watchdog: asm9260_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 assignments to otherwise unused variables
- Drop empty remove function
- Use devm_add_action_or_reset() for calls to clk_disable_unprepare
- Replace 'goto l; ... l: return e;' 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
- 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/asm9260_wdt.c

@@ -196,6 +196,11 @@ static const struct watchdog_ops asm9260_wdt_ops = {
 	.restart	= asm9260_restart,
 };
 
+static void asm9260_clk_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
 static int asm9260_wdt_get_dt_clks(struct asm9260_wdt_priv *priv)
 {
 	int err;
@@ -219,26 +224,32 @@ static int asm9260_wdt_get_dt_clks(struct asm9260_wdt_priv *priv)
 		dev_err(priv->dev, "Failed to enable ahb_clk!\n");
 		return err;
 	}
+	err = devm_add_action_or_reset(priv->dev,
+				       asm9260_clk_disable_unprepare,
+				       priv->clk_ahb);
+	if (err)
+		return err;
 
 	err = clk_set_rate(priv->clk, CLOCK_FREQ);
 	if (err) {
-		clk_disable_unprepare(priv->clk_ahb);
 		dev_err(priv->dev, "Failed to set rate!\n");
 		return err;
 	}
 
 	err = clk_prepare_enable(priv->clk);
 	if (err) {
-		clk_disable_unprepare(priv->clk_ahb);
 		dev_err(priv->dev, "Failed to enable clk!\n");
 		return err;
 	}
+	err = devm_add_action_or_reset(priv->dev,
+				       asm9260_clk_disable_unprepare,
+				       priv->clk);
+	if (err)
+		return err;
 
 	/* wdt has internal divider */
 	clk = clk_get_rate(priv->clk);
 	if (!clk) {
-		clk_disable_unprepare(priv->clk);
-		clk_disable_unprepare(priv->clk_ahb);
 		dev_err(priv->dev, "Failed, clk is 0!\n");
 		return -EINVAL;
 	}
@@ -274,23 +285,23 @@ static void asm9260_wdt_get_dt_mode(struct asm9260_wdt_priv *priv)
 
 static int asm9260_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct asm9260_wdt_priv *priv;
 	struct watchdog_device *wdd;
 	int ret;
 	static const char * const mode_name[] = { "hw", "sw", "debug", };
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(struct asm9260_wdt_priv),
-			    GFP_KERNEL);
+	priv = devm_kzalloc(dev, sizeof(struct asm9260_wdt_priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	priv->dev = &pdev->dev;
+	priv->dev = dev;
 
 	priv->iobase = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->iobase))
 		return PTR_ERR(priv->iobase);
 
-	priv->rst = devm_reset_control_get_exclusive(&pdev->dev, "wdt_rst");
+	priv->rst = devm_reset_control_get_exclusive(dev, "wdt_rst");
 	if (IS_ERR(priv->rst))
 		return PTR_ERR(priv->rst);
 
@@ -303,7 +314,7 @@ static int asm9260_wdt_probe(struct platform_device *pdev)
 	wdd->ops = &asm9260_wdt_ops;
 	wdd->min_timeout = 1;
 	wdd->max_timeout = BM_WDTC_MAX(priv->wdt_freq);
-	wdd->parent = &pdev->dev;
+	wdd->parent = dev;
 
 	watchdog_set_drvdata(wdd, priv);
 
@@ -313,7 +324,7 @@ static int asm9260_wdt_probe(struct platform_device *pdev)
 	 * the max instead.
 	 */
 	wdd->timeout = ASM9260_WDT_DEFAULT_TIMEOUT;
-	watchdog_init_timeout(wdd, 0, &pdev->dev);
+	watchdog_init_timeout(wdd, 0, dev);
 
 	asm9260_wdt_get_dt_mode(priv);
 
@@ -325,49 +336,25 @@ static int asm9260_wdt_probe(struct platform_device *pdev)
 		 * Not all supported platforms specify an interrupt for the
 		 * watchdog, so let's make it optional.
 		 */
-		ret = devm_request_irq(&pdev->dev, priv->irq,
-				       asm9260_wdt_irq, 0, pdev->name, priv);
+		ret = devm_request_irq(dev, priv->irq, asm9260_wdt_irq, 0,
+				       pdev->name, priv);
 		if (ret < 0)
-			dev_warn(&pdev->dev, "failed to request IRQ\n");
+			dev_warn(dev, "failed to request IRQ\n");
 	}
 
 	watchdog_set_restart_priority(wdd, 128);
 
-	ret = watchdog_register_device(wdd);
+	watchdog_stop_on_reboot(wdd);
+	watchdog_stop_on_unregister(wdd);
+	ret = devm_watchdog_register_device(dev, wdd);
 	if (ret)
-		goto clk_off;
+		return ret;
 
 	platform_set_drvdata(pdev, priv);
 
-	dev_info(&pdev->dev, "Watchdog enabled (timeout: %d sec, mode: %s)\n",
+	dev_info(dev, "Watchdog enabled (timeout: %d sec, mode: %s)\n",
 		 wdd->timeout, mode_name[priv->mode]);
 	return 0;
-
-clk_off:
-	clk_disable_unprepare(priv->clk);
-	clk_disable_unprepare(priv->clk_ahb);
-	return ret;
-}
-
-static void asm9260_wdt_shutdown(struct platform_device *pdev)
-{
-	struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev);
-
-	asm9260_wdt_disable(&priv->wdd);
-}
-
-static int asm9260_wdt_remove(struct platform_device *pdev)
-{
-	struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev);
-
-	asm9260_wdt_disable(&priv->wdd);
-
-	watchdog_unregister_device(&priv->wdd);
-
-	clk_disable_unprepare(priv->clk);
-	clk_disable_unprepare(priv->clk_ahb);
-
-	return 0;
 }
 
 static const struct of_device_id asm9260_wdt_of_match[] = {
@@ -382,8 +369,6 @@ static struct platform_driver asm9260_wdt_driver = {
 		.of_match_table	= asm9260_wdt_of_match,
 	},
 	.probe = asm9260_wdt_probe,
-	.remove = asm9260_wdt_remove,
-	.shutdown = asm9260_wdt_shutdown,
 };
 module_platform_driver(asm9260_wdt_driver);