power_supply: Add support for Richtek RT9455 battery charger

Based on the datasheet found here:
http://www.richtek.com/download_ds.jsp?p=RT9455

Signed-off-by: Anda-Maria Nicolae <anda-maria.nicolae@intel.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/power/Kconfig

@@ -460,6 +460,13 @@ config BATTERY_RT5033
 	  The fuelgauge calculates and determines the battery state of charge
 	  according to battery open circuit voltage.
 
+config CHARGER_RT9455
+	tristate "Richtek RT9455 battery charger driver"
+	depends on I2C && GPIOLIB
+	select REGMAP_I2C
+	help
+	  Say Y to enable support for Richtek RT9455 battery charger.
+
 source "drivers/power/reset/Kconfig"
 
 endif # POWER_SUPPLY

drivers/power/Makefile

@@ -37,6 +37,7 @@ obj-$(CONFIG_BATTERY_MAX17040)	+= max17040_battery.o
 obj-$(CONFIG_BATTERY_MAX17042)	+= max17042_battery.o
 obj-$(CONFIG_BATTERY_Z2)	+= z2_battery.o
 obj-$(CONFIG_BATTERY_RT5033)	+= rt5033_battery.o
+obj-$(CONFIG_CHARGER_RT9455)	+= rt9455_charger.o
 obj-$(CONFIG_BATTERY_S3C_ADC)	+= s3c_adc_battery.o
 obj-$(CONFIG_BATTERY_TWL4030_MADC)	+= twl4030_madc_battery.o
 obj-$(CONFIG_CHARGER_88PM860X)	+= 88pm860x_charger.o

drivers/power/rt9455_charger.c

@@ -0,0 +1,1751 @@
+/*
+ * Driver for Richtek RT9455WSC battery charger.
+ *
+ * Copyright (C) 2015 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/of_irq.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/power_supply.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/usb/phy.h>
+#include <linux/regmap.h>
+
+#define RT9455_MANUFACTURER			"Richtek"
+#define RT9455_MODEL_NAME			"RT9455"
+#define RT9455_DRIVER_NAME			"rt9455-charger"
+
+#define RT9455_IRQ_NAME				"interrupt"
+
+#define RT9455_PWR_RDY_DELAY			1 /* 1 second */
+#define RT9455_MAX_CHARGING_TIME		21600 /* 6 hrs */
+#define RT9455_BATT_PRESENCE_DELAY		60 /* 60 seconds */
+
+#define RT9455_CHARGE_MODE			0x00
+#define RT9455_BOOST_MODE			0x01
+
+#define RT9455_FAULT				0x03
+
+#define RT9455_IAICR_100MA			0x00
+#define RT9455_IAICR_500MA			0x01
+#define RT9455_IAICR_NO_LIMIT			0x03
+
+#define RT9455_CHARGE_DISABLE			0x00
+#define RT9455_CHARGE_ENABLE			0x01
+
+#define RT9455_PWR_FAULT			0x00
+#define RT9455_PWR_GOOD				0x01
+
+#define RT9455_REG_CTRL1			0x00 /* CTRL1 reg address */
+#define RT9455_REG_CTRL2			0x01 /* CTRL2 reg address */
+#define RT9455_REG_CTRL3			0x02 /* CTRL3 reg address */
+#define RT9455_REG_DEV_ID			0x03 /* DEV_ID reg address */
+#define RT9455_REG_CTRL4			0x04 /* CTRL4 reg address */
+#define RT9455_REG_CTRL5			0x05 /* CTRL5 reg address */
+#define RT9455_REG_CTRL6			0x06 /* CTRL6 reg address */
+#define RT9455_REG_CTRL7			0x07 /* CTRL7 reg address */
+#define RT9455_REG_IRQ1				0x08 /* IRQ1 reg address */
+#define RT9455_REG_IRQ2				0x09 /* IRQ2 reg address */
+#define RT9455_REG_IRQ3				0x0A /* IRQ3 reg address */
+#define RT9455_REG_MASK1			0x0B /* MASK1 reg address */
+#define RT9455_REG_MASK2			0x0C /* MASK2 reg address */
+#define RT9455_REG_MASK3			0x0D /* MASK3 reg address */
+
+enum rt9455_fields {
+	F_STAT, F_BOOST, F_PWR_RDY, F_OTG_PIN_POLARITY, /* CTRL1 reg fields */
+
+	F_IAICR, F_TE_SHDN_EN, F_HIGHER_OCP, F_TE, F_IAICR_INT, F_HIZ,
+	F_OPA_MODE, /* CTRL2 reg fields */
+
+	F_VOREG, F_OTG_PL, F_OTG_EN, /* CTRL3 reg fields */
+
+	F_VENDOR_ID, F_CHIP_REV, /* DEV_ID reg fields */
+
+	F_RST, /* CTRL4 reg fields */
+
+	F_TMR_EN, F_MIVR, F_IPREC, F_IEOC_PERCENTAGE, /* CTRL5 reg fields*/
+
+	F_IAICR_SEL, F_ICHRG, F_VPREC, /* CTRL6 reg fields */
+
+	F_BATD_EN, F_CHG_EN, F_VMREG, /* CTRL7 reg fields */
+
+	F_TSDI, F_VINOVPI, F_BATAB, /* IRQ1 reg fields */
+
+	F_CHRVPI, F_CHBATOVI, F_CHTERMI, F_CHRCHGI, F_CH32MI, F_CHTREGI,
+	F_CHMIVRI, /* IRQ2 reg fields */
+
+	F_BSTBUSOVI, F_BSTOLI, F_BSTLOWVI, F_BST32SI, /* IRQ3 reg fields */
+
+	F_TSDM, F_VINOVPIM, F_BATABM, /* MASK1 reg fields */
+
+	F_CHRVPIM, F_CHBATOVIM, F_CHTERMIM, F_CHRCHGIM, F_CH32MIM, F_CHTREGIM,
+	F_CHMIVRIM, /* MASK2 reg fields */
+
+	F_BSTVINOVIM, F_BSTOLIM, F_BSTLOWVIM, F_BST32SIM, /* MASK3 reg fields */
+
+	F_MAX_FIELDS
+};
+
+static const struct reg_field rt9455_reg_fields[] = {
+	[F_STAT]		= REG_FIELD(RT9455_REG_CTRL1, 4, 5),
+	[F_BOOST]		= REG_FIELD(RT9455_REG_CTRL1, 3, 3),
+	[F_PWR_RDY]		= REG_FIELD(RT9455_REG_CTRL1, 2, 2),
+	[F_OTG_PIN_POLARITY]	= REG_FIELD(RT9455_REG_CTRL1, 1, 1),
+
+	[F_IAICR]		= REG_FIELD(RT9455_REG_CTRL2, 6, 7),
+	[F_TE_SHDN_EN]		= REG_FIELD(RT9455_REG_CTRL2, 5, 5),
+	[F_HIGHER_OCP]		= REG_FIELD(RT9455_REG_CTRL2, 4, 4),
+	[F_TE]			= REG_FIELD(RT9455_REG_CTRL2, 3, 3),
+	[F_IAICR_INT]		= REG_FIELD(RT9455_REG_CTRL2, 2, 2),
+	[F_HIZ]			= REG_FIELD(RT9455_REG_CTRL2, 1, 1),
+	[F_OPA_MODE]		= REG_FIELD(RT9455_REG_CTRL2, 0, 0),
+
+	[F_VOREG]		= REG_FIELD(RT9455_REG_CTRL3, 2, 7),
+	[F_OTG_PL]		= REG_FIELD(RT9455_REG_CTRL3, 1, 1),
+	[F_OTG_EN]		= REG_FIELD(RT9455_REG_CTRL3, 0, 0),
+
+	[F_VENDOR_ID]		= REG_FIELD(RT9455_REG_DEV_ID, 4, 7),
+	[F_CHIP_REV]		= REG_FIELD(RT9455_REG_DEV_ID, 0, 3),
+
+	[F_RST]			= REG_FIELD(RT9455_REG_CTRL4, 7, 7),
+
+	[F_TMR_EN]		= REG_FIELD(RT9455_REG_CTRL5, 7, 7),
+	[F_MIVR]		= REG_FIELD(RT9455_REG_CTRL5, 4, 5),
+	[F_IPREC]		= REG_FIELD(RT9455_REG_CTRL5, 2, 3),
+	[F_IEOC_PERCENTAGE]	= REG_FIELD(RT9455_REG_CTRL5, 0, 1),
