/*-
 * Copyright (c) 2015 Luiz Otavio O Souza <loos@FreeBSD.org>
 * Copyright (c) 2022 Mathew McBride <matt@traverse.com.au>
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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>
/*
 * Driver for Maxim DS1307 I2C real-time clock/calendar.
 */

#include "opt_platform.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/clock.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>

#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#ifdef FDT
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif

#include <dev/iicbus/rtc/ds1307reg.h>

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

enum {
        TYPE_DS1307,
        TYPE_MAXIM1307,
        TYPE_MICROCHIP_MCP7941X,
        TYPE_EPSON_RX8035,
        TYPE_COUNT
};

struct ds1307_softc {
        device_t                        sc_dev;
        struct intr_config_hook         enum_hook;
        uint32_t                        chiptype;
        uint8_t                         sc_ctrl;
        bool                            sc_use_ampm;
};

static void ds1307_start(void *);

#ifdef FDT
static const struct ofw_compat_data ds1307_compat_data[] = {
        {"dallas,ds1307",               TYPE_DS1307},
        {"maxim,ds1307",                TYPE_MAXIM1307},
        {"microchip,mcp7941x",          TYPE_MICROCHIP_MCP7941X},
        {"epson,rx8035",                TYPE_EPSON_RX8035},
        { NULL, 0 }
};
#endif

static int
ds1307_read1(device_t dev, uint8_t reg, uint8_t *data)
{

        return (iicdev_readfrom(dev, reg, data, 1, IIC_INTRWAIT));
}

static int
ds1307_write1(device_t dev, uint8_t reg, uint8_t data)
{

        return (iicdev_writeto(dev, reg, &data, 1, IIC_INTRWAIT));
}

static int
ds1307_ctrl_read(struct ds1307_softc *sc)
{
        int error;

        sc->sc_ctrl = 0;
        error = ds1307_read1(sc->sc_dev, DS1307_CONTROL, &sc->sc_ctrl);
        if (error) {
                device_printf(sc->sc_dev, "%s: cannot read from RTC: %d\n",
                    __func__, error);
                return (error);
        }

        return (0);
}

static int
ds1307_ctrl_write(struct ds1307_softc *sc)
{
        int error;
        uint8_t ctrl;

        ctrl = sc->sc_ctrl & DS1307_CTRL_MASK;
        error = ds1307_write1(sc->sc_dev, DS1307_CONTROL, ctrl);
        if (error != 0)
                device_printf(sc->sc_dev, "%s: cannot write to RTC: %d\n",
                    __func__, error);

        return (error);
}

static int
ds1307_sqwe_sysctl(SYSCTL_HANDLER_ARGS)
{
        int sqwe, error, newv, sqwe_bit;
        struct ds1307_softc *sc;

        sc = (struct ds1307_softc *)arg1;
        error = ds1307_ctrl_read(sc);
        if (error != 0)
                return (error);
        if (sc->chiptype == TYPE_MICROCHIP_MCP7941X)
                sqwe_bit = MCP7941X_CTRL_SQWE;
        else
                sqwe_bit = DS1307_CTRL_SQWE;
        sqwe = newv = (sc->sc_ctrl & sqwe_bit) ? 1 : 0;
        error = sysctl_handle_int(oidp, &newv, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
        if (sqwe != newv) {
                sc->sc_ctrl &= ~sqwe_bit;
                if (newv)
                        sc->sc_ctrl |= sqwe_bit;
                error = ds1307_ctrl_write(sc);
                if (error != 0)
                        return (error);
        }

        return (error);
}

static int
ds1307_sqw_freq_sysctl(SYSCTL_HANDLER_ARGS)
{
        int ds1307_sqw_freq[] = { 1, 4096, 8192, 32768 };
        int error, freq, i, newf, tmp;
        struct ds1307_softc *sc;

        sc = (struct ds1307_softc *)arg1;
        error = ds1307_ctrl_read(sc);
        if (error != 0)
                return (error);
        tmp = (sc->sc_ctrl & DS1307_CTRL_RS_MASK);
        if (tmp >= nitems(ds1307_sqw_freq))
                tmp = nitems(ds1307_sqw_freq) - 1;
        freq = ds1307_sqw_freq[tmp];
        error = sysctl_handle_int(oidp, &freq, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
        if (freq != ds1307_sqw_freq[tmp]) {
                newf = 0;
                for (i = 0; i < nitems(ds1307_sqw_freq); i++)
                        if (freq >= ds1307_sqw_freq[i])
                                newf = i;
                sc->sc_ctrl &= ~DS1307_CTRL_RS_MASK;
                sc->sc_ctrl |= newf;
                error = ds1307_ctrl_write(sc);
                if (error != 0)
                        return (error);
        }

