linux-kernel - Re: [PATCH v4 7/8] power: supply: rt5033_battery: Adopt status property from charger

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Message-ID: <20230508220605.kderc3nihhezouit@mercury.elektranox.org>
Date:   Tue, 9 May 2023 00:06:05 +0200
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Jakob Hauser <jahau@...ketmail.com>
Cc:     Lee Jones <lee@...nel.org>, Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Beomho Seo <beomho.seo@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Stephan Gerhold <stephan@...hold.net>,
        Raymond Hackley <raymondhackley@...tonmail.com>,
        Pavel Machek <pavel@....cz>, Axel Lin <axel.lin@...ics.com>,
        ChiYuan Huang <cy_huang@...htek.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Henrik Grimler <henrik@...mler.se>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        phone-devel@...r.kernel.org, ~postmarketos/upstreaming@...ts.sr.ht
Subject: Re: [PATCH v4 7/8] power: supply: rt5033_battery: Adopt status
 property from charger

Hi,

On Mon, May 08, 2023 at 11:18:28PM +0200, Jakob Hauser wrote:
> On 08.05.23 13:35, Sebastian Reichel wrote:
> > On Sat, May 06, 2023 at 05:54:34PM +0200, Jakob Hauser wrote:
> > > The rt5033-battery fuelgauge can't get a status by itself. The rt5033-charger
> > > can, let's get this value.
> > > 
> > > Tested-by: Raymond Hackley <raymondhackley@...tonmail.com>
> > > Signed-off-by: Jakob Hauser <jahau@...ketmail.com>
> > > ---
> > >   drivers/power/supply/rt5033_battery.c | 24 ++++++++++++++++++++++++
> > >   1 file changed, 24 insertions(+)
> > > 
> > > diff --git a/drivers/power/supply/rt5033_battery.c b/drivers/power/supply/rt5033_battery.c
> > > index 5c04cf305219..a6520716d813 100644
> > > --- a/drivers/power/supply/rt5033_battery.c
> > > +++ b/drivers/power/supply/rt5033_battery.c
> > > @@ -12,6 +12,26 @@
> > >   #include <linux/mfd/rt5033-private.h>
> > >   #include <linux/mfd/rt5033.h>
> > > +static int rt5033_battery_get_status(struct i2c_client *client)
> > > +{
> > > +	struct power_supply *charger;
> > > +	union power_supply_propval val;
> > > +	int ret;
> > > +
> > > +	charger = power_supply_get_by_name("rt5033-charger");
> > > +	if (!charger)
> > > +		return POWER_SUPPLY_STATUS_UNKNOWN;
> > > +
> > > +	ret = power_supply_get_property(charger, POWER_SUPPLY_PROP_STATUS, &val);
> > > +	if (ret) {
> > > +		power_supply_put(charger);
> > > +		return POWER_SUPPLY_STATUS_UNKNOWN;
> > > +	}
> > 
> > struct rt5033_battery *battery = i2c_get_clientdata(client);
> > ret = power_supply_get_property_from_supplier(battery->psy, POWER_SUPPLY_PROP_STATUS, &val);
> > if (ret)
> >      val.intval = POWER_SUPPLY_STATUS_UNKNOWN;
> 
> I don't think this works. There is no direct relationship between
> rt5033-charger and rt5033-battery. They operate independently from each
> other.

That should be fine as long as the supply dependency is properly declared.

> I had a short try and the status property of rt5033-battery was "unknown".
> 
> Just for the record, the full function I tried was:
> 
> static int rt5033_battery_get_status(struct i2c_client *client)
> {
>         struct rt5033_battery *battery = i2c_get_clientdata(client);
>         union power_supply_propval val;
>         int ret;
> 
>         ret = power_supply_get_property_from_supplier(battery->psy,
>                                              POWER_SUPPLY_PROP_STATUS,
>                                              &val);
>         if (ret)
>                 val.intval = POWER_SUPPLY_STATUS_UNKNOWN;
> 
>         return val.intval;
> }
> 
> Later on I added a read-out of the "ret" value. It is "-19". I guess that's
> the "return -ENODEV;" from function
> power_supply_get_property_from_supplier(). [2]
> 
> [2] https://github.com/torvalds/linux/blob/v6.4-rc1/drivers/power/supply/power_supply_core.c#L397-L421

I suppose your DT is missing the connection between the charger and
the battery:

rt5033_charger: charger {
    compatible = "rt5033-charger";
    ...
}

fuel-gauge {
    compatible = "rt5033-battery";
    ...
    power-supplies = <&rt5033_charger>; // you are probably missing this
};

See also Documentation/devicetree/bindings/power/supply/power-supply.yaml

-- Sebastian

> 
> > > +
> > > +	power_supply_put(charger);
> > > +	return val.intval;
> > > +}
> > > +
> > >   static int rt5033_battery_get_capacity(struct i2c_client *client)
> > >   {
> > >   	struct rt5033_battery *battery = i2c_get_clientdata(client);
> > > @@ -84,6 +104,9 @@ static int rt5033_battery_get_property(struct power_supply *psy,
> > >   	case POWER_SUPPLY_PROP_CAPACITY:
> > >   		val->intval = rt5033_battery_get_capacity(battery->client);
> > >   		break;
> > > +	case POWER_SUPPLY_PROP_STATUS:
> > > +		val->intval = rt5033_battery_get_status(battery->client);
> > > +		break;
> > >   	default:
> > >   		return -EINVAL;
> > >   	}
> > > @@ -96,6 +119,7 @@ static enum power_supply_property rt5033_battery_props[] = {
> > >   	POWER_SUPPLY_PROP_VOLTAGE_OCV,
> > >   	POWER_SUPPLY_PROP_PRESENT,
> > >   	POWER_SUPPLY_PROP_CAPACITY,
> > > +	POWER_SUPPLY_PROP_STATUS,
> > >   };
> > >   static const struct regmap_config rt5033_battery_regmap_config = {
> > > -- 
> > > 2.39.2
> > > 
> > 
> > Otherwise LGTM.
> > 
> > -- Sebastian
> 
> Kind regards,
> Jakob

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