* Copyright (c) 2020 Jared McNeill <jmcneill@invisible.ca>

/* $NetBSD: cwfg.c,v 1.5 2021/11/07 17:14:38 jmcneill Exp $ */

/*-
* Copyright (c) 2020 Jared McNeill <[email protected]>
* 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 1.5 2021/11/07 17:14:38 jmcneill 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 = ia->ia_cookie;

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);