USB: Add optional match for interface class to dynamic ID facility

When adding the ID of a composite device dynamically to a driver, all
hitherto unbound interfaces are bound to this driver regardless of their
class, which may not be intended.
The patch adds the option to tell the targeted interface class to a driver
via the "new_id" attribute, in addition to the device ID.
Also, it appends the ABI documentation accordingly.

Example:
$ echo "1234 2a2a ff" >/sys/bus/usb-serial/drivers/option1/new_id
will bind only vendor-specific interfaces to the 3G driver.

Signed-off-by: Josua Dietze <digidietze@draisberghof.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 45887a0ff873..73abd8a0647d 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -45,10 +45,12 @@ ssize_t usb_store_new_id(struct usb_dynids *dynids,
         struct usb_dynid *dynid;
         u32 idVendor = 0;
         u32 idProduct = 0;
+        unsigned int bInterfaceClass = 0;
         int fields = 0;
         int retval = 0;
 
-        fields = sscanf(buf, "%x %x", &idVendor, &idProduct);
+        fields = sscanf(buf, "%x %x %x", &idVendor, &idProduct,
+                                        &bInterfaceClass);
         if (fields < 2)
                 return -EINVAL;
 
@@ -60,6 +62,10 @@ ssize_t usb_store_new_id(struct usb_dynids *dynids,
         dynid->id.idVendor = idVendor;
         dynid->id.idProduct = idProduct;
         dynid->id.match_flags = USB_DEVICE_ID_MATCH_DEVICE;
+        if (fields == 3) {
+                dynid->id.bInterfaceClass = (u8)bInterfaceClass;
+                dynid->id.match_flags |= USB_DEVICE_ID_MATCH_INT_CLASS;
+        }
 
         spin_lock(&dynids->lock);
         list_add_tail(&dynid->node, &dynids->list);