Re: [PATCH v3 3/3] power: supply: add CellWise cw2015 fuel gauge driver

[Andy Shevchenko]

On Wed, Mar 11, 2020 at 10:30:43AM +0100, Tobias Schramm wrote:
> This patch adds a driver for the CellWise cw2015 fuel gauge.
> 
> The CellWise cw2015 is a shuntless, single-cell Li-Ion fuel gauge used
> in the pine64 Pinebook Pro laptop and some Raspberry Pi UPS HATs.

Thank you for an update!
My comments below.

...

> +	/* wait for gauge to become ready */
> +	for (i = 0; i < CW2015_READ_TRIES; i++) {
> +		ret = regmap_read(cw_bat->regmap, CW2015_REG_SOC, &reg_val);
> +		if (ret)
> +			return ret;
> +		/* SoC must not be more than 100% */
> +		else if (reg_val <= 100)
> +			break;
> +
> +		msleep(100);
> +	}

Have you considered to use regmap_read_poll_timeout()?

> +
> +	if (i >= CW2015_READ_TRIES) {
> +		reg_val = CW2015_MODE_SLEEP;
> +		regmap_write(cw_bat->regmap, CW2015_REG_MODE, reg_val);
> +		dev_err(cw_bat->dev,
> +			"Gauge did not become ready after profile upload");
> +		return -ETIMEDOUT;
> +	}

...

> +		if (memcmp(bat_info, cw_bat->bat_profile,
> +				CW2015_SIZE_BATINFO)) {

I think it's pretty much okay to have this on one line, disregard 80 limit
(it's only 1 extra).

...

> +static int cw_get_soc(struct cw_battery *cw_bat)
> +{
> +	unsigned int soc;
> +	int ret;
> +
> +	ret = regmap_read(cw_bat->regmap, CW2015_REG_SOC, &soc);
> +	if (ret)
> +		return ret;
> +
> +	if (soc > 100) {

> +		int max_error_cycles = CW2015_BAT_SOC_ERROR_MS /
> +					cw_bat->poll_interval_ms;

The following looks better

		int max_error_cycles =
			CW2015_BAT_SOC_ERROR_MS / cw_bat->poll_interval_ms;

Applies to all similar places in the code.

> +		dev_err(cw_bat->dev, "Invalid SoC %d%%", soc);
> +		cw_bat->read_errors++;
> +		if (cw_bat->read_errors > max_error_cycles) {
> +			dev_warn(cw_bat->dev,
> +				"Too many invalid SoC reports, resetting gauge");
> +			cw_power_on_reset(cw_bat);
> +			cw_bat->read_errors = 0;
> +		}
> +		return cw_bat->soc;
> +	}
> +	cw_bat->read_errors = 0;
> +
> +	/* Reset gauge if stuck while charging */

> +	if (cw_bat->status == POWER_SUPPLY_STATUS_CHARGING &&
> +			soc == cw_bat->soc) {

A bit strange indentation, and honestly I would leave it on one line, but it's up to you.

> +		int max_stuck_cycles = CW2015_BAT_CHARGING_STUCK_MS /
> +					cw_bat->poll_interval_ms;
> +
> +		cw_bat->charge_stuck_cnt++;
> +		if (cw_bat->charge_stuck_cnt > max_stuck_cycles) {
> +			dev_warn(cw_bat->dev,
> +				"SoC stuck @%u%%, resetting gauge", soc);
> +			cw_power_on_reset(cw_bat);
> +			cw_bat->charge_stuck_cnt = 0;
> +		}
> +	} else {
> +		cw_bat->charge_stuck_cnt = 0;
> +	}
> +
> +	/* Ignore voltage dips during charge */

> +	if (cw_bat->charger_attached &&
> +			HYSTERESIS(soc, cw_bat->soc, 0, 3)) {

This is pretty much one line (77), check your editor settings and update all
similar places in the code.

> +		soc = cw_bat->soc;
> +	}
> +
> +	/* Ignore voltage spikes during discharge */
> +	if (!cw_bat->charger_attached &&
> +			HYSTERESIS(soc, cw_bat->soc, 3, 0)) {
> +		soc = cw_bat->soc;
> +	}
> +
> +	return soc;
> +}

...

> +	cw_bat =
> +		container_of(delay_work, struct cw_battery, battery_delay_work);

It will be better to read if it would be one line.

...

> +static bool cw_battery_valid_time_to_empty(struct cw_battery *cw_bat)
> +{
> +	return cw_bat->time_to_empty > 0 &&
> +		cw_bat->time_to_empty < CW2015_MASK_SOC &&
> +		cw_bat->status == POWER_SUPPLY_STATUS_DISCHARGING;

Fix indentation to be all 'c':s in one column.

> +}

...

> +static int cw2015_parse_properties(struct cw_battery *cw_bat)
> +{
> +	struct device *dev = cw_bat->dev;
> +	int length;
> +	u32 value;
> +	int ret;
> +

> +	length = device_property_read_u8_array(dev, "cellwise,battery-profile",
> +						NULL, 0);

device_property_count_u8();

> +	if (length) {
> +		if (length != CW2015_SIZE_BATINFO) {
> +			dev_err(cw_bat->dev, "battery-profile must be %d bytes",
> +				CW2015_SIZE_BATINFO);
> +			return -EINVAL;
> +		}
> +
> +		cw_bat->bat_profile =
> +			devm_kzalloc(dev, CW2015_SIZE_BATINFO, GFP_KERNEL);

Replace with length (so, you will have one point of validation), and put on
one line.

> +		if (!cw_bat->bat_profile) {
> +			dev_err(cw_bat->dev,
> +				"Failed to allocate memory for battery config info");
> +			return -ENOMEM;
> +		}
> +
> +		ret = device_property_read_u8_array(dev,
> +						"cellwise,battery-profile",
> +						cw_bat->bat_profile,

> +						CW2015_SIZE_BATINFO);

length.

> +		if (ret)
> +			return ret;
> +	} else {
> +		dev_warn(cw_bat->dev,
> +			"No battery-profile found, rolling with current flash contents");
> +	}
> +
> +	cw_bat->poll_interval_ms = CW2015_DEFAULT_POLL_INTERVAL_MS;

> +	ret = device_property_read_u32_array(dev,
> +						"cellwise,monitor-interval-ms",

It's fine to have it on one line.

> +						&value, 1);
> +	if (ret >= 0) {
> +		dev_dbg(cw_bat->dev, "Overriding default monitor-interval with %u ms",
> +			value);
> +		cw_bat->poll_interval_ms = value;
> +	}
> +
> +	return 0;
> +}

...

> +	regmap_reg_range(CW2015_REG_BATINFO,
> +				CW2015_REG_BATINFO + CW2015_SIZE_BATINFO - 1),

Indentation issue. Check all similar places.

...

> +	cw_bat->rk_bat = devm_power_supply_register(&client->dev,
> +		&cw2015_bat_desc, &psy_cfg);
> +	if (IS_ERR(cw_bat->rk_bat)) {
> +		dev_err(cw_bat->dev, "Failed to register power supply");

> +		return -1;

Do not shadow an error code.

> +	}

-- 
With Best Regards,
Andy Shevchenko