/* $NetBSD: cwfg.c,v 1.6 2025/09/17 13:42:42 thorpej Exp $ */

/*-
 * Copyright (c) 2020 Jared McNeill <jmcneill@invisible.ca>
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__KERNEL_RCSID(0, "$NetBSD: cwfg.c,v 1.6 2025/09/17 13:42:42 thorpej Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/bus.h>
#include <sys/kmem.h>

#include <dev/i2c/i2cvar.h>

#include <dev/sysmon/sysmonvar.h>
#include <dev/sysmon/sysmon_taskq.h>

#include <dev/fdt/fdtvar.h>

#define VERSION_REG     0x00
#define VCELL_HI_REG    0x02
#define  VCELL_HI       __BITS(5,0)
#define VCELL_LO_REG    0x03
#define  VCELL_LO       __BITS(7,0)
#define SOC_HI_REG      0x04
#define SOC_LO_REG      0x05
#define RTT_ALRT_HI_REG 0x06
#define  RTT_ALRT       __BIT(7)
#define  RTT_HI         __BITS(4,0)
#define RTT_ALRT_LO_REG 0x07
#define  RTT_LO         __BITS(7,0)
#define CONFIG_REG      0x08
#define  CONFIG_ATHD    __BITS(7,3)
#define  CONFIG_UFG     __BIT(1)
#define MODE_REG        0x0a
#define  MODE_SLEEP     __BITS(7,6)
#define   MODE_SLEEP_WAKE       0x0
#define   MODE_SLEEP_SLEEP      0x3
#define  MODE_QSTRT     __BITS(5,4)
#define  MODE_POR       __BITS(3,0)
#define BATINFO_REG(n)  (0x10 + (n))

#define VCELL_STEP      312
#define VCELL_DIV       1024
#define BATINFO_SIZE    64
#define RESET_COUNT     30
#define RESET_DELAY     100000

enum cwfg_sensor {
        CWFG_SENSOR_VCELL,
        CWFG_SENSOR_SOC,
        CWFG_SENSOR_RTT,
        CWFG_NSENSORS
};

struct cwfg_softc {
        device_t        sc_dev;
        i2c_tag_t       sc_i2c;
        i2c_addr_t      sc_addr;
        int             sc_phandle;

        uint8_t         sc_batinfo[BATINFO_SIZE];

        u_int           sc_alert_level;
        u_int           sc_monitor_interval;
        u_int           sc_design_capacity;

        struct sysmon_envsys *sc_sme;

        envsys_data_t   sc_sensor[CWFG_NSENSORS];
};

#define CWFG_MONITOR_INTERVAL_DEFAULT   8
#define CWFG_DESIGN_CAPACITY_DEFAULT    2000
#define CWFG_ALERT_LEVEL_DEFAULT        0

static const struct device_compatible_entry compat_data[] = {
        { .compat = "cellwise,cw2015" },
        { .compat = "cellwise,cw201x" },        /* DTCOMPAT */
        DEVICE_COMPAT_EOL
};

static int
cwfg_lock(struct cwfg_softc *sc)
{
        return iic_acquire_bus(sc->sc_i2c, 0);
}

static void
cwfg_unlock(struct cwfg_softc *sc)
{
        iic_release_bus(sc->sc_i2c, 0);
}

static int
cwfg_read(struct cwfg_softc *sc, uint8_t reg, uint8_t *val)
{
        return iic_smbus_read_byte(sc->sc_i2c, sc->sc_addr, reg, val, 0);
}

static int
cwfg_write(struct cwfg_softc *sc, uint8_t reg, uint8_t val)
{
        return iic_smbus_write_byte(sc->sc_i2c, sc->sc_addr, reg, val, 0);
}

static void
cwfg_sensor_refresh(struct sysmon_envsys *sme, envsys_data_t *e)
{
        struct cwfg_softc *sc = sme->sme_cookie;
        u_int vcell, rtt, tmp;
        uint8_t val;
        int error, n;

        e->state = ENVSYS_SINVALID;

        if ((error = cwfg_lock(sc)) != 0)
                return;

        switch (e->private) {
        case CWFG_SENSOR_VCELL:
                /* Take the average of three readings */
                vcell = 0;
                for (n = 0; n < 3; n++) {
                        if ((error = cwfg_read(sc, VCELL_HI_REG, &val)) != 0)
                                goto done;
                        tmp = __SHIFTOUT(val, VCELL_HI) << 8;
                        if ((error = cwfg_read(sc, VCELL_LO_REG, &val)) != 0)
                                goto done;
                        tmp |= __SHIFTOUT(val, VCELL_LO);
                        vcell += tmp;
                }
                vcell /= 3;

                e->state = ENVSYS_SVALID;
                e->value_cur = ((vcell * VCELL_STEP) / VCELL_DIV) * 1000;
                break;

        case CWFG_SENSOR_SOC:
                if ((error = cwfg_read(sc, SOC_HI_REG, &val)) != 0)
                        goto done;

                if (val != 0xff) {
                        e->state = ENVSYS_SVALID;
                        e->value_cur = val;                     /* batt % */
                }
                break;

        case CWFG_SENSOR_RTT:
                if ((error = cwfg_read(sc, RTT_ALRT_HI_REG, &val)) != 0)
                        goto done;
                rtt = __SHIFTOUT(val, RTT_HI) << 8;
                if ((error = cwfg_read(sc, RTT_ALRT_LO_REG, &val)) != 0)
                        goto done;
                rtt |= __SHIFTOUT(val, RTT_LO);

                if (rtt != 0x1fff) {
                        e->state = ENVSYS_SVALID;
                        e->value_cur = rtt;                     /* minutes */
                }
                break;
        }

done:
        cwfg_unlock(sc);
}

static void
cwfg_attach_battery(struct cwfg_softc *sc)
{
        envsys_data_t *e;

