Re: [PATCH v4 4/6] power: supply: lenovo_yoga_c630_battery: add Lenovo C630 driver

[Ilpo Järvinen]

On Tue, 28 May 2024, Dmitry Baryshkov wrote:

> On the Lenovo Yoga C630 WOS laptop the EC provides access to the adapter
> and battery status. Add the driver to read power supply status on the
> laptop.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> ---
>  drivers/power/supply/Kconfig                    |   9 +
>  drivers/power/supply/Makefile                   |   1 +
>  drivers/power/supply/lenovo_yoga_c630_battery.c | 479 ++++++++++++++++++++++++
>  3 files changed, 489 insertions(+)
> 
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index 3e31375491d5..55ab8e90747d 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -167,6 +167,15 @@ config BATTERY_LEGO_EV3
>  	help
>  	  Say Y here to enable support for the LEGO MINDSTORMS EV3 battery.
>  
> +config BATTERY_LENOVO_YOGA_C630
> +	tristate "Lenovo Yoga C630 battery"
> +	depends on OF && EC_LENOVO_YOGA_C630
> +	help
> +	  This driver enables battery support on the Lenovo Yoga C630 laptop.
> +
> +	  To compile the driver as a module, choose M here: the module will be
> +	  called lenovo_yoga_c630_battery.
> +
>  config BATTERY_PMU
>  	tristate "Apple PMU battery"
>  	depends on PPC32 && ADB_PMU
> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
> index 58b567278034..8ebbdcf92dac 100644
> --- a/drivers/power/supply/Makefile
> +++ b/drivers/power/supply/Makefile
> @@ -32,6 +32,7 @@ obj-$(CONFIG_BATTERY_DS2782)	+= ds2782_battery.o
>  obj-$(CONFIG_BATTERY_GAUGE_LTC2941)	+= ltc2941-battery-gauge.o
>  obj-$(CONFIG_BATTERY_GOLDFISH)	+= goldfish_battery.o
>  obj-$(CONFIG_BATTERY_LEGO_EV3)	+= lego_ev3_battery.o
> +obj-$(CONFIG_BATTERY_LENOVO_YOGA_C630) += lenovo_yoga_c630_battery.o
>  obj-$(CONFIG_BATTERY_PMU)	+= pmu_battery.o
>  obj-$(CONFIG_BATTERY_QCOM_BATTMGR)	+= qcom_battmgr.o
>  obj-$(CONFIG_BATTERY_OLPC)	+= olpc_battery.o
> diff --git a/drivers/power/supply/lenovo_yoga_c630_battery.c b/drivers/power/supply/lenovo_yoga_c630_battery.c
> new file mode 100644
> index 000000000000..76152ad38d46
> --- /dev/null
> +++ b/drivers/power/supply/lenovo_yoga_c630_battery.c
> @@ -0,0 +1,479 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2024, Linaro Ltd
> + * Authors:
> + *    Bjorn Andersson
> + *    Dmitry Baryshkov
> + */
> +#include <linux/auxiliary_bus.h>
> +#include <linux/delay.h>
> +#include <linux/module.h>
> +#include <linux/platform_data/lenovo-yoga-c630.h>
> +#include <linux/power_supply.h>
> +
> +struct yoga_c630_psy {
> +	struct yoga_c630_ec *ec;
> +	struct device *dev;
> +	struct device_node *of_node;
> +	struct notifier_block nb;
> +	struct mutex lock;

Missing a few includes, please check them here as well.

> +	struct power_supply *adp_psy;
> +	struct power_supply *bat_psy;
> +
> +	unsigned long last_status_update;
> +
> +	bool adapter_online;
> +
> +	bool unit_mA;
> +
> +	bool bat_present;
> +	unsigned int bat_status;
> +	unsigned int design_capacity;
> +	unsigned int design_voltage;
> +	unsigned int full_charge_capacity;
> +
> +	unsigned int capacity_now;
> +	unsigned int voltage_now;
> +
> +	int current_now;
> +	int rate_now;
> +};
> +
> +#define LENOVO_EC_CACHE_TIME		(10 * HZ)
> +
> +#define LENOVO_EC_ADPT_STATUS		0xa3
> +#define LENOVO_EC_ADPT_PRESENT		BIT(7)

Add include for BIT()

