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

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Date:   Mon, 26 Nov 2018 14:18:27 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Pavel Machek <pavel@....cz>
Cc:     Sebastian Reichel <sre@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Linux PM list <linux-pm@...r.kernel.org>,
        DTML <devicetree@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, yuanjiang.yu@...soc.com,
        Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH 5/5] power: supply: sc27xx: Save last battery capacity

Hi Pavel,
On Mon, 26 Nov 2018 at 05:48, Pavel Machek <pavel@....cz> wrote:
>
> 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?

Until now I think there are no writable properties, I think I can
change it like you suggested.

>
> > +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.

Sure. Thanks.

-- 
Baolin Wang
Best Regards