[v3] power/supply: Add ltc4162-l-charger

Commit Message

Mike Looijmans Nov. 2, 2020, 9:21 a.m. UTC

Add support for the LTC4162-L Li-Ion battery charger. The driver allows
reading back telemetry and to set some charging options like the input
current limit.

Signed-off-by: Mike Looijmans <[e-mail]>
---
v2: Use microohm units instead of milliohm
    Add interrupt support using smbalert
    Support obtaining cell-count from devicetree
v3: Fix overflows in calculations involving resistor values
resent, mail bounced

 drivers/power/supply/Kconfig             |   8 +
 drivers/power/supply/Makefile            |   1 +
 drivers/power/supply/ltc4162-l-charger.c | 898 +++++++++++++++++++++++
 3 files changed, 907 insertions(+)
 create mode 100644 drivers/power/supply/ltc4162-l-charger.c

Comments

Mike Looijmans Dec. 3, 2020, 4:01 p.m. UTC | #1

Gentle ping, haven't seen any response...


Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: [phone]
E: [e-mail]
W: www.topicproducts.com

Please consider the environment before printing this e-mail
On 02-11-2020 10:21, Mike Looijmans wrote:
> Add support for the LTC4162-L Li-Ion battery charger. The driver allows
> reading back telemetry and to set some charging options like the input
> current limit.
>
> Signed-off-by: Mike Looijmans <[e-mail]>
> ---
> v2: Use microohm units instead of milliohm
>      Add interrupt support using smbalert
>      Support obtaining cell-count from devicetree
> v3: Fix overflows in calculations involving resistor values
> resent, mail bounced
>
>   drivers/power/supply/Kconfig             |   8 +
>   drivers/power/supply/Makefile            |   1 +
>   drivers/power/supply/ltc4162-l-charger.c | 898 +++++++++++++++++++++++
>   3 files changed, 907 insertions(+)
>   create mode 100644 drivers/power/supply/ltc4162-l-charger.c
>
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index eec646c568b7..23000976cb42 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -513,6 +513,14 @@ config CHARGER_LT3651
>   	  Say Y to include support for the Analog Devices (Linear Technology)
>   	  LT3651 battery charger which reports its status via GPIO lines.
>   
> +config CHARGER_LTC4162L
> +	tristate "LTC4162-L charger"
> +	depends on I2C
> +	select REGMAP_I2C
> +	help
> +	  Say Y to include support for the Analog Devices (Linear Technology)
> +	  LTC4162-L battery charger connected to I2C.
> +
>   config CHARGER_MAX14577
>   	tristate "Maxim MAX14577/77836 battery charger driver"
>   	depends on MFD_MAX14577
> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
> index dd4b86318cd9..17b1cf921c44 100644
> --- a/drivers/power/supply/Makefile
> +++ b/drivers/power/supply/Makefile
> @@ -70,6 +70,7 @@ obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
>   obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
>   obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
>   obj-$(CONFIG_CHARGER_LT3651)	+= lt3651-charger.o
> +obj-$(CONFIG_CHARGER_LTC4162L)	+= ltc4162-l-charger.o
>   obj-$(CONFIG_CHARGER_MAX14577)	+= max14577_charger.o
>   obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
>   obj-$(CONFIG_CHARGER_MAX77650)	+= max77650-charger.o
> diff --git a/drivers/power/supply/ltc4162-l-charger.c b/drivers/power/supply/ltc4162-l-charger.c
> new file mode 100644
> index 000000000000..b2f666113125
> --- /dev/null
> +++ b/drivers/power/supply/ltc4162-l-charger.c
> @@ -0,0 +1,898 @@
> +// 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_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 input_voltage_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_VIN, &regval);
> +	if (ret)
> +		return ret;
> +
> +	/* 1.649mV/LSB */
> +	regval *= 1694;
> +
> +	return sprintf(buf, "%u\n", regval);
> +}
> +static DEVICE_ATTR_RO(input_voltage);
> +
> +static ssize_t input_current_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_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;
> +
> +	return sprintf(buf, "%d\n", ret);
> +}
> +static DEVICE_ATTR_RO(input_current);
> +
> +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_input_voltage.attr,
> +	&dev_attr_input_current.attr,
> +	&dev_attr_force_telemetry.attr,
> +	&dev_attr_arm_ship_mode.attr,
> +	NULL,
> +};
> +
> +static struct attribute_group ltc4162l_attr_group = {
> +	.name	= NULL,	/* put in device directory */
> +	.attrs	= ltc4162l_sysfs_entries,
> +};
> +
> +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_vbat(info, LTC4162L_VBAT, val);
> +	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
> +		return ltc4162l_get_vbat(info, LTC4162L_VBAT_FILT, val);
> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +		return ltc4162l_get_ibat(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, /* Reports battery voltage */
> +	POWER_SUPPLY_PROP_VOLTAGE_AVG,
> +	POWER_SUPPLY_PROP_CURRENT_NOW, /* Reports battery current */
> +	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;
> +
> +	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);
> +	}
> +
> +	ret = sysfs_create_group(&info->charger->dev.kobj,
> +				 &ltc4162l_attr_group);
> +	if (ret)
> +		dev_err(dev, "failed to create extra sysfs entries\n");
> +
> +	/* 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 int ltc4162l_remove(struct i2c_client *client)
> +{
> +	struct ltc4162l_info *info = i2c_get_clientdata(client);
> +
> +	sysfs_remove_group(&info->charger->dev.kobj, &ltc4162l_attr_group);
> +
> +	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,
> +	.remove		= ltc4162l_remove,
> +	.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 <[e-mail]>");
> +MODULE_DESCRIPTION("LTC4162-L charger driver");

