watchdog: sprd_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

- Replace devm_add_action() followed by failure action with
  devm_add_action_or_reset()
- Replace 'val = e; return val;' with 'return e;'
- Introduce local variable 'struct device *dev' and use it instead of
  dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/sprd_wdt.c

@@ -245,9 +245,7 @@ static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd)
 	u32 val;
 
 	val = sprd_wdt_get_cnt_value(wdt);
-	val = val / SPRD_WDT_CNT_STEP;
-
-	return val;
+	return val / SPRD_WDT_CNT_STEP;
 }
 
 static const struct watchdog_ops sprd_wdt_ops = {
@@ -269,10 +267,11 @@ static const struct watchdog_info sprd_wdt_info = {
 
 static int sprd_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct sprd_wdt *wdt;
 	int ret;
 
-	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 	if (!wdt)
 		return -ENOMEM;
 
@@ -280,57 +279,56 @@ static int sprd_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
-	wdt->enable = devm_clk_get(&pdev->dev, "enable");
+	wdt->enable = devm_clk_get(dev, "enable");
 	if (IS_ERR(wdt->enable)) {
-		dev_err(&pdev->dev, "can't get the enable clock\n");
+		dev_err(dev, "can't get the enable clock\n");
 		return PTR_ERR(wdt->enable);
 	}
 
-	wdt->rtc_enable = devm_clk_get(&pdev->dev, "rtc_enable");
+	wdt->rtc_enable = devm_clk_get(dev, "rtc_enable");
 	if (IS_ERR(wdt->rtc_enable)) {
-		dev_err(&pdev->dev, "can't get the rtc enable clock\n");
+		dev_err(dev, "can't get the rtc enable clock\n");
 		return PTR_ERR(wdt->rtc_enable);
 	}
 
 	wdt->irq = platform_get_irq(pdev, 0);
 	if (wdt->irq < 0) {
-		dev_err(&pdev->dev, "failed to get IRQ resource\n");
+		dev_err(dev, "failed to get IRQ resource\n");
 		return wdt->irq;
 	}
 
-	ret = devm_request_irq(&pdev->dev, wdt->irq, sprd_wdt_isr,
-			       IRQF_NO_SUSPEND, "sprd-wdt", (void *)wdt);
+	ret = devm_request_irq(dev, wdt->irq, sprd_wdt_isr, IRQF_NO_SUSPEND,
+			       "sprd-wdt", (void *)wdt);
 	if (ret) {
-		dev_err(&pdev->dev, "failed to register irq\n");
+		dev_err(dev, "failed to register irq\n");
 		return ret;
 	}
 
 	wdt->wdd.info = &sprd_wdt_info;
 	wdt->wdd.ops = &sprd_wdt_ops;
-	wdt->wdd.parent = &pdev->dev;
+	wdt->wdd.parent = dev;
 	wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMEOUT;
 	wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT;
 	wdt->wdd.timeout = SPRD_WDT_MAX_TIMEOUT;
 
 	ret = sprd_wdt_enable(wdt);
 	if (ret) {
-		dev_err(&pdev->dev, "failed to enable wdt\n");
+		dev_err(dev, "failed to enable wdt\n");
 		return ret;
 	}
-	ret = devm_add_action(&pdev->dev, sprd_wdt_disable, wdt);
+	ret = devm_add_action_or_reset(dev, sprd_wdt_disable, wdt);
 	if (ret) {
-		sprd_wdt_disable(wdt);
-		dev_err(&pdev->dev, "Failed to add wdt disable action\n");
+		dev_err(dev, "Failed to add wdt disable action\n");
 		return ret;
 	}
 
 	watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT);
-	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+	watchdog_init_timeout(&wdt->wdd, 0, dev);
 
-	ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdd);
+	ret = devm_watchdog_register_device(dev, &wdt->wdd);
 	if (ret) {
 		sprd_wdt_disable(wdt);
-		dev_err(&pdev->dev, "failed to register watchdog\n");
+		dev_err(dev, "failed to register watchdog\n");
 		return ret;
 	}
 	platform_set_drvdata(pdev, wdt);