Re: [PATCH v16 0/4] Introduce usb charger framework to deal with the usb gadget power negotation

From: Mark Brown
Date: Mon Sep 12 2016 - 08:26:40 EST


On Sat, Sep 10, 2016 at 07:57:26AM +1000, NeilBrown wrote:
> On Fri, Sep 09 2016, Mark Brown wrote:

> > The wm831x driver in the patch series is an example of such hardware -
> > it is purely a power manager, it has no USB PHY hardware at all. It's a

> The "probe" routine calls

> + usb_charger_find_by_name(wm831x_pdata->usb_gadget);

> Presumably wm831x_pdata is initialised by a board file?

Yes.

> I strongly suspect it is initialized to "usb-charger.0" because the
> names given to usb chargers are "usb-charger.%d" in discovery order.
> I don't see this being at all useful if there is ever more than one
> usb-charger.
> Do you?

It's no worse than any other board file situation - if someone has that
problem they get to fix it.

> So how can this wm831x driver actually find out what sort of charger is
> connected and so set the power limit? I just don't see this working *at*
> *all*.

The whole point from the point of view of the wm831x driver is that it
just wants something to tell it how much current it's allowed to draw, I
appreciate that doesn't change your analysis of the bit in the middle
but the consumer driver bit seems fine here.

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