Sebastian Reichel Dec. 29, 2020, 2:57 p.m. UTC | #2

Hi,

Sorry for slow processing of this. Driver looks mostly fine, but I
do have some comments.

On Mon, Nov 02, 2020 at 10:21:31AM +0100, Mike Looijmans wrote:
> Add support for the LTC4162-L Li-Ion battery charger. The driver allows
> reading back telemetry and to set some charging options like the input
> current limit.
> 
> Signed-off-by: Mike Looijmans <[e-mail]>
> ---
> v2: Use microohm units instead of milliohm
>     Add interrupt support using smbalert
>     Support obtaining cell-count from devicetree
> v3: Fix overflows in calculations involving resistor values
> resent, mail bounced
> 
>  drivers/power/supply/Kconfig             |   8 +
>  drivers/power/supply/Makefile            |   1 +
>  drivers/power/supply/ltc4162-l-charger.c | 898 +++++++++++++++++++++++
>  3 files changed, 907 insertions(+)
>  create mode 100644 drivers/power/supply/ltc4162-l-charger.c
> 
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index eec646c568b7..23000976cb42 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -513,6 +513,14 @@ config CHARGER_LT3651
>  	  Say Y to include support for the Analog Devices (Linear Technology)
>  	  LT3651 battery charger which reports its status via GPIO lines.
>  
> +config CHARGER_LTC4162L
> +	tristate "LTC4162-L charger"
> +	depends on I2C
> +	select REGMAP_I2C
> +	help
> +	  Say Y to include support for the Analog Devices (Linear Technology)
> +	  LTC4162-L battery charger connected to I2C.
> +
>  config CHARGER_MAX14577
>  	tristate "Maxim MAX14577/77836 battery charger driver"
>  	depends on MFD_MAX14577
> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
> index dd4b86318cd9..17b1cf921c44 100644
> --- a/drivers/power/supply/Makefile
> +++ b/drivers/power/supply/Makefile
> @@ -70,6 +70,7 @@ obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
>  obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
>  obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
>  obj-$(CONFIG_CHARGER_LT3651)	+= lt3651-charger.o
> +obj-$(CONFIG_CHARGER_LTC4162L)	+= ltc4162-l-charger.o
>  obj-$(CONFIG_CHARGER_MAX14577)	+= max14577_charger.o
>  obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
>  obj-$(CONFIG_CHARGER_MAX77650)	+= max77650-charger.o
> diff --git a/drivers/power/supply/ltc4162-l-charger.c b/drivers/power/supply/ltc4162-l-charger.c
> new file mode 100644
> index 000000000000..b2f666113125
> --- /dev/null
> +++ b/drivers/power/supply/ltc4162-l-charger.c
> @@ -0,0 +1,898 @@
> +// 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
> +};

+use BIT(0), BIT(1), ...