        /* Cell voltage */
        e = &sc->sc_sensor[CWFG_SENSOR_VCELL];
        e->private = CWFG_SENSOR_VCELL;
        e->units = ENVSYS_SVOLTS_DC;
        e->state = ENVSYS_SINVALID;
        strlcpy(e->desc, "battery voltage", sizeof(e->desc));
        sysmon_envsys_sensor_attach(sc->sc_sme, e);

        /* State of charge */
        e = &sc->sc_sensor[CWFG_SENSOR_SOC];
        e->private = CWFG_SENSOR_SOC;
        e->units = ENVSYS_INTEGER;
        e->state = ENVSYS_SINVALID;
        e->flags = ENVSYS_FPERCENT;
        strlcpy(e->desc, "battery percent", sizeof(e->desc));
        sysmon_envsys_sensor_attach(sc->sc_sme, e);

        /* Remaining run time */
        e = &sc->sc_sensor[CWFG_SENSOR_RTT];
        e->private = CWFG_SENSOR_RTT;
        e->units = ENVSYS_INTEGER;
        e->state = ENVSYS_SINVALID;
        strlcpy(e->desc, "battery remaining minutes", sizeof(e->desc));
        sysmon_envsys_sensor_attach(sc->sc_sme, e);
}

static void
cwfg_attach_sensors(struct cwfg_softc *sc)
{
        sc->sc_sme = sysmon_envsys_create();
        sc->sc_sme->sme_name = device_xname(sc->sc_dev);
        sc->sc_sme->sme_cookie = sc;
        sc->sc_sme->sme_refresh = cwfg_sensor_refresh;
        sc->sc_sme->sme_events_timeout = sc->sc_monitor_interval;
        sc->sc_sme->sme_class = SME_CLASS_BATTERY;
        sc->sc_sme->sme_flags = SME_INIT_REFRESH;

        cwfg_attach_battery(sc);

        sysmon_envsys_register(sc->sc_sme);
}

static int
cwfg_set_config(struct cwfg_softc *sc)
{
        u_int alert_level;
        bool need_update;
        uint8_t config, mode, val;
        int error, n;

        /* Read current config */
        if ((error = cwfg_read(sc, CONFIG_REG, &config)) != 0)
                return error;

        /* Update alert level, if necessary */
        alert_level = __SHIFTOUT(config, CONFIG_ATHD);
        if (alert_level != sc->sc_alert_level) {
                config &= ~CONFIG_ATHD;
                config |= __SHIFTIN(sc->sc_alert_level, CONFIG_ATHD);
                if ((error = cwfg_write(sc, CONFIG_REG, config)) != 0)
                        return error;
        }

        /* Re-read current config */
        if ((error = cwfg_read(sc, CONFIG_REG, &config)) != 0)
                return error;

        /*
         * We need to upload a battery profile if either the UFG flag
         * is unset, or the current battery profile differs from the
         * one in the DT.
         */
        need_update = (config & CONFIG_UFG) == 0;
        if (need_update == false) {
                for (n = 0; n < BATINFO_SIZE; n++) {
                        if ((error = cwfg_read(sc, BATINFO_REG(n), &val)) != 0)
                                return error;
                        if (sc->sc_batinfo[n] != val) {
                                need_update = true;
                                break;
                        }
                }
        }
        if (need_update == false)
                return 0;

        aprint_verbose_dev(sc->sc_dev, "updating battery profile\n");

        /* Update battery profile */
        for (n = 0; n < BATINFO_SIZE; n++) {
                val = sc->sc_batinfo[n];
                if ((error = cwfg_write(sc, BATINFO_REG(n), val)) != 0)
                        return error;
        }

        /* Set UFG flag to switch to new profile */
        if ((error = cwfg_read(sc, CONFIG_REG, &config)) != 0)
                return error;
        config |= CONFIG_UFG;
        if ((error = cwfg_write(sc, CONFIG_REG, config)) != 0)
                return error;

        /* Restart the IC with new profile */
        if ((error = cwfg_read(sc, MODE_REG, &mode)) != 0)
                return error;
        mode |= MODE_POR;
        if ((error = cwfg_write(sc, MODE_REG, mode)) != 0)
                return error;
        delay(20000);
        mode &= ~MODE_POR;
        if ((error = cwfg_write(sc, MODE_REG, mode)) != 0)
                return error;

        return error;
}

static int
cwfg_init(struct cwfg_softc *sc)
{
        uint8_t mode, soc;
        int error, retry;

        cwfg_lock(sc);

