// SPDX-License-Identifier: GPL-2.0+
/*
* max77976_charger.c - Driver for the Maxim MAX77976 battery charger
*
* Copyright (C) 2021 Luca Ceresoli
* Author: Luca Ceresoli <luca@lucaceresoli.net>
*/
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>
#define MAX77976_DRIVER_NAME "max77976-charger"
#define MAX77976_CHIP_ID 0x76
static const char *max77976_manufacturer = "Maxim Integrated";
static const char *max77976_model = "MAX77976";
/* --------------------------------------------------------------------------
* Register map
*/
#define MAX77976_REG_CHIP_ID 0x00
#define MAX77976_REG_CHIP_REVISION 0x01
#define MAX77976_REG_CHG_INT_OK 0x12
#define MAX77976_REG_CHG_DETAILS_01 0x14
#define MAX77976_REG_CHG_CNFG_00 0x16
#define MAX77976_REG_CHG_CNFG_02 0x18
#define MAX77976_REG_CHG_CNFG_06 0x1c
#define MAX77976_REG_CHG_CNFG_09 0x1f
/* CHG_DETAILS_01.CHG_DTLS values */
enum max77976_charging_state {
MAX77976_CHARGING_PREQUALIFICATION = 0x0,
MAX77976_CHARGING_FAST_CONST_CURRENT,
MAX77976_CHARGING_FAST_CONST_VOLTAGE,
MAX77976_CHARGING_TOP_OFF,
MAX77976_CHARGING_DONE,
MAX77976_CHARGING_RESERVED_05,
MAX77976_CHARGING_TIMER_FAULT,
MAX77976_CHARGING_SUSPENDED_QBATT_OFF,
MAX77976_CHARGING_OFF,
MAX77976_CHARGING_RESERVED_09,
MAX77976_CHARGING_THERMAL_SHUTDOWN,
MAX77976_CHARGING_WATCHDOG_EXPIRED,
MAX77976_CHARGING_SUSPENDED_JEITA,
MAX77976_CHARGING_SUSPENDED_THM_REMOVAL,
MAX77976_CHARGING_SUSPENDED_PIN,
MAX77976_CHARGING_RESERVED_0F,
};
/* CHG_DETAILS_01.BAT_DTLS values */
enum max77976_battery_state {
MAX77976_BATTERY_BATTERY_REMOVAL = 0x0,
MAX77976_BATTERY_PREQUALIFICATION,
MAX77976_BATTERY_TIMER_FAULT,
MAX77976_BATTERY_REGULAR_VOLTAGE,
MAX77976_BATTERY_LOW_VOLTAGE,
MAX77976_BATTERY_OVERVOLTAGE,
MAX77976_BATTERY_RESERVED,
MAX77976_BATTERY_BATTERY_ONLY, // No valid adapter is present
};
/* CHG_CNFG_00.MODE values */
enum max77976_mode {
MAX77976_MODE_CHARGER_BUCK = 0x5,
MAX77976_MODE_BOOST = 0x9,
};
/* CHG_CNFG_02.CHG_CC: charge current limit, 100..5500 mA, 50 mA steps */
#define MAX77976_CHG_CC_STEP 50000U
#define MAX77976_CHG_CC_MIN 100000U
#define MAX77976_CHG_CC_MAX 5500000U
/* CHG_CNFG_09.CHGIN_ILIM: input current limit, 100..3200 mA, 100 mA steps */
#define MAX77976_CHGIN_ILIM_STEP 100000U
#define MAX77976_CHGIN_ILIM_MIN 100000U
#define MAX77976_CHGIN_ILIM_MAX 3200000U
enum max77976_field_idx {
VERSION, REVISION, /* CHIP_REVISION */
CHGIN_OK, /* CHG_INT_OK */
BAT_DTLS, CHG_DTLS, /* CHG_DETAILS_01 */
MODE, /* CHG_CNFG_00 */
CHG_CC, /* CHG_CNFG_02 */
CHGPROT, /* CHG_CNFG_06 */
CHGIN_ILIM, /* CHG_CNFG_09 */
MAX77976_N_REGMAP_FIELDS
};
static const struct reg_field max77976_reg_field[MAX77976_N_REGMAP_FIELDS] = {
[VERSION] = REG_FIELD(MAX77976_REG_CHIP_REVISION, 4, 7),
[REVISION] = REG_FIELD(MAX77976_REG_CHIP_REVISION, 0, 3),
[CHGIN_OK] = REG_FIELD(MAX77976_REG_CHG_INT_OK, 6, 6),
[CHG_DTLS] = REG_FIELD(MAX77976_REG_CHG_DETAILS_01, 0, 3),
[BAT_DTLS] = REG_FIELD(MAX77976_REG_CHG_DETAILS_01, 4, 6),
[MODE] = REG_FIELD(MAX77976_REG_CHG_CNFG_00, 0, 3),
[CHG_CC] = REG_FIELD(MAX77976_REG_CHG_CNFG_02, 0, 6),
[CHGPROT] = REG_FIELD(MAX77976_REG_CHG_CNFG_06, 2, 3),
[CHGIN_ILIM] = REG_FIELD(MAX77976_REG_CHG_CNFG_09, 0, 5),
};
