USB: allow match on bInterfaceNumber

Some composite USB devices provide multiple interfaces
with different functions, all using "vendor-specific"
for class/subclass/protocol.  Another OS use interface
numbers to match the driver and interface. It seems
these devices are designed with that in mind - using
static interface numbers for the different functions.

This adds support for matching against the
bInterfaceNumber, allowing such devices to be supported
without having to resort to testing against interface
number whitelists and/or blacklists in the probe.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 5db93821f9c7..7771d453e5f3 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -78,6 +78,9 @@ struct ieee1394_device_id {
  *      of a given interface; other interfaces may support other classes.
  * @bInterfaceSubClass: Subclass of interface; associated with bInterfaceClass.
  * @bInterfaceProtocol: Protocol of interface; associated with bInterfaceClass.
+ * @bInterfaceNumber: Number of interface; composite devices may use
+ *      fixed interface numbers to differentiate between vendor-specific
+ *      interfaces.
  * @driver_info: Holds information used by the driver.  Usually it holds
  *      a pointer to a descriptor understood by the driver, or perhaps
  *      device flags.
@@ -115,6 +118,9 @@ struct usb_device_id {
         __u8            bInterfaceSubClass;
         __u8            bInterfaceProtocol;
 
+        /* Used for vendor-specific interface matches */
+        __u8            bInterfaceNumber;
+
         /* not matched against */
         kernel_ulong_t  driver_info;
 };
@@ -130,6 +136,7 @@ struct usb_device_id {
 #define USB_DEVICE_ID_MATCH_INT_CLASS           0x0080
 #define USB_DEVICE_ID_MATCH_INT_SUBCLASS        0x0100
 #define USB_DEVICE_ID_MATCH_INT_PROTOCOL        0x0200
+#define USB_DEVICE_ID_MATCH_INT_NUMBER          0x0400
 
 #define HID_ANY_ID                              (~0)
 #define HID_BUS_ANY                             0xffff
diff --git a/include/linux/usb.h b/include/linux/usb.h
index dea39dc551d4..f717fbdaee8e 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -777,6 +777,22 @@ static inline int usb_make_path(struct usb_device *dev, char *buf, size_t size)
         .bInterfaceProtocol = (pr)
 
 /**
+ * USB_DEVICE_INTERFACE_NUMBER - describe a usb device with a specific interface number
+ * @vend: the 16 bit USB Vendor ID
+ * @prod: the 16 bit USB Product ID
+ * @num: bInterfaceNumber value
+ *
+ * This macro is used to create a struct usb_device_id that matches a
+ * specific interface number of devices.
+ */
+#define USB_DEVICE_INTERFACE_NUMBER(vend, prod, num) \
+        .match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
+                       USB_DEVICE_ID_MATCH_INT_NUMBER, \
+        .idVendor = (vend), \
+        .idProduct = (prod), \
+        .bInterfaceNumber = (num)
+
+/**
  * USB_DEVICE_INFO - macro used to describe a class of usb devices
  * @cl: bDeviceClass value
  * @sc: bDeviceSubClass value