Hi Rob, Geert-san,
> From: Geert Uytterhoeven, Sent: Thursday, May 24, 2018 5:18 PM
>
> Hi Rob,
>
> On Wed, May 23, 2018 at 5:00 PM, Rob Herring <r...@kernel.org> wrote:
<snip>
> >>> > Optional properties:
> >>> > - phys: phandle + phy specifier pair
> >>> > - phy-names: must be "usb"
> >>> > + - The connection to a usb3.0 host node needs by using OF graph
> >>> > bindings for
> >>> > + usb role switch.
> >>> > + - port@0 = USB3.0 host port.
> >>>
> >>> On the host side, this might conflict with the USB connector binding.
> >>>
> >>> I would either make sure this can work with the connector binding by
> >>> having 2 endpoints on the HS or SS port or just use the 'companion'
> >>> property defined in usb-generic.txt.
> >>
> >> I don't understand the first one now... This means the renesas_usb3 should
> >> follow
> >> USB connector binding and have 2 endpoints for the usb role switch to avoid
> >> the conflict like below?
> >> - port1@0: Super Speed (SS), present in SS capable connectors (from
> >> usb-connector.txt).
> >> - port1@1: USB3.0 host port.
> >
> > I'm confused, SS and USB3.0 are the same essentially. It would be:
> >
> > port@1/endpoint@0: SS host port
> > port@1/endpoint@1: SS device port
Thank you for the comment. It's better than my description.
> >> About the 'companion' in usb-generic.txt, the property intends to be used
> >> for EHCI or host side
> >> like the commit log [1]. If there is accept to use 'companion' for this
> >> patch, I think it will
> >> be simple to achieve this role switch feature. However, in last month, I
> >> submitted a similar patch [2]
> >> that has "renesas,host" property, but I got reply from Andy [3] and Heikki
> >> [4]. So, I'm
> >> trying to improve the device connection framework [5] now.
> >
> > I think this case is rare enough that we don't need a general solution
> > using OF graph, so I'm fine with a simple, single property to link the
> > 2 nodes. Either reusing "companion" or "renesas,host" is fine by me.
>
> I'd go for the standard "companion" over "renesas,host"[*].
>
> [*] Doh, we have another one ("renesas,bonding"), invented when I wasn't
> aware of the existence of "companion" yet...
Thank you for the comments. So, I'll reuse "companion" for it.
Best regards,
Yoshihiro Shimoda
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> ge...@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like
> that.
> -- Linus Torvalds
