leds: ledtrig-heartbeat: Convert timers to use timer_setup()

Instead of using .data directly, convert to from_timer. Since the
trigger_data is allocated separately, the led_cdev must be explicitly
tracked for the callback.

Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Zhang Bo <bo.zhang@nxp.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-leds@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

drivers/leds/trigger/ledtrig-heartbeat.c

@@ -25,19 +25,23 @@
 static int panic_heartbeats;
 
 struct heartbeat_trig_data {
+	struct led_classdev *led_cdev;
 	unsigned int phase;
 	unsigned int period;
 	struct timer_list timer;
 	unsigned int invert;
 };
 
-static void led_heartbeat_function(unsigned long data)
+static void led_heartbeat_function(struct timer_list *t)
 {
-	struct led_classdev *led_cdev = (struct led_classdev *) data;
-	struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
+	struct heartbeat_trig_data *heartbeat_data =
+		from_timer(heartbeat_data, t, timer);
+	struct led_classdev *led_cdev;
 	unsigned long brightness = LED_OFF;
 	unsigned long delay = 0;
 
+	led_cdev = heartbeat_data->led_cdev;
+
 	if (unlikely(panic_heartbeats)) {
 		led_set_brightness_nosleep(led_cdev, LED_OFF);
 		return;
@@ -127,18 +131,18 @@ static void heartbeat_trig_activate(struct led_classdev *led_cdev)
 		return;
 
 	led_cdev->trigger_data = heartbeat_data;
+	heartbeat_data->led_cdev = led_cdev;
 	rc = device_create_file(led_cdev->dev, &dev_attr_invert);
 	if (rc) {
 		kfree(led_cdev->trigger_data);
 		return;
 	}
 
-	setup_timer(&heartbeat_data->timer,
-		    led_heartbeat_function, (unsigned long) led_cdev);
+	timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0);
 	heartbeat_data->phase = 0;
 	if (!led_cdev->blink_brightness)
 		led_cdev->blink_brightness = led_cdev->max_brightness;
-	led_heartbeat_function(heartbeat_data->timer.data);
+	led_heartbeat_function(&heartbeat_data->timer);
 	set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 	led_cdev->activated = true;
 }