linux/drivers/power/supply/ltc4162-l-charger.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Driver for Analog Devices (Linear Technology) LTC4162-L charger IC.
 *  Copyright (C) 2020, Topic Embedded Products
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/of_device.h>
#include <linux/pm_runtime.h>
#include <linux/power_supply.h>
#include <linux/i2c.h>
#include <linux/regmap.h>

/* Registers (names based on what datasheet uses) */
#define LTC4162L_EN_LIMIT_ALERTS_REG		0x0D
#define LTC4162L_EN_CHARGER_STATE_ALERTS_REG	0x0E
#define LTC4162L_EN_CHARGE_STATUS_ALERTS_REG	0x0F
#define LTC4162L_CONFIG_BITS_REG		0x14
#define LTC4162L_IIN_LIMIT_TARGET		0x15
#define LTC4162L_ARM_SHIP_MODE			0x19
#define LTC4162L_CHARGE_CURRENT_SETTING		0X1A
#define LTC4162L_VCHARGE_SETTING		0X1B
#define LTC4162L_C_OVER_X_THRESHOLD		0x1C
#define LTC4162L_MAX_CV_TIME			0X1D
#define LTC4162L_MAX_CHARGE_TIME		0X1E
#define LTC4162L_CHARGER_CONFIG_BITS		0x29
#define LTC4162L_CHARGER_STATE			0x34
#define LTC4162L_CHARGE_STATUS			0x35
#define LTC4162L_LIMIT_ALERTS_REG		0x36
#define LTC4162L_CHARGER_STATE_ALERTS_REG	0x37
#define LTC4162L_CHARGE_STATUS_ALERTS_REG	0x38
#define LTC4162L_SYSTEM_STATUS_REG		0x39
#define LTC4162L_VBAT				0x3A
#define LTC4162L_VIN				0x3B
#define LTC4162L_VOUT				0x3C
#define LTC4162L_IBAT				0x3D
#define LTC4162L_IIN				0x3E
#define LTC4162L_DIE_TEMPERATURE		0x3F
#define LTC4162L_THERMISTOR_VOLTAGE		0x40
#define LTC4162L_BSR				0x41
#define LTC4162L_JEITA_REGION			0x42
#define LTC4162L_CHEM_CELLS_REG			0x43
#define LTC4162L_ICHARGE_DAC			0x44
#define LTC4162L_VCHARGE_DAC			0x45
#define LTC4162L_IIN_LIMIT_DAC			0x46
#define LTC4162L_VBAT_FILT			0x47
#define LTC4162L_INPUT_UNDERVOLTAGE_DAC		0x4B

/* Enumeration as in datasheet. Individual bits are mutually exclusive. */
enum ltc4162l_state {
	battery_detection = 2048,
	charger_suspended = 256,
	precharge = 128,   /* trickle on low bat voltage */
	cc_cv_charge = 64, /* normal charge */
	ntc_pause = 32,
	timer_term = 16,
	c_over_x_term = 8, /* battery is full */
	max_charge_time_fault = 4,
	bat_missing_fault = 2,
	bat_short_fault = 1
};

/* Individual bits are mutually exclusive. Only active in charging states.*/
enum ltc4162l_charge_status {
	ilim_reg_active = 32,
	thermal_reg_active = 16,
	vin_uvcl_active = 8,
	iin_limit_active = 4,
	constant_current = 2,
	constant_voltage = 1,
	charger_off = 0
};

/* Magic number to write to ARM_SHIP_MODE register */
#define LTC4162L_ARM_SHIP_MODE_MAGIC 21325

struct ltc4162l_info {
	struct i2c_client	*client;
	struct regmap		*regmap;
	struct power_supply	*charger;
	u32 rsnsb;	/* Series resistor that sets charge current, microOhm */
	u32 rsnsi;	/* Series resistor to measure input current, microOhm */
	u8 cell_count;	/* Number of connected cells, 0 while unknown */
};

static u8 ltc4162l_get_cell_count(struct ltc4162l_info *info)
{
	int ret;
	unsigned int val;

	/* Once read successfully */
	if (info->cell_count)
		return info->cell_count;

	ret = regmap_read(info->regmap, LTC4162L_CHEM_CELLS_REG, &val);
	if (ret)
		return 0;

