drivers/power/supply/max1720x_battery.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Fuel gauge driver for Maxim 17201/17205
  *
  * based on max1721x_battery.c
  *
  * Copyright (C) 2024 Liebherr-Electronics and Drives GmbH
  */

 #include <linux/bitfield.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/power_supply.h>
 #include <linux/regmap.h>

 #include <asm/unaligned.h>

 /* Nonvolatile registers */
 #define MAX1720X_NRSENSE		0xCF	/* RSense in 10^-5 Ohm */

 /* ModelGauge m5 */
 #define MAX172XX_STATUS			0x00	/* Status */
 #define MAX172XX_STATUS_BAT_ABSENT	BIT(3)	/* Battery absent */
 #define MAX172XX_REPCAP			0x05	/* Average capacity */
 #define MAX172XX_REPSOC			0x06	/* Percentage of charge */
 #define MAX172XX_TEMP			0x08	/* Temperature */
 #define MAX172XX_CURRENT		0x0A	/* Actual current */
 #define MAX172XX_AVG_CURRENT		0x0B	/* Average current */
 #define MAX172XX_TTE			0x11	/* Time to empty */
 #define MAX172XX_AVG_TA			0x16	/* Average temperature */
 #define MAX172XX_CYCLES			0x17
 #define MAX172XX_DESIGN_CAP		0x18	/* Design capacity */
 #define MAX172XX_AVG_VCELL		0x19
 #define MAX172XX_TTF			0x20	/* Time to full */
 #define MAX172XX_DEV_NAME		0x21	/* Device name */
 #define MAX172XX_DEV_NAME_TYPE_MASK	GENMASK(3, 0)
 #define MAX172XX_DEV_NAME_TYPE_MAX17201	BIT(0)
 #define MAX172XX_DEV_NAME_TYPE_MAX17205	(BIT(0) | BIT(2))
 #define MAX172XX_QR_TABLE10		0x22
 #define MAX172XX_BATT			0xDA	/* Battery voltage */
 #define MAX172XX_ATAVCAP		0xDF

 static const char *const max1720x_manufacturer = "Maxim Integrated";
 static const char *const max17201_model = "MAX17201";
 static const char *const max17205_model = "MAX17205";

 struct max1720x_device_info {
 	struct regmap *regmap;
 	int rsense;
 };

 /*
  * Model Gauge M5 Algorithm output register
  * Volatile data (must not be cached)
  */
 static const struct regmap_range max1720x_volatile_allow[] = {
 	regmap_reg_range(MAX172XX_STATUS, MAX172XX_CYCLES),
 	regmap_reg_range(MAX172XX_AVG_VCELL, MAX172XX_TTF),
 	regmap_reg_range(MAX172XX_QR_TABLE10, MAX172XX_ATAVCAP),
 };

 static const struct regmap_range max1720x_readable_allow[] = {
 	regmap_reg_range(MAX172XX_STATUS, MAX172XX_ATAVCAP),
 };

 static const struct regmap_range max1720x_readable_deny[] = {
 	/* unused registers */
 	regmap_reg_range(0x24, 0x26),
 	regmap_reg_range(0x30, 0x31),
 	regmap_reg_range(0x33, 0x34),
 	regmap_reg_range(0x37, 0x37),
 	regmap_reg_range(0x3B, 0x3C),
 	regmap_reg_range(0x40, 0x41),
 	regmap_reg_range(0x43, 0x44),
 	regmap_reg_range(0x47, 0x49),
 	regmap_reg_range(0x4B, 0x4C),
 	regmap_reg_range(0x4E, 0xAF),
 	regmap_reg_range(0xB1, 0xB3),
 	regmap_reg_range(0xB5, 0xB7),
 	regmap_reg_range(0xBF, 0xD0),
 	regmap_reg_range(0xDB, 0xDB),
 	regmap_reg_range(0xE0, 0xFF),
 };

 static const struct regmap_access_table max1720x_readable_regs = {
 	.yes_ranges	= max1720x_readable_allow,
 	.n_yes_ranges	= ARRAY_SIZE(max1720x_readable_allow),
 	.no_ranges	= max1720x_readable_deny,
 	.n_no_ranges	= ARRAY_SIZE(max1720x_readable_deny),
 };

