leds: lm355x: fix attribute-creation race

Use the attribute groups of the led-class to create the indicator-LED
attributes during probe in order to avoid racing with userspace.

Note that the comment about the pattern attribute only being for LM3554
was incorrect and did not match the code (the original leds-lm3556
driver had the attribute before LM3554 support was added).
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/leds-lm355x.c

@@ -413,6 +413,12 @@ static ssize_t lm3556_indicator_pattern_store(struct device *dev,
 
 static DEVICE_ATTR(pattern, S_IWUSR, NULL, lm3556_indicator_pattern_store);
 
+static struct attribute *lm355x_indicator_attrs[] = {
+	&dev_attr_pattern.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(lm355x_indicator);
+
 static const struct regmap_config lm355x_regmap = {
 	.reg_bits = 8,
 	.val_bits = 8,
@@ -501,25 +507,18 @@ static int lm355x_probe(struct i2c_client *client,
 	else
 		chip->cdev_indicator.max_brightness = 8;
 	chip->cdev_indicator.brightness_set = lm355x_indicator_brightness_set;
+	/* indicator pattern control only for LM3556 */
+	if (id->driver_data == CHIP_LM3556)
+		chip->cdev_indicator.groups = lm355x_indicator_groups;
 	err = led_classdev_register((struct device *)
 				    &client->dev, &chip->cdev_indicator);
 	if (err < 0)
 		goto err_create_indicator_file;
-	/* indicator pattern control only for LM3554 */
-	if (id->driver_data == CHIP_LM3556) {
-		err =
-		    device_create_file(chip->cdev_indicator.dev,
-				       &dev_attr_pattern);
-		if (err < 0)
-			goto err_create_pattern_file;
-	}
 
 	dev_info(&client->dev, "%s is initialized\n",
 		 lm355x_name[id->driver_data]);
 	return 0;
 
-err_create_pattern_file:
-	led_classdev_unregister(&chip->cdev_indicator);
 err_create_indicator_file:
 	led_classdev_unregister(&chip->cdev_torch);
 err_create_torch_file:
@@ -534,8 +533,6 @@ static int lm355x_remove(struct i2c_client *client)
 	struct lm355x_reg_data *preg = chip->regs;
 
 	regmap_write(chip->regmap, preg[REG_OPMODE].regno, 0);
-	if (chip->type == CHIP_LM3556)
-		device_remove_file(chip->cdev_indicator.dev, &dev_attr_pattern);
 	led_classdev_unregister(&chip->cdev_indicator);
 	flush_work(&chip->work_indicator);
 	led_classdev_unregister(&chip->cdev_torch);