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From:   Saravanan Sekar <sravanhome@gmail.com>
To:     lee.jones@linaro.org, andy.shevchenko@gmail.com,
        robh+dt@kernel.org, jic23@kernel.org, knaack.h@gmx.de,
        lars@metafoo.de, pmeerw@pmeerw.net, sre@kernel.org
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-iio@vger.kernel.org, linux-pm@vger.kernel.org,
        Saravanan Sekar <sravanhome@gmail.com>
Subject: [PATCH v9 4/6] power: supply: Add support for mps mp2629 battery charger
Date:   Wed, 15 Apr 2020 18:20:28 +0200
Message-Id: <20200415162030.16414-5-sravanhome@gmail.com>
In-Reply-To: <20200415162030.16414-1-sravanhome@gmail.com>
References: <20200415162030.16414-1-sravanhome@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The mp2629 provides switching-mode battery charge management for
single-cell Li-ion or Li-polymer battery. Driver supports the
access/control input source and battery charging parameters.

Signed-off-by: Saravanan Sekar <sravanhome@gmail.com>
---
 drivers/power/supply/Kconfig          |  10 +
 drivers/power/supply/Makefile         |   1 +
 drivers/power/supply/mp2629_charger.c | 667 ++++++++++++++++++++++++++
 3 files changed, 678 insertions(+)
 create mode 100644 drivers/power/supply/mp2629_charger.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index f3424fdce341..05b3f66946ad 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -541,6 +541,16 @@ config CHARGER_MAX8998
 	  Say Y to enable support for the battery charger control sysfs and
 	  platform data of MAX8998/LP3974 PMICs.
 
+config CHARGER_MP2629
+	tristate "Monolithic power system MP2629 Battery charger"
+	depends on MFD_MP2629
+	depends on MP2629_ADC
+	depends on IIO
+	help
+	  Select this option to enable support for Monolithic power system
+	  Battery charger. This driver provies Battery charger power management
+	  functions on the systems.
+
 config CHARGER_QCOM_SMBB
 	tristate "Qualcomm Switch-Mode Battery Charger and Boost"
 	depends on MFD_SPMI_PMIC || COMPILE_TEST
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 6c7da920ea83..41cb64f09e49 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_CHARGER_MAX77650)	+= max77650-charger.o
 obj-$(CONFIG_CHARGER_MAX77693)	+= max77693_charger.o
 obj-$(CONFIG_CHARGER_MAX8997)	+= max8997_charger.o
 obj-$(CONFIG_CHARGER_MAX8998)	+= max8998_charger.o
+obj-$(CONFIG_CHARGER_MP2629)	+= mp2629_charger.o
 obj-$(CONFIG_CHARGER_QCOM_SMBB)	+= qcom_smbb.o
 obj-$(CONFIG_CHARGER_BQ2415X)	+= bq2415x_charger.o
 obj-$(CONFIG_CHARGER_BQ24190)	+= bq24190_charger.o
diff --git a/drivers/power/supply/mp2629_charger.c b/drivers/power/supply/mp2629_charger.c
new file mode 100644
index 000000000000..e6889daaf7d6
--- /dev/null
+++ b/drivers/power/supply/mp2629_charger.c
@@ -0,0 +1,667 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MP2629 battery charger driver
+ *
+ * Copyright 2020 Monolithic Power Systems, Inc
+ *
+ * Author: Saravanan Sekar <sravanhome@gmail.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/mp2629.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+
+#define MP2629_REG_INPUT_ILIM		0x00
+#define MP2629_REG_INPUT_VLIM		0x01
+#define MP2629_REG_CHARGE_CTRL		0x04
+#define MP2629_REG_CHARGE_ILIM		0x05
+#define MP2629_REG_PRECHARGE		0x06
+#define MP2629_REG_TERM_CURRENT		0x06
+#define MP2629_REG_CHARGE_VLIM		0x07
+#define MP2629_REG_TIMER_CTRL		0x08