+
+	[F_IAICR_SEL]		= REG_FIELD(RT9455_REG_CTRL6, 7, 7),
+	[F_ICHRG]		= REG_FIELD(RT9455_REG_CTRL6, 4, 6),
+	[F_VPREC]		= REG_FIELD(RT9455_REG_CTRL6, 0, 2),
+
+	[F_BATD_EN]		= REG_FIELD(RT9455_REG_CTRL7, 6, 6),
+	[F_CHG_EN]		= REG_FIELD(RT9455_REG_CTRL7, 4, 4),
+	[F_VMREG]		= REG_FIELD(RT9455_REG_CTRL7, 0, 3),
+
+	[F_TSDI]		= REG_FIELD(RT9455_REG_IRQ1, 7, 7),
+	[F_VINOVPI]		= REG_FIELD(RT9455_REG_IRQ1, 6, 6),
+	[F_BATAB]		= REG_FIELD(RT9455_REG_IRQ1, 0, 0),
+
+	[F_CHRVPI]		= REG_FIELD(RT9455_REG_IRQ2, 7, 7),
+	[F_CHBATOVI]		= REG_FIELD(RT9455_REG_IRQ2, 5, 5),
+	[F_CHTERMI]		= REG_FIELD(RT9455_REG_IRQ2, 4, 4),
+	[F_CHRCHGI]		= REG_FIELD(RT9455_REG_IRQ2, 3, 3),
+	[F_CH32MI]		= REG_FIELD(RT9455_REG_IRQ2, 2, 2),
+	[F_CHTREGI]		= REG_FIELD(RT9455_REG_IRQ2, 1, 1),
+	[F_CHMIVRI]		= REG_FIELD(RT9455_REG_IRQ2, 0, 0),
+
+	[F_BSTBUSOVI]		= REG_FIELD(RT9455_REG_IRQ3, 7, 7),
+	[F_BSTOLI]		= REG_FIELD(RT9455_REG_IRQ3, 6, 6),
+	[F_BSTLOWVI]		= REG_FIELD(RT9455_REG_IRQ3, 5, 5),
+	[F_BST32SI]		= REG_FIELD(RT9455_REG_IRQ3, 3, 3),
+
+	[F_TSDM]		= REG_FIELD(RT9455_REG_MASK1, 7, 7),
+	[F_VINOVPIM]		= REG_FIELD(RT9455_REG_MASK1, 6, 6),
+	[F_BATABM]		= REG_FIELD(RT9455_REG_MASK1, 0, 0),
+
+	[F_CHRVPIM]		= REG_FIELD(RT9455_REG_MASK2, 7, 7),
+	[F_CHBATOVIM]		= REG_FIELD(RT9455_REG_MASK2, 5, 5),
+	[F_CHTERMIM]		= REG_FIELD(RT9455_REG_MASK2, 4, 4),
+	[F_CHRCHGIM]		= REG_FIELD(RT9455_REG_MASK2, 3, 3),
+	[F_CH32MIM]		= REG_FIELD(RT9455_REG_MASK2, 2, 2),
+	[F_CHTREGIM]		= REG_FIELD(RT9455_REG_MASK2, 1, 1),
+	[F_CHMIVRIM]		= REG_FIELD(RT9455_REG_MASK2, 0, 0),
+
+	[F_BSTVINOVIM]		= REG_FIELD(RT9455_REG_MASK3, 7, 7),
+	[F_BSTOLIM]		= REG_FIELD(RT9455_REG_MASK3, 6, 6),
+	[F_BSTLOWVIM]		= REG_FIELD(RT9455_REG_MASK3, 5, 5),
+	[F_BST32SIM]		= REG_FIELD(RT9455_REG_MASK3, 3, 3),
+};
+
+#define GET_MASK(fid)	(BIT(rt9455_reg_fields[fid].msb + 1) - \
+			 BIT(rt9455_reg_fields[fid].lsb))
+
+/*
+ * Each array initialised below shows the possible real-world values for a
+ * group of bits belonging to RT9455 registers. The arrays are sorted in
+ * ascending order. The index of each real-world value represents the value
+ * that is encoded in the group of bits belonging to RT9455 registers.
+ */
+/* REG06[6:4] (ICHRG) in uAh */
+static const int rt9455_ichrg_values[] = {
+	 500000,  650000,  800000,  950000, 1100000, 1250000, 1400000, 1550000
+};
+
+/*
+ * When the charger is in charge mode, REG02[7:2] represent battery regulation
+ * voltage.
+ */
+/* REG02[7:2] (VOREG) in uV */
+static const int rt9455_voreg_values[] = {
+	3500000, 3520000, 3540000, 3560000, 3580000, 3600000, 3620000, 3640000,
+	3660000, 3680000, 3700000, 3720000, 3740000, 3760000, 3780000, 3800000,
+	3820000, 3840000, 3860000, 3880000, 3900000, 3920000, 3940000, 3960000,
+	3980000, 4000000, 4020000, 4040000, 4060000, 4080000, 4100000, 4120000,
+	4140000, 4160000, 4180000, 4200000, 4220000, 4240000, 4260000, 4280000,
+	4300000, 4330000, 4350000, 4370000, 4390000, 4410000, 4430000, 4450000,
+	4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000,
+	4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000, 4450000
+};
+
+/*
+ * When the charger is in boost mode, REG02[7:2] represent boost output
+ * voltage.
+ */
+/* REG02[7:2] (Boost output voltage) in uV */
+static const int rt9455_boost_voltage_values[] = {
+	4425000, 4450000, 4475000, 4500000, 4525000, 4550000, 4575000, 4600000,
+	4625000, 4650000, 4675000, 4700000, 4725000, 4750000, 4775000, 4800000,
+	4825000, 4850000, 4875000, 4900000, 4925000, 4950000, 4975000, 5000000,
+	5025000, 5050000, 5075000, 5100000, 5125000, 5150000, 5175000, 5200000,
+	5225000, 5250000, 5275000, 5300000, 5325000, 5350000, 5375000, 5400000,
+	5425000, 5450000, 5475000, 5500000, 5525000, 5550000, 5575000, 5600000,
+	5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000,
+	5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000, 5600000,
+};
+
+/* REG07[3:0] (VMREG) in uV */
+static const int rt9455_vmreg_values[] = {
+	4200000, 4220000, 4240000, 4260000, 4280000, 4300000, 4320000, 4340000,
+	4360000, 4380000, 4400000, 4430000, 4450000, 4450000, 4450000, 4450000
+};
+
+/* REG05[5:4] (IEOC_PERCENTAGE) */
+static const int rt9455_ieoc_percentage_values[] = {
+	10, 30, 20, 30
+};
+
+/* REG05[1:0] (MIVR) in uV */
+static const int rt9455_mivr_values[] = {
+	4000000, 4250000, 4500000, 5000000
+};
+
+/* REG05[1:0] (IAICR) in uA */
+static const int rt9455_iaicr_values[] = {
+	100000, 500000, 1000000, 2000000
+};
+
+struct rt9455_info {
+	struct i2c_client		*client;
+	struct regmap			*regmap;
+	struct regmap_field		*regmap_fields[F_MAX_FIELDS];
+	struct power_supply		*charger;
+#if IS_ENABLED(CONFIG_USB_PHY)
+	struct usb_phy			*usb_phy;
+	struct notifier_block		nb;
+#endif
+	struct delayed_work		pwr_rdy_work;
+	struct delayed_work		max_charging_time_work;
+	struct delayed_work		batt_presence_work;
+	u32				voreg;
+	u32				boost_voltage;
+};
+
+/*
+ * Iterate through each element of the 'tbl' array until an element whose value
+ * is greater than v is found. Return the index of the respective element,
+ * or the index of the last element in the array, if no such element is found.
