer(dev, msgs, 1));
}

static int
ds1672_init(device_t dev)
{
        uint8_t ctrl;
        int error;

        error = ds1672_read(dev, DS1672_CTRL, &ctrl, 1);
        if (error)
                return (error);

        /*
         * Check if oscialltor is not runned.
         */
        if (ctrl & DS1672_CTRL_EOSC) {
                device_printf(dev, "RTC oscillator was stopped. Check system"
                    " time and RTC battery.\n");
                ctrl &= ~DS1672_CTRL_EOSC;      /* Start oscillator. */
                error = ds1672_write(dev, DS1672_CTRL, &ctrl, 1);
        }
        return (error);
}

static int
ds1672_detach(device_t dev)
{

    clock_unregister(dev);
    return (0);
}

static int
ds1672_attach(device_t dev)
{
        struct ds1672_softc *sc = device_get_softc(dev);
        int error;

        sc->sc_dev = dev;
        error = ds1672_init(dev);
        if (error)
                return (error);
        clock_register(dev, 1000);
        return (0);
}

static int
ds1672_gettime(device_t dev, struct timespec *ts)
{
        uint8_t secs[4];
        int error;

        error = ds1672_read(dev, DS1672_COUNTER, secs, 4);
        if (error == 0) {
                /* counter has seconds since epoch */
                ts->tv_sec = (secs[3] << 24) | (secs[2] << 16)
                           | (secs[1] <<  8) | (secs[0] <<  0);
                ts->tv_nsec = 0;
        }
        clock_dbgprint_ts(dev, CLOCK_DBG_READ, ts); 
        return (error);
}

static int
ds1672_settime(device_t dev, struct timespec *ts)
{
        uint8_t data[4];

        data[0] = (ts->tv_sec >> 0) & 0xff;
        data[1] = (ts->tv_sec >> 8) & 0xff;
        data[2] = (ts->tv_sec >> 16) & 0xff;
        data[3] = (ts->tv_sec >> 24) & 0xff;

        ts->tv_nsec = 0;
        clock_dbgprint_ts(dev, CLOCK_DBG_WRITE, ts);
        return (ds1672_write(dev, DS1672_COUNTER, data, 4));
}

static device_method_t ds1672_methods[] = {
        DEVMETHOD(device_probe,         ds1672_probe),
        DEVMETHOD(device_attach,        ds1672_attach),
        DEVMETHOD(device_detach,        ds1672_detach),

        DEVMETHOD(clock_gettime,        ds1672_gettime),
        DEVMETHOD(clock_settime,        ds1672_settime),

        DEVMETHOD_END
};

static driver_t ds1672_driver = {
        "ds1672_rtc",
        ds1672_methods,
        sizeof(struct ds1672_softc),
};

DRIVER_MODULE(ds1672, iicbus, ds1672_driver, 0, 0);
MODULE_VERSION(ds1672, 1);
MODULE_DEPEND(ds1672, iicbus, 1, 1, 1);