> +/* 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_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 input_voltage_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_VIN, &regval);
> +	if (ret)
> +		return ret;
> +
> +	/* 1.649mV/LSB */
> +	regval *= 1694;
> +
> +	return sprintf(buf, "%u\n", regval);
> +}
> +static DEVICE_ATTR_RO(input_voltage);
> +
> +static ssize_t input_current_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_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;
> +
> +	return sprintf(buf, "%d\n", ret);
> +}
> +static DEVICE_ATTR_RO(input_current);
> +
> +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_input_voltage.attr,
> +	&dev_attr_input_current.attr,
> +	&dev_attr_force_telemetry.attr,
> +	&dev_attr_arm_ship_mode.attr,
> +	NULL,
> +};
> +
> +static struct attribute_group ltc4162l_attr_group = {
> +	.name	= NULL,	/* put in device directory */
> +	.attrs	= ltc4162l_sysfs_entries,
> +};
> +
> +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_vbat(info, LTC4162L_VBAT, val);
> +	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
> +		return ltc4162l_get_vbat(info, LTC4162L_VBAT_FILT, val);
> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +		return ltc4162l_get_ibat(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, /* Reports battery voltage */
> +	POWER_SUPPLY_PROP_VOLTAGE_AVG,
> +	POWER_SUPPLY_PROP_CURRENT_NOW, /* Reports battery current */

above 3 properties should describe input voltage/current for chargers,
see Documentation/ABI/testing/sysfs-class-power

Battery IBAT and VBAT can currently only be reported from
POWER_SUPPLY_TYPE_BATTERY.

> +	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;
> +
> +	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);
> +	}
> +
> +	ret = sysfs_create_group(&info->charger->dev.kobj,
> +				 &ltc4162l_attr_group);
> +	if (ret)
> +		dev_err(dev, "failed to create extra sysfs entries\n");

please use '.attr_grp' in ltc4162l_config, which means the
attributes are registered together with the power-supply
device avoiding a udev race condition. The change also
simplifies the driver code, since (de)registration happens
automatically :)

> +	/* 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 int ltc4162l_remove(struct i2c_client *client)
> +{
> +	struct ltc4162l_info *info = i2c_get_clientdata(client);
> +
> +	sysfs_remove_group(&info->charger->dev.kobj, &ltc4162l_attr_group);
> +
> +	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,
> +	.remove		= ltc4162l_remove,
> +	.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 <[e-mail]>");
> +MODULE_DESCRIPTION("LTC4162-L charger driver");

Otherwise LGTM. Please send bindings and driver as a series next
time :)

Thanks,

-- Sebastian

Mike Looijmans Jan. 4, 2021, 10:39 a.m. UTC | #3

Hello,

No worries on processing time. Only drawback is that since the project 
ended, I may no longer have access to the actual hardware for testing.

Further inline comments below.


Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: [phone]
E: [e-mail]
W: www.topicproducts.com

