/*      $OpenBSD: abx80x.c,v 1.8 2022/10/15 18:22:53 kettenis Exp $     */
/*
 * Copyright (c) 2018 Mark Kettenis <kettenis@openbsd.org>
 * Copyright (c) 2018 Patrick Wildt <patrick@blueri.se>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <dev/i2c/i2cvar.h>

#include <dev/clock_subr.h>

#if defined(__HAVE_FDT)
#include <dev/ofw/openfirm.h>
#endif

#define ABX8XX_HTH              0x00
#define ABX8XX_SC               0x01
#define ABX8XX_MN               0x02
#define ABX8XX_HR               0x03
#define ABX8XX_DA               0x04
#define ABX8XX_MO               0x05
#define ABX8XX_YR               0x06
#define ABX8XX_WD               0x07
#define ABX8XX_CTRL             0x10
#define  ABX8XX_CTRL_WRITE              (1 << 0)
#define  ABX8XX_CTRL_ARST               (1 << 2)
#define  ABX8XX_CTRL_12_24              (1 << 6)
#define ABX8XX_CD_TIMER_CTL     0x18
#define  ABX8XX_CD_TIMER_CTL_EN         (1 << 2)
#define ABX8XX_OSS              0x1d
#define ABX8XX_OSS_OF                   (1 << 1)
#define ABX8XX_OSS_OMODE                (1 << 4)
#define ABX8XX_CFG_KEY          0x1f
#define  ABX8XX_CFG_KEY_OSC             0xa1
#define  ABX8XX_CFG_KEY_MISC            0x9d
#define ABX8XX_TRICKLE          0x20
#define  ABX8XX_TRICKLE_RESISTOR_0      (0 << 0)
#define  ABX8XX_TRICKLE_RESISTOR_3      (1 << 0)
#define  ABX8XX_TRICKLE_RESISTOR_6      (2 << 0)
#define  ABX8XX_TRICKLE_RESISTOR_11     (3 << 0)
#define  ABX8XX_TRICKLE_DIODE_SCHOTTKY  (1 << 2)
#define  ABX8XX_TRICKLE_DIODE_STANDARD  (2 << 2)
#define  ABX8XX_TRICKLE_ENABLE          (0xa << 4)

#define ABX8XX_NRTC_REGS        8

struct abcrtc_softc {
        struct device sc_dev;
        i2c_tag_t sc_tag;
        i2c_addr_t sc_addr;

        struct todr_chip_handle sc_todr;
};

int     abcrtc_match(struct device *, void *, void *);
void    abcrtc_attach(struct device *, struct device *, void *);

const struct cfattach abcrtc_ca = {
        sizeof(struct abcrtc_softc), abcrtc_match, abcrtc_attach
};

struct cfdriver abcrtc_cd = {
        NULL, "abcrtc", DV_DULL
};

uint8_t abcrtc_reg_read(struct abcrtc_softc *, int);
void    abcrtc_reg_write(struct abcrtc_softc *, int, uint8_t);
int     abcrtc_clock_read(struct abcrtc_softc *, struct clock_ymdhms *);
int     abcrtc_clock_write(struct abcrtc_softc *, struct clock_ymdhms *);
int     abcrtc_gettime(struct todr_chip_handle *, struct timeval *);
int     abcrtc_settime(struct todr_chip_handle *, struct timeval *);

#if defined(__HAVE_FDT)
void    abcrtc_trickle_charger(struct abcrtc_softc *, int);
#endif

int
abcrtc_match(struct device *parent, void *match, void *aux)
{
        struct i2c_attach_args *ia = aux;

        if (strcmp(ia->ia_name, "abracon,ab1805") == 0)
                return 1;

        return 0;
}

void
abcrtc_attach(struct device *parent, struct device *self, void *aux)
{
        struct abcrtc_softc *sc = (struct abcrtc_softc *)self;
        struct i2c_attach_args *ia = aux;
        uint8_t reg;
#if defined(__HAVE_FDT)
        int node = *(int *)ia->ia_cookie;
#endif

        sc->sc_tag = ia->ia_tag;
        sc->sc_addr = ia->ia_addr;

        reg = abcrtc_reg_read(sc, ABX8XX_CTRL);
        reg &= ~(ABX8XX_CTRL_ARST | ABX8XX_CTRL_12_24);
        reg |= ABX8XX_CTRL_WRITE;
        abcrtc_reg_write(sc, ABX8XX_CTRL, reg);

#if defined(__HAVE_FDT)
        abcrtc_trickle_charger(sc, node);
#endif

        abcrtc_reg_write(sc, ABX8XX_CD_TIMER_CTL, ABX8XX_CD_TIMER_CTL_EN);

        sc->sc_todr.cookie = sc;
        sc->sc_todr.todr_gettime = abcrtc_gettime;
        sc->sc_todr.todr_settime = abcrtc_settime;
        sc->sc_todr.todr_quality = 1000;
        todr_attach(&sc->sc_todr);

        printf("\n");
}

int
abcrtc_gettime(struct todr_chip_handle *handle, struct timeval *tv)
{
        struct abcrtc_softc *sc = handle->cookie;
        struct clock_ymdhms dt;
        int error;

        error = abcrtc_clock_read(sc, &dt);
        if (error)
                return error;

        if (dt.dt_sec > 59 || dt.dt_min > 59 || dt.dt_hour > 23 ||
            dt.dt_day > 31 || dt.dt_day == 0 ||
            dt.dt_mon > 12 || dt.dt_mon == 0 ||
            dt.dt_year < POSIX_BASE_YEAR)
                return EINVAL;