	/* Lower 4 bits is the cell count, or 0 if the chip doesn't know yet */
	val &= 0x0f;
	if (!val)
		return 0;

	/* Once determined, keep the value */
	info->cell_count = val;

	return val;
};

/* Convert enum value to POWER_SUPPLY_STATUS value */
static int ltc4162l_state_decode(enum ltc4162l_state value)
{
	switch (value) {
	case precharge:
	case cc_cv_charge:
		return POWER_SUPPLY_STATUS_CHARGING;
	case c_over_x_term:
		return POWER_SUPPLY_STATUS_FULL;
	case bat_missing_fault:
	case bat_short_fault:
		return POWER_SUPPLY_STATUS_UNKNOWN;
	default:
		return POWER_SUPPLY_STATUS_NOT_CHARGING;
	}
};

static int ltc4162l_get_status(struct ltc4162l_info *info,
			       union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_CHARGER_STATE, &regval);
	if (ret) {
		dev_err(&info->client->dev, "Failed to read CHARGER_STATE\n");
		return ret;
	}

	val->intval = ltc4162l_state_decode(regval);

	return 0;
}

static int ltc4162l_charge_status_decode(enum ltc4162l_charge_status value)
{
	if (!value)
		return POWER_SUPPLY_CHARGE_TYPE_NONE;

	/* constant voltage/current and input_current limit are "fast" modes */
	if (value <= iin_limit_active)
		return POWER_SUPPLY_CHARGE_TYPE_FAST;

	/* Anything that's not fast we'll return as trickle */
	return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
}

static int ltc4162l_get_charge_type(struct ltc4162l_info *info,
				    union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_CHARGE_STATUS, &regval);
	if (ret)
		return ret;

	val->intval = ltc4162l_charge_status_decode(regval);

	return 0;
}

static int ltc4162l_state_to_health(enum ltc4162l_state value)
{
	switch (value) {
	case ntc_pause:
		return POWER_SUPPLY_HEALTH_OVERHEAT;
	case timer_term:
		return POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
	case max_charge_time_fault:
		return POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE;
	case bat_missing_fault:
		return POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
	case bat_short_fault:
		return POWER_SUPPLY_HEALTH_DEAD;
	default:
		return POWER_SUPPLY_HEALTH_GOOD;
	}
}

static int ltc4162l_get_health(struct ltc4162l_info *info,
			       union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_CHARGER_STATE, &regval);
	if (ret)
		return ret;

	val->intval = ltc4162l_state_to_health(regval);

	return 0;
}

static int ltc4162l_get_online(struct ltc4162l_info *info,
			       union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_SYSTEM_STATUS_REG, &regval);
	if (ret)
		return ret;

	/* BIT(2) indicates if input voltage is sufficient to charge */
	val->intval = !!(regval & BIT(2));

	return 0;
}

static int ltc4162l_get_vbat(struct ltc4162l_info *info,
				  unsigned int reg,
				  union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, reg, &regval);
	if (ret)
		return ret;

	/* cell_count × 192.4μV/LSB */
	regval *= 1924;
	regval *= ltc4162l_get_cell_count(info);
	regval /= 10;
	val->intval = regval;

	return 0;
}

static int ltc4162l_get_ibat(struct ltc4162l_info *info,
			     union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_IBAT, &regval);
	if (ret)
		return ret;

	/* Signed 16-bit number, 1.466μV / RSNSB amperes/LSB. */
	ret = (s16)(regval & 0xFFFF);
	val->intval = 100 * mult_frac(ret, 14660, (int)info->rsnsb);

	return 0;
}


static int ltc4162l_get_input_voltage(struct ltc4162l_info *info,
				      union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_VIN, &regval);
	if (ret)
		return ret;

	/* 1.649mV/LSB */
	val->intval =  regval * 1694;

	return 0;
}

static int ltc4162l_get_input_current(struct ltc4162l_info *info,
				      union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_IIN, &regval);
	if (ret)
		return ret;

