Re: [linux-sunxi] Re: [PATCH 5/5] ARM: sun5i: Add C.H.I.P DTS

[Maxime Ripard <maxime.ripard@free-electrons.com>]

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On Tue, Sep 22, 2015 at 04:30:04PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 22-09-15 16:04, Maxime Ripard wrote:
> >On Tue, Sep 22, 2015 at 03:01:58PM +0200, Hans de Goede wrote:
> >>>In short, this is not about "power supply" but VBUS detection. IIRC,
> >>>if no VBUS detection method is provided, the phy driver just waits a
> >>>period of time after an ID pin change and then considers VBUS invalid.
> >>
> >>Right, but that is a hack for boards with no / broken vbus detection
> >>(or vbus control), we really want to use vbus-det where available,
> >>so I agree that a TODO comment here would be good.
> >
> >What's so special in our SoCs that makes that we can't just rely on
> >the ID pin ? (which seems to be working just fine here)
> 
> There is nothing special, AFAIK all OTG ports (also for other SoCs)
> have some sort of vbus detection mechanism. We need the hack because
> vbus-det is broken on some of our boards.
> 
> And where it is not broken we should be using vbus-det normallu.

Ah, and most controllers embed that directly into the controller
itself and don't rely on a GPIO to do that. Understood.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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