        return (error);
}

static int
ds1307_sqw_out_sysctl(SYSCTL_HANDLER_ARGS)
{
        int sqwe, error, newv;
        struct ds1307_softc *sc;

        sc = (struct ds1307_softc *)arg1;
        error = ds1307_ctrl_read(sc);
        if (error != 0)
                return (error);
        sqwe = newv = (sc->sc_ctrl & DS1307_CTRL_OUT) ? 1 : 0;
        error = sysctl_handle_int(oidp, &newv, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
        if (sqwe != newv) {
                sc->sc_ctrl &= ~DS1307_CTRL_OUT;
                if (newv)
                        sc->sc_ctrl |= DS1307_CTRL_OUT;
                error = ds1307_ctrl_write(sc);
                if (error != 0)
                        return (error);
        }

        return (error);
}

static int
ds1307_probe(device_t dev)
{
#ifdef FDT
        const struct ofw_compat_data *compat;

        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        compat = ofw_bus_search_compatible(dev, ds1307_compat_data);
        if (compat->ocd_str != NULL) {
                switch(compat->ocd_data) {
                case TYPE_DS1307:
                        device_set_desc(dev, "Dallas DS1307");
                        break;
                case TYPE_MAXIM1307:
                        device_set_desc(dev, "Maxim DS1307");
                        break;
                case TYPE_MICROCHIP_MCP7941X:
                        device_set_desc(dev, "Microchip MCP7941X");
                        break;
                case TYPE_EPSON_RX8035:
                        device_set_desc(dev, "Epson RX-8035");
                        break;
                default:
                        device_set_desc(dev, "Unknown DS1307-like device");
                        break;
                }
                return (BUS_PROBE_DEFAULT);
        }
#endif

        device_set_desc(dev, "Maxim DS1307");
        return (BUS_PROBE_NOWILDCARD);
}

static int
ds1307_attach(device_t dev)
{
#ifdef FDT
        const struct ofw_compat_data *compat;
#endif
        struct ds1307_softc *sc;

        sc = device_get_softc(dev);
        sc->sc_dev = dev;
        sc->enum_hook.ich_func = ds1307_start;
        sc->enum_hook.ich_arg = dev;
#ifdef FDT
        compat = ofw_bus_search_compatible(dev, ds1307_compat_data);
        sc->chiptype = compat->ocd_data;
        /* Unify the chiptypes to DS1307 where possible. */
        if (sc->chiptype == TYPE_MAXIM1307)
                sc->chiptype = TYPE_DS1307;
#else
        sc->chiptype = TYPE_DS1307;
#endif

        /*
         * We have to wait until interrupts are enabled.  Usually I2C read
         * and write only works when the interrupts are available.
         */
        if (config_intrhook_establish(&sc->enum_hook) != 0)
                return (ENOMEM);

        return (0);
}

static int
ds1307_detach(device_t dev)
{

        clock_unregister(dev);
        return (0);
}

static bool
is_epson_time_valid(struct ds1307_softc *sc)
{
        device_t dev;
        int error;
        uint8_t ctrl2;

        dev = sc->sc_dev;

        /*
         * The RX-8035 single register read is non-standard
         * Refer to section 8.9.5 of the RX-8035 application manual:
         * "I2C bus basic transfer format", under "Standard Read Method".
         * Basically, register to read goes into the top 4 bits.
         */
        error = ds1307_read1(dev, (RX8035_CTRL_2 << 4), &ctrl2);
        if (error) {
                device_printf(dev, "%s cannot read Control 2 register: %d\n",
                    __func__, error);
                return (false);
        }

        if (ctrl2 & RX8035_CTRL_2_XSTP) {
                device_printf(dev, "Oscillation stop detected (ctrl2=%#02x)\n",
                    ctrl2);
                return (false);
        }

