Hi ! So I'm toying a bit with the gadget subsystem, writing an UDC driver for the Aspeed BMC SoC. One thing this HW does (which I'm not yet enabling) is that it can show as a virtual hub with up to 5 devices underneath. The hub and each device has independent EP0's, and there's a pool of 15 "generic" endpoints that can be assigned to them otherwise. There's additional HW support for the hub's EP1 to be mostly operating autonomously in HW, returning the virtual hub port status. However, all of the hub EP0 needs to be done in SW (descriptors etc...). So my question is how would you guys recommend I should structure this in my driver ? The "dumb" option is to implement all of the hub stuff locally in my driver, including the responses to all the descriptor request etc... and expose effectively 5 UDC gadget "slots" for the user to hookup gadget drivers to. Another approach would be to try to have a gadget "slot" for the hub itself that is somewhat hard-wired to a hub function (which I would implement separately). The latter "sounds" nicer, however there is a need for a back channel between the main driver and the hub function unless we lift the abstraction to contain hub controls which I'm not sure is worthwhile. Also, can somebody enlighten me a bit more on what the "vbus" stuff is about ? I haven't quite figured it out. There seem to be no documentation (unless I missed it) on the various interfaces and UDC driver is supposed to provide. Cheers, Ben. -- 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
