diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 44d3c8512fb8..1117a79860b6 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -739,4 +739,12 @@ config CHARGER_WILCO
 	  information can be found in
 	  Documentation/ABI/testing/sysfs-class-power-wilco
 
+config RN5T618_POWER
+	tristate "RN5T618 charger/fuel gauge support"
+	depends on MFD_RN5T618
+	help
+	  Say Y here to have support for RN5T618 PMIC family fuel gauge and charger.
+	  This driver can also be built as a module. If so, the module will be
+	  called rn5t618_power.
+
 endif # POWER_SUPPLY
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index b9644663e435..23866b6ccdae 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -95,3 +95,4 @@ obj-$(CONFIG_CHARGER_UCS1002)	+= ucs1002_power.o
 obj-$(CONFIG_CHARGER_BD70528)	+= bd70528-charger.o
 obj-$(CONFIG_CHARGER_BD99954)	+= bd99954-charger.o
 obj-$(CONFIG_CHARGER_WILCO)	+= wilco-charger.o
+obj-$(CONFIG_RN5T618_POWER)	+= rn5t618_power.o
diff --git a/drivers/power/supply/rn5t618_power.c b/drivers/power/supply/rn5t618_power.c
new file mode 100644
index 000000000000..424d2817bee5
--- /dev/null
+++ b/drivers/power/supply/rn5t618_power.c
@@ -0,0 +1,556 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Power supply driver for the RICOH RN5T618 power management chip family
+ *
+ * Copyright (C) 2020 Andreas Kemnade
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mfd/rn5t618.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define CHG_STATE_ADP_INPUT 0x40
+#define CHG_STATE_USB_INPUT 0x80
+#define CHG_STATE_MASK	0x1f
+#define CHG_STATE_CHG_OFF	0
+#define CHG_STATE_CHG_READY_VADP	1
+#define CHG_STATE_CHG_TRICKLE	2
+#define CHG_STATE_CHG_RAPID	3
+#define CHG_STATE_CHG_COMPLETE	4
+#define CHG_STATE_SUSPEND	5
+#define CHG_STATE_VCHG_OVER_VOL	6
+#define CHG_STATE_BAT_ERROR	7
+#define CHG_STATE_NO_BAT	8
+#define CHG_STATE_BAT_OVER_VOL	9
+#define CHG_STATE_BAT_TEMP_ERR	10
+#define CHG_STATE_DIE_ERR	11
+#define CHG_STATE_DIE_SHUTDOWN	12
+#define CHG_STATE_NO_BAT2	13
+#define CHG_STATE_CHG_READY_VUSB	14
+
+#define FG_ENABLE 1
+
+struct rn5t618_power_info {
+	struct rn5t618 *rn5t618;
+	struct platform_device *pdev;
+	struct power_supply *battery;
+	struct power_supply *usb;
+	struct power_supply *adp;
+	int irq;
+};
+
+static enum power_supply_property rn5t618_usb_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_ONLINE,
+};
+
+static enum power_supply_property rn5t618_adp_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_ONLINE,
+};
+
+
+static enum power_supply_property rn5t618_battery_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
+	POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
+	POWER_SUPPLY_PROP_TECHNOLOGY,
+	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
+};
+
+static int rn5t618_battery_read_doublereg(struct rn5t618_power_info *info,
+					  u8 reg, u16 *result)
+{
+	int ret, i;
+	u8 data[2];
+	u16 old, new;
+
+	old = 0;
+	/* Prevent races when registers are changing. */
+	for (i = 0; i < 3; i++) {
+		ret = regmap_bulk_read(info->rn5t618->regmap,
+				       reg, data, sizeof(data));
+		if (ret)
+			return ret;
+
+		new = data[0] << 8;
+		new |= data[1];
+		if (new == old)
+			break;
+
+		old = new;
+	}
+
+	*result = new;
+
+	return 0;
+}
+
+static int rn5t618_decode_status(unsigned int status)
+{
+	switch (status & CHG_STATE_MASK) {
+	case CHG_STATE_CHG_OFF:
+	case CHG_STATE_SUSPEND:
+	case CHG_STATE_VCHG_OVER_VOL:
+	case CHG_STATE_DIE_SHUTDOWN:
+		return POWER_SUPPLY_STATUS_DISCHARGING;
+
+	case CHG_STATE_CHG_TRICKLE:
