On Mon, May 11, 2015 at 04:26:58PM +0800, Chen-Yu Tsai wrote:
> >> >> +&usbphy1 {
> >> >> + phy-supply = <®_usb1_vbus>;
> >> >> + status = "okay";
> >> >> +};
> >> >> +
> >> >> +/*
> >> >> + * Unfortunately reg_usb1_vbus also powers one of the ports from
> >> >> usb3's hub.
> >> >> + * One should always make sure both regulators are enabled and working
> >> >> for
> >> >> + * all USB ports to have power.
> >> >> + */
> >> >
> >> > Can't we just provide the two regulators, and enable both of them so
> >> > that we know that we always have the needed regulators enabled,
> >> > disregarding which USB port is used?
> >>
> >> Would setting "always-on" for both regulators work for you?
> >> Or maybe just the one that's used by both USB hosts?
> >
> > I was more thinking of giving to the phy an additional regulator, so
> > that it would enable both the regulators needed to power up all ports.
>
> That would require adding back all the regulator-related code I
> removed from the phy driver before it was merged. (sigh) It's not
> like the regulator bindings takes a list.Yeah, but maybe we can just add an optional device-supply property or something like that to power up the devices connected on the bus. > I see this as more of a hardware design flaw, and we should label > it as such. This can be seen as one, and we can debate it for some time I guess, but if the hardware guys were not making crazy stuff like that, we would run out of work pretty quickly :) What we really need to do is find a proper and reliable way to handle this case. Whether we declare it as a flaw or not is a separate debate. > And it might still work for self-powered devices even if VBUS is > off. The USB hub chip is always on. That still leaves a significant amount of devices out and non functional, especially very standard devices like USB keys, keyboards or headsets that you would expect to just work. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
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