	/* Signed 16-bit number, 1.466μV / RSNSI amperes/LSB. */
	ret = (s16)(regval & 0xFFFF);
	ret *= 14660;
	ret /= info->rsnsi;
	ret *= 100;

	val->intval = ret;

	return 0;
}

static int ltc4162l_get_icharge(struct ltc4162l_info *info,
				unsigned int reg,
				union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, reg, &regval);
	if (ret)
		return ret;

	regval &= BIT(6) - 1; /* Only the lower 5 bits */

	/* The charge current servo level: (icharge_dac + 1) × 1mV/RSNSB */
	++regval;
	val->intval = 10000u * mult_frac(regval, 100000u, info->rsnsb);

	return 0;
}

static int ltc4162l_set_icharge(struct ltc4162l_info *info,
				unsigned int reg,
				unsigned int value)
{
	value = mult_frac(value, info->rsnsb, 100000u);
	value /= 10000u;

	/* Round to lowest possible */
	if (value)
		--value;

	if (value > 31)
		return -EINVAL;

	return regmap_write(info->regmap, reg, value);
}


static int ltc4162l_get_vcharge(struct ltc4162l_info *info,
				unsigned int reg,
				union power_supply_propval *val)
{
	unsigned int regval;
	int ret;
	u32 voltage;

	ret = regmap_read(info->regmap, reg, &regval);
	if (ret)
		return ret;

	regval &= BIT(6) - 1; /* Only the lower 5 bits */

	/*
	 * charge voltage setting can be computed from
	 * cell_count × (vcharge_setting × 12.5mV + 3.8125V)
	 * where vcharge_setting ranges from 0 to 31 (4.2V max).
	 */
	voltage = 3812500 + (regval * 12500);
	voltage *= ltc4162l_get_cell_count(info);
	val->intval = voltage;

	return 0;
}

static int ltc4162l_set_vcharge(struct ltc4162l_info *info,
				unsigned int reg,
				unsigned int value)
{
	u8 cell_count = ltc4162l_get_cell_count(info);

	if (!cell_count)
		return -EBUSY; /* Not available yet, try again later */

	value /= cell_count;

	if (value < 3812500)
		return -EINVAL;

	value -= 3812500;
	value /= 12500;

	if (value > 31)
		return -EINVAL;

	return regmap_write(info->regmap, reg, value);
}

static int ltc4162l_get_iin_limit_dac(struct ltc4162l_info *info,
				     union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_IIN_LIMIT_DAC, &regval);
	if (ret)
		return ret;

	regval &= BIT(6) - 1; /* Only 6 bits */

	/* (iin_limit_dac + 1) × 500μV / RSNSI */
	++regval;
	regval *= 5000000u;
	regval /= info->rsnsi;
	val->intval = 100u * regval;

	return 0;
}

static int ltc4162l_set_iin_limit(struct ltc4162l_info *info,
				  unsigned int value)
{
	unsigned int regval;

	regval = mult_frac(value, info->rsnsi, 50000u);
	regval /= 10000u;
	if (regval)
		--regval;
	if (regval > 63)
		regval = 63;

	return regmap_write(info->regmap, LTC4162L_IIN_LIMIT_TARGET, regval);
}

static int ltc4162l_get_die_temp(struct ltc4162l_info *info,
				 union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_DIE_TEMPERATURE, &regval);
	if (ret)
		return ret;

	/* die_temp × 0.0215°C/LSB - 264.4°C */
	ret = (s16)(regval & 0xFFFF);
	ret *= 215;
	ret /= 100; /* Centidegrees scale */
	ret -= 26440;
	val->intval = ret;

	return 0;
}

static int ltc4162l_get_term_current(struct ltc4162l_info *info,
				     union power_supply_propval *val)
{
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_CHARGER_CONFIG_BITS, &regval);
	if (ret)
		return ret;

	/* Check if C_OVER_X_THRESHOLD is enabled */
	if (!(regval & BIT(2))) {
		val->intval = 0;
		return 0;
	}

	ret = regmap_read(info->regmap, LTC4162L_C_OVER_X_THRESHOLD, &regval);
	if (ret)
		return ret;

