[PATCH v3 15/23] power: supply: max77705: Add fuel gauge driver for Maxim 77705

[Dzmitry Sankouski <dsankouski@gmail.com>]

Add driver for Maxim 77705 fuel gauge (part of max77705
MFD driver) providing power supply class information to userspace.

The driver is configured through DTS (battery and system related
settings).

Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com>
---
 drivers/power/supply/Kconfig              |   7 +
 drivers/power/supply/Makefile             |   1 +
 drivers/power/supply/max77705_fuelgauge.c | 624 ++++++++++++++++++++++++++++++
 include/linux/power/max77705_fuelgauge.h  | 107 +++++
 4 files changed, 739 insertions(+)

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 47ca8cc00a80..a3fdfcb5aa64 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -558,6 +558,13 @@ config CHARGER_MAX77705
 	help
 	  Say Y to enable support for the Maxim MAX77705 battery charger.
 
+config FUEL_GAUGE_MAX77705
+	tristate "MAX77705 fuel gauge driver"
+	depends on MFD_MAX77705
+	default n
+	help
+	  Say Y to enable support for MAXIM MAX77705 fuel gauge driver.
+
 config CHARGER_MAX77976
 	tristate "Maxim MAX77976 battery charger driver"
 	depends on I2C
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index dbec648c78c9..e1abad8b6b75 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
 obj-$(CONFIG_CHARGER_MAX77650)	+= max77650-charger.o
 obj-$(CONFIG_CHARGER_MAX77693)	+= max77693_charger.o
 obj-$(CONFIG_CHARGER_MAX77705)	+= max77705_charger.o
+obj-$(CONFIG_FUEL_GAUGE_MAX77705)	+= max77705_fuelgauge.o
 obj-$(CONFIG_CHARGER_MAX77976)	+= max77976_charger.o
 obj-$(CONFIG_CHARGER_MAX8997)	+= max8997_charger.o
 obj-$(CONFIG_CHARGER_MAX8998)	+= max8998_charger.o
diff --git a/drivers/power/supply/max77705_fuelgauge.c b/drivers/power/supply/max77705_fuelgauge.c
new file mode 100644
index 000000000000..108a829421d7
--- /dev/null
+++ b/drivers/power/supply/max77705_fuelgauge.c
@@ -0,0 +1,624 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  max77705_fuelgauge.c
+ *  Samsung max77705 Fuel Gauge Driver
+ *
+ *  Copyright (C) 2015 Samsung Electronics
+ *  Copyright (C) 2024 Dzmitry Sankouski <dsankouski@gmail.com>
+ */
+
+#include <linux/of_gpio.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+#include <linux/power/max77705_fuelgauge.h>
+#include <linux/mfd/max77705-private.h>
+
+static const char *max77705_fuelgauge_model		= "max77705";
+static const char *max77705_fuelgauge_manufacturer	= "Maxim Integrated";
+static struct dentry *debugfs_file;
+
+static enum power_supply_property max77705_fuelgauge_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_VOLTAGE_OCV,
+	POWER_SUPPLY_PROP_VOLTAGE_AVG,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CURRENT_AVG,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
+	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
+	POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
+};
+
+static int max77705_fg_read_vcell(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	u16 w_data;
+
+	if (regmap_noinc_read(regmap, VCELL_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read VCELL_REG\n", __func__);
+		return -1;
+	}
+
+	w_data = (data[1] << 8) | data[0];
+
+	return max77705_fg_vs_convert(w_data);
+}
+
+static int max77705_fg_read_vfocv(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	u16 w_data;
+
+	if (regmap_noinc_read(regmap, VFOCV_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read VFOCV_REG\n", __func__);
+		return -1;
+	}
+
+	w_data = (data[1] << 8) | data[0];
+
+	return max77705_fg_vs_convert(w_data);
+}
+
+static int max77705_fg_read_avg_vcell(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	u16 w_data;
+
+	if (regmap_noinc_read(regmap, AVR_VCELL_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read AVR_VCELL_REG\n", __func__);
