[U-Boot] [PATCH 12/13] sunxi: A13-Olinuxino: Enable the USB OTG controller

Maxime Ripard maxime.ripard at free-electrons.com
Mon Sep 14 23:19:20 CEST 2015


On Sun, Sep 13, 2015 at 07:38:27PM +0200, Hans de Goede wrote:
> >>The policy I'm thinking of (and which we are currently sorta following
> >>wrt enabling USB_MUSB_HOST) is that on devices with no normal usb
> >>ports we use USB_MUSB_HOST, so that people can interact with u-boot
> >>without needing a serial console (which often requires soldering).
> >>
> >>On boards which do have a normal usb port I fully agree that
> >>USB_MUSB_GADGET is a good default.
> >>
> >>In practice this will likely boil down to use USB_MUSB_HOST on tablets
> >>and USB_MUSB_GADGET everywhere else.
> >
> >Sounds good!
> >
> >If there's a UART gadget, we could also always select USB_MUSB_GADGET,
> >and export a UART there for the tablets, but I haven't seen such a
> >gadget in the code, so I guess your idea makes more sense :)
> 
> Ack. AFAIK u-boot currently lacks a serial gadget, once it gets one
> things get somewhat more complicated, for debugging a serial gadget
> is fine. But for now (no usable tablet ui) I sorta expect people to
> want to have hooked up a usb-keyb to a tablet (which is not running
> android) anyways, at which point the host option makes more sense.
> 
> Ideally we would build in both, and decide which one to use based
> on the id-pin. The sunxi musb-host code already checks the id-pin
> and does not touch the controller if it is not pulled down (iow
> if no host cable is inserted).

Looks like a good plan. I'll update my patch and resend it.

Thanks!
Maxime

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