        /* If the device is in sleep mode, wake it up */
        if ((error = cwfg_read(sc, MODE_REG, &mode)) != 0)
                goto done;
        if (__SHIFTOUT(mode, MODE_SLEEP) == MODE_SLEEP_SLEEP) {
                mode &= ~MODE_SLEEP;
                mode |= __SHIFTIN(MODE_SLEEP_WAKE, MODE_SLEEP);
                if ((error = cwfg_write(sc, MODE_REG, mode)) != 0)
                        goto done;
        }

        /* Load battery profile */
        if ((error = cwfg_set_config(sc)) != 0)
                goto done;

        /* Wait for chip to become ready */
        for (retry = RESET_COUNT; retry > 0; retry--) {
                if ((error = cwfg_read(sc, SOC_HI_REG, &soc)) != 0)
                        goto done;
                if (soc != 0xff)
                        break;
                delay(RESET_DELAY);
        }
        if (retry == 0) {
                aprint_error_dev(sc->sc_dev,
                    "WARNING: timeout waiting for chip ready\n");
        }

done:
        cwfg_unlock(sc);

        return error;
}

static int
cwfg_parse_resources(struct cwfg_softc *sc)
{
        const u_int *batinfo;
        u_int val;
        int len = 0, n;

        batinfo = fdtbus_get_prop(sc->sc_phandle,
            "cellwise,battery-profile", &len);
        if (batinfo == NULL) {
                /* DTCOMPAT */
                batinfo = fdtbus_get_prop(sc->sc_phandle,
                    "cellwise,bat-config-info", &len);
        }
        switch (len) {
        case BATINFO_SIZE:
                memcpy(sc->sc_batinfo, batinfo, BATINFO_SIZE);
                break;
        case BATINFO_SIZE * 4:
                for (n = 0; n < BATINFO_SIZE; n++)
                        sc->sc_batinfo[n] = be32toh(batinfo[n]);
                break;
        default:
                aprint_error_dev(sc->sc_dev,
                    "missing or invalid battery info\n");
                return EINVAL;
        }

        if (of_getprop_uint32(sc->sc_phandle,
            "cellwise,monitor-interval-ms", &val) == 0) {
                sc->sc_monitor_interval = howmany(val, 1000);
        } else if (of_getprop_uint32(sc->sc_phandle,
            "cellwise,monitor-interval", &val) == 0) {
                /* DTCOMPAT */
                sc->sc_monitor_interval = val;
        } else {
                sc->sc_monitor_interval = CWFG_MONITOR_INTERVAL_DEFAULT;
        }

        const int bphandle = fdtbus_get_phandle(sc->sc_phandle, "monitored-battery");
        if (bphandle != -1 && of_getprop_uint32(bphandle,
            "charge-full-design-microamp-hours", &val) == 0) {
                sc->sc_design_capacity = howmany(val, 1000);
        } else if (of_getprop_uint32(sc->sc_phandle,
            "cellwise,design-capacity", &val) == 0) {
                /* DTCOMPAT */
                sc->sc_design_capacity = val;
        } else {
                sc->sc_design_capacity = CWFG_DESIGN_CAPACITY_DEFAULT;
        }

        if (of_getprop_uint32(sc->sc_phandle,
            "cellwise,alert-level", &sc->sc_alert_level) != 0) {
                sc->sc_alert_level = CWFG_ALERT_LEVEL_DEFAULT;
        }

        return 0;
}

static int
cwfg_match(device_t parent, cfdata_t match, void *aux)
{
        struct i2c_attach_args *ia = aux;
        int match_result;

        if (iic_use_direct_match(ia, match, compat_data, &match_result))
                return match_result;

        /* This device is direct-config only. */

        return 0;
}

static void
cwfg_attach(device_t parent, device_t self, void *aux)
{
        struct cwfg_softc *sc = device_private(self);
        struct i2c_attach_args *ia = aux;
        uint8_t ver;
        int error;

        sc->sc_dev = self;
        sc->sc_i2c = ia->ia_tag;
        sc->sc_addr = ia->ia_addr;
        sc->sc_phandle = devhandle_to_of(device_handle(self));

        cwfg_lock(sc);
        error = cwfg_read(sc, VERSION_REG, &ver);
        cwfg_unlock(sc);

        if (error != 0) {
                aprint_error(": device not responding, error = %d\n", error);
                return;
        }

        aprint_naive("\n");
        aprint_normal(": CellWise CW2015 Fuel Gauge IC (ver. 0x%02x)\n", ver);

        if (cwfg_parse_resources(sc) != 0) {
                aprint_error_dev(self, "failed to parse resources\n");
                return;
        }

        if (cwfg_init(sc) != 0) {
                aprint_error_dev(self, "failed to initialize device\n");
                return;
        }

        cwfg_attach_sensors(sc);
}

CFATTACH_DECL_NEW(cwfg, sizeof(struct cwfg_softc),
    cwfg_match, cwfg_attach, NULL, NULL);