Hi, On 18/02/2019 11:23, Yu Chen wrote: [...] > @@ -522,6 +556,15 @@ int dwc3_drd_init(struct dwc3 *dwc) > dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG); > } > > + dwc3_role_switch.fwnode = dev_fwnode(dwc->dev); > + dwc3_role_switch.set = dwc3_usb_role_switch_set; > + dwc3_role_switch.get = dwc3_usb_role_switch_get; > + dwc->role_sw = usb_role_switch_register(dwc->dev, &dwc3_role_switch); Building arm64 defconfig gives me this: drivers/usb/dwc3/drd.o: In function `dwc3_drd_exit': /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:604: undefined reference to `usb_role_switch_unregister' /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:604:(.text+0x814): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `usb_role_switch_unregister' /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:604: undefined reference to `usb_role_switch_unregister' /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:604:(.text+0x844): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `usb_role_switch_unregister' drivers/usb/dwc3/drd.o: In function `dwc3_drd_init': /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:562: undefined reference to `usb_role_switch_register' /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:562:(.text+0xa20): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `usb_role_switch_register' /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:562: undefined reference to `usb_role_switch_register' /home/valsch01/Work/kernel/drivers/usb/dwc3/drd.c:562:(.text+0xb4c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `usb_role_switch_register' Makefile:1024: recipe for target 'vmlinux' failed make: *** [vmlinux] Error 1 This has CONFIG_USB_ROLE_SWITCH=m, setting it as a built-in makes the thing linkable. I suppose that's because defconfig gives us CONFIG_USB_DWC3_DUAL_ROLE=y but then that should probably force a CONFIG_USB_ROLE_SWITCH=y. My immediate reaction to this would be to add: --- diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig index 2b1494460d0c..661b1d2efc8b 100644 --- a/drivers/usb/dwc3/Kconfig +++ b/drivers/usb/dwc3/Kconfig @@ -44,6 +44,7 @@ config USB_DWC3_DUAL_ROLE bool "Dual Role mode" depends on ((USB=y || USB=USB_DWC3) && (USB_GADGET=y || USB_GADGET=USB_DWC3)) depends on (EXTCON=y || EXTCON=USB_DWC3) + select USB_ROLE_SWITCH help This is the default mode of working of DWC3 controller where both host and gadget features are enabled. --- Not sure how acceptable that is though. > + if (ret) { > + dwc3_drd_exit(dwc); > + return PTR_ERR(dwc->role_sw); > + } > + > return 0; > } > > @@ -557,4 +600,6 @@ void dwc3_drd_exit(struct dwc3 *dwc) > > if (!dwc->edev) > free_irq(dwc->otg_irq, dwc); > + > + usb_role_switch_unregister(dwc->role_sw); > } >