input: lm8323: fix attribute-creation race

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

drivers/input/keyboard/lm8323.c

@@ -558,6 +558,12 @@ static ssize_t lm8323_pwm_store_time(struct device *dev,
 }
 static DEVICE_ATTR(time, 0644, lm8323_pwm_show_time, lm8323_pwm_store_time);
 
+static struct attribute *lm8323_pwm_attrs[] = {
+	&dev_attr_time.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(lm8323_pwm);
+
 static int init_pwm(struct lm8323_chip *lm, int id, struct device *dev,
 		    const char *name)
 {
@@ -580,16 +586,11 @@ static int init_pwm(struct lm8323_chip *lm, int id, struct device *dev,
 	if (name) {
 		pwm->cdev.name = name;
 		pwm->cdev.brightness_set = lm8323_pwm_set_brightness;
+		pwm->cdev.groups = lm8323_pwm_groups;
 		if (led_classdev_register(dev, &pwm->cdev) < 0) {
 			dev_err(dev, "couldn't register PWM %d\n", id);
 			return -1;
 		}
-		if (device_create_file(pwm->cdev.dev,
-					&dev_attr_time) < 0) {
-			dev_err(dev, "couldn't register time attribute\n");
-			led_classdev_unregister(&pwm->cdev);
-			return -1;
-		}
 		pwm->enabled = true;
 	}
 
@@ -753,11 +754,8 @@ static int lm8323_probe(struct i2c_client *client,
 	device_remove_file(&client->dev, &dev_attr_disable_kp);
 fail2:
 	while (--pwm >= 0)
-		if (lm->pwm[pwm].enabled) {
-			device_remove_file(lm->pwm[pwm].cdev.dev,
-					   &dev_attr_time);
+		if (lm->pwm[pwm].enabled)
 			led_classdev_unregister(&lm->pwm[pwm].cdev);
-		}
 fail1:
 	input_free_device(idev);
 	kfree(lm);
@@ -777,10 +775,8 @@ static int lm8323_remove(struct i2c_client *client)
 	device_remove_file(&lm->client->dev, &dev_attr_disable_kp);
 
 	for (i = 0; i < 3; i++)
-		if (lm->pwm[i].enabled) {
-			device_remove_file(lm->pwm[i].cdev.dev, &dev_attr_time);
+		if (lm->pwm[i].enabled)
 			led_classdev_unregister(&lm->pwm[i].cdev);
-		}
 
 	kfree(lm);