Re: [PATCH v3 1/1] USB: core: let USB device know device node

Arnd Bergmann
2016-01-20T14:19:36Z

On Wednesday 20 January 2016 20:50:26 Peter Chen wrote:
> On Wed, Jan 20, 2016 at 10:07:13AM +0100, Arnd Bergmann wrote:
> > On Wednesday 20 January 2016 11:48:39 Peter Chen wrote:
> > > >
> > > > > Alternatively, you could use one of the high bits of the 'reg' value
> > > > > to indicate which root hub is used. I'm sure that would work as
> > > > > well, but be less obvious.
> > > >
> > > > It's probably best to stick with the same numbering that the hardware
> > > > uses.
> > >
> > > Seems we are talking about root hub, not the device in the
> > > root hub. So for multiple ports controller, we have to own node for
> > > root hub. Assume your example, there is a genesys HUB at physical
> > > port 1, I suggest a dts node description like below, please correct
> > > me if anything wrong.
> > >
> > > &usb1 {
> > > roothub_1: nxp@1 {
> > > compatible = "usb15a2,007d";
> > > reg = <0x01>;
> > >
> > > hub: genesys@1 {
> > > compatible = "usb05e3,0608";
> > > reg = <0x01>;
> > > };
> > > };
> > >
> > > roothub_2: nxp@2 {
> > > compatible = "usb15a2,007d";
> > > reg = <0x02>;
> > > };
> > >
> > > ...
> > >
> > > roothub_7: nxp@7 {
> > > compatible = "usb15a2,007d";
> > > reg = <0x07>;
> > >
> > > hub: genesys@1 {
> > > compatible = "usb05e3,0608";
> > > reg = <0x01>;
> > > };
> > > };
> > >
> > > ...
> > >
> > > roothub_9: nxp@9 {
> > > compatible = "usb15a2,007d";
> > > reg = <0x09>;
> > > };
> > > };
> >
> > This looks wrong to me: if I understand it right, you are now modeling
> > each port of the root hub as a separate hub, so you end up with
> > a total of 11 hub nodes when there should only be one or two.
> >
>
> How about below from both driver and device tree view:
>
> 1. From the USB driver view
>
> USB Controller
> |
> |
> ---------------------|----------------
> | |
> root hub(HS) root hub(SS, optional)
> | |
> --------------------- -------------------------
> | | ... | | | |
> port 1 port 2 port 6 port 1 port 2 port 3
> | |
> genesys hub (if HS) genesys hub (if SS)
>
> 2. dts node:
>
> &usb1 {
> port_1: nxp@1 {
> compatible = "usb15a2,007d";
> reg = <0x01>;
>
> hub: genesys@1 {
> compatible = "usb05e3,0608";
> reg = <0x01>;
> };
> };
>
> port_2: nxp@2 {
> compatible = "usb15a2,007d";
> reg = <0x02>;
> };
>
> ...
>
> port_7: nxp@7 {
> compatible = "usb15a2,007d";
> reg = <0x07>;
>
> hub: genesys@1 {
> compatible = "usb05e3,0608";
> reg = <0x01>;
> };
> };
>
> ...
>
> port_9: nxp@9 {
> compatible = "usb15a2,007d";
> reg = <0x09>;
> };
> };
>
> - If the above are ok, is it ok we add two nodes for the same device
> in case the speed negotiation is different at some situations?
> - Usually, it should be ok we only add nodes at device tree which
> the hard wired device on it, like port_1 and port 7 at above, right?

This looks identical to the version before, what is the difference?

You still list 11 hubs here, I'm completely puzzled what the meaning
of those should be.

Arnd