+ */
+static unsigned int rt9455_find_idx(const int tbl[], int tbl_size, int v)
+{
+	int i;
+
+	/*
+	 * No need to iterate until the last index in the table because
+	 * if no element greater than v is found in the table,
+	 * or if only the last element is greater than v,
+	 * function returns the index of the last element.
+	 */
+	for (i = 0; i < tbl_size - 1; i++)
+		if (v <= tbl[i])
+			return i;
+
+	return (tbl_size - 1);
+}
+
+static int rt9455_get_field_val(struct rt9455_info *info,
+				enum rt9455_fields field,
+				const int tbl[], int tbl_size, int *val)
+{
+	unsigned int v;
+	int ret;
+
+	ret = regmap_field_read(info->regmap_fields[field], &v);
+	if (ret)
+		return ret;
+
+	v = (v >= tbl_size) ? (tbl_size - 1) : v;
+	*val = tbl[v];
+
+	return 0;
+}
+
+static int rt9455_set_field_val(struct rt9455_info *info,
+				enum rt9455_fields field,
+				const int tbl[], int tbl_size, int val)
+{
+	unsigned int idx = rt9455_find_idx(tbl, tbl_size, val);
+
+	return regmap_field_write(info->regmap_fields[field], idx);
+}
+
+static int rt9455_register_reset(struct rt9455_info *info)
+{
+	struct device *dev = &info->client->dev;
+	unsigned int v;
+	int ret, limit = 100;
+
+	ret = regmap_field_write(info->regmap_fields[F_RST], 0x01);
+	if (ret) {
+		dev_err(dev, "Failed to set RST bit\n");
+		return ret;
+	}
+
+	/*
+	 * To make sure that reset operation has finished, loop until RST bit
+	 * is set to 0.
+	 */
+	do {
+		ret = regmap_field_read(info->regmap_fields[F_RST], &v);
+		if (ret) {
+			dev_err(dev, "Failed to read RST bit\n");
+			return ret;
+		}
+
+		if (!v)
+			break;
+
+		usleep_range(10, 100);
+	} while (--limit);
+
+	if (!limit)
+		return -EIO;
+
+	return 0;
+}
+
+/* Charger power supply property routines */
+static enum power_supply_property rt9455_charger_properties[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_ONLINE,
+	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_SCOPE,
+	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
+	POWER_SUPPLY_PROP_MODEL_NAME,
+	POWER_SUPPLY_PROP_MANUFACTURER,
+};
+
+static char *rt9455_charger_supplied_to[] = {
+	"main-battery",
+};
+
+static int rt9455_charger_get_status(struct rt9455_info *info,
+				     union power_supply_propval *val)
+{
+	unsigned int v, pwr_rdy;
+	int ret;
+
+	ret = regmap_field_read(info->regmap_fields[F_PWR_RDY],
+				&pwr_rdy);
+	if (ret) {
+		dev_err(&info->client->dev, "Failed to read PWR_RDY bit\n");
+		return ret;
+	}
+
+	/*
+	 * If PWR_RDY bit is unset, the battery is discharging. Otherwise,
+	 * STAT bits value must be checked.
+	 */
+	if (!pwr_rdy) {
+		val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		return 0;
+	}
+
+	ret = regmap_field_read(info->regmap_fields[F_STAT], &v);
+	if (ret) {
+		dev_err(&info->client->dev, "Failed to read STAT bits\n");
+		return ret;
+	}
+
+	switch (v) {
+	case 0:
+		/*
+		 * If PWR_RDY bit is set, but STAT bits value is 0, the charger
+		 * may be in one of the following cases:
+		 * 1. CHG_EN bit is 0.
+		 * 2. CHG_EN bit is 1 but the battery is not connected.
+		 * In any of these cases, POWER_SUPPLY_STATUS_NOT_CHARGING is
+		 * returned.
+		 */
+		val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+		return 0;
+	case 1:
+		val->intval = POWER_SUPPLY_STATUS_CHARGING;
+		return 0;
+	case 2:
+		val->intval = POWER_SUPPLY_STATUS_FULL;
+		return 0;
+	default:
+		val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+		return 0;
+	}
+}
+
+static int rt9455_charger_get_health(struct rt9455_info *info,
+				     union power_supply_propval *val)
+{
+	struct device *dev = &info->client->dev;
+	unsigned int v;
+	int ret;
+
+	val->intval = POWER_SUPPLY_HEALTH_GOOD;
+
+	ret = regmap_read(info->regmap, RT9455_REG_IRQ1, &v);
+	if (ret) {
+		dev_err(dev, "Failed to read IRQ1 register\n");
+		return ret;
+	}
+
+	if (v & GET_MASK(F_TSDI)) {
+		val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+		return 0;
+	}
+	if (v & GET_MASK(F_VINOVPI)) {
+		val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+		return 0;
+	}
+	if (v & GET_MASK(F_BATAB)) {
+		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+		return 0;
+	}
+
+	ret = regmap_read(info->regmap, RT9455_REG_IRQ2, &v);
+	if (ret) {
+		dev_err(dev, "Failed to read IRQ2 register\n");
+		return ret;
+	}
+
+	if (v & GET_MASK(F_CHBATOVI)) {
+		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+		return 0;
+	}
+	if (v & GET_MASK(F_CH32MI)) {
+		val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
+		return 0;
+	}
+
+	ret = regmap_read(info->regmap, RT9455_REG_IRQ3, &v);
+	if (ret) {
+		dev_err(dev, "Failed to read IRQ3 register\n");
+		return ret;
+	}
+
+	if (v & GET_MASK(F_BSTBUSOVI)) {
+		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+		return 0;
+	}
+	if (v & GET_MASK(F_BSTOLI)) {
+		val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+		return 0;
+	}
+	if (v & GET_MASK(F_BSTLOWVI)) {
+		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+		return 0;
+	}
+	if (v & GET_MASK(F_BST32SI)) {
+		val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
+		return 0;
+	}
+
+	ret = regmap_field_read(info->regmap_fields[F_STAT], &v);
+	if (ret) {
+		dev_err(dev, "Failed to read STAT bits\n");
+		return ret;
+	}
+
+	if (v == RT9455_FAULT) {
+		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+		return 0;
+	}
+
+	return 0;
+}
+
+static int rt9455_charger_get_battery_presence(struct rt9455_info *info,
+					       union power_supply_propval *val)
+{
+	unsigned int v;
+	int ret;
+
+	ret = regmap_field_read(info->regmap_fields[F_BATAB], &v);
+	if (ret) {
+		dev_err(&info->client->dev, "Failed to read BATAB bit\n");
+		return ret;
+	}
+
+	/*
+	 * Since BATAB is 1 when battery is NOT present and 0 otherwise,
+	 * !BATAB is returned.
