Hi Rob, Rob Herring wrote: > On Fri, Jun 03, 2022 at 07:48:08PM -0700, Thinh Nguyen wrote: >> Set this property to use xhci-snps extension to handle common Synopsys >> DWC_usb3x host quirks. > > I don't see why this needs to be in DT. > > The DWC3 stuff is a mess of quirks which doesn't work well. Quirk > properties in DT require either knowing the quirk up front (You don't > always) or updating the DT on a platform when you find one. Quirks > should be implied by the compatible string(s) instead. > Since different vendors share the same Synopsys DWC_usb3x IPs, the controller's behavior is predictable based on the IP versions. Just using the compatible strings will become unmanageable when we have the common behavior across different vendors. Can we rename this property to "xhci-snps-DWC_usb3x-ip" or something similar? The main goal for this device property is to indicate that it's Synopsys's DWC_usb3x IP. As long as we know this, the xhci-snps glue extension can handle the fine tuning for the controller's behavior. We could use compatible string for this goal also, but that would mean the host devices that go through the dwc3 driver path may not have the compatible string. (e.g. host on pci bus but get recreated as platform device). Then we would need a different way to determine that. We could match the parent device driver for "dwc3", but that implementation looks fragile. So, will the device property "xhci-snps-DWC_usb3x-ip" work for you? Thanks, Thinh >> >> Signed-off-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> >> --- >> Documentation/devicetree/bindings/usb/usb-xhci.yaml | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.yaml b/Documentation/devicetree/bindings/usb/usb-xhci.yaml >> index 965f87fef702..540044a087a7 100644 >> --- a/Documentation/devicetree/bindings/usb/usb-xhci.yaml >> +++ b/Documentation/devicetree/bindings/usb/usb-xhci.yaml >> @@ -29,6 +29,10 @@ properties: >> description: Interrupt moderation interval >> default: 5000 >> >> + xhci-snps-quirks: >> + description: Handles common Synopsys DWC_usb3x host quirks >> + type: boolean >> + >> additionalProperties: true >> >> examples: >> -- >> 2.28.0 >> >>
