Re: [PATCH 01/10] dt-bindings: usb: add support for dwc3 controller on HiSilicon SoCs

[Rob Herring <robh@kernel.org>]

On Fri, Nov 16, 2018 at 8:29 PM Chen Yu <chenyu56@huawei.com> wrote:
>
> Hi,
>
> On 2018/11/13 0:02, Rob Herring wrote:
> > On Sat, Oct 27, 2018 at 05:58:11PM +0800, Yu Chen wrote:
> >> This patch adds binding descriptions to support the dwc3 controller
> >> on HiSilicon SoCs and boards like the HiKey960.
> >>
> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >> Cc: Rob Herring <robh+dt@kernel.org>
> >> Cc: Mark Rutland <mark.rutland@arm.com>
> >> Cc: John Stultz <john.stultz@linaro.org>
> >> Signed-off-by: Yu Chen <chenyu56@huawei.com>
> >> ---
> >>  .../devicetree/bindings/usb/dwc3-hisi.txt          | 53 ++++++++++++++++++++++
> >>  1 file changed, 53 insertions(+)
> >>  create mode 100644 Documentation/devicetree/bindings/usb/dwc3-hisi.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/usb/dwc3-hisi.txt b/Documentation/devicetree/bindings/usb/dwc3-hisi.txt
> >> new file mode 100644
> >> index 000000000000..e715e7b1c324
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/usb/dwc3-hisi.txt
> >> @@ -0,0 +1,53 @@
> >> +HiSilicon DWC3 USB SoC controller
> >> +
> >> +This file documents the parameters for the dwc3-hisi driver.
> >> +
> >> +Required properties:
> >> +- compatible:       should be "hisilicon,hi3660-dwc3"
> >> +- clocks:   A list of phandle + clock-specifier pairs for the
> >> +            clocks listed in clock-names
> >> +- clock-names:      Specify clock names
> >> +- resets:   list of phandle and reset specifier pairs.
> >> +
> >> +Sub-nodes:
> >> +The dwc3 core should be added as subnode to HiSilicon DWC3 as shown in the
> >> +example below. The DT binding details of dwc3 can be found in:
> >> +Documentation/devicetree/bindings/usb/dwc3.txt
> >
> > If you only have clocks and resets and no glue registers, then you
> > don't need a sub-node. Just make the controller one node.
> >
>
> In dwc3 glue driver，the controller driver usually probed by call of_platform_populate
> which will search the child node of glue driver.
> The code of function of_platform_populate is as below:
>
>         for_each_child_of_node(root, child) {
>                  rc = of_platform_bus_create(child, matches, lookup, parent, true);
>                  if (rc) {
>                          of_node_put(child);
>                          break;
>                  }
>          }
>
> So I think the controller node should be a sub-node.

It was done that way, but has changed. See commit fe8abf332b8f ("usb:
dwc3: support clocks and resets for DWC3 core").

Rob