usb: core: allow a reference device for new_id

Often, usb drivers need some driver_info to get a device to work. To
have access to driver_info when using new_id, allow to pass a reference
vendor:product tuple from which new_id will inherit driver_info.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-usb

@@ -50,13 +50,19 @@ Description:
 		This may allow the driver to support more hardware than
 		was included in the driver's static device ID support
 		table at compile time. The format for the device ID is:
-		idVendor idProduct bInterfaceClass.
+		idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct
 		The vendor ID and device ID fields are required, the
-		interface class is optional.
+		rest is optional. The Ref* tuple can be used to tell the
+		driver to use the same driver_data for the new device as
+		it is used for the reference device.
 		Upon successfully adding an ID, the driver will probe
 		for the device and attempt to bind to it.  For example:
 		# echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id
 
+		Here add a new device (0458:7045) using driver_data from
+		an already supported device (0458:704c):
+		# echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id
+
 		Reading from this file will list all dynamically added
 		device IDs in the same format, with one entry per
 		line. For example:

drivers/usb/core/driver.c

@@ -37,6 +37,7 @@
  * and cause the driver to probe for all devices again.
  */
 ssize_t usb_store_new_id(struct usb_dynids *dynids,
+			 const struct usb_device_id *id_table,
 			 struct device_driver *driver,
 			 const char *buf, size_t count)
 {
@@ -44,11 +45,12 @@ ssize_t usb_store_new_id(struct usb_dynids *dynids,
 	u32 idVendor = 0;
 	u32 idProduct = 0;
 	unsigned int bInterfaceClass = 0;
+	u32 refVendor, refProduct;
 	int fields = 0;
 	int retval = 0;
 
-	fields = sscanf(buf, "%x %x %x", &idVendor, &idProduct,
-					&bInterfaceClass);
+	fields = sscanf(buf, "%x %x %x %x %x", &idVendor, &idProduct,
+			&bInterfaceClass, &refVendor, &refProduct);
 	if (fields < 2)
 		return -EINVAL;
 
@@ -68,6 +70,16 @@ ssize_t usb_store_new_id(struct usb_dynids *dynids,
 		dynid->id.match_flags |= USB_DEVICE_ID_MATCH_INT_CLASS;
 	}
 
+	if (fields > 4) {
+		const struct usb_device_id *id = id_table;
+
+		for (; id->match_flags; id++)
+			if (id->idVendor == refVendor && id->idProduct == refProduct) {
+				dynid->id.driver_info = id->driver_info;
+				break;
+			}
+	}
+
 	spin_lock(&dynids->lock);
 	list_add_tail(&dynid->node, &dynids->list);
 	spin_unlock(&dynids->lock);
@@ -109,7 +121,7 @@ static ssize_t new_id_store(struct device_driver *driver,
 {
 	struct usb_driver *usb_drv = to_usb_driver(driver);
 
-	return usb_store_new_id(&usb_drv->dynids, driver, buf, count);
+	return usb_store_new_id(&usb_drv->dynids, usb_drv->id_table, driver, buf, count);
 }
 static DRIVER_ATTR_RW(new_id);
 

drivers/usb/serial/bus.c

@@ -125,10 +125,12 @@ static ssize_t new_id_store(struct device_driver *driver,
 			    const char *buf, size_t count)
 {
 	struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
-	ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
+	ssize_t retval = usb_store_new_id(&usb_drv->dynids, usb_drv->id_table,
+					 driver, buf, count);
 
 	if (retval >= 0 && usb_drv->usb_driver != NULL)
 		retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
+					  usb_drv->usb_driver->id_table,
 					  &usb_drv->usb_driver->drvwrap.driver,
 					  buf, count);
 	return retval;

include/linux/usb.h

@@ -965,6 +965,7 @@ struct usb_dynid {
 };
 
 extern ssize_t usb_store_new_id(struct usb_dynids *dynids,
+				const struct usb_device_id *id_table,
 				struct device_driver *driver,
 				const char *buf, size_t count);