Please consider the environment before printing this e-mail
On 29-12-2020 15:57, Sebastian Reichel wrote:
> Hi,
>
> Sorry for slow processing of this. Driver looks mostly fine, but I
> do have some comments.
>
> On Mon, Nov 02, 2020 at 10:21:31AM +0100, Mike Looijmans wrote:
>> Add support for the LTC4162-L Li-Ion battery charger. The driver allows
>> reading back telemetry and to set some charging options like the input
>> current limit.
>>
>> Signed-off-by: Mike Looijmans <[e-mail]>
>> ---
>> v2: Use microohm units instead of milliohm
>>      Add interrupt support using smbalert
>>      Support obtaining cell-count from devicetree
>> v3: Fix overflows in calculations involving resistor values
>> resent, mail bounced
>>
>>   drivers/power/supply/Kconfig             |   8 +
>>   drivers/power/supply/Makefile            |   1 +
>>   drivers/power/supply/ltc4162-l-charger.c | 898 +++++++++++++++++++++++
>>   3 files changed, 907 insertions(+)
>>   create mode 100644 drivers/power/supply/ltc4162-l-charger.c
>>
>> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
>> index eec646c568b7..23000976cb42 100644
>> --- a/drivers/power/supply/Kconfig
>> +++ b/drivers/power/supply/Kconfig
>> @@ -513,6 +513,14 @@ config CHARGER_LT3651
>>   	  Say Y to include support for the Analog Devices (Linear Technology)
>>   	  LT3651 battery charger which reports its status via GPIO lines.
>>   
>> +config CHARGER_LTC4162L
>> +	tristate "LTC4162-L charger"
>> +	depends on I2C
>> +	select REGMAP_I2C
>> +	help
>> +	  Say Y to include support for the Analog Devices (Linear Technology)
>> +	  LTC4162-L battery charger connected to I2C.
>> +
>>   config CHARGER_MAX14577
>>   	tristate "Maxim MAX14577/77836 battery charger driver"
>>   	depends on MFD_MAX14577
>> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
>> index dd4b86318cd9..17b1cf921c44 100644
>> --- a/drivers/power/supply/Makefile
>> +++ b/drivers/power/supply/Makefile
>> @@ -70,6 +70,7 @@ obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
>>   obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
>>   obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
>>   obj-$(CONFIG_CHARGER_LT3651)	+= lt3651-charger.o
>> +obj-$(CONFIG_CHARGER_LTC4162L)	+= ltc4162-l-charger.o
>>   obj-$(CONFIG_CHARGER_MAX14577)	+= max14577_charger.o
>>   obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
>>   obj-$(CONFIG_CHARGER_MAX77650)	+= max77650-charger.o
>> diff --git a/drivers/power/supply/ltc4162-l-charger.c b/drivers/power/supply/ltc4162-l-charger.c
>> new file mode 100644
>> index 000000000000..b2f666113125
>> --- /dev/null
>> +++ b/drivers/power/supply/ltc4162-l-charger.c
>> @@ -0,0 +1,898 @@
>> +// 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
>> +};
> +use BIT(0), BIT(1), ...

I'm okay with that. This was actually a copy&paste job from the 
datasheet, and though these look like bit fields, only one bit is ever 
set. So BIT(x) might be misleading in that respect. Hence I preferred 
keeping it as the datasheet listed it.

>
>> +/* 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_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 input_voltage_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_VIN, &regval);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* 1.649mV/LSB */
>> +	regval *= 1694;
>> +
>> +	return sprintf(buf, "%u\n", regval);
>> +}
>> +static DEVICE_ATTR_RO(input_voltage);
>> +
>> +static ssize_t input_current_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_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;
>> +
>> +	return sprintf(buf, "%d\n", ret);
>> +}
>> +static DEVICE_ATTR_RO(input_current);
>> +
>> +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_input_voltage.attr,
>> +	&dev_attr_input_current.attr,
>> +	&dev_attr_force_telemetry.attr,
>> +	&dev_attr_arm_ship_mode.attr,
>> +	NULL,
>> +};
>> +
>> +static struct attribute_group ltc4162l_attr_group = {
>> +	.name	= NULL,	/* put in device directory */
>> +	.attrs	= ltc4162l_sysfs_entries,
>> +};
>> +
>> +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_vbat(info, LTC4162L_VBAT, val);
>> +	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
>> +		return ltc4162l_get_vbat(info, LTC4162L_VBAT_FILT, val);
>> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
>> +		return ltc4162l_get_ibat(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, /* Reports battery voltage */
>> +	POWER_SUPPLY_PROP_VOLTAGE_AVG,
>> +	POWER_SUPPLY_PROP_CURRENT_NOW, /* Reports battery current */
> above 3 properties should describe input voltage/current for chargers,
> see Documentation/ABI/testing/sysfs-class-power
>
> Battery IBAT and VBAT can currently only be reported from
> POWER_SUPPLY_TYPE_BATTERY.

So what should I do? Change the reported type to battery? Or make ibat 
ad vbat into custom properties and report input current/voltage here 
instead?

>
>> +	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;
>> +
>> +	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);
>> +	}
>> +
>> +	ret = sysfs_create_group(&info->charger->dev.kobj,
>> +				 &ltc4162l_attr_group);
>> +	if (ret)
>> +		dev_err(dev, "failed to create extra sysfs entries\n");
> please use '.attr_grp' in ltc4162l_config, which means the
> attributes are registered together with the power-supply
> device avoiding a udev race condition. The change also
> simplifies the driver code, since (de)registration happens
> automatically :)

Good tip, missed that.


