watchdog: rt2880_wdt: Convert to use device managed functions and other improvements

Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.
Other improvements as listed below.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

- Drop empty remove function
- Introduce local variable 'struct device *dev' and use it instead of
  dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device
- Replace shutdown function with call to watchdog_stop_on_reboot()
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/rt2880_wdt.c

@@ -141,17 +141,18 @@ static struct watchdog_device rt288x_wdt_dev = {
 
 static int rt288x_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	int ret;
 
 	rt288x_wdt_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(rt288x_wdt_base))
 		return PTR_ERR(rt288x_wdt_base);
 
-	rt288x_wdt_clk = devm_clk_get(&pdev->dev, NULL);
+	rt288x_wdt_clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(rt288x_wdt_clk))
 		return PTR_ERR(rt288x_wdt_clk);
 
-	rt288x_wdt_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	rt288x_wdt_reset = devm_reset_control_get_exclusive(dev, NULL);
 	if (!IS_ERR(rt288x_wdt_reset))
 		reset_control_deassert(rt288x_wdt_reset);
 
@@ -159,31 +160,20 @@ static int rt288x_wdt_probe(struct platform_device *pdev)
 
 	rt288x_wdt_dev.bootstatus = rt288x_wdt_bootcause();
 	rt288x_wdt_dev.max_timeout = (0xfffful / rt288x_wdt_freq);
-	rt288x_wdt_dev.parent = &pdev->dev;
+	rt288x_wdt_dev.parent = dev;
 
 	watchdog_init_timeout(&rt288x_wdt_dev, rt288x_wdt_dev.max_timeout,
-			      &pdev->dev);
+			      dev);
 	watchdog_set_nowayout(&rt288x_wdt_dev, nowayout);
 
-	ret = watchdog_register_device(&rt288x_wdt_dev);
+	watchdog_stop_on_reboot(&rt288x_wdt_dev);
+	ret = devm_watchdog_register_device(dev, &rt288x_wdt_dev);
 	if (!ret)
-		dev_info(&pdev->dev, "Initialized\n");
+		dev_info(dev, "Initialized\n");
 
 	return 0;
 }
 
-static int rt288x_wdt_remove(struct platform_device *pdev)
-{
-	watchdog_unregister_device(&rt288x_wdt_dev);
-
-	return 0;
-}
-
-static void rt288x_wdt_shutdown(struct platform_device *pdev)
-{
-	rt288x_wdt_stop(&rt288x_wdt_dev);
-}
-
 static const struct of_device_id rt288x_wdt_match[] = {
 	{ .compatible = "ralink,rt2880-wdt" },
 	{},
@@ -192,8 +182,6 @@ MODULE_DEVICE_TABLE(of, rt288x_wdt_match);
 
 static struct platform_driver rt288x_wdt_driver = {
 	.probe		= rt288x_wdt_probe,
-	.remove		= rt288x_wdt_remove,
-	.shutdown	= rt288x_wdt_shutdown,
 	.driver		= {
 		.name		= KBUILD_MODNAME,
 		.of_match_table	= rt288x_wdt_match,