+#define MP2629_REG_IMPEDANCE_COMP	0x09
+#define MP2629_REG_INTERRUPT		0x0b
+#define MP2629_REG_STATUS		0x0c
+#define MP2629_REG_FAULT		0x0d
+
+#define MP2629_MASK_INPUT_TYPE		GENMASK(7, 5)
+#define MP2629_MASK_CHARGE_TYPE		GENMASK(4, 3)
+#define MP2629_MASK_CHARGE_CTRL		GENMASK(5, 4)
+#define MP2629_MASK_WDOG_CTRL		GENMASK(5, 4)
+#define MP2629_MASK_IMPEDANCE		GENMASK(7, 4)
+
+#define MP2629_INPUTSOURCE_CHANGE	GENMASK(7, 5)
+#define MP2629_CHARGING_CHANGE		GENMASK(4, 3)
+#define MP2629_FAULT_BATTERY		BIT(3)
+#define MP2629_FAULT_THERMAL		BIT(4)
+#define MP2629_FAULT_INPUT		BIT(5)
+#define MP2629_FAULT_OTG		BIT(6)
+
+#define MP2629_MAX_BATT_CAPACITY	100
+
+#define MP2629_PROPS(_idx, _min, _max, _step)		\
+	[_idx] = {					\
+		.min	= _min,				\
+		.max	= _max,				\
+		.step	= _step,			\
+}
+
+enum mp2629_source_type {
+	MP2629_SOURCE_TYPE_NO_INPUT,
+	MP2629_SOURCE_TYPE_NON_STD,
+	MP2629_SOURCE_TYPE_SDP,
+	MP2629_SOURCE_TYPE_CDP,
+	MP2629_SOURCE_TYPE_DCP,
+	MP2629_SOURCE_TYPE_OTG = 7,
+};
+
+enum mp2629_field {
+	INPUT_ILIM,
+	INPUT_VLIM,
+	CHARGE_ILIM,
+	CHARGE_VLIM,
+	PRECHARGE,
+	TERM_CURRENT,
+	MP2629_MAX_FIELD
+};
+
+struct mp2629_charger {
+	struct device *dev;
+	int status;
+	int fault;
+
+	struct regmap *regmap;
+	struct regmap_field *regmap_fields[MP2629_MAX_FIELD];
+	struct mutex lock;
+	struct power_supply *usb;
+	struct power_supply *battery;
+	struct iio_channel *iiochan[MP2629_ADC_CHAN_END];
+};
+
+struct mp2629_prop {
+	int reg;
+	int mask;
+	int min;
+	int max;
+	int step;
+	int shift;
+};
+
+static enum power_supply_usb_type mp2629_usb_types[] = {
+	POWER_SUPPLY_USB_TYPE_SDP,
+	POWER_SUPPLY_USB_TYPE_DCP,
+	POWER_SUPPLY_USB_TYPE_CDP,
+	POWER_SUPPLY_USB_TYPE_PD_DRP,
+	POWER_SUPPLY_USB_TYPE_UNKNOWN
+};
+
+static enum power_supply_property mp2629_charger_usb_props[] = {
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_USB_TYPE,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
+	POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT,
+};
+
+static enum power_supply_property mp2629_charger_bat_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_CHARGE_TYPE,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_PRECHARGE_CURRENT,
+	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
+};
+
+static struct mp2629_prop props[] = {
+	MP2629_PROPS(INPUT_ILIM, 100000, 3250000, 50000),
+	MP2629_PROPS(INPUT_VLIM, 3800000, 5300000, 100000),
+	MP2629_PROPS(CHARGE_ILIM, 320000, 4520000, 40000),
+	MP2629_PROPS(CHARGE_VLIM, 3400000, 4670000, 10000),
+	MP2629_PROPS(PRECHARGE, 120000, 720000, 40000),
+	MP2629_PROPS(TERM_CURRENT, 80000, 680000, 40000),
+};
+
+static const struct reg_field mp2629_reg_fields[] = {
+	[INPUT_ILIM]	= REG_FIELD(MP2629_REG_INPUT_ILIM, 0, 5),
+	[INPUT_VLIM]	= REG_FIELD(MP2629_REG_INPUT_VLIM, 0, 3),
+	[CHARGE_ILIM]	= REG_FIELD(MP2629_REG_CHARGE_ILIM, 0, 6),
+	[CHARGE_VLIM]	= REG_FIELD(MP2629_REG_CHARGE_VLIM, 1, 7),
+	[PRECHARGE]	= REG_FIELD(MP2629_REG_PRECHARGE, 4, 7),
+	[TERM_CURRENT]	= REG_FIELD(MP2629_REG_TERM_CURRENT, 0, 3),
+};
+
+static char *adc_chan_name[] = {
+	"mp2629-batt-volt",
+	"mp2629-system-volt",
+	"mp2629-input-volt",
+	"mp2629-batt-current",
+	"mp2629-input-current",
+};
+
+static int mp2629_read_adc(struct mp2629_charger *charger,
+			   enum mp2629_adc_chan ch,
+			   union power_supply_propval *val)
+{
+	int ret;
+	int chval;
+
+	ret = iio_read_channel_processed(charger->iiochan[ch], &chval);
