Message-ID: <20200413204054.ezgtahixclkog2wi@earth.universe>
Date:   Mon, 13 Apr 2020 22:40:54 +0200
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Saravanan Sekar <sravanhome@...il.com>
Cc:     lee.jones@...aro.org, andy.shevchenko@...il.com,
        robh+dt@...nel.org, jic23@...nel.org, knaack.h@....de,
        lars@...afoo.de, pmeerw@...erw.net, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v7 4/5] power: supply: Add support for mps mp2629 battery
 charger

Hi,

On Fri, Apr 10, 2020 at 10:19:47PM +0200, Saravanan Sekar wrote:
> 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@...il.com>
> ---

Generally looks good, but I do have some comments.

>  drivers/power/supply/Kconfig          |  10 +
>  drivers/power/supply/Makefile         |   1 +
>  drivers/power/supply/mp2629_charger.c | 687 ++++++++++++++++++++++++++
>  3 files changed, 698 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..279edfe383ee
> --- /dev/null
> +++ b/drivers/power/supply/mp2629_charger.c
> @@ -0,0 +1,687 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * MP2629 battery charger driver
> + *
> + * Copyright 2020 Monolithic Power Systems, Inc
> + *
> + * Author: Saravanan Sekar <sravanhome@...il.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>
> +#include <linux/workqueue.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;
> +	struct work_struct charger_work;
> +	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;
> +}

This looks like a very rough estimate. Voltage does not drop
linearly for Li-Ion batteries. Is there a good reason for exposing
this and not letting userspace taking care of this estimation?

> +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_NOT_CHARGING;
> +			break;

This should probably set POWER_SUPPLY_STATUS_DISCHARGING vs
POWER_SUPPLY_STATUS_NOT_CHARGING based on the battery current.
NOT_CHARGING means, that the battery is idle.

> +		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 void mp2629_charger_work(struct work_struct *work)
> +{
> +	struct mp2629_charger *charger;
> +	unsigned int rval;
> +	int ret;
> +
> +	charger = container_of(work, struct mp2629_charger, charger_work);
> +
> +	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);
> +}
> +
> +static irqreturn_t mp2629_irq_handler(int irq, void *dev_id)
> +{
> +	struct mp2629_charger *charger = dev_id;
> +
> +	schedule_work(&charger->charger_work);
> +	return IRQ_HANDLED;
> +}

The worker is only called here, so it is an open coded
request_threaded_irq() without IRQF_ONESHOT. Please use
the standard request_threaded_irq() and remove the worker.

It simplifies the code and removes a race condition during
driver removal: If any interrupt arrives between canceling
the charger work and disabling the IRQ the driver might execute
the worker with free'd resources.

> +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);

Needs to be documented in device specific properties:

Documentation/ABI/testing/sysfs-class-power

> +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);
> +
> +	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] = iio_channel_get(dev, adc_chan_name[i]);

Why not devm_iio_channel_get() for further simplifying the code?

> +		if (IS_ERR(charger->iiochan[i])) {
> +			ret = PTR_ERR(charger->iiochan[i]);
> +			goto iio_fail;
> +		}
> +	}
> +
> +	charger->usb = devm_power_supply_register(dev, &mp2629_usb_desc, NULL);
> +	if (IS_ERR(charger->usb)) {
> +		ret = PTR_ERR(charger->usb);
> +		goto iio_fail;
> +	}

devm_ based resource allocation should not follow non-devm
allocation without a very good reason. Usually we release resources
in reverse allocation order, like unrolling a stack. Having a
non-devm requested resource request before a devm resource request
breaks this pattern.

> +	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)) {
> +		ret = PTR_ERR(charger->battery);
> +		goto iio_fail;
> +	}
> +
> +	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);
> +		goto iio_fail;
> +	}
> +
> +	regmap_update_bits(charger->regmap, MP2629_REG_TIMER_CTRL,
> +					MP2629_MASK_WDOG_CTRL, 0);
> +
> +	INIT_WORK(&charger->charger_work, mp2629_charger_work);
> +	mutex_init(&charger->lock);
> +
> +	irq = platform_get_irq(to_platform_device(pdev->dev.parent), 0);
> +	if (irq) {
> +		ret = devm_request_irq(dev, irq, mp2629_irq_handler,
> +				 IRQF_TRIGGER_RISING, "mp2629-charger",
> +				 charger);
> +		if (ret) {
> +			dev_err(dev, "failed to request gpio IRQ\n");
> +			goto iio_fail;
> +		}
> +	}
> +
> +	regmap_update_bits(charger->regmap, MP2629_REG_INTERRUPT,
> +				GENMASK(6, 5), BIT(6) | BIT(5));
> +
> +	return 0;
> +
> +iio_fail:
> +	while (i--)
> +		iio_channel_release(charger->iiochan[i]);
> +
> +	dev_err(dev, "driver register fail: %d\n", ret);
> +	return ret;
> +}
> +
> +static int mp2629_charger_remove(struct platform_device *pdev)
> +{
> +	struct mp2629_charger *charger = platform_get_drvdata(pdev);
> +	int i;
> +
> +	cancel_work_sync(&charger->charger_work);
> +
> +	for (i = 0; i < MP2629_ADC_CHAN_END; i++)
> +		iio_channel_release(charger->iiochan[i]);
> +
> +	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@...il.com>");
> +MODULE_DESCRIPTION("MP2629 Charger driver");
> +MODULE_LICENSE("GPL");

-- Sebastian

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