+	 */
+	val->intval = !v;
+
+	return 0;
+}
+
+static int rt9455_charger_get_online(struct rt9455_info *info,
+				     union power_supply_propval *val)
+{
+	unsigned int v;
+	int ret;
+
+	ret = regmap_field_read(info->regmap_fields[F_PWR_RDY], &v);
+	if (ret) {
+		dev_err(&info->client->dev, "Failed to read PWR_RDY bit\n");
+		return ret;
+	}
+
+	val->intval = (int)v;
+
+	return 0;
+}
+
+static int rt9455_charger_get_current(struct rt9455_info *info,
+				      union power_supply_propval *val)
+{
+	int curr;
+	int ret;
+
+	ret = rt9455_get_field_val(info, F_ICHRG,
+				   rt9455_ichrg_values,
+				   ARRAY_SIZE(rt9455_ichrg_values),
+				   &curr);
+	if (ret) {
+		dev_err(&info->client->dev, "Failed to read ICHRG value\n");
+		return ret;
+	}
+
+	val->intval = curr;
+
+	return 0;
+}
+
+static int rt9455_charger_get_current_max(struct rt9455_info *info,
+					  union power_supply_propval *val)
+{
+	int idx = ARRAY_SIZE(rt9455_ichrg_values) - 1;
+
+	val->intval = rt9455_ichrg_values[idx];
+
+	return 0;
+}
+
+static int rt9455_charger_get_voltage(struct rt9455_info *info,
+				      union power_supply_propval *val)
+{
+	int voltage;
+	int ret;
+
+	ret = rt9455_get_field_val(info, F_VOREG,
+				   rt9455_voreg_values,
+				   ARRAY_SIZE(rt9455_voreg_values),
+				   &voltage);
+	if (ret) {
+		dev_err(&info->client->dev, "Failed to read VOREG value\n");
+		return ret;
+	}
+
+	val->intval = voltage;
+
+	return 0;
+}
+
+static int rt9455_charger_get_voltage_max(struct rt9455_info *info,
+					  union power_supply_propval *val)
+{
+	int idx = ARRAY_SIZE(rt9455_vmreg_values) - 1;
+
+	val->intval = rt9455_vmreg_values[idx];
+
+	return 0;
+}
+
+static int rt9455_charger_get_term_current(struct rt9455_info *info,
+					   union power_supply_propval *val)
+{
+	struct device *dev = &info->client->dev;
+	int ichrg, ieoc_percentage, ret;
+
+	ret = rt9455_get_field_val(info, F_ICHRG,
+				   rt9455_ichrg_values,
+				   ARRAY_SIZE(rt9455_ichrg_values),
+				   &ichrg);
+	if (ret) {
+		dev_err(dev, "Failed to read ICHRG value\n");
+		return ret;
+	}
+
+	ret = rt9455_get_field_val(info, F_IEOC_PERCENTAGE,
+				   rt9455_ieoc_percentage_values,
+				   ARRAY_SIZE(rt9455_ieoc_percentage_values),
+				   &ieoc_percentage);
+	if (ret) {
+		dev_err(dev, "Failed to read IEOC value\n");
+		return ret;
+	}
+
+	val->intval = ichrg * ieoc_percentage / 100;
+
+	return 0;
+}
+
+static int rt9455_charger_get_property(struct power_supply *psy,
+				       enum power_supply_property psp,
+				       union power_supply_propval *val)
+{
+	struct rt9455_info *info = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		return rt9455_charger_get_status(info, val);
+	case POWER_SUPPLY_PROP_HEALTH:
+		return rt9455_charger_get_health(info, val);
+	case POWER_SUPPLY_PROP_PRESENT:
+		return rt9455_charger_get_battery_presence(info, val);
+	case POWER_SUPPLY_PROP_ONLINE:
+		return rt9455_charger_get_online(info, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		return rt9455_charger_get_current(info, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		return rt9455_charger_get_current_max(info, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		return rt9455_charger_get_voltage(info, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		return rt9455_charger_get_voltage_max(info, val);
+	case POWER_SUPPLY_PROP_SCOPE:
+		val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
+		return 0;
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		return rt9455_charger_get_term_current(info, val);
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = RT9455_MODEL_NAME;
+		return 0;
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = RT9455_MANUFACTURER;
+		return 0;
+	default:
+		return -ENODATA;
+	}
+}
+
+static int rt9455_hw_init(struct rt9455_info *info, u32 ichrg,
+			  u32 ieoc_percentage,
+			  u32 mivr, u32 iaicr)
+{
+	struct device *dev = &info->client->dev;
+	int idx, ret;
+
+	ret = rt9455_register_reset(info);
+	if (ret) {
+		dev_err(dev, "Power On Reset failed\n");
+		return ret;
+	}
+
+	/* Set TE bit in order to enable end of charge detection */
+	ret = regmap_field_write(info->regmap_fields[F_TE], 1);
+	if (ret) {
+		dev_err(dev, "Failed to set TE bit\n");
+		return ret;
+	}
+
+	/* Set TE_SHDN_EN bit in order to enable end of charge detection */
+	ret = regmap_field_write(info->regmap_fields[F_TE_SHDN_EN], 1);
+	if (ret) {
+		dev_err(dev, "Failed to set TE_SHDN_EN bit\n");
+		return ret;
+	}
+
+	/*
+	 * Set BATD_EN bit in order to enable battery detection
+	 * when charging is done
+	 */
+	ret = regmap_field_write(info->regmap_fields[F_BATD_EN], 1);
+	if (ret) {
+		dev_err(dev, "Failed to set BATD_EN bit\n");
+		return ret;
+	}
+
+	/*
+	 * Disable Safety Timer. In charge mode, this timer terminates charging
+	 * if no read or write via I2C is done within 32 minutes. This timer
+	 * avoids overcharging the baterry when the OS is not loaded and the
+	 * charger is connected to a power source.
+	 * In boost mode, this timer triggers BST32SI interrupt if no read or
+	 * write via I2C is done within 32 seconds.
+	 * When the OS is loaded and the charger driver is inserted, it is used
+	 * delayed_work, named max_charging_time_work, to avoid overcharging
+	 * the battery.
+	 */
+	ret = regmap_field_write(info->regmap_fields[F_TMR_EN], 0x00);
+	if (ret) {
+		dev_err(dev, "Failed to disable Safety Timer\n");
+		return ret;
+	}
+
+	/* Set ICHRG to value retrieved from device-specific data */
+	ret = rt9455_set_field_val(info, F_ICHRG,
+				   rt9455_ichrg_values,
+				   ARRAY_SIZE(rt9455_ichrg_values), ichrg);
+	if (ret) {
+		dev_err(dev, "Failed to set ICHRG value\n");
+		return ret;
+	}
+
+	/* Set IEOC Percentage to value retrieved from device-specific data */
+	ret = rt9455_set_field_val(info, F_IEOC_PERCENTAGE,
+				   rt9455_ieoc_percentage_values,
+				   ARRAY_SIZE(rt9455_ieoc_percentage_values),
+				   ieoc_percentage);
+	if (ret) {
+		dev_err(dev, "Failed to set IEOC Percentage value\n");
+		return ret;
+	}
+
+	/* Set VOREG to value retrieved from device-specific data */
+	ret = rt9455_set_field_val(info, F_VOREG,
+				   rt9455_voreg_values,
+				   ARRAY_SIZE(rt9455_voreg_values),
+				   info->voreg);
+	if (ret) {
+		dev_err(dev, "Failed to set VOREG value\n");
+		return ret;
+	}
+
+	/* Set VMREG value to maximum (4.45V). */
+	idx = ARRAY_SIZE(rt9455_vmreg_values) - 1;
+	ret = rt9455_set_field_val(info, F_VMREG,
+				   rt9455_vmreg_values,
+				   ARRAY_SIZE(rt9455_vmreg_values),
+				   rt9455_vmreg_values[idx]);
+	if (ret) {
+		dev_err(dev, "Failed to set VMREG value\n");
+		return ret;
+	}
+
+	/*
+	 * Set MIVR to value retrieved from device-specific data.
+	 * If no value is specified, default value for MIVR is 4.5V.
+	 */
+	if (mivr == -1)
+		mivr = 4500000;
+
+	ret = rt9455_set_field_val(info, F_MIVR,
+				   rt9455_mivr_values,
+				   ARRAY_SIZE(rt9455_mivr_values), mivr);
+	if (ret) {
+		dev_err(dev, "Failed to set MIVR value\n");
+		return ret;
+	}
+
+	/*
+	 * Set IAICR to value retrieved from device-specific data.
+	 * If no value is specified, default value for IAICR is 500 mA.
+	 */
+	if (iaicr == -1)
+		iaicr = 500000;
+
+	ret = rt9455_set_field_val(info, F_IAICR,
+				   rt9455_iaicr_values,
+				   ARRAY_SIZE(rt9455_iaicr_values), iaicr);
+	if (ret) {
+		dev_err(dev, "Failed to set IAICR value\n");
+		return ret;
+	}
+
+	/*
+	 * Set IAICR_INT bit so that IAICR value is determined by IAICR bits
+	 * and not by OTG pin.
+	 */
+	ret = regmap_field_write(info->regmap_fields[F_IAICR_INT], 0x01);
+	if (ret) {
+		dev_err(dev, "Failed to set IAICR_INT bit\n");
+		return ret;
+	}
+
+	/*
+	 * Disable CHMIVRI interrupt. Because the driver sets MIVR value,
+	 * CHMIVRI is triggered, but there is no action to be taken by the
+	 * driver when CHMIVRI is triggered.
