[RFC usb-next v5 1/3] dt-bindings: usb: add the documentation for USB root-hub

[Arnd Bergmann]

On Tue, Oct 17, 2017 at 11:00 PM, Martin Blumenstingl
<martin.blumenstingl at googlemail.com> wrote:
> On Fri, Oct 13, 2017 at 9:37 AM, Arnd Bergmann <arnd at arndb.de> wrote:
>> On Thu, Oct 12, 2017 at 10:56 PM, Martin Blumenstingl
>> <martin.blumenstingl at googlemail.com> wrote:
>>
>> It's possible that this has never worked on XHCI because of the lack
>> of the root-hub in DT. Either way, we should ensure that it does work
>> now and you didn't break it, so please at least test it with your patches.
>>
>> The patch below should be sufficient to see if any device has an
>> of_node pointer when you add it to your DT:
> I slightly modified your patch (see the attached version) and tried it:
> # lsusb -t
> /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/0p, 5000M
> /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/2p, 480M
>    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M
>        |__ Port 3: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 480M
>
> the roothub (bus 1 port 1 dev 1) and a soldered down hub (child of
> that root-hub, port 1 dev 2) have an entry in the .dts
>
> # dmesg | grep usb
> [    0.174097] usbcore: registered new interface driver usbfs
> [    0.174147] usbcore: registered new interface driver hub
> [    0.174217] usbcore: registered new device driver usb
> [    1.354280] usb usb2: We don't know the algorithms for LPM for this
> host, disabling LPM.
> [    1.373297] usbcore: registered new interface driver usb-storage
> [    1.512840] usbcore: registered new interface driver dvb_usb_rtl28xxu
> [    1.550506] usb 1-1: of_node /soc/usb at c9000000/hub at 1 parent /soc/usb at c9000000
> ^ this is the soldered down hub
> [    1.552579] usbcore: registered new interface driver bcm203x
> [    1.712033] usbcore: registered new interface driver usbhid
> [    1.716994] usbhid: USB HID core driver
> [    1.738827] usb 1-1: new high-speed USB device number 2 using xhci-hcd
> [    2.142392] usb 1-1.3: of_node <no-node> parent /soc/usb at c9000000/hub at 1
> ^ this is the thumb drive plugged into the hub (not specified in the .dts)
> [    2.220399] usb 1-1.3: new high-speed USB device number 3 using xhci-hcd
> [    2.326144] usb-storage 1-1.3:1.0: USB Mass Storage device detected
> [    2.328352] scsi host0: usb-storage 1-1.3:1.0
>
> so for me it seems to be working fine

Ok, very good!

> is there anything else you want me to test?

What about the same dtb when run on a kernel without your
patch series? Does that work as well, or are your patches
required to make it work?

       Arnd