> +#define LENOVO_EC_BAT_ATTRIBUTES	0xc0
> +#define LENOVO_EC_BAT_ATTR_UNIT_IS_MA	BIT(1)
> +#define LENOVO_EC_BAT_STATUS		0xc1
> +#define LENOVO_EC_BAT_REMAIN_CAPACITY	0xc2
> +#define LENOVO_EC_BAT_VOLTAGE		0xc6
> +#define LENOVO_EC_BAT_DESIGN_VOLTAGE	0xc8
> +#define LENOVO_EC_BAT_DESIGN_CAPACITY	0xca
> +#define LENOVO_EC_BAT_FULL_CAPACITY	0xcc
> +#define LENOVO_EC_BAT_CURRENT		0xd2
> +#define LENOVO_EC_BAT_FULL_FACTORY	0xd6
> +#define LENOVO_EC_BAT_PRESENT		0xda
> +#define LENOVO_EC_BAT_FULL_REGISTER	0xdb
> +#define LENOVO_EC_BAT_FULL_IS_FACTORY	BIT(0)
> +
> +/* the mutex should already be locked */
> +static int yoga_c630_psy_update_bat_info(struct yoga_c630_psy *ecbat)
> +{
> +	struct yoga_c630_ec *ec = ecbat->ec;
> +	int val;
> +
> +	val = yoga_c630_ec_read8(ec, LENOVO_EC_BAT_PRESENT);
> +	if (val < 0)
> +		return val;
> +	ecbat->bat_present = !!(val & BIT(0));

Name the bit with a define.

> +	if (!ecbat->bat_present)
> +		return val;
> +
> +	val = yoga_c630_ec_read8(ec, LENOVO_EC_BAT_ATTRIBUTES);
> +	if (val < 0)
> +		return val;
> +	ecbat->unit_mA = val & LENOVO_EC_BAT_ATTR_UNIT_IS_MA;
> +
> +	val = yoga_c630_ec_read16(ec, LENOVO_EC_BAT_DESIGN_CAPACITY);
> +	if (val < 0)
> +		return val;
> +	ecbat->design_capacity = val * 1000;

Check linux/units.h if some WATT related one matches to that literal 1000.

> +	msleep(50);
> +
> +	val = yoga_c630_ec_read16(ec, LENOVO_EC_BAT_DESIGN_VOLTAGE);
> +	if (val < 0)
> +		return val;
> +	ecbat->design_voltage = val;
> +
> +	msleep(50);
> +
> +	val = yoga_c630_ec_read8(ec, LENOVO_EC_BAT_FULL_REGISTER);
> +	if (val < 0)
> +		return val;
> +	if (val & LENOVO_EC_BAT_FULL_IS_FACTORY)
> +		val = yoga_c630_ec_read16(ec, LENOVO_EC_BAT_FULL_FACTORY);
> +	else
> +		val = yoga_c630_ec_read16(ec, LENOVO_EC_BAT_FULL_CAPACITY);

You could consider doing this instead of branching:

	val = yoga_c630_ec_read16(ec, val & LENOVO_EC_BAT_FULL_IS_FACTORY ?
				      LENOVO_EC_BAT_FULL_FACTORY :
				      LENOVO_EC_BAT_FULL_CAPACITY);

> +	if (val < 0)
> +		return val;
> +
> +	ecbat->full_charge_capacity = val * 1000;

Something from linux/units.h ?

> +	if (!ecbat->unit_mA) {
> +		ecbat->design_capacity *= 10;
> +		ecbat->full_charge_capacity *= 10;
> +	}
> +
> +	return 0;
> +}
> +
> +/* the mutex should already be locked */
> +static int yoga_c630_psy_maybe_update_bat_status(struct yoga_c630_psy *ecbat)
> +{
> +	struct yoga_c630_ec *ec = ecbat->ec;
> +	int current_mA;
> +	int val;
> +
> +	if (time_before(jiffies, ecbat->last_status_update + LENOVO_EC_CACHE_TIME))
> +		return 0;
> +
> +	val = yoga_c630_ec_read8(ec, LENOVO_EC_BAT_STATUS);
> +	if (val < 0)
> +		return val;
> +	ecbat->bat_status = val;
> +
> +	msleep(50);
> +
> +	val = yoga_c630_ec_read16(ec, LENOVO_EC_BAT_REMAIN_CAPACITY);
> +	if (val < 0)
> +		return val;
> +	ecbat->capacity_now = val * 1000;

units.h ?

> +	msleep(50);
> +
> +	val = yoga_c630_ec_read16(ec, LENOVO_EC_BAT_VOLTAGE);
> +	if (val < 0)
> +		return val;
> +	ecbat->voltage_now = val * 1000;

Ditto.

> +	msleep(50);
> +
> +	val = yoga_c630_ec_read16(ec, LENOVO_EC_BAT_CURRENT);
> +	if (val < 0)
> +		return val;
> +	current_mA = sign_extend32(val, 15);
> +	ecbat->current_now = current_mA * 1000;
> +	ecbat->rate_now = current_mA * (ecbat->voltage_now / 1000);

Ditto.