+		return -1;
+	}
+
+	w_data = (data[1] << 8) | data[0];
+	return max77705_fg_vs_convert(w_data);
+}
+
+static int max77705_fg_check_battery_present(struct max77705_fuelgauge_data
+					     *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 status_data[2];
+
+	if (regmap_noinc_read(regmap, STATUS_REG, status_data, sizeof(status_data)) < 0) {
+		dev_err(fuelgauge->dev, "Failed to read STATUS_REG\n");
+		return 0;
+	}
+
+	return !(status_data[0] & MAX77705_BAT_ABSENT_MASK);
+}
+
+static int max77705_fg_read_temp(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2] = { 0, 0 };
+	int temper = 0;
+
+	if (regmap_noinc_read(regmap, TEMPERATURE_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read TEMPERATURE_REG\n", __func__);
+		return -1;
+	}
+
+	if (data[1] & BIT(7))
+		temper = ((~(data[1])) & 0xFF) + 1;
+	else
+		temper = data[1] & 0x7f;
+
+	temper *= 10;
+	temper += data[0] * 10 / 256;
+
+	return temper;
+}
+
+static int max77705_fg_read_socrep(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	int soc;
+
+	if (regmap_noinc_read(regmap, SOCREP_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read SOCREP_REG\n", __func__);
+		return -1;
+	}
+
+	soc = data[1];
+
+	return min(soc, 100);
+}
+
+static int max77705_fg_read_fullcaprep(struct max77705_fuelgauge_data
+				       *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	int ret;
+
+	if (regmap_noinc_read(regmap, FULLCAP_REP_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read FULLCAP_REP_REG\n", __func__);
+		return -1;
+	}
+
+	ret = (data[1] << 8) + data[0];
+
+	return ret * 1000;
+}
+
+static int max77705_fg_read_repcap(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	int ret;
+
+	if (regmap_noinc_read(regmap, REMCAP_REP_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read REMCAP_REP_REG\n", __func__);
+		return -1;
+	}
+
+	ret = (data[1] << 8) + data[0];
+
+	return ret * 1000;
+}
+
+static int max77705_fg_read_charge_design(struct max77705_fuelgauge_data
+				       *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	int reg;
+
+	if (regmap_noinc_read(regmap, DESIGNCAP_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read DESIGNCAP_REG\n", __func__);
+		return -1;
+	}
+
+	reg = (data[1] << 8) | (data[0]);
+
+	return reg * 1000;
+}
+
+static int max77705_fg_set_charge_design(struct regmap *regmap, int value)
+{
+	u8 data[2];
+	int value_mah;
+
+	value_mah = value / 1000;
+	data[0] = value_mah & 0xFF;
+	data[1] = (value_mah >> 8) & 0xFF;
+
+	if (regmap_noinc_write(regmap, DESIGNCAP_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to write DESIGNCAP_REG\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int max77705_fg_read_current(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 reg_data[2];
+	s16 reg_value;
+	s32 i_current;
+
+	if (regmap_noinc_read(regmap, CURRENT_REG, reg_data, sizeof(reg_data)) < 0) {
+		pr_err("%s: Failed to read CURRENT\n", __func__);
+		return -1;
+	}
+
+	reg_value = ((reg_data[1] << 8) | reg_data[0]);
+	i_current = max77705_fg_cs_convert(reg_value, fuelgauge->rsense_conductance);
+
+	return i_current;
+}
+
+static int max77705_fg_read_avg_current(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 reg_data[2];
+	u32 reg_value;
+	s32 avg_current;
+
+	if (regmap_noinc_read(regmap, AVG_CURRENT_REG, reg_data, sizeof(reg_data)) < 0) {
+		pr_err("%s: Failed to read AVG_CURRENT_REG\n", __func__);
+		return -1;
+	}
+
+	reg_value = ((reg_data[1] << 8) | reg_data[0]);
+	avg_current = max77705_fg_cs_convert(reg_value, fuelgauge->rsense_conductance);
+
+	return avg_current;
+}
+
+static int max77705_fg_read_tte(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	int reg;
+