static const struct regmap_config max77976_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = 0x24,
};
/* --------------------------------------------------------------------------
* Data structures
*/
struct max77976 {
struct i2c_client *client;
struct regmap *regmap;
struct regmap_field *rfield[MAX77976_N_REGMAP_FIELDS];
};
/* --------------------------------------------------------------------------
* power_supply properties
*/
static int max77976_get_status(struct max77976 *chg, int *val)
{
unsigned int regval;
int err;
err = regmap_field_read(chg->rfield[CHG_DTLS], ®val);
if (err < 0)
return err;
switch (regval) {
case MAX77976_CHARGING_PREQUALIFICATION:
case MAX77976_CHARGING_FAST_CONST_CURRENT:
case MAX77976_CHARGING_FAST_CONST_VOLTAGE:
case MAX77976_CHARGING_TOP_OFF:
*val = POWER_SUPPLY_STATUS_CHARGING;
break;
case MAX77976_CHARGING_DONE:
*val = POWER_SUPPLY_STATUS_FULL;
break;
case MAX77976_CHARGING_TIMER_FAULT:
case MAX77976_CHARGING_SUSPENDED_QBATT_OFF:
case MAX77976_CHARGING_SUSPENDED_JEITA:
case MAX77976_CHARGING_SUSPENDED_THM_REMOVAL:
case MAX77976_CHARGING_SUSPENDED_PIN:
*val = POWER_SUPPLY_STATUS_NOT_CHARGING;
break;
case MAX77976_CHARGING_OFF:
case MAX77976_CHARGING_THERMAL_SHUTDOWN:
case MAX77976_CHARGING_WATCHDOG_EXPIRED:
*val = POWER_SUPPLY_STATUS_DISCHARGING;
break;
default:
*val = POWER_SUPPLY_STATUS_UNKNOWN;
}
return 0;
}
static int max77976_get_charge_type(struct max77976 *chg, int *val)
{
unsigned int regval;
int err;
err = regmap_field_read(chg->rfield[CHG_DTLS], ®val);
if (err < 0)
return err;
switch (regval) {
case MAX77976_CHARGING_PREQUALIFICATION:
*val = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
break;
case MAX77976_CHARGING_FAST_CONST_CURRENT:
case MAX77976_CHARGING_FAST_CONST_VOLTAGE:
*val = POWER_SUPPLY_CHARGE_TYPE_FAST;
break;
case MAX77976_CHARGING_TOP_OFF:
*val = POWER_SUPPLY_CHARGE_TYPE_STANDARD;
break;
case MAX77976_CHARGING_DONE:
case MAX77976_CHARGING_TIMER_FAULT:
case MAX77976_CHARGING_SUSPENDED_QBATT_OFF:
case MAX77976_CHARGING_OFF:
case MAX77976_CHARGING_THERMAL_SHUTDOWN:
case MAX77976_CHARGING_WATCHDOG_EXPIRED:
case MAX77976_CHARGING_SUSPENDED_JEITA:
case MAX77976_CHARGING_SUSPENDED_THM_REMOVAL:
case MAX77976_CHARGING_SUSPENDED_PIN:
*val = POWER_SUPPLY_CHARGE_TYPE_NONE;
break;
default:
*val = POWER_SUPPLY_CHARGE_TYPE_UNKNOWN;
}
return 0;
}
static int max77976_get_health(struct max77976 *chg, int *val)
{
unsigned int regval;
int err;
err = regmap_field_read(chg->rfield[BAT_DTLS], ®val);
if (err < 0)
return err;
switch (regval) {
case MAX77976_BATTERY_BATTERY_REMOVAL:
*val = POWER_SUPPLY_HEALTH_NO_BATTERY;
break;
case MAX77976_BATTERY_LOW_VOLTAGE:
case MAX77976_BATTERY_REGULAR_VOLTAGE:
*val = POWER_SUPPLY_HEALTH_GOOD;
break;
case MAX77976_BATTERY_TIMER_FAULT:
*val = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
break;
case MAX77976_BATTERY_OVERVOLTAGE:
*val = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
break;
case MAX77976_BATTERY_PREQUALIFICATION:
case MAX77976_BATTERY_BATTERY_ONLY:
*val = POWER_SUPPLY_HEALTH_UNKNOWN;
break;
default:
*val = POWER_SUPPLY_HEALTH_UNKNOWN;
}
return 0;
}
static int max77976_get_online(struct max77976 *chg, int *val)
{
unsigned int regval;
int err;