 static const struct regmap_access_table max1720x_volatile_regs = {
 	.yes_ranges	= max1720x_volatile_allow,
 	.n_yes_ranges	= ARRAY_SIZE(max1720x_volatile_allow),
 	.no_ranges	= max1720x_readable_deny,
 	.n_no_ranges	= ARRAY_SIZE(max1720x_readable_deny),
 };

 static const struct regmap_config max1720x_regmap_cfg = {
 	.reg_bits = 8,
 	.val_bits = 16,
 	.max_register = MAX172XX_ATAVCAP,
 	.val_format_endian = REGMAP_ENDIAN_LITTLE,
 	.rd_table = &max1720x_readable_regs,
 	.volatile_table = &max1720x_volatile_regs,
 	.cache_type = REGCACHE_RBTREE,
 };

 static const enum power_supply_property max1720x_battery_props[] = {
 	POWER_SUPPLY_PROP_PRESENT,
 	POWER_SUPPLY_PROP_CAPACITY,
 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 	POWER_SUPPLY_PROP_CHARGE_AVG,
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
 	POWER_SUPPLY_PROP_TEMP,
 	POWER_SUPPLY_PROP_CURRENT_NOW,
 	POWER_SUPPLY_PROP_CURRENT_AVG,
 	POWER_SUPPLY_PROP_MODEL_NAME,
 	POWER_SUPPLY_PROP_MANUFACTURER,
 };

 /* Convert regs value to power_supply units */

 static int max172xx_time_to_ps(unsigned int reg)
 {
 	return reg * 5625 / 1000;	/* in sec. */
 }

 static int max172xx_percent_to_ps(unsigned int reg)
 {
 	return reg / 256;	/* in percent from 0 to 100 */
 }

 static int max172xx_voltage_to_ps(unsigned int reg)
 {
 	return reg * 1250;	/* in uV */
 }

 static int max172xx_capacity_to_ps(unsigned int reg)
 {
 	return reg * 500;	/* in uAh */
 }

 /*
  * Current and temperature is signed values, so unsigned regs
  * value must be converted to signed type
  */

 static int max172xx_temperature_to_ps(unsigned int reg)
 {
 	int val = (int16_t)reg;

 	return val * 10 / 256; /* in tenths of deg. C */
 }

 /*
  * Calculating current registers resolution:
  *
  * RSense stored in 10^-5 Ohm, so mesaurment voltage must be
  * in 10^-11 Volts for get current in uA.
  * 16 bit current reg fullscale +/-51.2mV is 102400 uV.
  * So: 102400 / 65535 * 10^5 = 156252
  */
 static int max172xx_current_to_voltage(unsigned int reg)
 {
 	int val = (int16_t)reg;

 	return val * 156252;
 }

 static int max1720x_battery_get_property(struct power_supply *psy,
 					 enum power_supply_property psp,
 					 union power_supply_propval *val)
 {
 	struct max1720x_device_info *info = power_supply_get_drvdata(psy);
 	unsigned int reg_val;
 	int ret = 0;

 	switch (psp) {
 	case POWER_SUPPLY_PROP_PRESENT:
 		/*
 		 * POWER_SUPPLY_PROP_PRESENT will always readable via
 		 * sysfs interface. Value return 0 if battery not
 		 * present or unaccesable via I2c.
 		 */
 		ret = regmap_read(info->regmap, MAX172XX_STATUS, &reg_val);
 		if (ret < 0) {
 			val->intval = 0;
 			return 0;
 		}