+	 */
+	ret = regmap_field_write(info->regmap_fields[F_CHMIVRIM], 0x01);
+	if (ret) {
+		dev_err(dev, "Failed to mask CHMIVRI interrupt\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Before setting the charger into boost mode, boost output voltage is
+ * set. This is needed because boost output voltage may differ from battery
+ * regulation voltage. F_VOREG bits represent either battery regulation voltage
+ * or boost output voltage, depending on the mode the charger is. Both battery
+ * regulation voltage and boost output voltage are read from DT/ACPI during
+ * probe.
+ */
+static int rt9455_set_boost_voltage_before_boost_mode(struct rt9455_info *info)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	ret = rt9455_set_field_val(info, F_VOREG,
+				   rt9455_boost_voltage_values,
+				   ARRAY_SIZE(rt9455_boost_voltage_values),
+				   info->boost_voltage);
+	if (ret) {
+		dev_err(dev, "Failed to set boost output voltage value\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Before setting the charger into charge mode, battery regulation voltage is
+ * set. This is needed because boost output voltage may differ from battery
+ * regulation voltage. F_VOREG bits represent either battery regulation voltage
+ * or boost output voltage, depending on the mode the charger is. Both battery
+ * regulation voltage and boost output voltage are read from DT/ACPI during
+ * probe.
+ */
+static int rt9455_set_voreg_before_charge_mode(struct rt9455_info *info)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	ret = rt9455_set_field_val(info, F_VOREG,
+				   rt9455_voreg_values,
+				   ARRAY_SIZE(rt9455_voreg_values),
+				   info->voreg);
+	if (ret) {
+		dev_err(dev, "Failed to set VOREG value\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int rt9455_irq_handler_check_irq1_register(struct rt9455_info *info,
+						  bool *_is_battery_absent,
+						  bool *_alert_userspace)
+{
+	unsigned int irq1, mask1, mask2;
+	struct device *dev = &info->client->dev;
+	bool is_battery_absent = false;
+	bool alert_userspace = false;
+	int ret;
+
+	ret = regmap_read(info->regmap, RT9455_REG_IRQ1, &irq1);
+	if (ret) {
+		dev_err(dev, "Failed to read IRQ1 register\n");
+		return ret;
+	}
+
+	ret = regmap_read(info->regmap, RT9455_REG_MASK1, &mask1);
+	if (ret) {
+		dev_err(dev, "Failed to read MASK1 register\n");
+		return ret;
+	}
+
+	if (irq1 & GET_MASK(F_TSDI)) {
+		dev_err(dev, "Thermal shutdown fault occurred\n");
+		alert_userspace = true;
+	}
+
+	if (irq1 & GET_MASK(F_VINOVPI)) {
+		dev_err(dev, "Overvoltage input occurred\n");
+		alert_userspace = true;
+	}
+
+	if (irq1 & GET_MASK(F_BATAB)) {
+		dev_err(dev, "Battery absence occurred\n");
+		is_battery_absent = true;
+		alert_userspace = true;
+
+		if ((mask1 & GET_MASK(F_BATABM)) == 0) {
+			ret = regmap_field_write(info->regmap_fields[F_BATABM],
+						 0x01);
+			if (ret) {
+				dev_err(dev, "Failed to mask BATAB interrupt\n");
+				return ret;
+			}
+		}
+
+		ret = regmap_read(info->regmap, RT9455_REG_MASK2, &mask2);
+		if (ret) {
+			dev_err(dev, "Failed to read MASK2 register\n");
+			return ret;
+		}
+
+		if (mask2 & GET_MASK(F_CHTERMIM)) {
+			ret = regmap_field_write(
+				info->regmap_fields[F_CHTERMIM], 0x00);
+			if (ret) {
+				dev_err(dev, "Failed to unmask CHTERMI interrupt\n");
+				return ret;
+			}
+		}
+
+		if (mask2 & GET_MASK(F_CHRCHGIM)) {
+			ret = regmap_field_write(
+				info->regmap_fields[F_CHRCHGIM], 0x00);
+			if (ret) {
+				dev_err(dev, "Failed to unmask CHRCHGI interrupt\n");
+				return ret;
+			}
+		}
+
+		/*
+		 * When the battery is absent, max_charging_time_work is
+		 * cancelled, since no charging is done.
+		 */
+		cancel_delayed_work_sync(&info->max_charging_time_work);
+		/*
+		 * Since no interrupt is triggered when the battery is
+		 * reconnected, max_charging_time_work is not rescheduled.
+		 * Therefore, batt_presence_work is scheduled to check whether
+		 * the battery is still absent or not.
+		 */
+		queue_delayed_work(system_power_efficient_wq,
+				   &info->batt_presence_work,
+				   RT9455_BATT_PRESENCE_DELAY * HZ);
+	}
+
+	*_is_battery_absent = is_battery_absent;
+
+	if (alert_userspace)
+		*_alert_userspace = alert_userspace;
+
+	return 0;
+}
+
+static int rt9455_irq_handler_check_irq2_register(struct rt9455_info *info,
+						  bool is_battery_absent,
+						  bool *_alert_userspace)
+{
+	unsigned int irq2, mask2;
+	struct device *dev = &info->client->dev;
+	bool alert_userspace = false;
+	int ret;
+
+	ret = regmap_read(info->regmap, RT9455_REG_IRQ2, &irq2);
+	if (ret) {
+		dev_err(dev, "Failed to read IRQ2 register\n");
+		return ret;
+	}
+
+	ret = regmap_read(info->regmap, RT9455_REG_MASK2, &mask2);
+	if (ret) {
+		dev_err(dev, "Failed to read MASK2 register\n");
+		return ret;
+	}
+
+	if (irq2 & GET_MASK(F_CHRVPI)) {
+		dev_dbg(dev, "Charger fault occurred\n");
+		alert_userspace = true;
+		/*
+		 * CHRVPI bit is set in 2 cases:
+		 * 1. when the power source is connected to the charger.
+		 * 2. when the power source is disconnected from the charger.
+		 * To identify the case, PWR_RDY bit is checked. Because
+		 * PWR_RDY bit is set / cleared after CHRVPI interrupt is
+		 * triggered, it is used delayed_work to later read PWR_RDY bit.
+		 */
+		queue_delayed_work(system_power_efficient_wq,
+				   &info->pwr_rdy_work,
+				   RT9455_PWR_RDY_DELAY * HZ);
+	}
+	if (irq2 & GET_MASK(F_CHBATOVI)) {
+		dev_err(dev, "Battery OVP occurred\n");
+		alert_userspace = true;
+	}
+	if (irq2 & GET_MASK(F_CHTERMI)) {
+		dev_dbg(dev, "Charge terminated\n");
+		if (!is_battery_absent) {
+			if ((mask2 & GET_MASK(F_CHTERMIM)) == 0) {
+				ret = regmap_field_write(
+					info->regmap_fields[F_CHTERMIM], 0x01);
+				if (ret) {
+					dev_err(dev, "Failed to mask CHTERMI interrupt\n");
+					return ret;
+				}
+				/*
+				 * Update MASK2 value, since CHTERMIM bit is
+				 * set.
+				 */
+				mask2 = mask2 | GET_MASK(F_CHTERMIM);
+			}
+			cancel_delayed_work_sync(&info->max_charging_time_work);
+			alert_userspace = true;
+		}
+	}
+	if (irq2 & GET_MASK(F_CHRCHGI)) {
+		dev_dbg(dev, "Recharge request\n");
+		ret = regmap_field_write(info->regmap_fields[F_CHG_EN],
+					 RT9455_CHARGE_ENABLE);
+		if (ret) {
+			dev_err(dev, "Failed to enable charging\n");
+			return ret;
+		}
+		if (mask2 & GET_MASK(F_CHTERMIM)) {
+			ret = regmap_field_write(
+				info->regmap_fields[F_CHTERMIM], 0x00);
+			if (ret) {
+				dev_err(dev, "Failed to unmask CHTERMI interrupt\n");
+				return ret;
+			}
+			/* Update MASK2 value, since CHTERMIM bit is cleared. */
+			mask2 = mask2 & ~GET_MASK(F_CHTERMIM);
+		}
+		if (!is_battery_absent) {
+			/*
+			 * No need to check whether the charger is connected to
+			 * power source when CHRCHGI is received, since CHRCHGI
+			 * is not triggered if the charger is not connected to
+			 * the power source.
