Re: [RESEND][PATCH 1/2] dt-bindings: usb: add non-removable-ports hub property

From: Greg Kroah-Hartman
Date: Tue Jan 28 2020 - 08:47:51 EST


On Mon, Jan 27, 2020 at 04:56:15PM +0000, Måns Rullgård wrote:
> Rob Herring <robh@xxxxxxxxxx> writes:
>
> > On Fri, Jan 24, 2020 at 03:25:03PM +0000, Mans Rullgard wrote:
> >> Add a non-removable-ports property that lists the hardwired downstream
> >> ports of a hub. Although hubs can provide this information, they are
> >> not always configured correctly. An alternate means of indicating this
> >> for built-in USB devices is thus useful.
> >>
> >> Signed-off-by: Mans Rullgard <mans@xxxxxxxxx>
> >
> > I reviewed this already, but since you didn't add my reviewed-by, I'm
> > looking at it again and having 2nd thoughts.
> >
> >> ---
> >> Documentation/devicetree/bindings/usb/usb-device.txt | 4 ++++
> >> 1 file changed, 4 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
> >> index 036be172b1ae..92d863cc96b6 100644
> >> --- a/Documentation/devicetree/bindings/usb/usb-device.txt
> >> +++ b/Documentation/devicetree/bindings/usb/usb-device.txt
> >> @@ -66,6 +66,10 @@ Required properties for host-controller nodes with device nodes:
> >> - #size-cells: shall be 0
> >>
> >>
> >> +Optional properties for hub and host-controller nodes:
> >> +- non-removable-ports: list of hardwired downstream ports
> >
> > If you have a hardwired device and need to know that, doesn't that imply
> > there's some other stuff you need to describe beyond what a standard USB
> > device has. Such as a power supply that's not Vbus from the hub.
>
> I suppose there could be, but there isn't in my actual situation.
>
> > At a minimum, I think this should be a per port property.
>
> That's what I suggested first. Greg told me to do it like this instead.

I said that? I do not remember discussing this at all, when did that
happen?

> > Though really, I think this should just be implied by describing the
> > device in DT. I'm not sure if there's a case for hotpluggable devices
> > described in DT. Maybe with overlays.
>
> That's also an option. Greg, what do you think?

I have no idea, sorry, I'm totally lost here...

greg k-h

>
> --
> Måns Rullgård