Hi Rob,
On Fri, Oct 27, 2017 at 5:29 AM, Rob Herring <robh@xxxxxxxxxx> wrote:
> On Mon, Oct 23, 2017 at 11:57:18PM +0200, Martin Blumenstingl wrote:
>> This extends the existing example from the USB xHCI binding
>> documentation so it includes the roothub and an actual device.
>> The goal of this is to show that the roothub is specified alongside the
>> actual devices on the USB bus (which is important because a device on
>> the USB bus - for example a hub - might need it's own phys / phy-names
>> properties. modelling the roothub as separate device and not nesting the
>> other devices on the bus below the roothub allows us to keep the
>> properties, for example the PHYs, separated).
>>
>> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
>> ---
>> Documentation/devicetree/bindings/usb/usb-xhci.txt | 23 ++++++++++++++++++++++
>> 1 file changed, 23 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> index 5b49ba9f2f9a..20e5ce2b016a 100644
>> --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt
>> @@ -42,4 +42,27 @@ Example:
>> compatible = "generic-xhci";
>> reg = <0xf0931000 0x8c8>;
>> interrupts = <0x0 0x4e 0x0>;
>> +
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> +
>> + /* see usb-roothub.txt */
>> + roothub@0 {
>> + compatible = "usb1d6b,3", "usb1d6b,2";
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> + reg = <0>;
>> +
>> + port@1 {
>> + reg = <1>;
>> + phys = <&usb2_phy1>, <&usb3_phy1>;
>> + phy-names = "usb2-phy", "usb3-phy";
>> + };
>> + };
>> +
>> + /* see usb-device.txt */
>> + hub: genesys@1 {
>
> What do the 0 and 1 addresses correspond to?
0 is the address of the root-hub, 1 is the first device on the root-hub
based on my previous dt-binding patch Arnd assumed that the devices
would be moved in the hierarchy: [0]
however, my understanding is that (at least for now) the root-hub node
(identified by reg = <0>) is used to describe only the root-hub (which
allows initializing the PHYs), not the devices that are connected to
it
here's an example from my Khadas VIM (which matches the example from
my patch, except: a) it has a different USB hub connected at port 1 b)
it has two ports on the root-hub)
this is a stripped and commented version of "cat /sys/kernel/debug/usb/devices"
T: Bus=02 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=5000 MxCh= 0
D: Ver= 3.00 Cls=09(hub ) Sub=00 Prot=03 MxPS= 9 #Cfgs= 1
P: Vendor=1d6b ProdID=0003 Rev= 3.14
-> (USB3 root-hub from a dwc3 controller) in the device-tree example
this belongs to &usb/roothub@0
T: Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=480 MxCh= 2
D: Ver= 2.00 Cls=09(hub ) Sub=00 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=1d6b ProdID=0002 Rev= 3.14
-> (USB2 root-hub from a dwc3 controller) in the device-tree example
this also belongs to &usb/roothub@0
T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=480 MxCh= 4
D: Ver= 2.00 Cls=09(hub ) Sub=00 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=1a40 ProdID=0801 Rev= 1.00
-> (USB2 hub soldered to the board, connected to root-hub port 1) in
the device-tree example this belongs to &usb/genesys@1
T: Bus=01 Lev=02 Prnt=02 Port=02 Cnt=01 Dev#= 3 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=090c ProdID=1000 Rev= 7.22
-> USB thumb drive connected to the USB hub, not listed in the
device-tree example but it would be listed below &usb/genesys@1
>> + compatible = "usb5e3,608";
>> + reg = <1>;
>> + };
>> };
>> --
>> 2.14.2
>>
Martin
[0] http://lists.infradead.org/pipermail/linux-amlogic/2017-October/005091.html
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