USB: add IAD support to usbfs and sysfs

USB_IAD: Adds support for USB Interface Association Descriptors.

This patch adds support to the USB host stack for parsing, storing, and
displaying Interface Association Descriptors. In /proc/bus/usb/devices
lines starting with A: show the fields in an IAD. In sysfs if an
interface on a USB device is referenced by an IAD the following files
will be added to the sysfs directory for that interface:
iad_bFirstInterface, iad_bInterfaceCount, iad_bFunctionClass, and
iad_bFunctionSubClass, iad_bFunctionProtocol

Signed-off-by: Craig W. Nadler <craig@nadler.us>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/usb.h b/include/linux/usb.h
index 533c32374e01..7a60946df3b6 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -146,6 +146,10 @@ struct usb_interface {
                                          * active alternate setting */
         unsigned num_altsetting;        /* number of alternate settings */
 
+        /* If there is an interface association descriptor then it will list
+         * the associated interfaces */
+        struct usb_interface_assoc_descriptor *intf_assoc;
+
         int minor;                      /* minor number this interface is
                                          * bound to */
         enum usb_interface_condition condition;         /* state of binding */
@@ -175,6 +179,7 @@ void usb_put_intf(struct usb_interface *intf);
 
 /* this maximum is arbitrary */
 #define USB_MAXINTERFACES       32
+#define USB_MAXIADS             USB_MAXINTERFACES/2
 
 /**
  * struct usb_interface_cache - long-term representation of a device interface
@@ -245,6 +250,11 @@ struct usb_host_config {
         struct usb_config_descriptor    desc;
 
         char *string;           /* iConfiguration string, if present */
+
+        /* List of any Interface Association Descriptors in this
+         * configuration. */
+        struct usb_interface_assoc_descriptor *intf_assoc[USB_MAXIADS];
+
         /* the interfaces associated with this configuration,
          * stored in no particular order */
         struct usb_interface *interface[USB_MAXINTERFACES];