 		val->intval = !FIELD_GET(MAX172XX_STATUS_BAT_ABSENT, reg_val);
 		break;
 	case POWER_SUPPLY_PROP_CAPACITY:
 		ret = regmap_read(info->regmap, MAX172XX_REPSOC, &reg_val);
 		val->intval = max172xx_percent_to_ps(reg_val);
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 		ret = regmap_read(info->regmap, MAX172XX_BATT, &reg_val);
 		val->intval = max172xx_voltage_to_ps(reg_val);
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 		ret = regmap_read(info->regmap, MAX172XX_DESIGN_CAP, &reg_val);
 		val->intval = max172xx_capacity_to_ps(reg_val);
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_AVG:
 		ret = regmap_read(info->regmap, MAX172XX_REPCAP, &reg_val);
 		val->intval = max172xx_capacity_to_ps(reg_val);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
 		ret = regmap_read(info->regmap, MAX172XX_TTE, &reg_val);
 		val->intval = max172xx_time_to_ps(reg_val);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
 		ret = regmap_read(info->regmap, MAX172XX_TTF, &reg_val);
 		val->intval = max172xx_time_to_ps(reg_val);
 		break;
 	case POWER_SUPPLY_PROP_TEMP:
 		ret = regmap_read(info->regmap, MAX172XX_TEMP, &reg_val);
 		val->intval = max172xx_temperature_to_ps(reg_val);
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
 		ret = regmap_read(info->regmap, MAX172XX_CURRENT, &reg_val);
 		val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_AVG:
 		ret = regmap_read(info->regmap, MAX172XX_AVG_CURRENT, &reg_val);
 		val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
 		break;
 	case POWER_SUPPLY_PROP_MODEL_NAME:
 		ret = regmap_read(info->regmap, MAX172XX_DEV_NAME, &reg_val);
 		reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
 		if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
 			val->strval = max17201_model;
 		else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
 			val->strval = max17205_model;
 		else
 			return -ENODEV;
 		break;
 	case POWER_SUPPLY_PROP_MANUFACTURER:
 		val->strval = max1720x_manufacturer;
 		break;
 	default:
 		return -EINVAL;
 	}

 	return ret;
 }

 static int max1720x_probe_sense_resistor(struct i2c_client *client,
 					 struct max1720x_device_info *info)
 {
 	struct device *dev = &client->dev;
 	struct i2c_client *ancillary;
 	int ret;

 	ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
 	if (IS_ERR(ancillary)) {
 		dev_err(dev, "Failed to initialize ancillary i2c device\n");
 		return PTR_ERR(ancillary);
 	}

 	ret = i2c_smbus_read_word_data(ancillary, MAX1720X_NRSENSE);
 	i2c_unregister_device(ancillary);
 	if (ret < 0)
 		return ret;

 	info->rsense = ret;
 	if (!info->rsense) {
 		dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
 		info->rsense = 1000; /* in regs in 10^-5 */
 	}

 	return 0;
 }

 static const struct power_supply_desc max1720x_bat_desc = {
 	.name = "max1720x",
 	.no_thermal = true,
 	.type = POWER_SUPPLY_TYPE_BATTERY,
 	.properties = max1720x_battery_props,
 	.num_properties = ARRAY_SIZE(max1720x_battery_props),
 	.get_property = max1720x_battery_get_property,
 };

 static int max1720x_probe(struct i2c_client *client)
 {
 	struct power_supply_config psy_cfg = {};
 	struct device *dev = &client->dev;
 	struct max1720x_device_info *info;
 	struct power_supply *bat;
 	int ret;

 	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;

 	psy_cfg.drv_data = info;
 	psy_cfg.fwnode = dev_fwnode(dev);
 	info->regmap = devm_regmap_init_i2c(client, &max1720x_regmap_cfg);
 	if (IS_ERR(info->regmap))
 		return dev_err_probe(dev, PTR_ERR(info->regmap),
 				     "regmap initialization failed\n");

 	ret = max1720x_probe_sense_resistor(client, info);
 	if (ret)
 		return dev_err_probe(dev, ret,
 				     "Failed to read sense resistor value\n");

 	bat = devm_power_supply_register(dev, &max1720x_bat_desc, &psy_cfg);
 	if (IS_ERR(bat))
 		return dev_err_probe(dev, PTR_ERR(bat),
 				     "Failed to register power supply\n");

 	return 0;
 }

 static const struct of_device_id max1720x_of_match[] = {
 	{ .compatible = "maxim,max17201" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, max1720x_of_match);

 static struct i2c_driver max1720x_i2c_driver = {
 	.driver = {
 		.name = "max1720x",
 		.of_match_table = max1720x_of_match,
 	},
 	.probe = max1720x_probe,
 };
 module_i2c_driver(max1720x_i2c_driver);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Dimitri Fedrau <dima.fedrau@gmail.com>");
 MODULE_DESCRIPTION("Maxim MAX17201/MAX17205 Fuel Gauge IC driver");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Fuel gauge driver for Maxim 17201/17205
	*
	* based on max1721x_battery.c
	*
	* Copyright (C) 2024 Liebherr-Electronics and Drives GmbH
	*/