	/* 1.466μV / RSNSB amperes/LSB */
	regval *= 14660u;
	regval /= info->rsnsb;
	val->intval = 100 * regval;

	return 0;
}

static int ltc4162l_set_term_current(struct ltc4162l_info *info,
				     unsigned int value)
{
	int ret;
	unsigned int regval;

	if (!value) {
		/* Disable en_c_over_x_term when set to zero */
		return regmap_update_bits(info->regmap,
					  LTC4162L_CHARGER_CONFIG_BITS,
					  BIT(2), 0);
	}

	regval = mult_frac(value, info->rsnsb, 14660u);
	regval /= 100u;

	ret =  regmap_write(info->regmap, LTC4162L_C_OVER_X_THRESHOLD, regval);
	if (ret)
		return ret;

	/* Set en_c_over_x_term after changing the threshold value */
	return regmap_update_bits(info->regmap, LTC4162L_CHARGER_CONFIG_BITS,
				  BIT(2), BIT(2));
}

/* Custom properties */
static const char * const ltc4162l_charge_status_name[] = {
	"ilim_reg_active", /* 32 */
	"thermal_reg_active",
	"vin_uvcl_active",
	"iin_limit_active",
	"constant_current",
	"constant_voltage",
	"charger_off" /* 0 */
};

static ssize_t charge_status_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	const char *result = ltc4162l_charge_status_name[
				ARRAY_SIZE(ltc4162l_charge_status_name) - 1];
	unsigned int regval;
	unsigned int mask;
	unsigned int index;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_CHARGE_STATUS, &regval);
	if (ret)
		return ret;

	/* Only one bit is set according to datasheet, let's be safe here */
	for (mask = 32, index = 0; mask != 0; mask >>= 1, ++index) {
		if (regval & mask) {
			result = ltc4162l_charge_status_name[index];
			break;
		}
	}

	return sprintf(buf, "%s\n", result);
}
static DEVICE_ATTR_RO(charge_status);

static ssize_t vbat_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	union power_supply_propval val;
	int ret;

	ret = ltc4162l_get_vbat(info, LTC4162L_VBAT, &val);
	if (ret)
		return ret;

	return sprintf(buf, "%d\n", val.intval);
}
static DEVICE_ATTR_RO(vbat);

static ssize_t vbat_avg_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	union power_supply_propval val;
	int ret;

	ret = ltc4162l_get_vbat(info, LTC4162L_VBAT_FILT, &val);
	if (ret)
		return ret;

	return sprintf(buf, "%d\n", val.intval);
}
static DEVICE_ATTR_RO(vbat_avg);

static ssize_t ibat_show(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	union power_supply_propval val;
	int ret;

	ret = ltc4162l_get_ibat(info, &val);
	if (ret)
		return ret;

	return sprintf(buf, "%d\n", val.intval);
}
static DEVICE_ATTR_RO(ibat);

static ssize_t force_telemetry_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_CONFIG_BITS_REG, &regval);
	if (ret)
		return ret;

	return sprintf(buf, "%u\n", regval & BIT(2) ? 1 : 0);
}

static ssize_t force_telemetry_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t count)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	int ret;
	unsigned int value;

	ret = kstrtouint(buf, 0, &value);
	if (ret < 0)
		return ret;

	ret = regmap_update_bits(info->regmap, LTC4162L_CONFIG_BITS_REG,
				 BIT(2), value ? BIT(2) : 0);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR_RW(force_telemetry);

static ssize_t arm_ship_mode_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	unsigned int regval;
	int ret;

	ret = regmap_read(info->regmap, LTC4162L_ARM_SHIP_MODE, &regval);
	if (ret)
		return ret;

	return sprintf(buf, "%u\n",
		regval == LTC4162L_ARM_SHIP_MODE_MAGIC ? 1 : 0);
}

static ssize_t arm_ship_mode_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t count)
{
	struct power_supply *psy = to_power_supply(dev);
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);
	int ret;
	unsigned int value;

	ret = kstrtouint(buf, 0, &value);
	if (ret < 0)
		return ret;

	ret = regmap_write(info->regmap, LTC4162L_ARM_SHIP_MODE,
				value ? LTC4162L_ARM_SHIP_MODE_MAGIC : 0);
	if (ret < 0)
		return ret;

	return count;
}

static DEVICE_ATTR_RW(arm_ship_mode);

static struct attribute *ltc4162l_sysfs_entries[] = {
	&dev_attr_charge_status.attr,
	&dev_attr_ibat.attr,
	&dev_attr_vbat.attr,
	&dev_attr_vbat_avg.attr,
	&dev_attr_force_telemetry.attr,
	&dev_attr_arm_ship_mode.attr,
	NULL,
};

static const struct attribute_group ltc4162l_attr_group = {
	.name	= NULL,	/* put in device directory */
	.attrs	= ltc4162l_sysfs_entries,
};

static const struct attribute_group *ltc4162l_attr_groups[] = {
	&ltc4162l_attr_group,
	NULL,
};

static int ltc4162l_get_property(struct power_supply *psy,
				 enum power_supply_property psp,
				 union power_supply_propval *val)
{
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);

