/* $OpenBSD: cwfg.c,v 1.7 2022/04/06 18:59:28 naddy Exp $ */
/* $NetBSD: cwfg.c,v 1.1 2020/01/03 18:00:05 jmcneill 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/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/malloc.h>
#include <sys/sensors.h>

#include <machine/apmvar.h>
#include <machine/fdt.h>

#include <dev/ofw/openfirm.h>

#include <dev/i2c/i2cvar.h>

#include "apm.h"

#define VERSION_REG             0x00
#define VCELL_HI_REG            0x02
#define  VCELL_HI_MASK                  0x3f
#define  VCELL_HI_SHIFT                 0
#define VCELL_LO_REG            0x03
#define  VCELL_LO_MASK                  0xff
#define  VCELL_LO_SHIFT                 0
#define SOC_HI_REG              0x04
#define SOC_LO_REG              0x05
#define RTT_ALRT_HI_REG         0x06
#define  RTT_ALRT                       (1 << 7)
#define  RTT_HI_MASK                    0x1f
#define  RTT_HI_SHIFT                   0
#define RTT_ALRT_LO_REG         0x07
#define  RTT_LO_MASK                    0xff
#define  RTT_LO_SHIFT                   0
#define CONFIG_REG              0x08
#define  CONFIG_UFG                     (1 << 1)
#define MODE_REG                0x0a
#define  MODE_SLEEP_MASK                (0x3 << 6)
#define  MODE_SLEEP_WAKE                (0x0 << 6)
#define  MODE_SLEEP_SLEEP               (0x3 << 6)
#define  MODE_QSTRT_MASK                0x3
#define  MODE_QSTRT_SHIFT               4
#define  MODE_POR                       (0xf << 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 {
        struct device   sc_dev;
        i2c_tag_t       sc_tag;
        i2c_addr_t      sc_addr;
        int             sc_node;

        uint8_t         sc_batinfo[BATINFO_SIZE];

        struct ksensor  sc_sensor[CWFG_NSENSORS];
        struct ksensordev sc_sensordev;
};

int cwfg_match(struct device *, void *, void *);
void cwfg_attach(struct device *, struct device *, void *);

int cwfg_init(struct cwfg_softc *);
int cwfg_set_config(struct cwfg_softc *);
int cwfg_lock(struct cwfg_softc *);
void cwfg_unlock(struct cwfg_softc *);
int cwfg_read(struct cwfg_softc *, uint8_t, uint8_t *);
int cwfg_write(struct cwfg_softc *, uint8_t, uint8_t);
void cwfg_update_sensors(void *);

const struct cfattach cwfg_ca = {
        sizeof(struct cwfg_softc), cwfg_match, cwfg_attach
};

struct cfdriver cwfg_cd = {
        NULL, "cwfg", DV_DULL
};

#if NAPM > 0
struct apm_power_info cwfg_power = {
        .battery_state = APM_BATT_UNKNOWN,
        .ac_state = APM_AC_UNKNOWN,
        .battery_life = 0,
        .minutes_left = -1,
};

int
cwfg_apminfo(struct apm_power_info *info)
{
        memcpy(info, &cwfg_power, sizeof(*info));
        return 0;
}
#endif

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

        if (strcmp(ia->ia_name, "cellwise,cw2015") == 0)
                return 1;

        return 0;
}

void
cwfg_attach(struct device *parent, struct device *self, void *aux)
{
        struct cwfg_softc *sc = (struct cwfg_softc *)self;
        struct i2c_attach_args *ia = aux;
        uint32_t *batinfo;
        ssize_t len;
        int n;

        sc->sc_tag = ia->ia_tag;
        sc->sc_addr = ia->ia_addr;
        sc->sc_node = *(int *)ia->ia_cookie;

        len = OF_getproplen(sc->sc_node, "cellwise,battery-profile");
        if (len <= 0) {
                printf(": missing or invalid battery info\n");
                return;
        }

        batinfo = malloc(len, M_TEMP, M_WAITOK);
        OF_getprop(sc->sc_node, "cellwise,battery-profile", batinfo, 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:
                printf(": invalid battery info\n");
                free(batinfo, M_TEMP, len);
                return;
        }
        free(batinfo, M_TEMP, len);

        if (cwfg_init(sc) != 0) {
                printf(": failed to initialize device\n");
                return;
        }

        strlcpy(sc->sc_sensor[CWFG_SENSOR_VCELL].desc, "battery voltage",
            sizeof(sc->sc_sensor[CWFG_SENSOR_VCELL].desc));
        sc->sc_sensor[CWFG_SENSOR_VCELL].type = SENSOR_VOLTS_DC;
        sc->sc_sensor[CWFG_SENSOR_VCELL].flags = SENSOR_FINVALID;
        sensor_attach(&sc->sc_sensordev, &sc->sc_sensor[CWFG_SENSOR_VCELL]);

