if (minor < 0 || minor >= COMEDI_NUM_BOARD_MINORS) {
                        dev_err(dev->class_dev,
                                "Minor %d is invalid!\n", minor);
-                       return 0;
+                       return -EINVAL;
                }
                if (minor == dev->minor) {
                        dev_err(dev->class_dev,
                                "Cannot bond this driver to itself!\n");
-                       return 0;
+                       return -EINVAL;
                }
                if (devs_opened[minor]) {
                        dev_err(dev->class_dev,
                                "Minor %d specified more than once!\n", minor);
-                       return 0;
+                       return -EINVAL;
                }
 
                snprintf(file, sizeof(file), "/dev/comedi%u", minor);
                if (!d) {
                        dev_err(dev->class_dev,
                                "Minor %u could not be opened\n", minor);
-                       return 0;
+                       return -ENODEV;
                }
 
                /* Do DIO, as that's all we support now.. */
                                dev_err(dev->class_dev,
                                        "comedi_get_n_channels() returned %d on minor %u subdev %d!\n",
                                        nchans, minor, sdev);
-                               return 0;
+                               return -EINVAL;
                        }
                        bdev = kmalloc(sizeof(*bdev), GFP_KERNEL);
                        if (!bdev)
-                               return 0;
+                               return -ENOMEM;
 
                        bdev->dev = d;
                        bdev->minor = minor;
                        if (!devpriv->devs) {
                                dev_err(dev->class_dev,
                                        "Could not allocate memory. Out of memory?\n");
-                               return 0;
+                               return -ENOMEM;
                        }
 
                        devpriv->devs[devpriv->ndevs - 1] = bdev;
 
        if (!devpriv->nchans) {
                dev_err(dev->class_dev, "No channels found!\n");
-               return 0;
+               return -EINVAL;
        }
 
-       return 1;
+       return 0;
 }
 
 static int bonding_attach(struct comedi_device *dev,
        /*
         * Setup our bonding from config params.. sets up our private struct..
         */
-       if (!do_dev_config(dev, it))
-               return -EINVAL;
+       ret = do_dev_config(dev, it);
+       if (ret)
+               return ret;
 
        dev->board_name = devpriv->name;