	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
		return ltc4162l_get_status(info, val);
	case POWER_SUPPLY_PROP_CHARGE_TYPE:
		return ltc4162l_get_charge_type(info, val);
	case POWER_SUPPLY_PROP_HEALTH:
		return ltc4162l_get_health(info, val);
	case POWER_SUPPLY_PROP_ONLINE:
		return ltc4162l_get_online(info, val);
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		return ltc4162l_get_input_voltage(info, val);
	case POWER_SUPPLY_PROP_CURRENT_NOW:
		return ltc4162l_get_input_current(info, val);
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
		return ltc4162l_get_icharge(info,
				LTC4162L_ICHARGE_DAC, val);
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
		return ltc4162l_get_icharge(info,
				LTC4162L_CHARGE_CURRENT_SETTING, val);
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
		return ltc4162l_get_vcharge(info,
				LTC4162L_VCHARGE_DAC, val);
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
		return ltc4162l_get_vcharge(info,
				LTC4162L_VCHARGE_SETTING, val);
	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
		return ltc4162l_get_iin_limit_dac(info, val);
	case POWER_SUPPLY_PROP_TEMP:
		return ltc4162l_get_die_temp(info, val);
	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
		return ltc4162l_get_term_current(info, val);
	default:
		return -EINVAL;
	}
}

static int ltc4162l_set_property(struct power_supply *psy,
					 enum power_supply_property psp,
					 const union power_supply_propval *val)
{
	struct ltc4162l_info *info = power_supply_get_drvdata(psy);

	switch (psp) {
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
		return ltc4162l_set_icharge(info,
				LTC4162L_CHARGE_CURRENT_SETTING, val->intval);
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
		return ltc4162l_set_vcharge(info,
				LTC4162L_VCHARGE_SETTING, val->intval);
	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
		return ltc4162l_set_iin_limit(info, val->intval);
	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
		return ltc4162l_set_term_current(info, val->intval);
	default:
		return -EINVAL;
	}
}

static int ltc4162l_property_is_writeable(struct power_supply *psy,
						enum power_supply_property psp)
{
	switch (psp) {
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
		return 1;
	default:
		return 0;
	}
}

/* Charger power supply property routines */
static enum power_supply_property ltc4162l_properties[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_CHARGE_TYPE,
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_ONLINE,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
};

static const struct power_supply_desc ltc4162l_desc = {
	.name		= "ltc4162-l",
	.type		= POWER_SUPPLY_TYPE_MAINS,
	.properties	= ltc4162l_properties,
	.num_properties	= ARRAY_SIZE(ltc4162l_properties),
	.get_property	= ltc4162l_get_property,
	.set_property	= ltc4162l_set_property,
	.property_is_writeable = ltc4162l_property_is_writeable,
};

static bool ltc4162l_is_writeable_reg(struct device *dev, unsigned int reg)
{
	/* all registers up to this one are writeable */
	if (reg <= LTC4162L_CHARGER_CONFIG_BITS)
		return true;

	/* The ALERTS registers can be written to clear alerts */
	if (reg >= LTC4162L_LIMIT_ALERTS_REG &&
	    reg <= LTC4162L_CHARGE_STATUS_ALERTS_REG)
		return true;

	return false;
}

static bool ltc4162l_is_volatile_reg(struct device *dev, unsigned int reg)
{
	/* all registers after this one are read-only status registers */
	return reg > LTC4162L_CHARGER_CONFIG_BITS;
}

static const struct regmap_config ltc4162l_regmap_config = {
	.reg_bits	= 8,
	.val_bits	= 16,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
	.writeable_reg	= ltc4162l_is_writeable_reg,
	.volatile_reg	= ltc4162l_is_volatile_reg,
	.max_register	= LTC4162L_INPUT_UNDERVOLTAGE_DAC,
	.cache_type	= REGCACHE_RBTREE,
};