        strlcpy(sc->sc_sensor[CWFG_SENSOR_SOC].desc, "battery percent",
            sizeof(sc->sc_sensor[CWFG_SENSOR_SOC].desc));
        sc->sc_sensor[CWFG_SENSOR_SOC].type = SENSOR_PERCENT;
        sc->sc_sensor[CWFG_SENSOR_SOC].flags = SENSOR_FINVALID;
        sensor_attach(&sc->sc_sensordev, &sc->sc_sensor[CWFG_SENSOR_SOC]);

        strlcpy(sc->sc_sensor[CWFG_SENSOR_RTT].desc, "battery remaining "
            "minutes", sizeof(sc->sc_sensor[CWFG_SENSOR_RTT].desc));
        sc->sc_sensor[CWFG_SENSOR_RTT].type = SENSOR_INTEGER;
        sc->sc_sensor[CWFG_SENSOR_RTT].flags = SENSOR_FINVALID;
        sensor_attach(&sc->sc_sensordev, &sc->sc_sensor[CWFG_SENSOR_RTT]);

        strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
            sizeof(sc->sc_sensordev.xname));
        sensordev_install(&sc->sc_sensordev);

        sensor_task_register(sc, cwfg_update_sensors, 5);

#if NAPM > 0
        apm_setinfohook(cwfg_apminfo);
#endif

        printf("\n");
}

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 ((mode & MODE_SLEEP_MASK) == MODE_SLEEP_SLEEP) {
                mode &= ~MODE_SLEEP_MASK;
                mode |= MODE_SLEEP_WAKE;
                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)
                printf("%s: timeout waiting for chip ready\n",
                    sc->sc_dev.dv_xname);

done:
        cwfg_unlock(sc);

        return error;
}

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

        /* 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);
        if (!need_update) {
                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 = 1;
                                break;
                        }
                }
        }
        if (!need_update)
                return 0;

        /* 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;
}

void
cwfg_update_sensors(void *arg)
{
        struct cwfg_softc *sc = arg;
        uint32_t vcell, rtt, tmp;
        uint8_t val;
        int error, n;

        /* invalidate all previous reads to avoid stale/incoherent values
         * in case of transient cwfg_read() failures below */
        sc->sc_sensor[CWFG_SENSOR_VCELL].flags |= SENSOR_FINVALID;
        sc->sc_sensor[CWFG_SENSOR_SOC].flags |= SENSOR_FINVALID;
        sc->sc_sensor[CWFG_SENSOR_RTT].flags |= SENSOR_FINVALID;

#if NAPM > 0
        cwfg_power.battery_state = APM_BATT_UNKNOWN;
        cwfg_power.ac_state = APM_AC_UNKNOWN;
        cwfg_power.battery_life = 0;
        cwfg_power.minutes_left = -1;
#endif

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

        /* 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 = ((val >> VCELL_HI_SHIFT) & VCELL_HI_MASK) << 8;
                if ((error = cwfg_read(sc, VCELL_LO_REG, &val)) != 0)
                        goto done;
                tmp |= ((val >> VCELL_LO_SHIFT) & VCELL_LO_MASK);
                vcell += tmp;
        }
        vcell /= 3;
        sc->sc_sensor[CWFG_SENSOR_VCELL].value =
            ((vcell * VCELL_STEP) / VCELL_DIV) * 1000;
        sc->sc_sensor[CWFG_SENSOR_VCELL].flags &= ~SENSOR_FINVALID;

        /* SOC */
        if ((error = cwfg_read(sc, SOC_HI_REG, &val)) != 0)
                goto done;
        if (val != 0xff) {
                sc->sc_sensor[CWFG_SENSOR_SOC].value = val * 1000;
                sc->sc_sensor[CWFG_SENSOR_SOC].flags &= ~SENSOR_FINVALID;
#if NAPM > 0
                cwfg_power.battery_life = val;
                if (val > 50)
                        cwfg_power.battery_state = APM_BATT_HIGH;
                else if (val > 25)
                        cwfg_power.battery_state = APM_BATT_LOW;
                else
                        cwfg_power.battery_state = APM_BATT_CRITICAL;
#endif
        }

        /* RTT */
        if ((error = cwfg_read(sc, RTT_ALRT_HI_REG, &val)) != 0)
                goto done;
        rtt = ((val >> RTT_HI_SHIFT) & RTT_HI_MASK) << 8;
        if ((error = cwfg_read(sc, RTT_ALRT_LO_REG, &val)) != 0)
                goto done;
        rtt |= ((val >> RTT_LO_SHIFT) & RTT_LO_MASK);
        if (rtt != 0x1fff) {
                sc->sc_sensor[CWFG_SENSOR_RTT].value = rtt;
                sc->sc_sensor[CWFG_SENSOR_RTT].flags &= ~SENSOR_FINVALID;
#if NAPM > 0
                cwfg_power.minutes_left = rtt;
#endif
        }

done:
        cwfg_unlock(sc);
}

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

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

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

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