在 2017-11-02 23:50，Maxime Ripard 写道：
On Thu, Nov 02, 2017 at 05:07:30PM +0800, Icenowy Zheng wrote:> > +&mmc0 { > > + pinctrl-names = "default"; > > + pinctrl-0 = <&mmc0_pins_a>; > > + vmmc-supply = <®_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
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