linux-kernel - Re: [PATCH 5/5] power: supply: sc27xx: Save last battery capacity

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Message-ID: <20181125214823.GB9913@amd>
Date:   Sun, 25 Nov 2018 22:48:23 +0100
From:   Pavel Machek <pavel@....cz>
To:     Baolin Wang <baolin.wang@...aro.org>
Cc:     sre@...nel.org, robh+dt@...nel.org, mark.rutland@....com,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, yuanjiang.yu@...soc.com,
        broonie@...nel.org
Subject: Re: [PATCH 5/5] power: supply: sc27xx: Save last battery capacity

Hi!

> Our charger manager can optimize the battery capacity periodically, so
> we can save last battery capacity into registers. Then next system
> power-on, we can read the last saved battery capacity as the initial
> battery capacity, which can make the battery capacity more accurate.
> 
> Signed-off-by: Yuanjiang Yu <yuanjiang.yu@...soc.com>
> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> ---
>  drivers/power/supply/sc27xx_fuel_gauge.c |  143 +++++++++++++++++++++++++++++-
>  1 file changed, 142 insertions(+), 1 deletion(-)
> 

> +static int sc27xx_fgu_set_property(struct power_supply *psy,
> +				   enum power_supply_property psp,
> +				   const union power_supply_propval *val)
> +{
> +	struct sc27xx_fgu_data *data = power_supply_get_drvdata(psy);
> +	int ret;
> +
> +	mutex_lock(&data->lock);
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_CAPACITY:
> +		ret = sc27xx_fgu_save_last_cap(data, val->intval);
> +		if (ret < 0)
> +			dev_err(data->dev, "failed to save battery capacity\n");
> +		break;
> +
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	mutex_unlock(&data->lock);
> +	return ret;

if (psp != ....) return -EINVAL; And you can do that outside
lock...

Ok, OTOH this is easier to extend in future. Do you expect more
writable properties?

> +static int sc27xx_fgu_property_is_writeable(struct power_supply *psy,
> +					    enum power_supply_property psp)
> +{
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_CAPACITY:
> +		return 1;
> +
> +	default:
> +		return 0;
> +	}
> +}


Same here. return psp == POWER_SUPPLY_PROP_CAPACITY; really looks
strange written like this.

Best regards,
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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