+	if (regmap_noinc_read(regmap, TIME_TO_EMPTY_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read TIME_TO_EMPTY_REG\n", __func__);
+		return -1;
+	}
+
+	reg = (data[1] << 8) | (data[0]);
+
+	return reg;
+}
+
+static int max77705_fg_read_ttf(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	int reg;
+
+	if (regmap_noinc_read(regmap, TIME_TO_FULL_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read TIME_TO_FULL_REG\n", __func__);
+		return -1;
+	}
+
+	reg = (data[1] << 8) | (data[0]);
+
+	return reg;
+}
+
+static int max77705_fg_read_cycle(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2];
+	int ret;
+
+	if (regmap_noinc_read(regmap, CYCLES_REG, data, sizeof(data)) < 0) {
+		pr_err("%s: Failed to read CYCLES_REG\n", __func__);
+		return -1;
+	}
+
+	ret = (data[1] << 8) + data[0];
+
+	return ret;
+}
+
+static int max77705_battery_get_status(struct max77705_fuelgauge_data *fuelgauge)
+{
+	int current_now;
+	int am_i_supplied;
+
+	am_i_supplied = power_supply_am_i_supplied(fuelgauge->psy_fg);
+	if (am_i_supplied) {
+		if (am_i_supplied == -ENODEV)
+			dev_err(fuelgauge->dev,
+				"power supply not found, fall back to current-based status checking\n");
+		else
+			return POWER_SUPPLY_STATUS_CHARGING;
+	}
+	if (max77705_fg_read_socrep(fuelgauge) < 100) {
+		current_now = max77705_fg_read_current(fuelgauge);
+		if (current_now > 0)
+			return POWER_SUPPLY_STATUS_CHARGING;
+		else if (current_now < 0)
+			return POWER_SUPPLY_STATUS_DISCHARGING;
+		else
+			return POWER_SUPPLY_STATUS_NOT_CHARGING;
+	} else {
+		return POWER_SUPPLY_STATUS_FULL;
+	}
+	return POWER_SUPPLY_STATUS_DISCHARGING;
+}
+
+static bool max77705_fg_init(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	u8 data[2] = { 0, 0 };
+	u32 volt_threshold = 0;
+	u32 temp_threshold = 0;
+
+	if (fuelgauge->auto_discharge_en) {
+		/* Auto discharge EN & Alert Enable */
+		regmap_noinc_read(regmap, CONFIG2_REG, data, sizeof(data));
+		data[1] |= MAX77705_AUTO_DISCHARGE_EN_MASK >> 8;
+		regmap_noinc_write(regmap, CONFIG2_REG, data, sizeof(data));
+
+		/* Set Auto Discharge temperature & Voltage threshold */
+		volt_threshold =
+		    fuelgauge->discharge_volt_threshold < 3900 ? 0x0 :
+		    fuelgauge->discharge_volt_threshold > 4540 ? 0x20 :
+		    (fuelgauge->discharge_volt_threshold - 3900) / 20;
+
+		temp_threshold =
+		    fuelgauge->discharge_temp_threshold < 470 ? 0x0 :
+		    fuelgauge->discharge_temp_threshold > 630 ? 0x20 :
+		    (fuelgauge->discharge_temp_threshold - 470) / 5;
+
+		regmap_noinc_read(regmap, DISCHARGE_THRESHOLD_REG, data, sizeof(data));
+		data[1] &= ~MAX77705_AUTO_DISCHARGE_VALUE_MASK;
+		data[1] |= volt_threshold << MAX77705_AUTO_DISCHARGE_VALUE_SHIFT;
+
+		data[0] &= ~MAX77705_AUTO_DISCHARGE_VALUE_MASK;
+		data[0] |= temp_threshold << MAX77705_AUTO_DISCHARGE_VALUE_SHIFT;
+
+		regmap_noinc_write(regmap, DISCHARGE_THRESHOLD_REG, data, sizeof(data));
+
+		pr_info("%s: DISCHARGE_THRESHOLD Value : 0x%x\n",
+			__func__, (data[1] << 8) | data[0]);
+	}
+
+	return true;
+}
+
+static int max77705_fg_get_property(struct power_supply *psy,
+				    enum power_supply_property psp,
+				    union power_supply_propval *val)
+{
+	struct max77705_fuelgauge_data *fuelgauge =
+	    power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		val->intval = max77705_battery_get_status(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_PRESENT:
+		val->intval = max77705_fg_check_battery_present(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		val->intval = max77705_fg_read_vcell(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_OCV:
+		val->intval = max77705_fg_read_vfocv(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
+		val->intval = max77705_fg_read_avg_vcell(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		val->intval = max77705_fg_read_current(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_AVG:
+		val->intval = max77705_fg_read_avg_current(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_NOW:
+		val->intval = max77705_fg_read_repcap(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL:
+		val->intval = max77705_fg_read_fullcaprep(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+		val->intval = max77705_fg_read_charge_design(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_CAPACITY:
+		val->intval = max77705_fg_read_socrep(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_TEMP:
+		val->intval = max77705_fg_read_temp(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
+		val->intval = max77705_fg_read_tte(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
+		val->intval = max77705_fg_read_ttf(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_CYCLE_COUNT:
+		val->intval = max77705_fg_read_cycle(fuelgauge);
+		break;
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = max77705_fuelgauge_model;
+		break;
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = max77705_fuelgauge_manufacturer;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int max77705_fuelgauge_debugfs_show(struct seq_file *s, void *data)
+{
+	struct max77705_fuelgauge_data *fuelgauge = s->private;
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+	int i;
+	u16 reg_data;
+	int regs[] = { 0x00, 0x01, 0x02, 0x03, 0x05, 0x06, 0x08, 0x09, 0x11, 0x13, 0x0A,
+			0x0B, 0x0D, 0x0E, 0x0F, 0x10, 0x15, 0x16, 0x17, 0x18, 0x19, 0x20,
+			0x1D, 0x1E, 0x1F, 0x23, 0x28, 0x29, 0x2B, 0x32, 0x35, 0x38, 0x3A,
+			0x3D, 0x40, 0x42, 0x43, 0x45, 0x46, 0x4B, 0x4D, 0xB1, 0xB2, 0xB3,
+			0xBB, 0xD0, 0xEE, 0xFB, 0xFF, };
+
+	seq_puts(s, "MAX77705 FUELGAUGE IC :\n");
+	seq_puts(s, "===================\n");
+	for (i = 0; i < ARRAY_SIZE(regs); i++) {
+		regmap_noinc_read(regmap, regs[i], &reg_data, 2);
+		seq_printf(s, "0x%02x:\t0x%02x\n", regs[i], reg_data);
+	}
+	seq_puts(s, "\n");
+	return 0;
+}
+
+static int max77705_fuelgauge_debugfs_open(struct inode *inode,
+					   struct file *file)
+{
+	return single_open(file, max77705_fuelgauge_debugfs_show, inode->i_private);
+}
+
+static const struct file_operations max77705_fuelgauge_debugfs_fops = {
+	.open = max77705_fuelgauge_debugfs_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static void max77705_battery_settings(struct max77705_fuelgauge_data *fuelgauge)
+{
+	struct power_supply_battery_info *info;
+	struct regmap *regmap = fuelgauge->max77705->regmap_fg;
+
+	if (power_supply_get_battery_info(fuelgauge->psy_fg, &info) < 0)
+		return;
+
+	fuelgauge->bat_info = info;
+
+	if (!regmap) {
+		dev_warn(fuelgauge->dev, "data memory update not supported for chip\n");
+		return;
+	}
+
+	if (info->energy_full_design_uwh != info->charge_full_design_uah) {
+		if (info->charge_full_design_uah == -EINVAL)
+			dev_warn(fuelgauge->dev, "missing battery:charge-full-design-microamp-hours\n");
+		max77705_fg_set_charge_design(regmap, info->charge_full_design_uah);
+	}
+}
+
+static int max77705_fuelgauge_parse_dt(struct max77705_fuelgauge_data
+				       *fuelgauge)
+{
+	struct device *dev = fuelgauge->dev;
+	struct device_node *np = dev->of_node;
+	unsigned int rsense;
+
+	if (!np) {
+		dev_err(dev, "no fuelgauge OF node\n");
+		return -EINVAL;
+	}
+
+	int ret;
+
+	if (np == NULL) {
+		pr_err("%s np NULL\n", __func__);
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32(np, "rsense",
+				   &rsense);
+	if (ret < 0) {
+		pr_err("%s error reading rsense %d\n",
+		       __func__, ret);
+		fuelgauge->rsense_conductance = 100;
+	} else
+		fuelgauge->rsense_conductance = 1000 / rsense; /* rsense in Ohm^-1 */
+
+	fuelgauge->auto_discharge_en = of_property_read_bool(np,