static void ltc4162l_clear_interrupts(struct ltc4162l_info *info)
{
	/* Acknowledge interrupt to chip by clearing all events */
	regmap_write(info->regmap, LTC4162L_LIMIT_ALERTS_REG, 0);
	regmap_write(info->regmap, LTC4162L_CHARGER_STATE_ALERTS_REG, 0);
	regmap_write(info->regmap, LTC4162L_CHARGE_STATUS_ALERTS_REG, 0);
}

static int ltc4162l_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct i2c_adapter *adapter = client->adapter;
	struct device *dev = &client->dev;
	struct ltc4162l_info *info;
	struct power_supply_config ltc4162l_config = {};
	u32 value;
	int ret;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) {
		dev_err(dev, "No support for SMBUS_WORD_DATA\n");
		return -ENODEV;
	}
	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	info->client = client;
	i2c_set_clientdata(client, info);

	info->regmap = devm_regmap_init_i2c(client, &ltc4162l_regmap_config);
	if (IS_ERR(info->regmap)) {
		dev_err(dev, "Failed to initialize register map\n");
		return PTR_ERR(info->regmap);
	}

	ret = device_property_read_u32(dev, "lltc,rsnsb-micro-ohms",
				       &info->rsnsb);
	if (ret) {
		dev_err(dev, "Missing lltc,rsnsb-micro-ohms property\n");
		return ret;
	}
	if (!info->rsnsb)
		return -EINVAL;

	ret = device_property_read_u32(dev, "lltc,rsnsi-micro-ohms",
				       &info->rsnsi);
	if (ret) {
		dev_err(dev, "Missing lltc,rsnsi-micro-ohms property\n");
		return ret;
	}
	if (!info->rsnsi)
		return -EINVAL;

	if (!device_property_read_u32(dev, "lltc,cell-count", &value))
		info->cell_count = value;

	ltc4162l_config.of_node = dev->of_node;
	ltc4162l_config.drv_data = info;
	ltc4162l_config.attr_grp = ltc4162l_attr_groups;

	info->charger = devm_power_supply_register(dev, &ltc4162l_desc,
						   &ltc4162l_config);
	if (IS_ERR(info->charger)) {
		dev_err(dev, "Failed to register charger\n");
		return PTR_ERR(info->charger);
	}

	/* Disable the threshold alerts, we're not using them */
	regmap_write(info->regmap, LTC4162L_EN_LIMIT_ALERTS_REG, 0);

	/* Enable interrupts on all status changes */
	regmap_write(info->regmap, LTC4162L_EN_CHARGER_STATE_ALERTS_REG,
		     0x1fff);
	regmap_write(info->regmap, LTC4162L_EN_CHARGE_STATUS_ALERTS_REG, 0x1f);

	ltc4162l_clear_interrupts(info);

	return 0;
}

static void ltc4162l_alert(struct i2c_client *client,
			   enum i2c_alert_protocol type, unsigned int flag)
{
	struct ltc4162l_info *info = i2c_get_clientdata(client);

	if (type != I2C_PROTOCOL_SMBUS_ALERT)
		return;

	ltc4162l_clear_interrupts(info);
	power_supply_changed(info->charger);
}

static const struct i2c_device_id ltc4162l_i2c_id_table[] = {
	{ "ltc4162-l", 0 },
	{ },
};
MODULE_DEVICE_TABLE(i2c, ltc4162l_i2c_id_table);

static const struct of_device_id ltc4162l_of_match[] = {
	{ .compatible = "lltc,ltc4162-l", },
	{ },
};
MODULE_DEVICE_TABLE(of, ltc4162l_of_match);

static struct i2c_driver ltc4162l_driver = {
	.probe		= ltc4162l_probe,
	.alert		= ltc4162l_alert,
	.id_table	= ltc4162l_i2c_id_table,
	.driver = {
		.name		= "ltc4162-l-charger",
		.of_match_table	= of_match_ptr(ltc4162l_of_match),
	},
};
module_i2c_driver(ltc4162l_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
MODULE_DESCRIPTION("LTC4162-L charger driver");