err = regmap_field_read(chg->rfield[CHGIN_OK], ®val);
if (err < 0)
return err;
*val = (regval ? 1 : 0);
return 0;
}
static int max77976_get_integer(struct max77976 *chg, enum max77976_field_idx fidx,
unsigned int clamp_min, unsigned int clamp_max,
unsigned int mult, int *val)
{
unsigned int regval;
int err;
err = regmap_field_read(chg->rfield[fidx], ®val);
if (err < 0)
return err;
*val = clamp_val(regval * mult, clamp_min, clamp_max);
return 0;
}
static int max77976_set_integer(struct max77976 *chg, enum max77976_field_idx fidx,
unsigned int clamp_min, unsigned int clamp_max,
unsigned int div, int val)
{
unsigned int regval;
regval = clamp_val(val, clamp_min, clamp_max) / div;
return regmap_field_write(chg->rfield[fidx], regval);
}
static int max77976_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct max77976 *chg = power_supply_get_drvdata(psy);
int err = 0;
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
err = max77976_get_status(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_CHARGE_TYPE:
err = max77976_get_charge_type(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_HEALTH:
err = max77976_get_health(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_ONLINE:
err = max77976_get_online(chg, &val->intval);
break;
case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX:
val->intval = MAX77976_CHG_CC_MAX;
break;
case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
err = max77976_get_integer(chg, CHG_CC,
MAX77976_CHG_CC_MIN,
MAX77976_CHG_CC_MAX,
MAX77976_CHG_CC_STEP,
&val->intval);
break;
case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
err = max77976_get_integer(chg, CHGIN_ILIM,
MAX77976_CHGIN_ILIM_MIN,
MAX77976_CHGIN_ILIM_MAX,
MAX77976_CHGIN_ILIM_STEP,
&val->intval);
break;
case POWER_SUPPLY_PROP_MODEL_NAME:
val->strval = max77976_model;
break;
case POWER_SUPPLY_PROP_MANUFACTURER:
val->strval = max77976_manufacturer;
break;
default:
err = -EINVAL;
}
return err;
}
static int max77976_set_property(struct power_supply *psy,
enum power_supply_property psp,
const union power_supply_propval *val)
{
struct max77976 *chg = power_supply_get_drvdata(psy);
int err = 0;
switch (psp) {
case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
err = max77976_set_integer(chg, CHG_CC,
MAX77976_CHG_CC_MIN,
MAX77976_CHG_CC_MAX,
MAX77976_CHG_CC_STEP,
val->intval);
break;
case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
err = max77976_set_integer(chg, CHGIN_ILIM,
MAX77976_CHGIN_ILIM_MIN,
MAX77976_CHGIN_ILIM_MAX,
MAX77976_CHGIN_ILIM_STEP,
val->intval);
break;
default:
err = -EINVAL;
}
return err;
};
static int max77976_property_is_writeable(struct power_supply *psy,
enum power_supply_property psp)
{
switch (psp) {
case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
return true;
default:
return false;
}
}
static enum power_supply_property max77976_psy_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_CHARGE_TYPE,
POWER_SUPPLY_PROP_HEALTH,
POWER_SUPPLY_PROP_ONLINE,
POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT,
POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX,
POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
POWER_SUPPLY_PROP_MODEL_NAME,
POWER_SUPPLY_PROP_MANUFACTURER,
};
