/*      $OpenBSD: owsbm.c,v 1.12 2025/07/15 13:40:02 jsg Exp $  */

/*
 * Copyright (c) 2007 Aaron Linville <aaron@linville.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.
 */

/*
 * 1-Wire Smart Battery Monitor family type device driver.
 * Provides on-board temperature, an A/D converter for voltage/current,
 * current accumulator, elapsed time meter, and 40 bytes of nonvolatile
 * memory.
 */

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

#include <dev/onewire/onewiredevs.h>
#include <dev/onewire/onewirereg.h>
#include <dev/onewire/onewirevar.h>

/* Commands */
#define DSSBM_CMD_READ_SCRATCHPAD       0xbe
#define DSSBM_CMD_WRITE_SCRATCHPAD      0x4e
#define DSSBM_CMD_COPY_SCRATCHPAD       0x48

#define DSSBM_CMD_RECALL_MEMORY         0xb8

#define DSSBM_CMD_CONVERT_T             0x44
#define DSSBM_CMD_CONVERT_V             0xb4    

/* Scratchpad layout */
#define DS2438_SP_STATUS                0
#define DS2438_SP_TEMP_LSB              1
#define DS2438_SP_TEMP_MSB              2
#define DS2438_SP_VOLT_LSB              3
#define DS2438_SP_VOLT_MSB              4
#define DS2438_SP_CURRENT_LSB           5
#define DS2438_SP_CURRENT_MSB           6
#define DS2438_SP_THRESHOLD             7
#define DS2438_SP_CRC                   8

struct owsbm_softc {
        struct device           sc_dev;

        void *                  sc_onewire;
        u_int64_t               sc_rom;

        struct ksensordev       sc_sensordev;

        struct ksensor          sc_temp;
        struct ksensor          sc_voltage_vdd; /* Battery, AD = 1*/
        struct ksensor          sc_voltage_vad; /* General purpose, AD = 0 */
        struct ksensor          sc_voltage_cr; /* Current Register */

        struct sensor_task      *sc_sensortask;

        struct rwlock           sc_lock;
};

int     owsbm_match(struct device *, void *, void *);
void    owsbm_attach(struct device *, struct device *, void *);
int     owsbm_detach(struct device *, int);
int     owsbm_activate(struct device *, int);

void    owsbm_update(void *);

const struct cfattach owsbm_ca = {
        sizeof(struct owsbm_softc),
        owsbm_match,
        owsbm_attach,
        owsbm_detach,
        owsbm_activate
};

struct cfdriver owsbm_cd = {
        NULL, "owsbm", DV_DULL
};

static const struct onewire_matchfam owsbm_fams[] = {
        { ONEWIRE_FAMILY_DS2438 }
};

int
owsbm_match(struct device *parent, void *match, void *aux)
{
        return (onewire_matchbyfam(aux, owsbm_fams, nitems(owsbm_fams)));
}

void
owsbm_attach(struct device *parent, struct device *self, void *aux)
{
        struct owsbm_softc *sc = (struct owsbm_softc *)self;
        struct onewire_attach_args *oa = aux;

        sc->sc_onewire = oa->oa_onewire;
        sc->sc_rom = oa->oa_rom;

        /* Initialize temp sensor */
        strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
            sizeof(sc->sc_sensordev.xname));
        sc->sc_temp.type = SENSOR_TEMP;
        snprintf(sc->sc_temp.desc, sizeof(sc->sc_temp.desc), "sn %012llx",
            ONEWIRE_ROM_SN(oa->oa_rom));
        sensor_attach(&sc->sc_sensordev, &sc->sc_temp);

        /* Initialize voltage sensor */
        sc->sc_voltage_vdd.type = SENSOR_VOLTS_DC;
        strlcpy(sc->sc_voltage_vdd.desc, "VDD", sizeof(sc->sc_voltage_vdd.desc));
        sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_vdd);

        /* Initialize voltage sensor */
        sc->sc_voltage_vad.type = SENSOR_VOLTS_DC;
        strlcpy(sc->sc_voltage_vad.desc, "VAD", sizeof(sc->sc_voltage_vad.desc));
        sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_vad);