	#include <linux/bitfield.h>
	#include <linux/i2c.h>
	#include <linux/module.h>
	#include <linux/power_supply.h>
	#include <linux/regmap.h>

	#include <asm/unaligned.h>

	/* Nonvolatile registers */
	#define MAX1720X_NRSENSE 0xCF /* RSense in 10^-5 Ohm */

	/* ModelGauge m5 */
	#define MAX172XX_STATUS 0x00 /* Status */
	#define MAX172XX_STATUS_BAT_ABSENT BIT(3) /* Battery absent */
	#define MAX172XX_REPCAP 0x05 /* Average capacity */
	#define MAX172XX_REPSOC 0x06 /* Percentage of charge */
	#define MAX172XX_TEMP 0x08 /* Temperature */
	#define MAX172XX_CURRENT 0x0A /* Actual current */
	#define MAX172XX_AVG_CURRENT 0x0B /* Average current */
	#define MAX172XX_TTE 0x11 /* Time to empty */
	#define MAX172XX_AVG_TA 0x16 /* Average temperature */
	#define MAX172XX_CYCLES 0x17
	#define MAX172XX_DESIGN_CAP 0x18 /* Design capacity */
	#define MAX172XX_AVG_VCELL 0x19
	#define MAX172XX_TTF 0x20 /* Time to full */
	#define MAX172XX_DEV_NAME 0x21 /* Device name */
	#define MAX172XX_DEV_NAME_TYPE_MASK GENMASK(3, 0)
	#define MAX172XX_DEV_NAME_TYPE_MAX17201 BIT(0)
	#define MAX172XX_DEV_NAME_TYPE_MAX17205 (BIT(0) \| BIT(2))
	#define MAX172XX_QR_TABLE10 0x22
	#define MAX172XX_BATT 0xDA /* Battery voltage */
	#define MAX172XX_ATAVCAP 0xDF

	static const char *const max1720x_manufacturer = "Maxim Integrated";
	static const char *const max17201_model = "MAX17201";
	static const char *const max17205_model = "MAX17205";

	struct max1720x_device_info {
	struct regmap *regmap;
	int rsense;
	};

	/*
	* Model Gauge M5 Algorithm output register
	* Volatile data (must not be cached)
	*/
	static const struct regmap_range max1720x_volatile_allow[] = {
	regmap_reg_range(MAX172XX_STATUS, MAX172XX_CYCLES),
	regmap_reg_range(MAX172XX_AVG_VCELL, MAX172XX_TTF),
	regmap_reg_range(MAX172XX_QR_TABLE10, MAX172XX_ATAVCAP),
	};

	static const struct regmap_range max1720x_readable_allow[] = {
	regmap_reg_range(MAX172XX_STATUS, MAX172XX_ATAVCAP),
	};

	static const struct regmap_range max1720x_readable_deny[] = {
	/* unused registers */
	regmap_reg_range(0x24, 0x26),
	regmap_reg_range(0x30, 0x31),
	regmap_reg_range(0x33, 0x34),
	regmap_reg_range(0x37, 0x37),
	regmap_reg_range(0x3B, 0x3C),
	regmap_reg_range(0x40, 0x41),
	regmap_reg_range(0x43, 0x44),
	regmap_reg_range(0x47, 0x49),
	regmap_reg_range(0x4B, 0x4C),
	regmap_reg_range(0x4E, 0xAF),
	regmap_reg_range(0xB1, 0xB3),
	regmap_reg_range(0xB5, 0xB7),
	regmap_reg_range(0xBF, 0xD0),
	regmap_reg_range(0xDB, 0xDB),
	regmap_reg_range(0xE0, 0xFF),
	};

