LinuxCon North America/CloudOpen North America

A USB gadget is a device which has a USB Device Controller and can be connected to a host to extend it with additional functions. Creating a gadget means deciding what configurations there are and which functions each configuration provides. So far the choice had to be made statically at kernel compile time. Configfs can be used instead at runtime; no need to compile anything, the required components are available in mainline. Composing a new gadget of existing functions does not involve USB maintainers any more, basic shell scripting is enough.

The presentation is kept at middle technical level and is mainly for distributors of (embedded) Linux and kernel USB developers. It is about how to create gadgets with configfs, examples given, and about how configfs is integrated into the USB gadget framework. The current status, things to do and the future of legacy gadgets are outlined.