+			 */
+			queue_delayed_work(system_power_efficient_wq,
+					   &info->max_charging_time_work,
+					   RT9455_MAX_CHARGING_TIME * HZ);
+			alert_userspace = true;
+		}
+	}
+	if (irq2 & GET_MASK(F_CH32MI)) {
+		dev_err(dev, "Charger fault. 32 mins timeout occurred\n");
+		alert_userspace = true;
+	}
+	if (irq2 & GET_MASK(F_CHTREGI)) {
+		dev_warn(dev,
+			 "Charger warning. Thermal regulation loop active\n");
+		alert_userspace = true;
+	}
+	if (irq2 & GET_MASK(F_CHMIVRI)) {
+		dev_dbg(dev,
+			"Charger warning. Input voltage MIVR loop active\n");
+	}
+
+	if (alert_userspace)
+		*_alert_userspace = alert_userspace;
+
+	return 0;
+}
+
+static int rt9455_irq_handler_check_irq3_register(struct rt9455_info *info,
+						  bool *_alert_userspace)
+{
+	unsigned int irq3, mask3;
+	struct device *dev = &info->client->dev;
+	bool alert_userspace = false;
+	int ret;
+
+	ret = regmap_read(info->regmap, RT9455_REG_IRQ3, &irq3);
+	if (ret) {
+		dev_err(dev, "Failed to read IRQ3 register\n");
+		return ret;
+	}
+
+	ret = regmap_read(info->regmap, RT9455_REG_MASK3, &mask3);
+	if (ret) {
+		dev_err(dev, "Failed to read MASK3 register\n");
+		return ret;
+	}
+
+	if (irq3 & GET_MASK(F_BSTBUSOVI)) {
+		dev_err(dev, "Boost fault. Overvoltage input occurred\n");
+		alert_userspace = true;
+	}
+	if (irq3 & GET_MASK(F_BSTOLI)) {
+		dev_err(dev, "Boost fault. Overload\n");
+		alert_userspace = true;
+	}
+	if (irq3 & GET_MASK(F_BSTLOWVI)) {
+		dev_err(dev, "Boost fault. Battery voltage too low\n");
+		alert_userspace = true;
+	}
+	if (irq3 & GET_MASK(F_BST32SI)) {
+		dev_err(dev, "Boost fault. 32 seconds timeout occurred.\n");
+		alert_userspace = true;
+	}
+
+	if (alert_userspace) {
+		dev_info(dev, "Boost fault occurred, therefore the charger goes into charge mode\n");
+		ret = rt9455_set_voreg_before_charge_mode(info);
+		if (ret) {
+			dev_err(dev, "Failed to set VOREG before entering charge mode\n");
+			return ret;
+		}
+		ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
+					 RT9455_CHARGE_MODE);
+		if (ret) {
+			dev_err(dev, "Failed to set charger in charge mode\n");
+			return ret;
+		}
+		*_alert_userspace = alert_userspace;
+	}
+
+	return 0;
+}
+
+static irqreturn_t rt9455_irq_handler_thread(int irq, void *data)
+{
+	struct rt9455_info *info = data;
+	struct device *dev;
+	bool alert_userspace = false;
+	bool is_battery_absent = false;
+	unsigned int status;
+	int ret;
+
+	if (!info)
+		return IRQ_NONE;
+
+	dev = &info->client->dev;
+
+	if (irq != info->client->irq) {
+		dev_err(dev, "Interrupt is not for RT9455 charger\n");
+		return IRQ_NONE;
+	}
+
+	ret = regmap_field_read(info->regmap_fields[F_STAT], &status);
+	if (ret) {
+		dev_err(dev, "Failed to read STAT bits\n");
+		return IRQ_HANDLED;
+	}
+	dev_dbg(dev, "Charger status is %d\n", status);
+
+	/*
+	 * Each function that processes an IRQ register receives as output
+	 * parameter alert_userspace pointer. alert_userspace is set to true
+	 * in such a function only if an interrupt has occurred in the
+	 * respective interrupt register. This way, it is avoided the following
+	 * case: interrupt occurs only in IRQ1 register,
+	 * rt9455_irq_handler_check_irq1_register() function sets to true
+	 * alert_userspace, but rt9455_irq_handler_check_irq2_register()
+	 * and rt9455_irq_handler_check_irq3_register() functions set to false
+	 * alert_userspace and power_supply_changed() is never called.
+	 */
+	ret = rt9455_irq_handler_check_irq1_register(info, &is_battery_absent,
+						     &alert_userspace);
+	if (ret) {
+		dev_err(dev, "Failed to handle IRQ1 register\n");
+		return IRQ_HANDLED;
+	}
+
+	ret = rt9455_irq_handler_check_irq2_register(info, is_battery_absent,
+						     &alert_userspace);
+	if (ret) {
+		dev_err(dev, "Failed to handle IRQ2 register\n");
+		return IRQ_HANDLED;
+	}
+
+	ret = rt9455_irq_handler_check_irq3_register(info, &alert_userspace);
+	if (ret) {
+		dev_err(dev, "Failed to handle IRQ3 register\n");
+		return IRQ_HANDLED;
+	}
+
+	if (alert_userspace) {
+		/*
+		 * Sometimes, an interrupt occurs while rt9455_probe() function
+		 * is executing and power_supply_register() is not yet called.
+		 * Do not call power_supply_charged() in this case.
+		 */
+		if (info->charger)
+			power_supply_changed(info->charger);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int rt9455_discover_charger(struct rt9455_info *info, u32 *ichrg,
+				   u32 *ieoc_percentage,
+				   u32 *mivr, u32 *iaicr)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	if (!dev->of_node && !ACPI_HANDLE(dev)) {
+		dev_err(dev, "No support for either device tree or ACPI\n");
+		return -EINVAL;
+	}
+	/*
+	 * ICHRG, IEOC_PERCENTAGE, VOREG and boost output voltage are mandatory
+	 * parameters.
+	 */
+	ret = device_property_read_u32(dev, "richtek,output-charge-current",
+				       ichrg);
+	if (ret) {
+		dev_err(dev, "Error: missing \"output-charge-current\" property\n");
+		return ret;
+	}
+
+	ret = device_property_read_u32(dev, "richtek,end-of-charge-percentage",
+				       ieoc_percentage);
+	if (ret) {
+		dev_err(dev, "Error: missing \"end-of-charge-percentage\" property\n");
+		return ret;
+	}
+
+	ret = device_property_read_u32(dev,
+				       "richtek,battery-regulation-voltage",
+				       &info->voreg);
+	if (ret) {
+		dev_err(dev, "Error: missing \"battery-regulation-voltage\" property\n");
+		return ret;
+	}
+
+	ret = device_property_read_u32(dev, "richtek,boost-output-voltage",
+				       &info->boost_voltage);
+	if (ret) {
+		dev_err(dev, "Error: missing \"boost-output-voltage\" property\n");
+		return ret;
+	}
+
+	/*
+	 * MIVR and IAICR are optional parameters. Do not return error if one of
+	 * them is not present in ACPI table or device tree specification.
+	 */
+	device_property_read_u32(dev, "richtek,min-input-voltage-regulation",
+				 mivr);
+	device_property_read_u32(dev, "richtek,avg-input-current-regulation",
+				 iaicr);
+
+	return 0;
+}
+
+static int rt9455_usb_event_none(struct rt9455_info *info,
+				 u8 opa_mode, u8 iaicr)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	if (opa_mode == RT9455_BOOST_MODE) {
+		ret = rt9455_set_voreg_before_charge_mode(info);
+		if (ret) {
+			dev_err(dev, "Failed to set VOREG before entering charge mode\n");
+			return ret;
+		}
+		/*
+		 * If the charger is in boost mode, and it has received
+		 * USB_EVENT_NONE, this means the consumer device powered by the
+		 * charger is not connected anymore.
+		 * In this case, the charger goes into charge mode.
