On Mon, Dec 05, 2016 at 04:59:44PM +0800, Icenowy Zheng wrote:
> 
> 2016年12月5日 16:52于 Maxime Ripard <maxime.ripard@free-electrons.com>写道：
> >
> > On Fri, Dec 02, 2016 at 10:22:30PM +0800, Icenowy Zheng wrote: 
> > > 
> > > 
> > > 01.12.2016, 17:36, "Maxime Ripard" <maxime.ripard@free-electrons.com>: 
> > > > On Mon, Nov 28, 2016 at 12:29:07AM +0000, André Przywara wrote: 
> > > >>  > Something more interesting happened. 
> > > >>  > 
> > > >>  > Xunlong made a add-on board for Orange Pi Zero, which exposes the 
> > > >>  > two USB Controllers exported at expansion bus as USB Type-A 
> > > >>  > connectors. 
> > > >>  > 
> > > >>  > Also it exposes a analog A/V jack and a microphone. 
> > > >>  > 
> > > >>  > Should I enable {e,o}hci{2.3} in the device tree? 
> > > >> 
> > > >>  Actually we should do this regardless of this extension board. The USB 
> > > >>  pins are not multiplexed and are exposed on user accessible pins (just 
> > > >>  not soldered, but that's a detail), so I think they qualify for DT 
> > > >>  enablement. And even if a user can't use them, it doesn't hurt to have 
> > > >>  them (since they are not multiplexed). 
> > > > 
> > > > My main concern about this is that we'll leave regulators enabled by 
> > > > default, for a minority of users. And that minority will prevent to do 
> > > > a proper power management when the times come since we'll have to keep 
> > > > that behaviour forever. 
> > > 
> > > I think these users can add a 'fdt set /xxx/xxx status "disabled" ' . 
> >
> > You can't ask that from the majority of users. These users will take 
> > debian or fedora, install it, and expect everything to work 
> > properly. I would make the opposite argument actually. If someone is 
> > knowledgeable enough to solder the USB pins a connector, then (s)he'll 
> > be able to make that u-boot call. 
> 
> Now (s)he do not need soldering.
> 
> (S)he needs only paying $1.99 more to Xunlong to get the expansion
> board, and insert it on the OPi Zero.

Which is going to require an overlay anyway, so we could have the USB
bits in there too.

Maxime

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