	static const struct regmap_access_table max1720x_readable_regs = {
	.yes_ranges = max1720x_readable_allow,
	.n_yes_ranges = ARRAY_SIZE(max1720x_readable_allow),
	.no_ranges = max1720x_readable_deny,
	.n_no_ranges = ARRAY_SIZE(max1720x_readable_deny),
	};

	static const struct regmap_access_table max1720x_volatile_regs = {
	.yes_ranges = max1720x_volatile_allow,
	.n_yes_ranges = ARRAY_SIZE(max1720x_volatile_allow),
	.no_ranges = max1720x_readable_deny,
	.n_no_ranges = ARRAY_SIZE(max1720x_readable_deny),
	};

	static const struct regmap_config max1720x_regmap_cfg = {
	.reg_bits = 8,
	.val_bits = 16,
	.max_register = MAX172XX_ATAVCAP,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
	.rd_table = &max1720x_readable_regs,
	.volatile_table = &max1720x_volatile_regs,
	.cache_type = REGCACHE_RBTREE,
	};

	static const enum power_supply_property max1720x_battery_props[] = {
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
	POWER_SUPPLY_PROP_CHARGE_AVG,
	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CURRENT_AVG,
	POWER_SUPPLY_PROP_MODEL_NAME,
	POWER_SUPPLY_PROP_MANUFACTURER,
	};

	/* Convert regs value to power_supply units */

	static int max172xx_time_to_ps(unsigned int reg)
	{
	return reg * 5625 / 1000; /* in sec. */
	}

	static int max172xx_percent_to_ps(unsigned int reg)
	{
	return reg / 256; /* in percent from 0 to 100 */
	}

	static int max172xx_voltage_to_ps(unsigned int reg)
	{
	return reg * 1250; /* in uV */
	}

	static int max172xx_capacity_to_ps(unsigned int reg)
	{
	return reg * 500; /* in uAh */
	}

	/*
	* Current and temperature is signed values, so unsigned regs
	* value must be converted to signed type
	*/

	static int max172xx_temperature_to_ps(unsigned int reg)
	{
	int val = (int16_t)reg;

	return val * 10 / 256; /* in tenths of deg. C */
	}

	/*
	* Calculating current registers resolution:
	*
	* RSense stored in 10^-5 Ohm, so mesaurment voltage must be
	* in 10^-11 Volts for get current in uA.
	* 16 bit current reg fullscale +/-51.2mV is 102400 uV.
	* So: 102400 / 65535 * 10^5 = 156252
	*/
	static int max172xx_current_to_voltage(unsigned int reg)
	{
	int val = (int16_t)reg;

	return val * 156252;
	}

	static int max1720x_battery_get_property(struct power_supply *psy,
	enum power_supply_property psp,
	union power_supply_propval *val)
	{
	struct max1720x_device_info *info = power_supply_get_drvdata(psy);
	unsigned int reg_val;
	int ret = 0;

	switch (psp) {
	case POWER_SUPPLY_PROP_PRESENT:
	/*
	* POWER_SUPPLY_PROP_PRESENT will always readable via
	* sysfs interface. Value return 0 if battery not
	* present or unaccesable via I2c.
	*/
	ret = regmap_read(info->regmap, MAX172XX_STATUS, &reg_val);
	if (ret < 0) {
	val->intval = 0;
	return 0;
	}