+		 */
+		dev_dbg(dev, "USB_EVENT_NONE received, therefore the charger goes into charge mode\n");
+		ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
+					 RT9455_CHARGE_MODE);
+		if (ret) {
+			dev_err(dev, "Failed to set charger in charge mode\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	dev_dbg(dev, "USB_EVENT_NONE received, therefore IAICR is set to its minimum value\n");
+	if (iaicr != RT9455_IAICR_100MA) {
+		ret = regmap_field_write(info->regmap_fields[F_IAICR],
+					 RT9455_IAICR_100MA);
+		if (ret) {
+			dev_err(dev, "Failed to set IAICR value\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	return NOTIFY_OK;
+}
+
+static int rt9455_usb_event_vbus(struct rt9455_info *info,
+				 u8 opa_mode, u8 iaicr)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	if (opa_mode == RT9455_BOOST_MODE) {
+		ret = rt9455_set_voreg_before_charge_mode(info);
+		if (ret) {
+			dev_err(dev, "Failed to set VOREG before entering charge mode\n");
+			return ret;
+		}
+		/*
+		 * If the charger is in boost mode, and it has received
+		 * USB_EVENT_VBUS, this means the consumer device powered by the
+		 * charger is not connected anymore.
+		 * In this case, the charger goes into charge mode.
+		 */
+		dev_dbg(dev, "USB_EVENT_VBUS received, therefore the charger goes into charge mode\n");
+		ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
+					 RT9455_CHARGE_MODE);
+		if (ret) {
+			dev_err(dev, "Failed to set charger in charge mode\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	dev_dbg(dev, "USB_EVENT_VBUS received, therefore IAICR is set to 500 mA\n");
+	if (iaicr != RT9455_IAICR_500MA) {
+		ret = regmap_field_write(info->regmap_fields[F_IAICR],
+					 RT9455_IAICR_500MA);
+		if (ret) {
+			dev_err(dev, "Failed to set IAICR value\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	return NOTIFY_OK;
+}
+
+static int rt9455_usb_event_id(struct rt9455_info *info,
+			       u8 opa_mode, u8 iaicr)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	if (opa_mode == RT9455_CHARGE_MODE) {
+		ret = rt9455_set_boost_voltage_before_boost_mode(info);
+		if (ret) {
+			dev_err(dev, "Failed to set boost output voltage before entering boost mode\n");
+			return ret;
+		}
+		/*
+		 * If the charger is in charge mode, and it has received
+		 * USB_EVENT_ID, this means a consumer device is connected and
+		 * it should be powered by the charger.
+		 * In this case, the charger goes into boost mode.
+		 */
+		dev_dbg(dev, "USB_EVENT_ID received, therefore the charger goes into boost mode\n");
+		ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
+					 RT9455_BOOST_MODE);
+		if (ret) {
+			dev_err(dev, "Failed to set charger in boost mode\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	dev_dbg(dev, "USB_EVENT_ID received, therefore IAICR is set to its minimum value\n");
+	if (iaicr != RT9455_IAICR_100MA) {
+		ret = regmap_field_write(info->regmap_fields[F_IAICR],
+					 RT9455_IAICR_100MA);
+		if (ret) {
+			dev_err(dev, "Failed to set IAICR value\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	return NOTIFY_OK;
+}
+
+static int rt9455_usb_event_charger(struct rt9455_info *info,
+				    u8 opa_mode, u8 iaicr)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	if (opa_mode == RT9455_BOOST_MODE) {
+		ret = rt9455_set_voreg_before_charge_mode(info);
+		if (ret) {
+			dev_err(dev, "Failed to set VOREG before entering charge mode\n");
+			return ret;
+		}
+		/*
+		 * If the charger is in boost mode, and it has received
+		 * USB_EVENT_CHARGER, this means the consumer device powered by
+		 * the charger is not connected anymore.
+		 * In this case, the charger goes into charge mode.
+		 */
+		dev_dbg(dev, "USB_EVENT_CHARGER received, therefore the charger goes into charge mode\n");
+		ret = regmap_field_write(info->regmap_fields[F_OPA_MODE],
+					 RT9455_CHARGE_MODE);
+		if (ret) {
+			dev_err(dev, "Failed to set charger in charge mode\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	dev_dbg(dev, "USB_EVENT_CHARGER received, therefore IAICR is set to no current limit\n");
+	if (iaicr != RT9455_IAICR_NO_LIMIT) {
+		ret = regmap_field_write(info->regmap_fields[F_IAICR],
+					 RT9455_IAICR_NO_LIMIT);
+		if (ret) {
+			dev_err(dev, "Failed to set IAICR value\n");
+			return NOTIFY_DONE;
+		}
+	}
+
+	return NOTIFY_OK;
+}
+
+static int rt9455_usb_event(struct notifier_block *nb,
+			    unsigned long event, void *power)
+{
+	struct rt9455_info *info = container_of(nb, struct rt9455_info, nb);
+	struct device *dev = &info->client->dev;
+	unsigned int opa_mode, iaicr;
+	int ret;
+
+	if (!info)
+		return NOTIFY_DONE;
+
+	/*
+	 * Determine whether the charger is in charge mode
+	 * or in boost mode.
+	 */
+	ret = regmap_field_read(info->regmap_fields[F_OPA_MODE],
+				&opa_mode);
+	if (ret) {
+		dev_err(dev, "Failed to read OPA_MODE value\n");
+		return NOTIFY_DONE;
+	}
+
+	ret = regmap_field_read(info->regmap_fields[F_IAICR],
+				&iaicr);
+	if (ret) {
+		dev_err(dev, "Failed to read IAICR value\n");
+		return NOTIFY_DONE;
+	}
+
+	dev_dbg(dev, "Received USB event %lu\n", event);
+	switch (event) {
+	case USB_EVENT_NONE:
+		return rt9455_usb_event_none(info, opa_mode, iaicr);
+	case USB_EVENT_VBUS:
+		return rt9455_usb_event_vbus(info, opa_mode, iaicr);
+	case USB_EVENT_ID:
+		return rt9455_usb_event_id(info, opa_mode, iaicr);
+	case USB_EVENT_CHARGER:
+		return rt9455_usb_event_charger(info, opa_mode, iaicr);
+	default:
+		dev_err(dev, "Unknown USB event\n");
+	}
+	return NOTIFY_DONE;
+}
+
+static void rt9455_pwr_rdy_work_callback(struct work_struct *work)
+{
+	struct rt9455_info *info = container_of(work, struct rt9455_info,
+						pwr_rdy_work.work);
+	struct device *dev = &info->client->dev;
+	unsigned int pwr_rdy;
+	int ret;
+
+	ret = regmap_field_read(info->regmap_fields[F_PWR_RDY], &pwr_rdy);
+	if (ret) {
+		dev_err(dev, "Failed to read PWR_RDY bit\n");
+		return;
+	}
+	switch (pwr_rdy) {
+	case RT9455_PWR_FAULT:
+		dev_dbg(dev, "Charger disconnected from power source\n");
+		cancel_delayed_work_sync(&info->max_charging_time_work);
+		break;
+	case RT9455_PWR_GOOD:
+		dev_dbg(dev, "Charger connected to power source\n");
+		ret = regmap_field_write(info->regmap_fields[F_CHG_EN],
+					 RT9455_CHARGE_ENABLE);
+		if (ret) {
+			dev_err(dev, "Failed to enable charging\n");
+			return;
+		}
+		queue_delayed_work(system_power_efficient_wq,
+				   &info->max_charging_time_work,
+				   RT9455_MAX_CHARGING_TIME * HZ);
+		break;
+	}
+}
+
+static void rt9455_max_charging_time_work_callback(struct work_struct *work)
+{
+	struct rt9455_info *info = container_of(work, struct rt9455_info,
+						max_charging_time_work.work);
+	struct device *dev = &info->client->dev;
+	int ret;
+
+	dev_err(dev, "Battery has been charging for at least 6 hours and is not yet fully charged. Battery is dead, therefore charging is disabled.\n");
+	ret = regmap_field_write(info->regmap_fields[F_CHG_EN],
+				 RT9455_CHARGE_DISABLE);
+	if (ret)
+		dev_err(dev, "Failed to disable charging\n");
+}
+
+static void rt9455_batt_presence_work_callback(struct work_struct *work)
+{
+	struct rt9455_info *info = container_of(work, struct rt9455_info,
+						batt_presence_work.work);
+	struct device *dev = &info->client->dev;
+	unsigned int irq1, mask1;
+	int ret;
+
+	ret = regmap_read(info->regmap, RT9455_REG_IRQ1, &irq1);
+	if (ret) {
+		dev_err(dev, "Failed to read IRQ1 register\n");
+		return;
+	}
+
+	/*
+	 * If the battery is still absent, batt_presence_work is rescheduled.