> +	msleep(50);
> +
> +	if (!ecbat->unit_mA)
> +		ecbat->capacity_now *= 10;
> +
> +	ecbat->last_status_update = jiffies;

Add jiffies.h

> +	return 0;
> +}
> +
> +static int yoga_c630_psy_update_adapter_status(struct yoga_c630_psy *ecbat)
> +{
> +	struct yoga_c630_ec *ec = ecbat->ec;
> +	int val;
> +
> +	mutex_lock(&ecbat->lock);

This kind of functions coul use guard to take the mutex so unlock will be 
handled for you by the cleanup automation.

> +	val = yoga_c630_ec_read8(ec, LENOVO_EC_ADPT_STATUS);
> +	if (val > 0)
> +		ecbat->adapter_online = FIELD_GET(LENOVO_EC_ADPT_PRESENT, val);
> +
> +	mutex_unlock(&ecbat->lock);
> +
> +	return val;
> +}
> +
> +static bool yoga_c630_psy_is_charged(struct yoga_c630_psy *ecbat)
> +{
> +	if (ecbat->bat_status != 0)
> +		return false;
> +
> +	if (ecbat->full_charge_capacity <= ecbat->capacity_now)
> +		return true;
> +
> +	if (ecbat->design_capacity <= ecbat->capacity_now)
> +		return true;
> +
> +	return false;
> +}
> +
> +static int yoga_c630_psy_bat_get_property(struct power_supply *psy,
> +					 enum power_supply_property psp,
> +					 union power_supply_propval *val)
> +{
> +	struct yoga_c630_psy *ecbat = power_supply_get_drvdata(psy);
> +	int rc = 0;
> +
> +	if (!ecbat->bat_present &&
> +	    psp != POWER_SUPPLY_PROP_PRESENT)

Fits to one line.

> +		return -ENODEV;
> +
> +	mutex_lock(&ecbat->lock);
> +	rc = yoga_c630_psy_maybe_update_bat_status(ecbat);
> +	mutex_unlock(&ecbat->lock);
> +
> +	if (rc)

Remove empty line in between since this is the error handling.

> +		return rc;
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_STATUS:
> +		if (ecbat->bat_status & BIT(0))

Name bits with defines.

> +			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
> +		else if (ecbat->bat_status & BIT(1))

Ditto.

> +			val->intval = POWER_SUPPLY_STATUS_CHARGING;
> +		else if (yoga_c630_psy_is_charged(ecbat))
> +			val->intval = POWER_SUPPLY_STATUS_FULL;
> +		else
> +			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
> +		break;
> +	case POWER_SUPPLY_PROP_PRESENT:
> +		val->intval = ecbat->bat_present;
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
> +		val->intval = ecbat->design_voltage;
> +		break;
> +	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
> +	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
> +		val->intval = ecbat->design_capacity;
> +		break;
> +	case POWER_SUPPLY_PROP_CHARGE_FULL:
> +	case POWER_SUPPLY_PROP_ENERGY_FULL:
> +		val->intval = ecbat->full_charge_capacity;
> +		break;
> +	case POWER_SUPPLY_PROP_CHARGE_NOW:
> +	case POWER_SUPPLY_PROP_ENERGY_NOW:
> +		val->intval = ecbat->capacity_now;
> +		break;
> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +		val->intval = ecbat->current_now;
> +		break;
> +	case POWER_SUPPLY_PROP_POWER_NOW:
> +		val->intval = ecbat->rate_now;
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> +		val->intval = ecbat->voltage_now;
> +		break;
> +	case POWER_SUPPLY_PROP_TECHNOLOGY:
> +		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
> +		break;
> +	case POWER_SUPPLY_PROP_MODEL_NAME:
> +		val->strval = "PABAS0241231";
> +		break;
> +	case POWER_SUPPLY_PROP_MANUFACTURER:
> +		val->strval = "Compal";
> +		break;
> +	default:
> +		rc = -EINVAL;
> +		break;
> +	}
> +
> +	return rc;
> +}


> +static int yoga_c630_psy_register_bat_psy(struct yoga_c630_psy *ecbat)
> +{
> +	struct power_supply_config bat_cfg = {};
> +
> +	bat_cfg.drv_data = ecbat;
> +	bat_cfg.of_node = ecbat->of_node;
> +	if (ecbat->unit_mA)
> +		ecbat->bat_psy = power_supply_register_no_ws(ecbat->dev, &yoga_c630_psy_bat_psy_desc_mA, &bat_cfg);
> +	else
> +		ecbat->bat_psy = power_supply_register_no_ws(ecbat->dev, &yoga_c630_psy_bat_psy_desc_mWh, &bat_cfg);

Again, it might be easier to see what's different in here if the relevant 
parameter just uses ?: instead of full blown if/else.

> +	if (IS_ERR(ecbat->bat_psy)) {
> +		dev_err(ecbat->dev, "failed to register battery supply\n");
> +		return PTR_ERR(ecbat->bat_psy);
> +	}
> +
> +	return 0;
> +}


-- 
 i.