+							     "auto_discharge_en");
+	if (fuelgauge->auto_discharge_en) {
+		ret = of_property_read_u32(np,
+						"discharge_temp_threshold",
+						&fuelgauge->discharge_temp_threshold);
+		if (ret < 0) {
+			dev_err(dev, "error reading rsense_conductance %d\n", ret);
+			fuelgauge->discharge_temp_threshold = 600;
+		}
+
+		ret = of_property_read_u32(np,
+						"discharge_volt_threshold",
+						&fuelgauge->discharge_volt_threshold);
+		if (ret < 0)
+			fuelgauge->discharge_volt_threshold = 4200;
+	}
+
+	return 0;
+}
+
+static const struct power_supply_desc max77705_fuelgauge_power_supply_desc = {
+	.name = "max77705-fuelgauge",
+	.type = POWER_SUPPLY_TYPE_BATTERY,
+	.properties = max77705_fuelgauge_props,
+	.num_properties = ARRAY_SIZE(max77705_fuelgauge_props),
+	.get_property = max77705_fg_get_property,
+};
+
+static int max77705_fuelgauge_probe(struct platform_device *pdev)
+{
+	struct max77705_dev *max77705 = dev_get_drvdata(pdev->dev.parent);
+	struct max77705_platform_data *pdata = dev_get_platdata(max77705->dev);
+	struct max77705_fuelgauge_data *fuelgauge;
+	struct power_supply_config fuelgauge_cfg = { };
+	int ret = 0;
+
+	fuelgauge = kzalloc(sizeof(*fuelgauge), GFP_KERNEL);
+	if (!fuelgauge)
+		return -ENOMEM;
+
+	mutex_init(&fuelgauge->fg_lock);
+
+	fuelgauge->dev = &pdev->dev;
+	fuelgauge->max77705 = max77705;
+	fuelgauge->max77705_pdata = pdata;
+
+	ret = max77705_fuelgauge_parse_dt(fuelgauge);
+	if (ret < 0)
+		pr_err("%s not found charger dt! ret[%d]\n", __func__, ret);
+
+	platform_set_drvdata(pdev, fuelgauge);
+
+
+	debugfs_file = debugfs_create_file("max77705-fuelgauge-regs",
+				0664, NULL, (void *)fuelgauge,
+				  &max77705_fuelgauge_debugfs_fops);
+	if (!debugfs_file)
+		dev_err(fuelgauge->dev, "Failed to create debugfs file\n");
+
+	fuelgauge_cfg.drv_data = fuelgauge;
+	fuelgauge_cfg.of_node = fuelgauge->dev->of_node;
+
+	fuelgauge->psy_fg =
+	    devm_power_supply_register(&pdev->dev,
+				  &max77705_fuelgauge_power_supply_desc,
+				  &fuelgauge_cfg);
+
+	if (IS_ERR(fuelgauge->psy_fg)) {
+		pr_err("%s: Failed to Register psy_fg\n", __func__);
+		goto err_data_free;
+	}
+
+	fuelgauge->fg_irq = max77705->irq_base + MAX77705_FG_IRQ_ALERT;
+	pr_info("[%s]IRQ_BASE(%d) FG_IRQ(%d)\n",
+		__func__, max77705->irq_base, fuelgauge->fg_irq);
+
+	if (!max77705_fg_init(fuelgauge)) {
+		pr_err("%s: Failed to Initialize Fuelgauge\n", __func__);
+		goto err_supply_unreg;
+	}
+
+	max77705_battery_settings(fuelgauge);
+
+	return 0;
+
+err_supply_unreg:
+	power_supply_unregister(fuelgauge->psy_fg);
+	kfree(fuelgauge->bat_info);
+err_data_free:
+	mutex_destroy(&fuelgauge->fg_lock);
+
+	return ret;
+}
+
+static void max77705_fuelgauge_remove(struct platform_device *pdev)
+{
+	if (debugfs_file)
+		debugfs_remove(debugfs_file);
+}
+static const struct platform_device_id max77705_fuelgauge_id[] = {
+	{ "max77705-fuelgauge", 0, },
+	{ }
+};
+MODULE_DEVICE_TABLE(platform, max77705_fuelgauge_id);
+
+static struct platform_driver max77705_fuelgauge_driver = {
+	.driver = {
+		.name = "max77705-fuelgauge",
+	},
+	.probe = max77705_fuelgauge_probe,
+	.remove_new = max77705_fuelgauge_remove,
+	.id_table	= max77705_fuelgauge_id,
+};
+module_platform_driver(max77705_fuelgauge_driver);
+
+MODULE_DESCRIPTION("Samsung max77705 Fuel Gauge Driver");
+MODULE_AUTHOR("Samsung Electronics");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/power/max77705_fuelgauge.h b/include/linux/power/max77705_fuelgauge.h
new file mode 100644
index 000000000000..718cd47bc7b6
--- /dev/null
+++ b/include/linux/power/max77705_fuelgauge.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * max77705_fuelgauge.h
+ * Samsung max77705 Fuel Gauge Header
+ *
+ * Copyright (C) 2015 Samsung Electronics, Inc.