        /*
         * Power on reset (PON) generally implies oscillation stop,
         * but catch it as well to be sure.
         */
        if (ctrl2 & RX8035_CTRL_2_PON) {
                device_printf(dev, "Power-on reset detected (ctrl2=%#02x)\n",
                    ctrl2);
                return (false);
        }

        return (true);
}

static int
mark_epson_time_valid(struct ds1307_softc *sc)
{
        device_t dev;
        int error;
        uint8_t ctrl2;
        uint8_t control_mask;

        dev = sc->sc_dev;

        error = ds1307_read1(dev, (RX8035_CTRL_2 << 4), &ctrl2);
        if (error) {
                device_printf(dev, "%s cannot read Control 2 register: %d\n",
                    __func__, error);
                return (error);
        }

        control_mask = (RX8035_CTRL_2_PON | RX8035_CTRL_2_XSTP | RX8035_CTRL_2_VDET);
        ctrl2 = ctrl2 & ~(control_mask);

        error = ds1307_write1(dev, (RX8035_CTRL_2 << 4), ctrl2);
        if (error) {
                device_printf(dev, "%s cannot write to Control 2 register: %d\n",
                    __func__, error);
                return (error);
        }
        return (0);
}

static bool is_dev_time_valid(struct ds1307_softc *sc)
{
        device_t dev;
        int error;
        uint8_t osc_en;
        uint8_t secs;

        /* Epson RTCs have different control/status registers. */
        if (sc->chiptype == TYPE_EPSON_RX8035)
                return (is_epson_time_valid(sc));

        dev = sc->sc_dev;
        /* Check if the oscillator is disabled. */
        error = ds1307_read1(dev, DS1307_SECS, &secs);
        if (error) {
                device_printf(dev, "%s: cannot read from RTC: %d\n",
                    __func__, error);
                return (false);
        }

        switch (sc->chiptype) {
        case TYPE_MICROCHIP_MCP7941X:
                osc_en = 0x80;
                break;
        default:
                osc_en = 0x00;
                break;
        }
        if (((secs & DS1307_SECS_CH) ^ osc_en) != 0)
                return (false);

        return (true);
}

static void
ds1307_start(void *xdev)
{
        device_t dev;
        struct ds1307_softc *sc;
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid *tree_node;
        struct sysctl_oid_list *tree;

        dev = (device_t)xdev;
        sc = device_get_softc(dev);

        config_intrhook_disestablish(&sc->enum_hook);

        if (!is_dev_time_valid(sc))
                device_printf(dev,
                    "WARNING: RTC clock stopped, check the battery.\n");

        /*
         * Configuration parameters:
         * square wave output cannot be changed or inhibited on the RX-8035,
         * so don't present the sysctls there.
         */
        if (sc->chiptype == TYPE_EPSON_RX8035)
                goto skip_sysctl;

        ctx = device_get_sysctl_ctx(dev);
        tree_node = device_get_sysctl_tree(dev);
        tree = SYSCTL_CHILDREN(tree_node);

        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "sqwe",
            CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
            ds1307_sqwe_sysctl, "IU", "DS1307 square-wave enable");
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "sqw_freq",
            CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
            ds1307_sqw_freq_sysctl, "IU",
            "DS1307 square-wave output frequency");
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "sqw_out",
            CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, sc, 0,
            ds1307_sqw_out_sysctl, "IU", "DS1307 square-wave output state");
skip_sysctl:

        /*
         * Register as a clock with 1 second resolution.  Schedule the
         * clock_settime() method to be called just after top-of-second;
         * resetting the time resets top-of-second in the hardware.
         */
        clock_register_flags(dev, 1000000, CLOCKF_SETTIME_NO_ADJ);
        clock_schedule(dev, 1);
}

static int
ds1307_gettime(device_t dev, struct timespec *ts)
{
        struct bcd_clocktime bct;
        struct ds1307_softc *sc;
        int error;
        uint8_t data[7], hourmask, ampm_mode;

        sc = device_get_softc(dev);
        error = iicdev_readfrom(sc->sc_dev, DS1307_SECS, data, sizeof(data),
            IIC_INTRWAIT);
        if (error != 0) {
                device_printf(dev, "%s: cannot read from RTC: %d\n",
                    __func__, error);
                return (error);
        }

        if (!is_dev_time_valid(sc)) {
                device_printf(dev, "Device time not valid.\n");
                return (EINVAL);
        }

