leds: backlight trigger: simplifications from core changes

Use the new module_led_trigger() helper. Also use
attribute support from the trigger core. Drop error message on
allocation failure as kzalloc() already screams loudly when failing. Use
wrappers to get and set trigger data.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

drivers/leds/trigger/ledtrig-backlight.c

@@ -64,8 +64,7 @@ static int fb_notifier_callback(struct notifier_block *p,
 static ssize_t bl_trig_invert_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
-	struct led_classdev *led = dev_get_drvdata(dev);
-	struct bl_trig_notifier *n = led->trigger_data;
+	struct bl_trig_notifier *n = led_trigger_get_drvdata(dev);
 
 	return sprintf(buf, "%u\n", n->invert);
 }
@@ -73,8 +72,8 @@ static ssize_t bl_trig_invert_show(struct device *dev,
 static ssize_t bl_trig_invert_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t num)
 {
-	struct led_classdev *led = dev_get_drvdata(dev);
-	struct bl_trig_notifier *n = led->trigger_data;
+	struct led_classdev *led = led_trigger_get_led(dev);
+	struct bl_trig_notifier *n = led_trigger_get_drvdata(dev);
 	unsigned long invert;
 	int ret;
 
@@ -97,6 +96,12 @@ static ssize_t bl_trig_invert_store(struct device *dev,
 }
 static DEVICE_ATTR(inverted, 0644, bl_trig_invert_show, bl_trig_invert_store);
 
+static struct attribute *bl_trig_attrs[] = {
+	&dev_attr_inverted.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(bl_trig);
+
 static int bl_trig_activate(struct led_classdev *led)
 {
 	int ret;
@@ -104,15 +109,9 @@ static int bl_trig_activate(struct led_classdev *led)
 	struct bl_trig_notifier *n;
 
 	n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL);
-	led->trigger_data = n;
-	if (!n) {
-		dev_err(led->dev, "unable to allocate backlight trigger\n");
-		return 0;
-	}
-
-	ret = device_create_file(led->dev, &dev_attr_inverted);
-	if (ret)
-		goto err_invert;
+	if (!n)
+		return -ENOMEM;
+	led_set_trigger_data(led, n);
 
 	n->led = led;
 	n->brightness = led->brightness;
@@ -122,48 +121,25 @@ static int bl_trig_activate(struct led_classdev *led)
 	ret = fb_register_client(&n->notifier);
 	if (ret)
 		dev_err(led->dev, "unable to register backlight trigger\n");
-	led->activated = true;
-
-	return 0;
-
-err_invert:
-	led->trigger_data = NULL;
-	kfree(n);
 
 	return 0;
 }
 
 static void bl_trig_deactivate(struct led_classdev *led)
 {
-	struct bl_trig_notifier *n =
-		(struct bl_trig_notifier *) led->trigger_data;
+	struct bl_trig_notifier *n = led_get_trigger_data(led);
 
-	if (led->activated) {
-		device_remove_file(led->dev, &dev_attr_inverted);
 	fb_unregister_client(&n->notifier);
 	kfree(n);
-		led->activated = false;
-	}
 }
 
 static struct led_trigger bl_led_trigger = {
 	.name		= "backlight",
 	.activate	= bl_trig_activate,
-	.deactivate	= bl_trig_deactivate
+	.deactivate	= bl_trig_deactivate,
+	.groups		= bl_trig_groups,
 };
-
-static int __init bl_trig_init(void)
-{
-	return led_trigger_register(&bl_led_trigger);
-}
-
-static void __exit bl_trig_exit(void)
-{
-	led_trigger_unregister(&bl_led_trigger);
-}
-
-module_init(bl_trig_init);
-module_exit(bl_trig_exit);
+module_led_trigger(bl_led_trigger);
 
 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 MODULE_DESCRIPTION("Backlight emulation LED trigger");