On Sat, Jun 15, 2013 at 4:01 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 14 Jun 2013, Roger Quadros wrote: > >> >> hi >> >> The following is my understanding. >> >> I think for PHY initialization and shutdown part, it is generic for >> >> other parts. >> >> PHY initialization need to be called before hc_driver->reset is called. >> >> I think it can be added at usb_add_hcd. >> >> For PHY shutdown, it can be added at usb_remove_hcd. >> > >> > Yes, that should work. >> >> I don't think this will work with OMAP USB host controller when used in >> Transceiver-less mode (e.g. HSIC). In this mode we need to release the HSIC >> reset (mapped to PHY init), after the EHCI controller is up and running. >> >> On the other hand, in the PHY mode, the PHY needs to be initialized (brought out >> of reset) before the EHCI controller starts. > > In other words, transceiver-less mode effectively works without using a > software-controlled PHY? > >> This behavior might be different on other controllers. Generalization is good >> as long as there is an override available for the controllers to handle the >> PHY init/shutdown themselves. > > To avoid PHY init/shutdown, the platform driver should simply leave the > generic PHY pointer (which has not yet been added to struct hcd) set to > NULL. > So does it mean that i need add adtional usb_phy to struct hcd? I think we can still make use of struct hcd->phy without add addtional members. For OMAP transceiver-less mode, you can still use your own phy init/shutdown and leave the hcd->phy to be NULL, and for the PHY mode, hcd->phy can be set. It will do ->init at usb_add_hcd and ->shutdown at usb_remove_hcd. > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