        /*
         * If the chip is in AM/PM mode remember that.
         * The EPSON uses a 1 to signify 24 hour mode, while the DS uses a 0,
         * in slightly different positions.
         */
        if (sc->chiptype == TYPE_EPSON_RX8035)
                ampm_mode = !(data[DS1307_HOUR] & RX8035_HOUR_USE_24);
        else
                ampm_mode = data[DS1307_HOUR] & DS1307_HOUR_USE_AMPM;

        if (ampm_mode) {
                sc->sc_use_ampm = true;
                hourmask = DS1307_HOUR_MASK_12HR;
        } else
                hourmask = DS1307_HOUR_MASK_24HR;

        bct.nsec = 0;
        bct.ispm = (data[DS1307_HOUR] & DS1307_HOUR_IS_PM) != 0;
        bct.sec  = data[DS1307_SECS]  & DS1307_SECS_MASK;
        bct.min  = data[DS1307_MINS]  & DS1307_MINS_MASK;
        bct.hour = data[DS1307_HOUR]  & hourmask;
        bct.day  = data[DS1307_DATE]  & DS1307_DATE_MASK;
        bct.mon  = data[DS1307_MONTH] & DS1307_MONTH_MASK;
        bct.year = data[DS1307_YEAR]  & DS1307_YEAR_MASK;

        clock_dbgprint_bcd(sc->sc_dev, CLOCK_DBG_READ, &bct); 
        return (clock_bcd_to_ts(&bct, ts, sc->sc_use_ampm));
}

static int
ds1307_settime(device_t dev, struct timespec *ts)
{
        struct bcd_clocktime bct;
        struct ds1307_softc *sc;
        int error, year;
        uint8_t data[7];
        uint8_t pmflags;

        sc = device_get_softc(dev);

        /*
         * We request a timespec with no resolution-adjustment.  That also
         * disables utc adjustment, so apply that ourselves.
         */
        ts->tv_sec -= utc_offset();
        clock_ts_to_bcd(ts, &bct, sc->sc_use_ampm);
        clock_dbgprint_bcd(sc->sc_dev, CLOCK_DBG_WRITE, &bct);

        /*
         * If the chip is in AM/PM mode, adjust hour and set flags as needed.
         * The AM/PM bit polarity and position is different on the EPSON.
         */
        if (sc->sc_use_ampm) {
                pmflags = (sc->chiptype != TYPE_EPSON_RX8035) ?
                                DS1307_HOUR_USE_AMPM : 0;
                if (bct.ispm)
                        pmflags |= DS1307_HOUR_IS_PM;

        } else if (sc->chiptype == TYPE_EPSON_RX8035)
                pmflags = RX8035_HOUR_USE_24;
        else
                pmflags = 0;

        data[DS1307_SECS]    = bct.sec;
        data[DS1307_MINS]    = bct.min;
        data[DS1307_HOUR]    = bct.hour | pmflags;
        data[DS1307_DATE]    = bct.day;
        data[DS1307_WEEKDAY] = bct.dow;
        data[DS1307_MONTH]   = bct.mon;
        data[DS1307_YEAR]    = bct.year & 0xff;
        if (sc->chiptype == TYPE_MICROCHIP_MCP7941X) {
                data[DS1307_SECS] |= MCP7941X_SECS_ST;
                data[DS1307_WEEKDAY] |= MCP7941X_WEEKDAY_VBATEN;
                year = bcd2bin(bct.year >> 8) * 100 + bcd2bin(bct.year & 0xff);
                if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
                        data[DS1307_MONTH] |= MCP7941X_MONTH_LPYR;
        }

        /* Write the time back to RTC. */
        error = iicdev_writeto(sc->sc_dev, DS1307_SECS, data, sizeof(data),
            IIC_INTRWAIT);
        if (error != 0)
                device_printf(dev, "%s: cannot write to RTC: %d\n",
                    __func__, error);

        if (sc->chiptype == TYPE_EPSON_RX8035)
                error = mark_epson_time_valid(sc);

        return (error);
}

static device_method_t ds1307_methods[] = {
        DEVMETHOD(device_probe,         ds1307_probe),
        DEVMETHOD(device_attach,        ds1307_attach),
        DEVMETHOD(device_detach,        ds1307_detach),

        DEVMETHOD(clock_gettime,        ds1307_gettime),
        DEVMETHOD(clock_settime,        ds1307_settime),

        DEVMETHOD_END
};

static driver_t ds1307_driver = {
        "ds1307",
        ds1307_methods,
        sizeof(struct ds1307_softc),
};

DRIVER_MODULE(ds1307, iicbus, ds1307_driver, NULL, NULL);
MODULE_VERSION(ds1307, 1);
MODULE_DEPEND(ds1307, iicbus, 1, 1, 1);
IICBUS_FDT_PNP_INFO(ds1307_compat_data);