rtc: shrink devm_rtc_allocate_device()

We don't need to use devres_alloc() & devres_add() manually if all we
want to manage is a single pointer. We can shrink the code by using
devm_add_action_or_reset() instead. The number of allocations stays
the same.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-9-brgl@bgdev.pl

drivers/rtc/class.c

@@ -337,48 +337,37 @@ static void devm_rtc_unregister_device(void *data)
 	put_device(&rtc->dev);
 }
 
-static void devm_rtc_release_device(struct device *dev, void *res)
+static void devm_rtc_release_device(void *res)
 {
-	struct rtc_device *rtc = *(struct rtc_device **)res;
+	struct rtc_device *rtc = res;
 
 	put_device(&rtc->dev);
 }
 
 struct rtc_device *devm_rtc_allocate_device(struct device *dev)
 {
-	struct rtc_device **ptr, *rtc;
+	struct rtc_device *rtc;
 	int id, err;
 
 	id = rtc_device_get_id(dev);
 	if (id < 0)
 		return ERR_PTR(id);
 
-	ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr) {
-		err = -ENOMEM;
-		goto exit_ida;
-	}
-
 	rtc = rtc_allocate_device();
 	if (!rtc) {
-		err = -ENOMEM;
-		goto exit_devres;
+		ida_simple_remove(&rtc_ida, id);
+		return ERR_PTR(-ENOMEM);
 	}
 
-	*ptr = rtc;
-	devres_add(dev, ptr);
-
 	rtc->id = id;
 	rtc->dev.parent = dev;
 	dev_set_name(&rtc->dev, "rtc%d", id);
 
-	return rtc;
-
-exit_devres:
-	devres_free(ptr);
-exit_ida:
-	ida_simple_remove(&rtc_ida, id);
+	err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc);
+	if (err)
 		return ERR_PTR(err);
+
+	return rtc;
 }
 EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);