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

int
abcrtc_settime(struct todr_chip_handle *handle, struct timeval *tv)
{
        struct abcrtc_softc *sc = handle->cookie;
        struct clock_ymdhms dt;

        clock_secs_to_ymdhms(tv->tv_sec, &dt);

        return abcrtc_clock_write(sc, &dt);
}

uint8_t
abcrtc_reg_read(struct abcrtc_softc *sc, int reg)
{
        uint8_t cmd = reg;
        uint8_t val[2];
        int error;

        iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
        error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
            &cmd, sizeof cmd, &val, sizeof val, I2C_F_POLL);
        iic_release_bus(sc->sc_tag, I2C_F_POLL);

        if (error) {
                printf("%s: can't read register 0x%02x\n",
                    sc->sc_dev.dv_xname, reg);
                return 0xff;
        }

        return val[1];
}

void
abcrtc_reg_write(struct abcrtc_softc *sc, int reg, uint8_t data)
{
        uint8_t cmd = reg;
        uint8_t val[2];
        int error;

        val[0] = 1;
        val[1] = data;

        iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
        error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
            &cmd, sizeof cmd, &val, sizeof val, I2C_F_POLL);
        iic_release_bus(sc->sc_tag, I2C_F_POLL);

        if (error) {
                printf("%s: can't write register 0x%02x\n",
                    sc->sc_dev.dv_xname, reg);
        }
}

int
abcrtc_clock_read(struct abcrtc_softc *sc, struct clock_ymdhms *dt)
{
        uint8_t regs[ABX8XX_NRTC_REGS];
        uint8_t cmd = ABX8XX_HTH;
        int error;

        /* Don't trust the RTC if the oscillator failure is set. */
        if ((abcrtc_reg_read(sc, ABX8XX_OSS) & ABX8XX_OSS_OMODE) == 0 &&
            (abcrtc_reg_read(sc, ABX8XX_OSS) & ABX8XX_OSS_OF) != 0)
                return EIO;

        iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
        error = iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr,
            &cmd, sizeof(cmd), regs, sizeof(regs), I2C_F_POLL);
        iic_release_bus(sc->sc_tag, I2C_F_POLL);

        if (error) {
                printf("%s: can't read RTC\n", sc->sc_dev.dv_xname);
                return error;
        }

        /*
         * Convert the ABX8XX's register values into something useable.
         */
        dt->dt_sec = FROMBCD(regs[1] & 0x7f);
        dt->dt_min = FROMBCD(regs[2] & 0x7f);
        dt->dt_hour = FROMBCD(regs[3] & 0x3f);
        dt->dt_day = FROMBCD(regs[4] & 0x3f);
        dt->dt_mon = FROMBCD(regs[5] & 0x1f);
        dt->dt_year = FROMBCD(regs[6]) + 2000;
        dt->dt_wday = regs[7] & 0x7;

        return 0;
}

int
abcrtc_clock_write(struct abcrtc_softc *sc, struct clock_ymdhms *dt)
{
        uint8_t regs[ABX8XX_NRTC_REGS];
        uint8_t cmd = ABX8XX_HTH;
        uint8_t reg;
        int error;

        /*
         * Convert our time representation into something the ABX8XX
         * can understand.
         */
        regs[0] = 0;
        regs[1] = TOBCD(dt->dt_sec);
        regs[2] = TOBCD(dt->dt_min);
        regs[3] = TOBCD(dt->dt_hour);
        regs[4] = TOBCD(dt->dt_day);
        regs[5] = TOBCD(dt->dt_mon);
        regs[6] = TOBCD(dt->dt_year - 2000);
        regs[7] = dt->dt_wday;

        iic_acquire_bus(sc->sc_tag, I2C_F_POLL);
        error = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_addr,
            &cmd, sizeof(cmd), regs, sizeof(regs), I2C_F_POLL);
        iic_release_bus(sc->sc_tag, I2C_F_POLL);

        if (error) {
                printf("%s: can't write RTC\n", sc->sc_dev.dv_xname);
                return error;
        }

        /* Clear oscillator failure. */
        reg = abcrtc_reg_read(sc, ABX8XX_OSS);
        reg &= ~ABX8XX_OSS_OF;
        abcrtc_reg_write(sc, ABX8XX_OSS, reg);

        return 0;
}

#if defined(__HAVE_FDT)
void
abcrtc_trickle_charger(struct abcrtc_softc *sc, int node)
{
        char diode[16] = { 0 };
        uint8_t reg = ABX8XX_TRICKLE_ENABLE;

        OF_getprop(node, "abracon,tc-diode", diode, sizeof(diode));
        if (!strcmp(diode, "standard"))
                reg |= ABX8XX_TRICKLE_DIODE_STANDARD;
        else if (!strcmp(diode, "schottky"))
                reg |= ABX8XX_TRICKLE_DIODE_SCHOTTKY;
        else
                return;

        switch (OF_getpropint(node, "abracon,tc-resistor", -1)) {
        case 0:
                reg |= ABX8XX_TRICKLE_RESISTOR_0;
                break;
        case 3:
                reg |= ABX8XX_TRICKLE_RESISTOR_3;
                break;
        case 6:
                reg |= ABX8XX_TRICKLE_RESISTOR_6;
                break;
        case 11:
                reg |= ABX8XX_TRICKLE_RESISTOR_11;
                break;
        default:
                return;
        }

        abcrtc_reg_write(sc, ABX8XX_CFG_KEY, ABX8XX_CFG_KEY_MISC);
        abcrtc_reg_write(sc, ABX8XX_TRICKLE, reg);
}
#endif