+	if (ret)
+		return ret;
+
+	val->intval = chval * 1000;
+
+	return 0;
+}
+
+static int mp2629_get_prop(struct mp2629_charger *charger,
+			   enum mp2629_field fld,
+			   union power_supply_propval *val)
+{
+	int ret;
+	unsigned int rval;
+
+	ret = regmap_field_read(charger->regmap_fields[fld], &rval);
+	if (ret)
+		return ret;
+
+	val->intval = rval * props[fld].step + props[fld].min;
+
+	return 0;
+}
+
+static int mp2629_set_prop(struct mp2629_charger *charger,
+			   enum mp2629_field fld,
+			   const union power_supply_propval *val)
+{
+	unsigned int rval;
+
+	if (val->intval < props[fld].min || val->intval > props[fld].max)
+		return -EINVAL;
+
+	rval = (val->intval - props[fld].min) / props[fld].step;
+	return regmap_field_write(charger->regmap_fields[fld], rval);
+}
+
+static int mp2629_get_battery_capacity(struct mp2629_charger *charger,
+				       union power_supply_propval *val)
+{
+	union power_supply_propval vnow, vlim;
+	int ret;
+
+	ret = mp2629_read_adc(charger, MP2629_BATT_VOLT, &vnow);
+	if (ret)
+		return ret;
+
+	ret = mp2629_get_prop(charger, CHARGE_VLIM, &vlim);
+	if (ret)
+		return ret;
+
+	val->intval = (vnow.intval * 100) / vlim.intval;
+	val->intval = min(val->intval, MP2629_MAX_BATT_CAPACITY);
+
+	return 0;
+}
+
+static int mp2629_charger_battery_get_prop(struct power_supply *psy,
+					enum power_supply_property psp,
+					union power_supply_propval *val)
+{
+	struct mp2629_charger *charger = dev_get_drvdata(psy->dev.parent);
+	unsigned int rval;
+	int ret = 0;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		ret = mp2629_read_adc(charger, MP2629_BATT_VOLT, val);
+		break;
+
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		ret = mp2629_read_adc(charger, MP2629_BATT_CURRENT, val);
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		val->intval = 4520000;
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		val->intval = 4670000;
+		break;
+
+	case POWER_SUPPLY_PROP_CAPACITY:
+		ret = mp2629_get_battery_capacity(charger, val);
+		break;
+
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		ret = mp2629_get_prop(charger, TERM_CURRENT, val);
+		break;
+
+	case POWER_SUPPLY_PROP_PRECHARGE_CURRENT:
+		ret = mp2629_get_prop(charger, PRECHARGE, val);
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		ret = mp2629_get_prop(charger, CHARGE_VLIM, val);
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		ret = mp2629_get_prop(charger, CHARGE_ILIM, val);
+		break;
+
+	case POWER_SUPPLY_PROP_HEALTH:
+		if (!charger->fault)
+			val->intval = POWER_SUPPLY_HEALTH_GOOD;
+		if (MP2629_FAULT_BATTERY & charger->fault)
+			val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+		else if (MP2629_FAULT_THERMAL & charger->fault)
+			val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+		else if (MP2629_FAULT_INPUT & charger->fault)
+			val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+		break;
+
+	case POWER_SUPPLY_PROP_STATUS:
+		ret = regmap_read(charger->regmap, MP2629_REG_STATUS, &rval);
+		if (ret)
+			break;
+
+		rval = (rval & MP2629_MASK_CHARGE_TYPE) >> 3;
+		switch (rval) {
+		case 0x00:
+			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+			break;
+		case 0x01:
+		case 0x10:
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+			break;
+		case 0x11:
+			val->intval = POWER_SUPPLY_STATUS_FULL;
+		}
+		break;
+
+	case POWER_SUPPLY_PROP_CHARGE_TYPE:
+		ret = regmap_read(charger->regmap, MP2629_REG_STATUS, &rval);
+		if (ret)
+			break;
+
+		rval = (rval & MP2629_MASK_CHARGE_TYPE) >> 3;
+		switch (rval) {
+		case 0x00:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
+			break;
+		case 0x01:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
+			break;
+		case 0x10:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_STANDARD;
+			break;
+		default:
+			val->intval = POWER_SUPPLY_CHARGE_TYPE_UNKNOWN;
+		}
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int mp2629_charger_battery_set_prop(struct power_supply *psy,
+					enum power_supply_property psp,
+					const union power_supply_propval *val)
+{
+	struct mp2629_charger *charger = dev_get_drvdata(psy->dev.parent);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		return mp2629_set_prop(charger, TERM_CURRENT, val);
+
+	case POWER_SUPPLY_PROP_PRECHARGE_CURRENT:
+		return mp2629_set_prop(charger, PRECHARGE, val);
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		return mp2629_set_prop(charger, CHARGE_VLIM, val);
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		return mp2629_set_prop(charger, CHARGE_ILIM, val);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mp2629_charger_usb_get_prop(struct power_supply *psy,
+				enum power_supply_property psp,
+				union power_supply_propval *val)
+{
+	struct mp2629_charger *charger = dev_get_drvdata(psy->dev.parent);
+	unsigned int rval;
+	int ret;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		ret = regmap_read(charger->regmap, MP2629_REG_STATUS, &rval);
+		if (ret)
+			break;
+
+		val->intval = !!(rval & MP2629_MASK_INPUT_TYPE);
+		break;
+
+	case POWER_SUPPLY_PROP_USB_TYPE:
+		ret = regmap_read(charger->regmap, MP2629_REG_STATUS, &rval);
+		if (ret)
+			break;
+
+		rval = (rval & MP2629_MASK_INPUT_TYPE) >> 5;
+		switch (rval) {
+		case MP2629_SOURCE_TYPE_SDP:
+			val->intval = POWER_SUPPLY_USB_TYPE_SDP;
+			break;
+		case MP2629_SOURCE_TYPE_CDP:
+			val->intval = POWER_SUPPLY_USB_TYPE_CDP;
+			break;
+		case MP2629_SOURCE_TYPE_DCP:
+			val->intval = POWER_SUPPLY_USB_TYPE_DCP;
+			break;
+		case MP2629_SOURCE_TYPE_OTG:
+			val->intval = POWER_SUPPLY_USB_TYPE_PD_DRP;
+			break;
+		default:
+			val->intval = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+			break;
+		}
+		break;
+
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		ret = mp2629_read_adc(charger, MP2629_INPUT_VOLT, val);
+		break;
+
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		ret = mp2629_read_adc(charger, MP2629_INPUT_CURRENT, val);
+		break;
+
+	case POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT:
+		ret = mp2629_get_prop(charger, INPUT_VLIM, val);
+		break;
+
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		ret = mp2629_get_prop(charger, INPUT_ILIM, val);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int mp2629_charger_usb_set_prop(struct power_supply *psy,
+				enum power_supply_property psp,
+				const union power_supply_propval *val)
+{
+	struct mp2629_charger *charger = dev_get_drvdata(psy->dev.parent);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT:
+		return mp2629_set_prop(charger, INPUT_VLIM, val);
+
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		return mp2629_set_prop(charger, INPUT_ILIM, val);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mp2629_charger_battery_prop_writeable(struct power_supply *psy,