>
>> +	/* 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 int ltc4162l_remove(struct i2c_client *client)
>> +{
>> +	struct ltc4162l_info *info = i2c_get_clientdata(client);
>> +
>> +	sysfs_remove_group(&info->charger->dev.kobj, &ltc4162l_attr_group);
>> +
>> +	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,
>> +	.remove		= ltc4162l_remove,
>> +	.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 <[e-mail]>");
>> +MODULE_DESCRIPTION("LTC4162-L charger driver");
> Otherwise LGTM. Please send bindings and driver as a series next
> time :)
>
> Thanks,
>
> -- Sebastian

Patch

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index eec646c568b7..23000976cb42 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -513,6 +513,14 @@  config CHARGER_LT3651
 	  Say Y to include support for the Analog Devices (Linear Technology)
 	  LT3651 battery charger which reports its status via GPIO lines.
 
+config CHARGER_LTC4162L
+	tristate "LTC4162-L charger"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Say Y to include support for the Analog Devices (Linear Technology)
+	  LTC4162-L battery charger connected to I2C.
+
 config CHARGER_MAX14577
 	tristate "Maxim MAX14577/77836 battery charger driver"
 	depends on MFD_MAX14577
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index dd4b86318cd9..17b1cf921c44 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -70,6 +70,7 @@  obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
 obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
 obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
 obj-$(CONFIG_CHARGER_LT3651)	+= lt3651-charger.o
+obj-$(CONFIG_CHARGER_LTC4162L)	+= ltc4162-l-charger.o
 obj-$(CONFIG_CHARGER_MAX14577)	+= max14577_charger.o
 obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
 obj-$(CONFIG_CHARGER_MAX77650)	+= max77650-charger.o
diff --git a/drivers/power/supply/ltc4162-l-charger.c b/drivers/power/supply/ltc4162-l-charger.c
new file mode 100644
index 000000000000..b2f666113125
--- /dev/null
+++ b/drivers/power/supply/ltc4162-l-charger.c
@@ -0,0 +1,898 @@ 
+// 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_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 input_voltage_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_VIN, &regval);
+	if (ret)
+		return ret;
+
+	/* 1.649mV/LSB */
+	regval *= 1694;
+
+	return sprintf(buf, "%u\n", regval);
+}
+static DEVICE_ATTR_RO(input_voltage);
+
+static ssize_t input_current_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_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;
+
+	return sprintf(buf, "%d\n", ret);
+}
+static DEVICE_ATTR_RO(input_current);
+
+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_input_voltage.attr,
+	&dev_attr_input_current.attr,
+	&dev_attr_force_telemetry.attr,
+	&dev_attr_arm_ship_mode.attr,
+	NULL,
+};
+
+static struct attribute_group ltc4162l_attr_group = {
+	.name	= NULL,	/* put in device directory */
+	.attrs	= ltc4162l_sysfs_entries,
+};
+
+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_vbat(info, LTC4162L_VBAT, val);
+	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+		return ltc4162l_get_vbat(info, LTC4162L_VBAT_FILT, val);
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		return ltc4162l_get_ibat(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, /* Reports battery voltage */
+	POWER_SUPPLY_PROP_VOLTAGE_AVG,
+	POWER_SUPPLY_PROP_CURRENT_NOW, /* Reports battery current */
+	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;
+
+	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);
+	}
+
+	ret = sysfs_create_group(&info->charger->dev.kobj,
+				 &ltc4162l_attr_group);
+	if (ret)
+		dev_err(dev, "failed to create extra sysfs entries\n");
+
+	/* 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 int ltc4162l_remove(struct i2c_client *client)
+{
+	struct ltc4162l_info *info = i2c_get_clientdata(client);
+
+	sysfs_remove_group(&info->charger->dev.kobj, &ltc4162l_attr_group);
+
+	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,
+	.remove		= ltc4162l_remove,
+	.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 <[e-mail]>");
+MODULE_DESCRIPTION("LTC4162-L charger driver");