+	case CHG_STATE_CHG_RAPID:
+		return POWER_SUPPLY_STATUS_CHARGING;
+
+	case CHG_STATE_CHG_COMPLETE:
+		return POWER_SUPPLY_STATUS_FULL;
+
+	default:
+		return POWER_SUPPLY_STATUS_NOT_CHARGING;
+	}
+}
+
+static int rn5t618_battery_status(struct rn5t618_power_info *info,
+				  union power_supply_propval *val)
+{
+	unsigned int v;
+	int ret;
+
+	ret = regmap_read(info->rn5t618->regmap, RN5T618_CHGSTATE, &v);
+	if (ret)
+		return ret;
+
+	val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+
+	if (v & 0xc0) { /* USB or ADP plugged */
+		val->intval = rn5t618_decode_status(v);
+	} else
+		val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+
+	return ret;
+}
+
+static int rn5t618_battery_present(struct rn5t618_power_info *info,
+				   union power_supply_propval *val)
+{
+	unsigned int v;
+	int ret;
+
+	ret = regmap_read(info->rn5t618->regmap, RN5T618_CHGSTATE, &v);
+	if (ret)
+		return ret;
+
+	v &= CHG_STATE_MASK;
+	if ((v == CHG_STATE_NO_BAT) || (v == CHG_STATE_NO_BAT2))
+		val->intval = 0;
+	else
+		val->intval = 1;
+
+	return ret;
+}
+
+static int rn5t618_battery_voltage_now(struct rn5t618_power_info *info,
+				       union power_supply_propval *val)
+{
+	u16 res;
+	int ret;
+
+	ret = rn5t618_battery_read_doublereg(info, RN5T618_VOLTAGE_1, &res);
+	if (ret)
+		return ret;
+
+	val->intval = res * 2 * 2500 / 4095 * 1000;
+
+	return 0;
+}
+
+static int rn5t618_battery_current_now(struct rn5t618_power_info *info,
+				       union power_supply_propval *val)
+{
+	u16 res;
+	int ret;
+
+	ret = rn5t618_battery_read_doublereg(info, RN5T618_CC_AVEREG1, &res);
+	if (ret)
+		return ret;
+
+	/* current is negative when discharging */
+	val->intval = sign_extend32(res, 13) * 1000;
+
+	return 0;
+}
+
+static int rn5t618_battery_capacity(struct rn5t618_power_info *info,
+				    union power_supply_propval *val)
+{
+	unsigned int v;
+	int ret;
+
+	ret = regmap_read(info->rn5t618->regmap, RN5T618_SOC, &v);
+	if (ret)
+		return ret;
+
+	val->intval = v;
+
+	return 0;
+}
+
+static int rn5t618_battery_temp(struct rn5t618_power_info *info,
+				union power_supply_propval *val)
+{
+	u16 res;
+	int ret;
+
+	ret = rn5t618_battery_read_doublereg(info, RN5T618_TEMP_1, &res);
+	if (ret)
+		return ret;
+
+	val->intval = sign_extend32(res, 11) * 10 / 16;
+
+	return 0;
+}
+
+static int rn5t618_battery_tte(struct rn5t618_power_info *info,
+			       union power_supply_propval *val)
+{
+	u16 res;
+	int ret;
+
+	ret = rn5t618_battery_read_doublereg(info, RN5T618_TT_EMPTY_H, &res);
+	if (ret)
+		return ret;
+
+	if (res == 65535)
+		return -ENODATA;
+
+	val->intval = res * 60;
+
+	return 0;
+}
+
+static int rn5t618_battery_ttf(struct rn5t618_power_info *info,
+			       union power_supply_propval *val)
+{
+	u16 res;
+	int ret;
+
+	ret = rn5t618_battery_read_doublereg(info, RN5T618_TT_FULL_H, &res);
+	if (ret)
+		return ret;
+
+	if (res == 65535)
+		return -ENODATA;
+
+	val->intval = res * 60;
+
+	return 0;
+}
+
+static int rn5t618_battery_charge_full(struct rn5t618_power_info *info,
+				       union power_supply_propval *val)
+{
+	u16 res;
+	int ret;
+
+	ret = rn5t618_battery_read_doublereg(info, RN5T618_FA_CAP_H, &res);
+	if (ret)
+		return ret;
+
+	val->intval = res * 1000;
+
+	return 0;
+}
+
+static int rn5t618_battery_charge_now(struct rn5t618_power_info *info,
+				      union power_supply_propval *val)
+{
+	u16 res;
+	int ret;
+
+	ret = rn5t618_battery_read_doublereg(info, RN5T618_RE_CAP_H, &res);
+	if (ret)
+		return ret;
+
+	val->intval = res * 1000;
+
+	return 0;
+}
+
