Quoting Sandeep Maheswaram (2020-03-31 22:15:43) > diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c > index 1dfd024..d33ae86 100644 > --- a/drivers/usb/dwc3/dwc3-qcom.c > +++ b/drivers/usb/dwc3/dwc3-qcom.c > @@ -76,8 +85,13 @@ struct dwc3_qcom { > enum usb_dr_mode mode; > bool is_suspended; > bool pm_suspended; > + struct icc_path *usb_ddr_icc_path; > + struct icc_path *apps_usb_icc_path; > }; > > +static int dwc3_qcom_interconnect_enable(struct dwc3_qcom *qcom); > +static int dwc3_qcom_interconnect_disable(struct dwc3_qcom *qcom); Please get rid of these. We shouldn't need forward declarations. > + > static inline void dwc3_qcom_setbits(void __iomem *base, u32 offset, u32 val) > { > u32 reg; > @@ -285,6 +307,101 @@ static int dwc3_qcom_resume(struct dwc3_qcom *qcom) > return 0; > } > > + > +/** > + * dwc3_qcom_interconnect_init() - Get interconnect path handles > + * @qcom: Pointer to the concerned usb core. > + * > + */ > +static int dwc3_qcom_interconnect_init(struct dwc3_qcom *qcom) > +{ > + struct device *dev = qcom->dev; > + int ret; > + > + if (!device_is_bound(&qcom->dwc3->dev)) > + return -EPROBE_DEFER; How is this supposed to work? I see that this was added in an earlier revision of this patch series but there isn't any mention of why device_is_bound() is used here. It would be great if there was a comment detailing why this is necessary. It sounds like maximum_speed is important? Furthermore, dwc3_qcom_interconnect_init() is called by dwc3_qcom_probe() which is the function that registers the device for qcom->dwc3->dev. If that device doesn't probe between the time it is registered by dwc3_qcom_probe() and this function is called then we'll fail dwc3_qcom_probe() with -EPROBE_DEFER. And that will remove the qcom->dwc3->dev device from the platform bus because we call of_platform_depopulate() on the error path of dwc3_qcom_probe(). So isn't this whole thing racy and can potentially lead us to a driver probe loop where the wrapper (dwc3_qcom) and the core (dwc3) are probing and we're trying to time it just right so that driver for dwc3 binds before we setup interconnects? I don't know if dwc3 can communicate to the wrapper but that would be more of a direct way to do this. Or maybe the wrapper should try to read the DT property for maximum speed and fallback to a worst case high bandwidth value if it can't figure it out itself without help from dwc3 core.