linux-imx/drivers/usb/README
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

2.4 KiB

To understand all the Linux-USB framework, you'll use these resources:

* This source code.  This is necessarily an evolving work, and
  includes kerneldoc that should help you get a current overview.
  ("make pdfdocs", and then look at "usb.pdf" for host side and
  "gadget.pdf" for peripheral side.)  Also, Documentation/usb has
  more information.

* The USB 2.0 specification (from www.usb.org), with supplements
  such as those for USB OTG and the various device classes.
  The USB specification has a good overview chapter, and USB
  peripherals conform to the widely known "Chapter 9".

* Chip specifications for USB controllers.  Examples include
  host controllers (on PCs, servers, and more); peripheral
  controllers (in devices with Linux firmware, like printers or
  cell phones); and hard-wired peripherals like Ethernet adapters.

* Specifications for other protocols implemented by USB peripheral
  functions.  Some are vendor-specific; others are vendor-neutral
  but just standardized outside of the www.usb.org team.

Here is a list of what each subdirectory here is, and what is contained in them.

core/ - This is for the core USB host code, including the usbfs files and the hub class driver ("khubd").

host/ - This is for USB host controller drivers. This includes UHCI, OHCI, EHCI, and others that might be used with more specialized "embedded" systems.

gadget/ - This is for USB peripheral controller drivers and the various gadget drivers which talk to them.

Individual USB driver directories. A new driver should be added to the first subdirectory in the list below that it fits into.

image/ - This is for still image drivers, like scanners or digital cameras. input/ - This is for any driver that uses the input subsystem, like keyboard, mice, touchscreens, tablets, etc. media/ - This is for multimedia drivers, like video cameras, radios, and any other drivers that talk to the v4l subsystem. net/ - This is for network drivers. serial/ - This is for USB to serial drivers. storage/ - This is for USB mass-storage drivers. class/ - This is for all USB device drivers that do not fit into any of the above categories, and work for a range of USB Class specified devices. misc/ - This is for all USB device drivers that do not fit into any of the above categories.