+static int rn5t618_battery_get_property(struct power_supply *psy,
+					enum power_supply_property psp,
+					union power_supply_propval *val)
+{
+	int ret = 0;
+	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		ret = rn5t618_battery_status(info, val);
+		break;
+	case POWER_SUPPLY_PROP_PRESENT:
+		ret = rn5t618_battery_present(info, val);
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		ret = rn5t618_battery_voltage_now(info, val);
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		ret = rn5t618_battery_current_now(info, val);
+		break;
+	case POWER_SUPPLY_PROP_CAPACITY:
+		ret = rn5t618_battery_capacity(info, val);
+		break;
+	case POWER_SUPPLY_PROP_TEMP:
+		ret = rn5t618_battery_temp(info, val);
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
+		ret = rn5t618_battery_tte(info, val);
+		break;
+	case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
+		ret = rn5t618_battery_ttf(info, val);
+		break;
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL:
+		ret = rn5t618_battery_charge_full(info, val);
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_NOW:
+		ret = rn5t618_battery_charge_now(info, val);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int rn5t618_adp_get_property(struct power_supply *psy,
+				    enum power_supply_property psp,
+				    union power_supply_propval *val)
+{
+	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
+	unsigned int chgstate;
+	bool online;
+	int ret;
+
+	ret = regmap_read(info->rn5t618->regmap, RN5T618_CHGSTATE, &chgstate);
+	if (ret)
+		return ret;
+
+	online = !!(chgstate & CHG_STATE_ADP_INPUT);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = online;
+		break;
+	case POWER_SUPPLY_PROP_STATUS:
+		if (!online) {
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+			break;
+		}
+		val->intval = rn5t618_decode_status(chgstate);
+		if (val->intval != POWER_SUPPLY_STATUS_CHARGING)
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int rn5t618_usb_get_property(struct power_supply *psy,
+				    enum power_supply_property psp,
+				    union power_supply_propval *val)
+{
+	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
+	unsigned int chgstate;
+	bool online;
+	int ret;
+
+	ret = regmap_read(info->rn5t618->regmap, RN5T618_CHGSTATE, &chgstate);
+	if (ret)
+		return ret;
+
+	online = !!(chgstate & CHG_STATE_USB_INPUT);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = online;
+		break;
+	case POWER_SUPPLY_PROP_STATUS:
+		if (!online) {
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+			break;
+		}
+		val->intval = rn5t618_decode_status(chgstate);
+		if (val->intval != POWER_SUPPLY_STATUS_CHARGING)
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct power_supply_desc rn5t618_battery_desc = {
+	.name                   = "rn5t618-battery",
+	.type                   = POWER_SUPPLY_TYPE_BATTERY,
+	.properties             = rn5t618_battery_props,
+	.num_properties         = ARRAY_SIZE(rn5t618_battery_props),
+	.get_property           = rn5t618_battery_get_property,
+};
+
+static const struct power_supply_desc rn5t618_adp_desc = {
+	.name                   = "rn5t618-adp",
+	.type                   = POWER_SUPPLY_TYPE_MAINS,
+	.properties             = rn5t618_adp_props,
+	.num_properties         = ARRAY_SIZE(rn5t618_adp_props),
+	.get_property           = rn5t618_adp_get_property,
+};
+
+static const struct power_supply_desc rn5t618_usb_desc = {
+	.name                   = "rn5t618-usb",
+	.type                   = POWER_SUPPLY_TYPE_USB,
+	.properties             = rn5t618_usb_props,