+ *
+ * This software is 77854 under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __MAX77705_FUELGAUGE_H
+#define __MAX77705_FUELGAUGE_H __FILE__
+
+#include <linux/mfd/core.h>
+#include <linux/mfd/max77705.h>
+#include <linux/mfd/max77705-private.h>
+#include <linux/regulator/machine.h>
+
+#define ALERT_EN 0x04
+#define CAPACITY_SCALE_DEFAULT_CURRENT 1000
+#define CAPACITY_SCALE_HV_CURRENT 600
+/*
+ * Current and capacity values are displayed as a voltage
+ * and must be divided by the sense resistor to determine Amps or Amp-hours.
+ * This should be applied to all current, charge, energy registers,
+ * except ModelGauge m5 Algorithm related ones.
+ */
+/* current sense resolution */
+#define MAX77705_FG_CS_ADC_RESOLUTION 15625 /* 1.5625 microvolts */
+/* voltage sense resolution */
+#define MAX77705_FG_VS_ADC_RESOLUTION 78125 /* 78.125 microvolts */
+/* CONFIG register */
+#define MAX77705_SOC_ALERT_EN_MASK		BIT(2)
+/* When set to 1, external temperature measurements should be written from the host */
+#define MAX77705_TEX_MASK		BIT(8)
+/* Enable Thermistor */
+#define MAX77705_ETHRM_MASK		BIT(5)
+/* CONFIG2 register */
+#define MAX77705_AUTO_DISCHARGE_EN_MASK BIT(9)
+/* DISCHARGE register*/
+#define MAX77705_AUTO_DISCHARGE_VALUE_SHIFT 3
+#define MAX77705_AUTO_DISCHARGE_VALUE_MASK 0xF8
+
+#define MAX77705_FG_CS_MASK BIT(15)
+/* MISCCFG register */
+#define MAX77705_AUTO_DISCHARGE_VALUE_MASK 0xF8
+
+/* adc resolution for voltage sensing is 78.125 microvolts */
+inline u64 max77705_fg_vs_convert(u16 reg_val)
+{
+	u64 result = (u64)reg_val * MAX77705_FG_VS_ADC_RESOLUTION;
+
+	return result / 1000;
+}
+
+/* adc resolution for current sensing is 1.5625 microvolts */
+inline s32 max77705_fg_cs_convert(s16 reg_val, u32 rsense_conductance)
+{
+	s64 result = (s64)reg_val * rsense_conductance * MAX77705_FG_CS_ADC_RESOLUTION;
+
+	return result / 10000;
+}
+
+struct max77705_fuelgauge_data {
+	struct device           *dev;
+	struct i2c_client       *i2c;
+	struct i2c_client       *pmic;
+	struct mutex            fuelgauge_mutex;
+	struct max77705_dev	*max77705;
+	struct max77705_platform_data *max77705_pdata;
+	struct power_supply	      *psy_fg;
+	struct delayed_work isr_work;
+
+	int cable_type;
+	bool is_charging;
+
+	struct power_supply_battery_info *bat_info;
+
+	struct mutex fg_lock;
+
+	/* register programming */
+	int reg_addr;
+	u8 reg_data[2];
+
+	unsigned int pre_soc;
+	int fg_irq;
+
+	int temperature;
+	int low_temp_limit;
+
+	bool auto_discharge_en;
+	u32 discharge_temp_threshold;
+	u32 discharge_volt_threshold;
+
+	u32 rsense_conductance;
+	u32 fuel_alert_soc;
+};
+
+#endif /* __MAX77705_FUELGAUGE_H */

-- 
2.39.2