Re: [PATCH v4 01/20] power: supply: core: Refactor power_supply_set_input_current_limit_from_supplier()

Andy Shevchenko
2022-01-31T13:38:34Z

On Sun, Jan 30, 2022 at 09:45:38PM +0100, Hans de Goede wrote:
> Some (USB) charger ICs have variants with USB D+ and D- pins to do their
> own builtin charger-type detection, like e.g. the bq24190 and bq25890 and
> also variants which lack this functionality, e.g. the bq24192 and bq25892.
>
> In case the charger-type; and thus the input-current-limit detection is
> done outside the charger IC then we need some way to communicate this to
> the charger IC. In the past extcon was used for this, but if the external
> detection does e.g. full USB PD negotiation then the extcon cable-types do
> not convey enough information.
>
> For these setups it was decided to model the external charging "brick"
> and the parameters negotiated with it as a power_supply class-device
> itself; and power_supply_set_input_current_limit_from_supplier() was
> introduced to allow drivers to get the input-current-limit this way.
>
> But in some cases psy drivers may want to know other properties, e.g. the
> bq25892 can do "quick-charge" negotiation by pulsing its current draw,
> but this should only be done if the usb_type psy-property of its supplier
> is set to DCP (and device-properties indicate the board allows higher
> voltages).
>
> Instead of adding extra helper functions for each property which
> a psy-driver wants to query from its supplier, refactor
> power_supply_set_input_current_limit_from_supplier() into a
> more generic power_supply_get_property_from_supplier() function.

...

> + ret = power_supply_get_property_from_supplier(bdi->charger,
> + POWER_SUPPLY_PROP_CURRENT_MAX,
> + &val);
> + if (ret == 0)

Can it be as simple as

if (ret)
return;

...

?

Or did I misunderstand the meaning of 0?

--
With Best Regards,
Andy Shevchenko