+	.num_properties         = ARRAY_SIZE(rn5t618_usb_props),
+	.get_property           = rn5t618_usb_get_property,
+};
+
+static irqreturn_t rn5t618_charger_irq(int irq, void *data)
+{
+	struct device *dev = data;
+	struct rn5t618_power_info *info = dev_get_drvdata(dev);
+
+	unsigned int ctrl, stat1, stat2, err;
+
+	regmap_read(info->rn5t618->regmap, RN5T618_CHGERR_IRR, &err);
+	regmap_read(info->rn5t618->regmap, RN5T618_CHGCTRL_IRR, &ctrl);
+	regmap_read(info->rn5t618->regmap, RN5T618_CHGSTAT_IRR1, &stat1);
+	regmap_read(info->rn5t618->regmap, RN5T618_CHGSTAT_IRR2, &stat2);
+
+	regmap_write(info->rn5t618->regmap, RN5T618_CHGERR_IRR, 0);
+	regmap_write(info->rn5t618->regmap, RN5T618_CHGCTRL_IRR, 0);
+	regmap_write(info->rn5t618->regmap, RN5T618_CHGSTAT_IRR1, 0);
+	regmap_write(info->rn5t618->regmap, RN5T618_CHGSTAT_IRR2, 0);
+
+	dev_dbg(dev, "chgerr: %x chgctrl: %x chgstat: %x chgstat2: %x\n",
+		err, ctrl, stat1, stat2);
+
+	power_supply_changed(info->usb);
+	power_supply_changed(info->adp);
+	power_supply_changed(info->battery);
+
+	return IRQ_HANDLED;
+}
+
+static int rn5t618_power_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+	unsigned int v;
+	struct power_supply_config psy_cfg = {};
+	struct rn5t618_power_info *info;
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->pdev = pdev;
+	info->rn5t618 = dev_get_drvdata(pdev->dev.parent);
+	info->irq = -1;
+
+	platform_set_drvdata(pdev, info);
+
+	ret = regmap_read(info->rn5t618->regmap, RN5T618_CONTROL, &v);
+	if (ret)
+		return ret;
+
+	if (!(v & FG_ENABLE)) {
+		/* E.g. the vendor kernels of various Kobo and Tolino Ebook
+		 * readers disable the fuel gauge on shutdown. If a kernel
+		 * without fuel gauge support is booted after that, the fuel
+		 * gauge will get decalibrated.
+		 */
+		dev_info(&pdev->dev, "Fuel gauge not enabled, enabling now\n");
+		dev_info(&pdev->dev, "Expect unprecise results\n");
+		regmap_update_bits(info->rn5t618->regmap, RN5T618_CONTROL,
+				   FG_ENABLE, FG_ENABLE);
+	}
+
+	psy_cfg.drv_data = info;
+	info->battery = devm_power_supply_register(&pdev->dev,
+						   &rn5t618_battery_desc,
+						   &psy_cfg);
+	if (IS_ERR(info->battery)) {
+		ret = PTR_ERR(info->battery);
+		dev_err(&pdev->dev, "failed to register battery: %d\n", ret);
+		return ret;
+	}
+
+	info->adp = devm_power_supply_register(&pdev->dev,
+					       &rn5t618_adp_desc,
+					       &psy_cfg);
+	if (IS_ERR(info->adp)) {
+		ret = PTR_ERR(info->adp);
+		dev_err(&pdev->dev, "failed to register adp: %d\n", ret);
+		return ret;
+	}
+
+	info->usb = devm_power_supply_register(&pdev->dev,
+					       &rn5t618_usb_desc,
+					       &psy_cfg);
+	if (IS_ERR(info->usb)) {
+		ret = PTR_ERR(info->usb);
+		dev_err(&pdev->dev, "failed to register usb: %d\n", ret);
+		return ret;
+	}
+
+	if (info->rn5t618->irq_data)
+		info->irq = regmap_irq_get_virq(info->rn5t618->irq_data,
+						RN5T618_IRQ_CHG);
+
+	if (info->irq < 0)
+		info->irq = -1;
+	else {
+		ret = devm_request_threaded_irq(&pdev->dev, info->irq, NULL,
+						rn5t618_charger_irq,
+						IRQF_ONESHOT,
+						"rn5t618_power",
+						&pdev->dev);
+
+		if (ret < 0) {
+			dev_err(&pdev->dev, "request IRQ:%d fail\n",
+				info->irq);
+			info->irq = -1;
+		}
+	}
+
+	return 0;
+}
+
+static struct platform_driver rn5t618_power_driver = {
+	.driver = {
+		.name   = "rn5t618-power",
+	},
+	.probe = rn5t618_power_probe,
+};
+
+module_platform_driver(rn5t618_power_driver);
+MODULE_ALIAS("platform:rn5t618-power");
+MODULE_DESCRIPTION("Power supply driver for RICOH RN5T618");
+MODULE_LICENSE("GPL");
