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

[maxime.ripard@free-electrons.com (Maxime Ripard)]

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?

Maxime

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