Re: [PATCH v2 08/14] power: supply: Add power_supply_set_input_current_limit_from_supplier helper

[Hans de Goede]

Hi,

On 16-08-17 17:54, Tony Lindgren wrote:
> * Hans de Goede <hdegoede@xxxxxxxxxx> [170815 13:06]:
> > On some devices the USB Type-C port power (USB PD 2.0) negotiation is
> > done by a separate port-controller IC, while the current limit is
> > controlled through another (charger) IC.
> >
> > It has been decided to model this by modelling the external Type-C
> > power brick (adapter/charger) as a power-supply class device which
> > supplies the charger-IC, with its voltage-now and current-max representing
> > the negotiated voltage and max current draw.
> >
> > This commit adds a power_supply_set_input_current_limit_from_supplier
> > helper function which charger power-supply drivers can call to get
> > the max-current from their supplier and have this applied
> > through their set_property call-back to their input-current-limit.
>
> Hmm so can this also be used for the USB gadget subsystem
> to tell charge controller when it's OK to enable 500mA
> charging after enumeration?

I'm not sure that that would be best modeled this way. Perhaps
the phy-driver can directly control the gpio you have for that,
that seems better then trying to solve this with cross subsystem
calls which are always tricky.

> FYI, that's controlled by the bq24190 pin named OTG that should
> be only set high after enumeration. Any ideas how that is wired
> on your device? Does it connect to the USB PHY or to a GPIO
> line?

I believe it is just hardwired to be logical high all the time
on my board.

Regards,

Hans