	val->intval = !FIELD_GET(MAX172XX_STATUS_BAT_ABSENT, reg_val);
	break;
	case POWER_SUPPLY_PROP_CAPACITY:
	ret = regmap_read(info->regmap, MAX172XX_REPSOC, &reg_val);
	val->intval = max172xx_percent_to_ps(reg_val);
	break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
	ret = regmap_read(info->regmap, MAX172XX_BATT, &reg_val);
	val->intval = max172xx_voltage_to_ps(reg_val);
	break;
	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
	ret = regmap_read(info->regmap, MAX172XX_DESIGN_CAP, &reg_val);
	val->intval = max172xx_capacity_to_ps(reg_val);
	break;
	case POWER_SUPPLY_PROP_CHARGE_AVG:
	ret = regmap_read(info->regmap, MAX172XX_REPCAP, &reg_val);
	val->intval = max172xx_capacity_to_ps(reg_val);
	break;
	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
	ret = regmap_read(info->regmap, MAX172XX_TTE, &reg_val);
	val->intval = max172xx_time_to_ps(reg_val);
	break;
	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
	ret = regmap_read(info->regmap, MAX172XX_TTF, &reg_val);
	val->intval = max172xx_time_to_ps(reg_val);
	break;
	case POWER_SUPPLY_PROP_TEMP:
	ret = regmap_read(info->regmap, MAX172XX_TEMP, &reg_val);
	val->intval = max172xx_temperature_to_ps(reg_val);
	break;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
	ret = regmap_read(info->regmap, MAX172XX_CURRENT, &reg_val);
	val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
	break;
	case POWER_SUPPLY_PROP_CURRENT_AVG:
	ret = regmap_read(info->regmap, MAX172XX_AVG_CURRENT, &reg_val);
	val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
	break;
	case POWER_SUPPLY_PROP_MODEL_NAME:
	ret = regmap_read(info->regmap, MAX172XX_DEV_NAME, &reg_val);
	reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
	if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
	val->strval = max17201_model;
	else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
	val->strval = max17205_model;
	else
	return -ENODEV;
	break;
	case POWER_SUPPLY_PROP_MANUFACTURER:
	val->strval = max1720x_manufacturer;
	break;
	default:
	return -EINVAL;
	}

	return ret;
	}

	static int max1720x_probe_sense_resistor(struct i2c_client *client,
	struct max1720x_device_info *info)
	{
	struct device *dev = &client->dev;
	struct i2c_client *ancillary;
	int ret;

	ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
	if (IS_ERR(ancillary)) {
	dev_err(dev, "Failed to initialize ancillary i2c device\n");
	return PTR_ERR(ancillary);
	}

	ret = i2c_smbus_read_word_data(ancillary, MAX1720X_NRSENSE);
	i2c_unregister_device(ancillary);
	if (ret < 0)
	return ret;

	info->rsense = ret;
	if (!info->rsense) {
	dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
	info->rsense = 1000; /* in regs in 10^-5 */
	}

	return 0;
	}

	static const struct power_supply_desc max1720x_bat_desc = {
	.name = "max1720x",
	.no_thermal = true,
	.type = POWER_SUPPLY_TYPE_BATTERY,
	.properties = max1720x_battery_props,
	.num_properties = ARRAY_SIZE(max1720x_battery_props),
	.get_property = max1720x_battery_get_property,
	};

	static int max1720x_probe(struct i2c_client *client)
	{
	struct power_supply_config psy_cfg = {};
	struct device *dev = &client->dev;
	struct max1720x_device_info *info;
	struct power_supply *bat;
	int ret;

	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
	if (!info)
	return -ENOMEM;

	psy_cfg.drv_data = info;
	psy_cfg.fwnode = dev_fwnode(dev);
	info->regmap = devm_regmap_init_i2c(client, &max1720x_regmap_cfg);
	if (IS_ERR(info->regmap))
	return dev_err_probe(dev, PTR_ERR(info->regmap),
	"regmap initialization failed\n");

	ret = max1720x_probe_sense_resistor(client, info);
	if (ret)
	return dev_err_probe(dev, ret,
	"Failed to read sense resistor value\n");

	bat = devm_power_supply_register(dev, &max1720x_bat_desc, &psy_cfg);
	if (IS_ERR(bat))
	return dev_err_probe(dev, PTR_ERR(bat),
	"Failed to register power supply\n");

	return 0;
	}

	static const struct of_device_id max1720x_of_match[] = {
	{ .compatible = "maxim,max17201" },
	{}
	};
	MODULE_DEVICE_TABLE(of, max1720x_of_match);

	static struct i2c_driver max1720x_i2c_driver = {
	.driver = {
	.name = "max1720x",
	.of_match_table = max1720x_of_match,
	},
	.probe = max1720x_probe,
	};
	module_i2c_driver(max1720x_i2c_driver);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Dimitri Fedrau <dima.fedrau@gmail.com>");
	MODULE_DESCRIPTION("Maxim MAX17201/MAX17205 Fuel Gauge IC driver");