On Wed, Sep 07, 2016 at 10:52:46AM +0200, Arnd Bergmann wrote: > On Wednesday, September 7, 2016 3:44:28 PM CEST Peter Chen wrote: > > > > The pre-condition of DT function at USB HCD core works is the host > > controller device has of_node, since it is the root node for USB tree > > described at DT. If the host controller device is not at DT, it needs > > to try to get its of_node, the chipidea driver gets it through its > > parent node [1] > > > > > [1] https://lkml.org/lkml/2016/8/8/119 > > > > Ah, this is what I was referring to in the other mail. > > However, the way you set the of_node might be dangerous too: > We should generally not have two platform_device structures with > the same of_node pointer, most importantly it may cause the > child device to be bound to the same driver as the parent > device since the probing is done by compatible string. > > As you tested it successfully, it must work at the moment on your > machine, but it could easily break depending on deferred probing > or module load order. > Currently, I work around above problems by setting core device of_node as NULL at both probe error path and platform driver .remove routine. I admit it is not a good way, but if we only have of_node at device's life periods after probe, it seems ok currently. It is hard to create of_node dynamically when create device, and keep some contents of parent's of_node, and some are not. -- Best Regards, Peter Chen -- 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