+				     enum power_supply_property psp)
+{
+	return (psp == POWER_SUPPLY_PROP_PRECHARGE_CURRENT) ||
+	       (psp == POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT) ||
+	       (psp == POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT) ||
+	       (psp == POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE);
+}
+
+static int mp2629_charger_usb_prop_writeable(struct power_supply *psy,
+				     enum power_supply_property psp)
+{
+	return (psp == POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT) ||
+	       (psp == POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT);
+}
+
+static irqreturn_t mp2629_irq_handler(int irq, void *dev_id)
+{
+	struct mp2629_charger *charger = dev_id;
+	unsigned int rval;
+	int ret;
+
+	mutex_lock(&charger->lock);
+
+	ret = regmap_read(charger->regmap, MP2629_REG_FAULT, &rval);
+	if (ret)
+		goto unlock;
+
+	if (rval) {
+		charger->fault = rval;
+		if (MP2629_FAULT_BATTERY & rval)
+			dev_err(charger->dev, "Battery fault OVP");
+		else if (MP2629_FAULT_THERMAL & rval)
+			dev_err(charger->dev, "Thermal shutdown fault");
+		else if (MP2629_FAULT_INPUT & rval)
+			dev_err(charger->dev, "no input or input OVP");
+		else if (MP2629_FAULT_OTG & rval)
+			dev_err(charger->dev, "VIN overloaded");
+
+		goto unlock;
+	}
+
+	ret = regmap_read(charger->regmap, MP2629_REG_STATUS, &rval);
+	if (ret)
+		goto unlock;
+
+	if (rval & MP2629_INPUTSOURCE_CHANGE)
+		power_supply_changed(charger->usb);
+	else if (rval & MP2629_CHARGING_CHANGE)
+		power_supply_changed(charger->battery);
+
+unlock:
+	mutex_unlock(&charger->lock);
+
+	return IRQ_HANDLED;
+}
+
+static const struct power_supply_desc mp2629_usb_desc = {
+	.name		= "mp2629_usb",
+	.type		= POWER_SUPPLY_TYPE_USB,
+	.usb_types      = mp2629_usb_types,
+	.num_usb_types  = ARRAY_SIZE(mp2629_usb_types),
+	.properties	= mp2629_charger_usb_props,
+	.num_properties	= ARRAY_SIZE(mp2629_charger_usb_props),
+	.get_property	= mp2629_charger_usb_get_prop,
+	.set_property	= mp2629_charger_usb_set_prop,
+	.property_is_writeable = mp2629_charger_usb_prop_writeable,
+};
+
+static const struct power_supply_desc mp2629_battery_desc = {
+	.name		= "mp2629_battery",
+	.type		= POWER_SUPPLY_TYPE_BATTERY,
+	.properties	= mp2629_charger_bat_props,
+	.num_properties	= ARRAY_SIZE(mp2629_charger_bat_props),
+	.get_property	= mp2629_charger_battery_get_prop,
+	.set_property	= mp2629_charger_battery_set_prop,
+	.property_is_writeable = mp2629_charger_battery_prop_writeable,
+};
+
+static ssize_t batt_impedance_compensation_show(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct mp2629_charger *charger = dev_get_drvdata(dev->parent);
+	unsigned int rval;
+	int ret;
+
+	ret = regmap_read(charger->regmap, MP2629_REG_IMPEDANCE_COMP, &rval);
+	if (ret)
+		return ret;
+
+	rval = (rval >> 4) * 10;
+	return sprintf(buf, "%d mohm\n", rval);
+}
+
+static ssize_t batt_impedance_compensation_store(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf,
+					    size_t count)
+{
+	struct mp2629_charger *charger = dev_get_drvdata(dev->parent);
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val > 140)
+		return -ERANGE;
+
+	/* multiples of 10 mohm so round off */
+	val = val / 10;
+	ret = regmap_update_bits(charger->regmap, MP2629_REG_IMPEDANCE_COMP,
+					MP2629_MASK_IMPEDANCE, val << 4);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(batt_impedance_compensation);
