/*      $OpenBSD: smtpmic.c,v 1.1 2026/04/06 19:48:07 kettenis Exp $    */
/*
 * Copyright (c) 2026 Mark Kettenis <kettenis@openbsd.org>
 *
 * 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 <sys/malloc.h>
#include <sys/task.h>
#include <sys/proc.h>
#include <sys/signalvar.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/fdt.h>

#include <dev/i2c/i2cvar.h>

#include <dev/clock_subr.h>

#include <machine/fdt.h>

extern void (*cpuresetfn)(void);
extern void (*powerdownfn)(void);

/* Registers */
#define COUNT_S                 0x0d
#define  COUNT_S_COUNT_SEC              0x3f
#define COUNT_MI                0x0e
#define  COUNT_MI_COUNT_MIN             0x3f
#define COUNT_H                 0x0f
#define  COUNT_H_COUNT_HOUR             0x1f
#define COUNT_D                 0x10
#define  COUNT_D_COUNT_DAY              0x1f
#define COUNT_MO                0x11
#define  COUNT_MO_COUNT_MONTH           0x0f
#define COUNT_Y                 0x12
#define  COUNT_Y_COUNT_YEAR             0x3f
#define RTC_CTRL                0x1d
#define  RTC_CTRL_RTC_EN                (1 << 2)
#define PWR_CTRL2               0x7e
#define  PWR_CTRL2_SW_SD                (1 << 2)
#define  PWR_CTRL2_SW_RST               (1 << 1)

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

        int (*sc_ih)(void *);

        struct todr_chip_handle sc_todr;
};

int     smtpmic_match(struct device *, void *, void *);
void    smtpmic_attach(struct device *, struct device *, void *);

const struct cfattach smtpmic_ca = {
        sizeof(struct smtpmic_softc), smtpmic_match, smtpmic_attach
};

struct cfdriver smtpmic_cd = {
        NULL, "smtpmic", DV_DULL
};

uint8_t smtpmic_reg_read(struct smtpmic_softc *, int);
void    smtpmic_reg_write(struct smtpmic_softc *, int, uint8_t);
int     smtpmic_clock_read(struct smtpmic_softc *, struct clock_ymdhms *);
int     smtpmic_clock_write(struct smtpmic_softc *, struct clock_ymdhms *);
int     smtpmic_gettime(struct todr_chip_handle *, struct timeval *);
int     smtpmic_settime(struct todr_chip_handle *, struct timeval *);
void    smtpmic_reset_irq_mask(struct smtpmic_softc *);
void    smtpmic_reset(void);
void    smtpmic_powerdown(void);
int     smtpmic_intr(void *);

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

        return (strcmp(ia->ia_name, "spacemit,p1") == 0);
}

void
smtpmic_attach(struct device *parent, struct device *self, void *aux)
{
        struct smtpmic_softc *sc = (struct smtpmic_softc *)self;
        struct i2c_attach_args *ia = aux;

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

        sc->sc_todr.cookie = sc;
        sc->sc_todr.todr_gettime = smtpmic_gettime;
        sc->sc_todr.todr_settime = smtpmic_settime;
        sc->sc_todr.todr_quality = 0;
        todr_attach(&sc->sc_todr);

        if (cpuresetfn == NULL)
                cpuresetfn = smtpmic_reset;
        if (powerdownfn == NULL)
                powerdownfn = smtpmic_powerdown;

        printf("\n");
}

uint8_t
smtpmic_reg_read(struct smtpmic_softc *sc, int reg)
{
        uint8_t cmd = reg;
        uint8_t val;
        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);
                val = 0xff;
        }

        return val;
}

void
smtpmic_reg_write(struct smtpmic_softc *sc, int reg, uint8_t val)
{
        uint8_t cmd = reg;
        int error;

        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
smtpmic_clock_read(struct smtpmic_softc *sc, struct clock_ymdhms *dt)
{
        uint8_t regs[6];
        uint8_t cmd = COUNT_S;
        uint8_t ctrl;
        int retry, sec = -1;
        int error;

        /* Consider the time to be invalid if the RTC_EN bit isn't set. */
        ctrl = smtpmic_reg_read(sc, RTC_CTRL);
        if ((ctrl & RTC_CTRL_RTC_EN) == 0)
                return EINVAL;

        /*
         * The datasheet says that reading COUNT_S latches the current
         * calendar values into COUNT_S through COUNT_Y. But according
         * to the Linux driver this isn't how the hardware behaves.
         * Repeatedly read the registers until we get a consistent
         * reading.
         */
        for (retry = 0; retry < 20; retry++) {
                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)
                        return error;

                dt->dt_sec = (regs[0] & COUNT_S_COUNT_SEC);
                dt->dt_min = (regs[1] & COUNT_MI_COUNT_MIN);
                dt->dt_hour = (regs[2] & COUNT_H_COUNT_HOUR);
                dt->dt_day = (regs[3] & COUNT_D_COUNT_DAY);
                dt->dt_mon = (regs[4] & COUNT_MO_COUNT_MONTH);
                dt->dt_year = (regs[5] & COUNT_Y_COUNT_YEAR) + 2000;

                if (dt->dt_sec == sec)
                        break;
                sec = dt->dt_sec;
        }

        /*
         * If we still don't have a consistent reading, declare the
         * hardware broken.
         */
        if (sec != dt->dt_sec)
                return EIO;

        return 0;
}

int
smtpmic_clock_write(struct smtpmic_softc *sc, struct clock_ymdhms *dt)
{
        uint8_t regs[6];
        uint8_t cmd = COUNT_S;
        uint8_t ctrl;
        int error;

        /*
         * The datasheet says that writing COUNT_Y updates the
         * calendar counter with the current COUNT_S through COUNT_Y
         * values.  Again the Linux driver tells us this isn't how the
         * hardware behaves.  Disable the RTC before updating the
         * registers and enable it again afterwards.
         */

        ctrl = smtpmic_reg_read(sc, RTC_CTRL);
        ctrl &= ~RTC_CTRL_RTC_EN;
        smtpmic_reg_write(sc, RTC_CTRL, ctrl);

        regs[0] = dt->dt_sec;
        regs[1] = dt->dt_min;
        regs[2] = dt->dt_hour;
        regs[3] = dt->dt_day;
        regs[4] = dt->dt_mon;
        regs[5] = dt->dt_year - 2000;

        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)
                return error;

        smtpmic_reg_write(sc, RTC_CTRL, ctrl | RTC_CTRL_RTC_EN);

        return 0;
}

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

        error = smtpmic_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
smtpmic_settime(struct todr_chip_handle *handle, struct timeval *tv)
{
        struct smtpmic_softc *sc = handle->cookie;
        struct clock_ymdhms dt;

        clock_secs_to_ymdhms(tv->tv_sec, &dt);

        return smtpmic_clock_write(sc, &dt);
}

void
smtpmic_reset(void)
{
        struct smtpmic_softc *sc = smtpmic_cd.cd_devs[0];
        uint8_t ctrl;

        ctrl = smtpmic_reg_read(sc, PWR_CTRL2);
        smtpmic_reg_write(sc, PWR_CTRL2, ctrl | PWR_CTRL2_SW_RST);
}

void
smtpmic_powerdown(void)
{
        struct smtpmic_softc *sc = smtpmic_cd.cd_devs[0];
        uint8_t ctrl;

        ctrl = smtpmic_reg_read(sc, PWR_CTRL2);
        smtpmic_reg_write(sc, PWR_CTRL2, ctrl | PWR_CTRL2_SW_SD);
}