static const struct power_supply_desc max77976_psy_desc = {
.name = MAX77976_DRIVER_NAME,
.type = POWER_SUPPLY_TYPE_USB,
.properties = max77976_psy_props,
.num_properties = ARRAY_SIZE(max77976_psy_props),
.get_property = max77976_get_property,
.set_property = max77976_set_property,
.property_is_writeable = max77976_property_is_writeable,
};
/* --------------------------------------------------------------------------
* Entry point
*/
static int max77976_detect(struct max77976 *chg)
{
struct device *dev = &chg->client->dev;
unsigned int id, ver, rev;
int err;
err = regmap_read(chg->regmap, MAX77976_REG_CHIP_ID, &id);
if (err)
return dev_err_probe(dev, err, "cannot read chip ID\n");
if (id != MAX77976_CHIP_ID)
return dev_err_probe(dev, -ENXIO, "unknown model ID 0x%02x\n", id);
err = regmap_field_read(chg->rfield[VERSION], &ver);
if (!err)
err = regmap_field_read(chg->rfield[REVISION], &rev);
if (err)
return dev_err_probe(dev, -ENXIO, "cannot read version/revision\n");
dev_info(dev, "detected model MAX779%02x ver %u rev %u", id, ver, rev);
return 0;
}
static int max77976_configure(struct max77976 *chg)
{
struct device *dev = &chg->client->dev;
int err;
/* Magic value to unlock writing to some registers */
err = regmap_field_write(chg->rfield[CHGPROT], 0x3);
if (err)
goto err;
/*
* Mode 5 = Charger ON, OTG OFF, buck ON, boost OFF.
* Other modes are not implemented by this driver.
*/
err = regmap_field_write(chg->rfield[MODE], MAX77976_MODE_CHARGER_BUCK);
if (err)
goto err;
return 0;
err:
return dev_err_probe(dev, err, "error while configuring");
}
static int max77976_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct power_supply_config psy_cfg = {};
struct power_supply *psy;
struct max77976 *chg;
int err;
int i;
chg = devm_kzalloc(dev, sizeof(*chg), GFP_KERNEL);
if (!chg)
return -ENOMEM;
i2c_set_clientdata(client, chg);
psy_cfg.drv_data = chg;
chg->client = client;
chg->regmap = devm_regmap_init_i2c(client, &max77976_regmap_config);
if (IS_ERR(chg->regmap))
return dev_err_probe(dev, PTR_ERR(chg->regmap),
"cannot allocate regmap\n");
for (i = 0; i < MAX77976_N_REGMAP_FIELDS; i++) {
chg->rfield[i] = devm_regmap_field_alloc(dev, chg->regmap,
max77976_reg_field[i]);
if (IS_ERR(chg->rfield[i]))
return dev_err_probe(dev, PTR_ERR(chg->rfield[i]),
"cannot allocate regmap field\n");
}
err = max77976_detect(chg);
if (err)
return err;
err = max77976_configure(chg);
if (err)
return err;
psy = devm_power_supply_register_no_ws(dev, &max77976_psy_desc, &psy_cfg);
if (IS_ERR(psy))
return dev_err_probe(dev, PTR_ERR(psy), "cannot register\n");
return 0;
}
static const struct i2c_device_id max77976_i2c_id[] = {
{ MAX77976_DRIVER_NAME, 0 },
{ },
};
MODULE_DEVICE_TABLE(i2c, max77976_i2c_id);
static const struct of_device_id max77976_of_id[] = {
{ .compatible = "maxim,max77976" },
{ },
};
MODULE_DEVICE_TABLE(of, max77976_of_id);
static struct i2c_driver max77976_driver = {
.driver = {
.name = MAX77976_DRIVER_NAME,
.of_match_table = max77976_of_id,
},
.probe_new = max77976_probe,
.id_table = max77976_i2c_id,
};
module_i2c_driver(max77976_driver);
MODULE_AUTHOR("Luca Ceresoli <luca@lucaceresoli.net>");
MODULE_DESCRIPTION("Maxim MAX77976 charger driver");
MODULE_LICENSE("GPL v2");