+
+static struct attribute *mp2629_charger_sysfs_attrs[] = {
+	&dev_attr_batt_impedance_compensation.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(mp2629_charger_sysfs);
+
+static int mp2629_charger_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mp2629_info *ddata = dev_get_drvdata(dev->parent);
+	struct mp2629_charger *charger;
+	struct power_supply_config psy_cfg = {};
+	int ret, i, irq;
+
+	charger = devm_kzalloc(dev, sizeof(*charger), GFP_KERNEL);
+	if (!charger)
+		return -ENOMEM;
+
+	charger->regmap = ddata->regmap;
+	charger->dev = dev;
+	platform_set_drvdata(pdev, charger);
+
+	irq = platform_get_irq_optional(to_platform_device(dev->parent), 0);
+	if (irq < 0) {
+		dev_err(dev, "get irq fail: %d\n", irq);
+		return irq;
+	}
+
+	for (i = 0; i < MP2629_MAX_FIELD; i++) {
+		charger->regmap_fields[i] = devm_regmap_field_alloc(dev,
+					charger->regmap, mp2629_reg_fields[i]);
+		if (IS_ERR(charger->regmap_fields[i])) {
+			dev_err(dev, "regmap field alloc fail %d\n", i);
+			return PTR_ERR(charger->regmap_fields[i]);
+		}
+	}
+
+	for (i = 0; i < MP2629_ADC_CHAN_END; i++) {
+		charger->iiochan[i] = devm_iio_channel_get(dev,
+							adc_chan_name[i]);
+		if (IS_ERR(charger->iiochan[i])) {
+			dev_err(dev, "iio chan get %s err\n", adc_chan_name[i]);
+			return PTR_ERR(charger->iiochan[i]);
+		}
+	}
+
+	charger->usb = devm_power_supply_register(dev, &mp2629_usb_desc, NULL);
+	if (IS_ERR(charger->usb)) {
+		dev_err(dev, "power supply register usb failed\n");
+		return PTR_ERR(charger->usb);
+	}
+
+	psy_cfg.drv_data = charger;
+	psy_cfg.attr_grp = mp2629_charger_sysfs_groups;
+	charger->battery = devm_power_supply_register(dev,
+					 &mp2629_battery_desc, &psy_cfg);
+	if (IS_ERR(charger->battery)) {
+		dev_err(dev, "power supply register battery failed\n");
+		return PTR_ERR(charger->battery);
+	}
+
+	ret = regmap_update_bits(charger->regmap, MP2629_REG_CHARGE_CTRL,
+					MP2629_MASK_CHARGE_CTRL, BIT(4));
+	if (ret) {
+		dev_err(dev, "enable charge fail: %d\n", ret);
+		return ret;
+	}
+
+	regmap_update_bits(charger->regmap, MP2629_REG_TIMER_CTRL,
+					MP2629_MASK_WDOG_CTRL, 0);
+
+	mutex_init(&charger->lock);
+
+	ret = devm_request_threaded_irq(dev, irq, NULL,	mp2629_irq_handler,
+					IRQF_ONESHOT | IRQF_TRIGGER_RISING,
+					"mp2629-charger", charger);
+	if (ret) {
+		dev_err(dev, "failed to request gpio IRQ\n");
+		return ret;
+	}
+
+	regmap_update_bits(charger->regmap, MP2629_REG_INTERRUPT,
+				GENMASK(6, 5), BIT(6) | BIT(5));
+
+	return 0;
+}
+
+static int mp2629_charger_remove(struct platform_device *pdev)
+{
+	struct mp2629_charger *charger = platform_get_drvdata(pdev);
+
+	regmap_update_bits(charger->regmap, MP2629_REG_CHARGE_CTRL,
+					MP2629_MASK_CHARGE_CTRL, 0);
+	return 0;
+}
+
+static const struct of_device_id mp2629_charger_of_match[] = {
+	{ .compatible = "mps,mp2629_charger"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, mp2629_charger_of_match);
+
+static struct platform_driver mp2629_charger_driver = {
+	.driver = {
+		.name = "mp2629_charger",
+		.of_match_table = mp2629_charger_of_match,
+	},
+	.probe		= mp2629_charger_probe,
+	.remove		= mp2629_charger_remove,
+};
+module_platform_driver(mp2629_charger_driver);
+
+MODULE_AUTHOR("Saravanan Sekar <sravanhome@gmail.com>");
+MODULE_DESCRIPTION("MP2629 Charger driver");
+MODULE_LICENSE("GPL");
-- 
2.17.1