Re: [linux-sunxi] Re: [PATCH] ARM: sun8i: h2+: add support for Banana Pi M2 Zero board

[Icenowy Zheng]

å 2017-11-02 23:50ïMaxime Ripard åéï
> On Thu, Nov 02, 2017 at 05:07:30PM +0800, Icenowy Zheng wrote:
> > > > +&mmc0 {
> > > > +	pinctrl-names = "default";
> > > > +	pinctrl-0 = <&mmc0_pins_a>;
> > > > +	vmmc-supply = <&reg_vcc3v3>;
> > > > +	bus-width = <4>;
> > > > +	/*
> > > > +	 * In different revisions the board have different card detect
> > > > +	 * configuration.
> > > > +	 */
> > >
> > > Which ones?
> >
> > In the sample batch (1.2V fixed voltage) the card detect is normal
> > (PF6 low as inserted), however in the final batch (1.1V/1.3V
> > switchable) it's inverted at PF6 (high as inserted).
>
> Then just use the final version's.
>
> > > > +&usbphy {
> > > > +	usb0_id_det-gpios = <&r_pio 0 6 GPIO_ACTIVE_HIGH>; /* PL6 */
> > > > +	/* USB OTG VBUS is directly connected to 5V without any regulators
> > > > */
> > >
> > > So it cannot operate in OTG, but it's host only?
> >
> > It can operate in OTG -- you can power the board via the OTG port,
> > as the VBUS is not gated from 5V at all, so 5V power at VBUS will
> > power up the board. Yes, it's a bit unsafe, but the board designer
> > did it.
>
> What will provide the 5v in the first place then if a USB device is
> connected to the micro-USB connector?

There're two micro-USB connectors, one is power-only and another is
OTG. The Vbus of these two connectors are connected together, so
the external USB device will be powered just by the power input
from the power-only USB port.

> Maxime