USB: add remove_id sysfs attr for usb drivers

Accroding commit 0994375e, which is adding remove_id sysfs attr
for pci drivers, for management tools dynamically bind/unbind
a pci/usb devices to a specified drivers; with this patch,
the management tools can be simplied.

And the original code didn't handle the failure of
usb_create_newid_file, fixed in this patch.

Signed-off-by: CHENG Renquan <rqcheng@smu.edu.sg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 7772928..deb6b48 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -144,3 +144,16 @@ Description:
 
                Write a 1 to force the device to disconnect
                (equivalent to unplugging a wired USB device).
+
+What:          /sys/bus/usb/drivers/.../remove_id
+Date:          November 2009
+Contact:       CHENG Renquan <rqcheng@smu.edu.sg>
+Description:
+               Writing a device ID to this file will remove an ID
+               that was dynamically added via the new_id sysfs entry.
+               The format for the device ID is:
+               idVendor idProduct.     After successfully
+               removing an ID, the driver will no longer support the
+               device.  This is useful to ensure auto probing won't
+               match the driver to the device.  For example:
+               # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 7a05bab..60a45f1 100644 (file)
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -83,6 +83,47 @@ static ssize_t store_new_id(struct device_driver *driver,
 }
 static DRIVER_ATTR(new_id, S_IWUSR, NULL, store_new_id);
 
+/**
+ * store_remove_id - remove a USB device ID from this driver
+ * @driver: target device driver
+ * @buf: buffer for scanning device ID data
+ * @count: input size
+ *
+ * Removes a dynamic usb device ID from this driver.
+ */
+static ssize_t
+store_remove_id(struct device_driver *driver, const char *buf, size_t count)
+{
+       struct usb_dynid *dynid, *n;
+       struct usb_driver *usb_driver = to_usb_driver(driver);
+       u32 idVendor = 0;
+       u32 idProduct = 0;
+       int fields = 0;
+       int retval = 0;
+
+       fields = sscanf(buf, "%x %x", &idVendor, &idProduct);
+       if (fields < 2)
+               return -EINVAL;
+
+       spin_lock(&usb_driver->dynids.lock);
+       list_for_each_entry_safe(dynid, n, &usb_driver->dynids.list, node) {
+               struct usb_device_id *id = &dynid->id;
+               if ((id->idVendor == idVendor) &&
+                   (id->idProduct == idProduct)) {
+                       list_del(&dynid->node);
+                       kfree(dynid);
+                       retval = 0;
+                       break;
+               }
+       }
+       spin_unlock(&usb_driver->dynids.lock);
+
+       if (retval)
+               return retval;
+       return count;
+}
+static DRIVER_ATTR(remove_id, S_IWUSR, NULL, store_remove_id);
+
 static int usb_create_newid_file(struct usb_driver *usb_drv)
 {
        int error = 0;
@@ -107,6 +148,21 @@ static void usb_remove_newid_file(struct usb_driver *usb_drv)
                                   &driver_attr_new_id);
 }
 
+static int
+usb_create_removeid_file(struct usb_driver *drv)
+{
+       int error = 0;
+       if (drv->probe != NULL)
+               error = driver_create_file(&drv->drvwrap.driver,
+                               &driver_attr_remove_id);
+       return error;
+}
+
+static void usb_remove_removeid_file(struct usb_driver *drv)
+{
+       driver_remove_file(&drv->drvwrap.driver, &driver_attr_remove_id);
+}
+
 static void usb_free_dynids(struct usb_driver *usb_drv)
 {
        struct usb_dynid *dynid, *n;
@@ -128,6 +184,16 @@ static void usb_remove_newid_file(struct usb_driver *usb_drv)
 {
 }
 
+static int
+usb_create_removeid_file(struct usb_driver *drv)
+{
+       return 0;
+}
+
+static void usb_remove_removeid_file(struct usb_driver *drv)
+{
+}
+
 static inline void usb_free_dynids(struct usb_driver *usb_drv)
 {
 }
@@ -774,19 +840,34 @@ int usb_register_driver(struct usb_driver *new_driver, struct module *owner,
        INIT_LIST_HEAD(&new_driver->dynids.list);
 
        retval = driver_register(&new_driver->drvwrap.driver);
+       if (retval)
+               goto out;
 
-       if (!retval) {
-               pr_info("%s: registered new interface driver %s\n",
+       usbfs_update_special();
+
+       retval = usb_create_newid_file(new_driver);
+       if (retval)
+               goto out_newid;
+
+       retval = usb_create_removeid_file(new_driver);
+       if (retval)
+               goto out_removeid;
+
+       pr_info("%s: registered new interface driver %s\n",
                        usbcore_name, new_driver->name);
-               usbfs_update_special();
-               usb_create_newid_file(new_driver);
-       } else {
-               printk(KERN_ERR "%s: error %d registering interface "
-                       "       driver %s\n",
-                       usbcore_name, retval, new_driver->name);
-       }
 
+out:
        return retval;
+
+out_removeid:
+       usb_remove_newid_file(new_driver);
+out_newid:
+       driver_unregister(&new_driver->drvwrap.driver);
+
+       printk(KERN_ERR "%s: error %d registering interface "
+                       "       driver %s\n",
+                       usbcore_name, retval, new_driver->name);
+       goto out;
 }
 EXPORT_SYMBOL_GPL(usb_register_driver);
 
@@ -806,6 +887,7 @@ void usb_deregister(struct usb_driver *driver)
        pr_info("%s: deregistering interface driver %s\n",
                        usbcore_name, driver->name);
 
+       usb_remove_removeid_file(driver);
        usb_remove_newid_file(driver);
        usb_free_dynids(driver);
        driver_unregister(&driver->drvwrap.driver);