Re: [PATCH v2 3/3] power/supply: Add generic USB charger driver

[Paul Cercueil]

Hi Rob,


Le jeu., déc. 19, 2019 at 13:38, Rob Herring <robh@xxxxxxxxxx> a 
écrit :
> On Mon, Dec 16, 2019 at 11:52:05AM +0100, Paul Cercueil wrote:
> >  Hi Peter,
> >
> >
> >  Le lun., déc. 16, 2019 at 01:24, Peter Chen <peter.chen@xxxxxxx> a 
> > écrit :
> >  >
> >  > >  >>  +
> >  > >  >>  +	desc = &charger->desc;
> >  > >  >>  +	desc->name = "usb-charger";
> >  > >  >>  +	desc->properties = usb_charger_properties;
> >  > >  >>  +	desc->num_properties = 
> > ARRAY_SIZE(usb_charger_properties);
> >  > >  >>  +	desc->get_property = usb_charger_get_property;
> >  > >  >>  +	desc->type = POWER_SUPPLY_TYPE_USB;
> >  > >  >
> >  > >  > What's your further plan for this generic USB charger?
> >  > >  > To support BC1.2, we need to know charger type, and how we 
> > could
> >  > > get
> >  > >  > it?
> >  > >  >
> >  > >  > Peter
> >  > >
> >  > >  Well I don't really know. The USB role framework does not give 
> > any
> >  > > info about
> >  > >  what's plugged.
> >  > >
> >  >
> >  > What's the use case for this patch set? How it be used?
> >
> >  My devicetree:
> >
> >  usb_otg: usb@13440000 {
> >  	compatible = "ingenic,jz4770-musb", "simple-mfd";
> >  	reg = <0x13440000 0x10000>;
> >  	[...]
> >
> >  	usb-role-switch;
> >
> >  	connector {
> >  		compatible = "gpio-usb-b-connector", "usb-b-connector";
> >  		label = "mini-USB";
> >  		type = "mini";
> >
> >  		id-gpios = <&gpf 18 GPIO_ACTIVE_HIGH>;
> >  		vbus-gpios = <&gpb 5 GPIO_ACTIVE_HIGH>;
> >  		[...]
> >  	};
> >
> >  	usb_charger: usb-charger {
> >  		compatible = "usb-charger";
>
> What h/w device is this?

GCW Zero: arch/mips/boot/dts/ingenic/gcw0.dts

Most of it isn't upstream, so I can still experiment things to get the 
perfect devicetree.

> >  	};
> >  };
> >
> >  The new gpio-usb-connector driver uses the ID/VBUS GPIOs to detect 
> > in which
> >  state (device, host, unconnected) a OTG connector is. However, that 
> > means I
> >  cannot use the standard gpio-charger driver to detect the presence 
> > of a
> >  charger based on the state of the VBUS gpio, since it's already 
> > requested
> >  here. So the point of this patchset is to provide an alternative to
> >  gpio-charger that works with OTG controllers compatible with
> >  'usb-role-switch'.
>
> Why not fix gpio-charger or make whatever 'owns' vbus-gpios to 
> register
> a charger device?

I see there is a GPIOD_FLAGS_BIT_NONEXCLUSIVE bit that could be used, 
I'll have a look.

Thanks,
-Paul

> I guess you could have Vbus sensing with no charging capability, but
> that sounds like a new property, not a node to me.
>
> Rob