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STRUCT USB_COMPOSITE(9) Kernel Mode Gadget API STRUCT USB_COMPOSITE(9)

NAME

struct_usb_composite_dev - represents one composite usb gadget

SYNOPSIS

struct usb_composite_dev {
  struct usb_gadget * gadget;
  struct usb_request * req;
  struct usb_request * os_desc_req;
  struct usb_configuration * config;
  u8 qw_sign[OS_STRING_QW_SIGN_LEN];
  u8 b_vendor_code;
  struct usb_configuration * os_desc_config;
  unsigned int use_os_string:1;
};  

MEMBERS

gadget
read-only, abstracts the gadget's usb peripheral controller
req
used for control responses; buffer is pre-allocated
os_desc_req
used for OS descriptors responses; buffer is pre-allocated
config
the currently active configuration
qw_sign[OS_STRING_QW_SIGN_LEN]
qwSignature part of the OS string
b_vendor_code
bMS_VendorCode part of the OS string
os_desc_config
the configuration to be used with OS descriptors
use_os_string
false by default, interested gadgets set it

DESCRIPTION

One of these devices is allocated and initialized before the associated device driver's bind is called.

OPEN ISSUE

it appears that some WUSB devices will need to be built by combining a normal (wired) gadget with a wireless one. This revision of the gadget framework should probably try to make sure doing that won't hurt too much.

ONE NOTION FOR HOW TO HANDLE WIRELESS USB DEVICES INVOLVES

(a) a second gadget here, discovery mechanism TBD, but likely needing separate “register/unregister WUSB gadget” calls; (b) updates to usb_gadget to include flags “is it wireless”, “is it wired”, plus (presumably in a wrapper structure) bandgroup and PHY info; (c) presumably a wireless_ep wrapping a usb_ep, and reporting wireless-specific parameters like maxburst and maxsequence; (d) configurations that are specific to wireless links; (e) function drivers that understand wireless configs and will support wireless for (additional) function instances; (f) a function to support association setup (like CBAF), not necessarily requiring a wireless adapter; (g) composite device setup that can create one or more wireless configs, including appropriate association setup support; (h) more, TBD.

AUTHOR

David Brownell <dbrownell@users.sourceforge.net>
Author.

COPYRIGHT

May 2018 Kernel Hackers Manual 3.16