On Wed, Oct 14, 2020 at 05:09:37PM +0300, Felipe Balbi wrote:

Hi Serge,

Serge Semin [off-list ref] writes:

quoted

In accordance with the DWC USB3 bindings the corresponding node name is
suppose to comply with Generic USB HCD DT schema, which requires the USB

DWC3 is not a simple HDC, though.

Yeah, strictly speaking it is equipped with a lot of vendor-specific stuff,
which are tuned by the DWC USB3 driver in the kernel. But after that the
controller is registered as xhci-hcd device so it's serviced by the xHCI driver,
which then registers the HCD device so the corresponding DT node is supposed
to be compatible with the next bindings: usb/usb-hcd.yaml, usb/usb-xhci.yaml
and usb/snps,dwc3,yaml. I've created the later one so to validate the denoted
compatibility.

quoted

nodes to have the name acceptable by the regexp: "^usb(@.*)?" . But a lot
of the DWC USB3-compatible nodes defined in the ARM/ARM64 DTS files have
name as "^dwc3@.*" or "^usb[1-3]@.*" or even "^dwusb@.*", which will cause
the dtbs_check procedure failure. Let's fix the nodes naming to be
compatible with the DWC USB3 DT schema to make dtbs_check happy.

Note we don't change the DWC USB3-compatible nodes names of
arch/arm64/boot/dts/apm/{apm-storm.dtsi,apm-shadowcat.dtsi} since the
in-source comment says that the nodes name need to be preserved as
"^dwusb@.*" for some backward compatibility.

interesting, compatibility with what? Some debugfs files, perhaps? :-)

Don't really know.) In my experience the worst type of such compatibility is
connected with some bootloader magic, which may add/remove/modify properties
to nodes with pre-defined names.

-Sergey

In any case, I don't have any problems with this, so I'll let other
folks comment.

-- 
balbi