leds: lm3550: fix attribute-creation race

Use the attribute groups of the led-class to create the mode attribute
during probe in order to avoid racing with userspace.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/leds-lm3530.c

@@ -400,6 +400,12 @@ static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
 }
 static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
 
+static struct attribute *lm3530_attrs[] = {
+	&dev_attr_mode.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(lm3530);
+
 static int lm3530_probe(struct i2c_client *client,
 			   const struct i2c_device_id *id)
 {
@@ -436,6 +442,7 @@ static int lm3530_probe(struct i2c_client *client,
 	drvdata->led_dev.name = LM3530_LED_DEV;
 	drvdata->led_dev.brightness_set = lm3530_brightness_set;
 	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
+	drvdata->led_dev.groups = lm3530_groups;
 
 	i2c_set_clientdata(client, drvdata);
 
@@ -461,26 +468,13 @@ static int lm3530_probe(struct i2c_client *client,
 		return err;
 	}
 
-	err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode);
-	if (err < 0) {
-		dev_err(&client->dev, "File device creation failed: %d\n", err);
-		err = -ENODEV;
-		goto err_create_file;
-	}
-
 	return 0;
-
-err_create_file:
-	led_classdev_unregister(&drvdata->led_dev);
-	return err;
 }
 
 static int lm3530_remove(struct i2c_client *client)
 {
 	struct lm3530_data *drvdata = i2c_get_clientdata(client);
 
-	device_remove_file(drvdata->led_dev.dev, &dev_attr_mode);
-
 	lm3530_led_disable(drvdata);
 	led_classdev_unregister(&drvdata->led_dev);
 	return 0;