i2c: dev: fix notifier return values

We have a set of return values that notifier callbacks can return. They
should not return 0, error codes or anything other than those predefined
values. Make the i2c character device's callback return NOTIFY_DONE or
NOTIFY_OK depending on the situation.

Signed-off-by: Bartosz Golaszewski <[e-mail]>
Signed-off-by: Wolfram Sang <[e-mail]>

drivers/i2c/i2c-dev.c

···
 	int res;
 
 	if (dev->type != &i2c_adapter_type)
-		return 0;
+		return NOTIFY_DONE;
 	adap = to_i2c_adapter(dev);
 
 	i2c_dev = get_free_i2c_dev(adap);
 	if (IS_ERR(i2c_dev))
-		return PTR_ERR(i2c_dev);
+		return NOTIFY_DONE;
 
 	cdev_init(&i2c_dev->cdev, &i2cdev_fops);
 	i2c_dev->cdev.owner = THIS_MODULE;
···
 		goto err_put_i2c_dev;
 
 	pr_debug("adapter [%s] registered as minor %d\n", adap->name, adap->nr);
-	return 0;
+	return NOTIFY_OK;
 
 err_put_i2c_dev:
 	put_i2c_dev(i2c_dev, false);
-	return res;
+	return NOTIFY_DONE;
 }
 
 static int i2cdev_detach_adapter(struct device *dev, void *dummy)
···
 	struct i2c_dev *i2c_dev;
 
 	if (dev->type != &i2c_adapter_type)
-		return 0;
+		return NOTIFY_DONE;
 	adap = to_i2c_adapter(dev);
 
 	i2c_dev = i2c_dev_get_by_minor(adap->nr);
 	if (!i2c_dev) /* attach_adapter must have failed */
-		return 0;
+		return NOTIFY_DONE;
 
 	put_i2c_dev(i2c_dev, true);
 
 	pr_debug("adapter [%s] unregistered\n", adap->name);
-	return 0;
+	return NOTIFY_OK;
 }
 
 static int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,
···
 		return i2cdev_detach_adapter(dev, NULL);
 	}
 
-	return 0;
+	return NOTIFY_DONE;
 }
 
 static struct notifier_block i2cdev_notifier = {