        /* Initialize the current sensor */
        sc->sc_voltage_cr.type = SENSOR_VOLTS_DC;
        strlcpy(sc->sc_voltage_cr.desc, "CR", sizeof(sc->sc_voltage_cr.desc));
        sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_cr);

        sc->sc_sensortask = sensor_task_register(sc, owsbm_update, 10);
        if (sc->sc_sensortask == NULL) {
                printf(": unable to register update task\n");
                return;
        }

        sensordev_install(&sc->sc_sensordev);

        rw_init(&sc->sc_lock, sc->sc_dev.dv_xname);
        printf("\n");
}

int
owsbm_detach(struct device *self, int flags)
{
        struct owsbm_softc *sc = (struct owsbm_softc *)self;

        rw_enter_write(&sc->sc_lock);
        sensordev_deinstall(&sc->sc_sensordev);
        if (sc->sc_sensortask != NULL)
                sensor_task_unregister(sc->sc_sensortask);
        rw_exit_write(&sc->sc_lock);

        return (0);
}

int
owsbm_activate(struct device *self, int act)
{
        return (0);
}

void
owsbm_update(void *arg)
{
        struct owsbm_softc *sc = arg;
        u_int8_t data[9];

        rw_enter_write(&sc->sc_lock);
        onewire_lock(sc->sc_onewire, 0);
        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_T);
        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;
        
        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_V);
        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        /* Issue Recall Memory page 00h cmd */
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_RECALL_MEMORY);
        onewire_write_byte(sc->sc_onewire, 0);

        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        /* Read page 0 of Memory Map from Scratchpad */
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_READ_SCRATCHPAD);
        onewire_write_byte(sc->sc_onewire, 0);
        onewire_read_block(sc->sc_onewire, data, 9);
        if (onewire_crc(data, 8) == data[DS2438_SP_CRC]) {
                sc->sc_temp.value = 273150000 +
                     (int)(((u_int16_t)data[DS2438_SP_TEMP_MSB] << 5) |
                     ((u_int16_t)data[DS2438_SP_TEMP_LSB] >> 3)) * 31250;
                sc->sc_voltage_vdd.value =
                     (int)(((u_int16_t)data[DS2438_SP_VOLT_MSB] << 8) |
                     data[DS2438_SP_VOLT_LSB]) * 10000;

                sc->sc_voltage_cr.value =
                    (int)(((u_int16_t)data[DS2438_SP_CURRENT_MSB] << 8) |
                    data[DS2438_SP_CURRENT_LSB]) * 244;
        }

        /* Reconfigure DS2438 to measure VAD */

        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_WRITE_SCRATCHPAD);
        onewire_write_byte(sc->sc_onewire, 0);
        onewire_write_byte(sc->sc_onewire, 0x7); /* AD = 0 */

        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_V);
        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        /* Issue Recall Memory page 00h cmd */
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_RECALL_MEMORY);
        onewire_write_byte(sc->sc_onewire, 0);

        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_READ_SCRATCHPAD);
        onewire_write_byte(sc->sc_onewire, 0);
        onewire_read_block(sc->sc_onewire, data, 9);
        if (onewire_crc(data, 8) == data[8]) {
                sc->sc_voltage_vad.value =
                    (int)(((u_int16_t)data[DS2438_SP_VOLT_MSB] << 8) |
                    data[DS2438_SP_VOLT_LSB]) * 10000;
        }

        /* Reconfigure back DS2438 to measure VDD (default) */

        if (onewire_reset(sc->sc_onewire) != 0)
                goto done;

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        onewire_write_byte(sc->sc_onewire, DSSBM_CMD_WRITE_SCRATCHPAD);
        onewire_write_byte(sc->sc_onewire, 0);
        onewire_write_byte(sc->sc_onewire, 0xf); /* AD = 1 */
        onewire_reset(sc->sc_onewire);

done:
        onewire_unlock(sc->sc_onewire);
        rw_exit_write(&sc->sc_lock);
}