/*      $OpenBSD: owctr.c,v 1.9 2022/04/06 18:59:29 naddy Exp $ */
/*
 * Copyright (c) 2010 John L. Scarfone <john@scarfone.net>
 *
 * 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.
 */

/*
 * DS2423 1-Wire 4kbit SRAM with Counter family type device driver.
 * Provides 4096 bits of SRAM and four 32-bit, read-only counters.
 * This driver provides access to the two externally triggered
 * counters.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/malloc.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 DSCTR_CMD_READ_MEMCOUNTER       0xa5

/* External counter banks */
#define DS2423_COUNTER_BANK_A           0x1c0
#define DS2423_COUNTER_BANK_B           0x1e0

/* Buffer offsets */
#define DS2423_COUNTER_BUF_COUNTER      35
#define DS2423_COUNTER_BUF_CRC          43

#define DS2423_COUNTER_BUFSZ            45

struct owctr_softc {
        struct device           sc_dev;

        void *                  sc_onewire;
        u_int64_t               sc_rom;

        struct ksensordev       sc_sensordev;

        struct ksensor          sc_counterA;
        struct ksensor          sc_counterB;

        struct sensor_task      *sc_sensortask;

        struct rwlock           sc_lock;
};

int     owctr_match(struct device *, void *, void *);
void    owctr_attach(struct device *, struct device *, void *);
int     owctr_detach(struct device *, int);
int     owctr_activate(struct device *, int);

void    owctr_update(void *);
void    owctr_update_counter(void *, int);

const struct cfattach owctr_ca = {
        sizeof(struct owctr_softc),
        owctr_match,
        owctr_attach,
        owctr_detach,
        owctr_activate
};

struct cfdriver owctr_cd = {
        NULL, "owctr", DV_DULL
};

static const struct onewire_matchfam owctr_fams[] = {
        { ONEWIRE_FAMILY_DS2423 }
};

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

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

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

        /* Initialize counter sensors */
        strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
                sizeof(sc->sc_sensordev.xname));
        sc->sc_counterA.type = SENSOR_INTEGER;
        snprintf(sc->sc_counterA.desc, sizeof(sc->sc_counterA.desc),
                "Counter A sn %012llx", ONEWIRE_ROM_SN(oa->oa_rom));
        sensor_attach(&sc->sc_sensordev, &sc->sc_counterA);
        sc->sc_counterB.type = SENSOR_INTEGER;
        snprintf(sc->sc_counterB.desc, sizeof(sc->sc_counterB.desc),
                "Counter B sn %012llx", ONEWIRE_ROM_SN(oa->oa_rom));
        sensor_attach(&sc->sc_sensordev, &sc->sc_counterB);

        sc->sc_sensortask = sensor_task_register(sc, owctr_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
owctr_detach(struct device *self, int flags)
{
        struct owctr_softc *sc = (struct owctr_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
owctr_activate(struct device *self, int act)
{
        return (0);
}

void
owctr_update(void *arg)
{
        owctr_update_counter(arg, DS2423_COUNTER_BANK_A);
        owctr_update_counter(arg, DS2423_COUNTER_BANK_B);
}

void
owctr_update_counter(void *arg, int bank)
{
        struct owctr_softc *sc = arg;
        u_int32_t counter;
        u_int16_t crc;
        u_int8_t *buf;

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

        buf = malloc(DS2423_COUNTER_BUFSZ, M_DEVBUF, M_NOWAIT);
        if (buf == NULL) {
                printf("%s: malloc() failed\n", sc->sc_dev.dv_xname);
                goto done;
        }

        onewire_matchrom(sc->sc_onewire, sc->sc_rom);
        buf[0] = DSCTR_CMD_READ_MEMCOUNTER;
        buf[1] = bank;
        buf[2] = bank >> 8;
        onewire_write_byte(sc->sc_onewire, buf[0]);
        onewire_write_byte(sc->sc_onewire, buf[1]);
        onewire_write_byte(sc->sc_onewire, buf[2]);
        onewire_read_block(sc->sc_onewire, &buf[3], DS2423_COUNTER_BUFSZ-3);

        crc = onewire_crc16(buf, DS2423_COUNTER_BUFSZ-2);
        crc ^= buf[DS2423_COUNTER_BUF_CRC]
                | (buf[DS2423_COUNTER_BUF_CRC+1] << 8);
        if ( crc != 0xffff) {
                printf("%s: invalid CRC\n", sc->sc_dev.dv_xname);
                if (bank == DS2423_COUNTER_BANK_A) {
                        sc->sc_counterA.value = 0;
                        sc->sc_counterA.status = SENSOR_S_UNKNOWN;
                        sc->sc_counterA.flags |= SENSOR_FUNKNOWN;
                } else {
                        sc->sc_counterB.value = 0;
                        sc->sc_counterB.status = SENSOR_S_UNKNOWN;
                        sc->sc_counterB.flags |= SENSOR_FUNKNOWN;
                }
        } else {
                counter = buf[DS2423_COUNTER_BUF_COUNTER]
                        | (buf[DS2423_COUNTER_BUF_COUNTER+1] << 8)
                        | (buf[DS2423_COUNTER_BUF_COUNTER+2] << 16)
                        | (buf[DS2423_COUNTER_BUF_COUNTER+3] << 24);
                if (bank == DS2423_COUNTER_BANK_A) {
                        sc->sc_counterA.value = counter;
                        sc->sc_counterA.status = SENSOR_S_UNSPEC;
                        sc->sc_counterA.flags &= ~SENSOR_FUNKNOWN;
                } else {
                        sc->sc_counterB.value = counter;
                        sc->sc_counterB.status = SENSOR_S_UNSPEC;
                        sc->sc_counterB.flags &= ~SENSOR_FUNKNOWN;
                }
        }

        onewire_reset(sc->sc_onewire);
        free(buf, M_DEVBUF, DS2423_COUNTER_BUFSZ);

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