+	 * Otherwise, max_charging_time is scheduled.
+	 */
+	if (irq1 & GET_MASK(F_BATAB)) {
+		queue_delayed_work(system_power_efficient_wq,
+				   &info->batt_presence_work,
+				   RT9455_BATT_PRESENCE_DELAY * HZ);
+	} else {
+		queue_delayed_work(system_power_efficient_wq,
+				   &info->max_charging_time_work,
+				   RT9455_MAX_CHARGING_TIME * HZ);
+
+		ret = regmap_read(info->regmap, RT9455_REG_MASK1, &mask1);
+		if (ret) {
+			dev_err(dev, "Failed to read MASK1 register\n");
+			return;
+		}
+
+		if (mask1 & GET_MASK(F_BATABM)) {
+			ret = regmap_field_write(info->regmap_fields[F_BATABM],
+						 0x00);
+			if (ret)
+				dev_err(dev, "Failed to unmask BATAB interrupt\n");
+		}
+	}
+}
+
+static const struct power_supply_desc rt9455_charger_desc = {
+	.name			= RT9455_DRIVER_NAME,
+	.type			= POWER_SUPPLY_TYPE_USB,
+	.properties		= rt9455_charger_properties,
+	.num_properties		= ARRAY_SIZE(rt9455_charger_properties),
+	.get_property		= rt9455_charger_get_property,
+};
+
+static bool rt9455_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case RT9455_REG_DEV_ID:
+	case RT9455_REG_IRQ1:
+	case RT9455_REG_IRQ2:
+	case RT9455_REG_IRQ3:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static bool rt9455_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case RT9455_REG_DEV_ID:
+	case RT9455_REG_CTRL5:
+	case RT9455_REG_CTRL6:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static const struct regmap_config rt9455_regmap_config = {
+	.reg_bits	= 8,
+	.val_bits	= 8,
+	.writeable_reg	= rt9455_is_writeable_reg,
+	.volatile_reg	= rt9455_is_volatile_reg,
+	.max_register	= RT9455_REG_MASK3,
+	.cache_type	= REGCACHE_RBTREE,
+};
+
+static int rt9455_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+	struct device *dev = &client->dev;
+	struct rt9455_info *info;
+	struct power_supply_config rt9455_charger_config = {};
+	/*
+	 * Mandatory device-specific data values. Also, VOREG and boost output
+	 * voltage are mandatory values, but they are stored in rt9455_info
+	 * structure.
+	 */
+	u32 ichrg, ieoc_percentage;
+	/* Optional device-specific data values. */
+	u32 mivr = -1, iaicr = -1;
+	int i, ret;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_err(dev, "No support for SMBUS_BYTE_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,
+					    &rt9455_regmap_config);
+	if (IS_ERR(info->regmap)) {
+		dev_err(dev, "Failed to initialize register map\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < F_MAX_FIELDS; i++) {
+		info->regmap_fields[i] =
+			devm_regmap_field_alloc(dev, info->regmap,
+						rt9455_reg_fields[i]);
+		if (IS_ERR(info->regmap_fields[i])) {
+			dev_err(dev,
+				"Failed to allocate regmap field = %d\n", i);
+			return PTR_ERR(info->regmap_fields[i]);
+		}
+	}
+
+	ret = rt9455_discover_charger(info, &ichrg, &ieoc_percentage,
+				      &mivr, &iaicr);
+	if (ret) {
+		dev_err(dev, "Failed to discover charger\n");
+		return ret;
+	}
+
+#if IS_ENABLED(CONFIG_USB_PHY)
+	info->usb_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
+	if (IS_ERR(info->usb_phy)) {
+		dev_err(dev, "Failed to get USB transceiver\n");
+	} else {
+		info->nb.notifier_call = rt9455_usb_event;
+		ret = usb_register_notifier(info->usb_phy, &info->nb);
+		if (ret) {
+			dev_err(dev, "Failed to register USB notifier\n");
+			/*
+			 * If usb_register_notifier() fails, set notifier_call
+			 * to NULL, to avoid calling usb_unregister_notifier().
+			 */
+			info->nb.notifier_call = NULL;
+		}
+	}
+#endif
+
+	INIT_DEFERRABLE_WORK(&info->pwr_rdy_work, rt9455_pwr_rdy_work_callback);
+	INIT_DEFERRABLE_WORK(&info->max_charging_time_work,
+			     rt9455_max_charging_time_work_callback);
+	INIT_DEFERRABLE_WORK(&info->batt_presence_work,
+			     rt9455_batt_presence_work_callback);
+
+	rt9455_charger_config.of_node		= dev->of_node;
+	rt9455_charger_config.drv_data		= info;
+	rt9455_charger_config.supplied_to	= rt9455_charger_supplied_to;
+	rt9455_charger_config.num_supplicants	=
+					ARRAY_SIZE(rt9455_charger_supplied_to);
+	ret = devm_request_threaded_irq(dev, client->irq, NULL,
+					rt9455_irq_handler_thread,
+					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					RT9455_DRIVER_NAME, info);
+	if (ret) {
+		dev_err(dev, "Failed to register IRQ handler\n");
+		goto put_usb_notifier;
+	}
+
+	ret = rt9455_hw_init(info, ichrg, ieoc_percentage, mivr, iaicr);
+	if (ret) {
+		dev_err(dev, "Failed to set charger to its default values\n");
+		goto put_usb_notifier;
+	}
+
+	info->charger = devm_power_supply_register(dev, &rt9455_charger_desc,
+						   &rt9455_charger_config);
+	if (IS_ERR(info->charger)) {
+		dev_err(dev, "Failed to register charger\n");
+		ret = PTR_ERR(info->charger);
+		goto put_usb_notifier;
+	}
+
+	return 0;
+
+put_usb_notifier:
+#if IS_ENABLED(CONFIG_USB_PHY)
+	if (info->nb.notifier_call)  {
+		usb_unregister_notifier(info->usb_phy, &info->nb);
+		info->nb.notifier_call = NULL;
+	}
+#endif
+	return ret;
+}
+
+static int rt9455_remove(struct i2c_client *client)
+{
+	int ret;
+	struct rt9455_info *info = i2c_get_clientdata(client);
+
+	ret = rt9455_register_reset(info);
+	if (ret)
+		dev_err(&info->client->dev, "Failed to set charger to its default values\n");
+
+#if IS_ENABLED(CONFIG_USB_PHY)
+	if (info->nb.notifier_call)
+		usb_unregister_notifier(info->usb_phy, &info->nb);
+#endif
+
+	cancel_delayed_work_sync(&info->pwr_rdy_work);
+	cancel_delayed_work_sync(&info->max_charging_time_work);
+	cancel_delayed_work_sync(&info->batt_presence_work);
+
+	return ret;
+}
+
+static const struct i2c_device_id rt9455_i2c_id_table[] = {
+	{ RT9455_DRIVER_NAME, 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, rt9455_i2c_id_table);
+
+static const struct of_device_id rt9455_of_match[] = {
+	{ .compatible = "richtek,rt9455", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rt9455_of_match);
+
+static const struct acpi_device_id rt9455_i2c_acpi_match[] = {
+	{ "RT945500", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, rt9455_i2c_acpi_match);
+
+static struct i2c_driver rt9455_driver = {
+	.probe		= rt9455_probe,
+	.remove		= rt9455_remove,
+	.id_table	= rt9455_i2c_id_table,
+	.driver = {
+		.name		= RT9455_DRIVER_NAME,
+		.of_match_table	= of_match_ptr(rt9455_of_match),
+		.acpi_match_table = ACPI_PTR(rt9455_i2c_acpi_match),
+	},
+};
+module_i2c_driver(rt9455_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Anda-Maria Nicolae <anda-maria.nicolae@intel.com>");
+MODULE_ALIAS("i2c:rt9455-charger");
+MODULE_DESCRIPTION("Richtek RT9455 Charger Driver");