watchdog: imgpdc_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
- 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/imgpdc_wdt.c

@@ -178,14 +178,20 @@ static const struct watchdog_ops pdc_wdt_ops = {
 	.restart        = pdc_wdt_restart,
 };
 
+static void pdc_clk_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
 static int pdc_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	u64 div;
 	int ret, val;
 	unsigned long clk_rate;
 	struct pdc_wdt_dev *pdc_wdt;
 
-	pdc_wdt = devm_kzalloc(&pdev->dev, sizeof(*pdc_wdt), GFP_KERNEL);
+	pdc_wdt = devm_kzalloc(dev, sizeof(*pdc_wdt), GFP_KERNEL);
 	if (!pdc_wdt)
 		return -ENOMEM;
 
@@ -193,42 +199,48 @@ static int pdc_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(pdc_wdt->base))
 		return PTR_ERR(pdc_wdt->base);
 
-	pdc_wdt->sys_clk = devm_clk_get(&pdev->dev, "sys");
+	pdc_wdt->sys_clk = devm_clk_get(dev, "sys");
 	if (IS_ERR(pdc_wdt->sys_clk)) {
-		dev_err(&pdev->dev, "failed to get the sys clock\n");
+		dev_err(dev, "failed to get the sys clock\n");
 		return PTR_ERR(pdc_wdt->sys_clk);
 	}
 
-	pdc_wdt->wdt_clk = devm_clk_get(&pdev->dev, "wdt");
+	pdc_wdt->wdt_clk = devm_clk_get(dev, "wdt");
 	if (IS_ERR(pdc_wdt->wdt_clk)) {
-		dev_err(&pdev->dev, "failed to get the wdt clock\n");
+		dev_err(dev, "failed to get the wdt clock\n");
 		return PTR_ERR(pdc_wdt->wdt_clk);
 	}
 
 	ret = clk_prepare_enable(pdc_wdt->sys_clk);
 	if (ret) {
-		dev_err(&pdev->dev, "could not prepare or enable sys clock\n");
+		dev_err(dev, "could not prepare or enable sys clock\n");
 		return ret;
 	}
+	ret = devm_add_action_or_reset(dev, pdc_clk_disable_unprepare,
+				       pdc_wdt->sys_clk);
+	if (ret)
+		return ret;
 
 	ret = clk_prepare_enable(pdc_wdt->wdt_clk);
 	if (ret) {
-		dev_err(&pdev->dev, "could not prepare or enable wdt clock\n");
-		goto disable_sys_clk;
+		dev_err(dev, "could not prepare or enable wdt clock\n");
+		return ret;
 	}
+	ret = devm_add_action_or_reset(dev, pdc_clk_disable_unprepare,
+				       pdc_wdt->wdt_clk);
+	if (ret)
+		return ret;
 
 	/* We use the clock rate to calculate the max timeout */
 	clk_rate = clk_get_rate(pdc_wdt->wdt_clk);
 	if (clk_rate == 0) {
-		dev_err(&pdev->dev, "failed to get clock rate\n");
-		ret = -EINVAL;
-		goto disable_wdt_clk;
+		dev_err(dev, "failed to get clock rate\n");
+		return -EINVAL;
 	}
 
 	if (order_base_2(clk_rate) > PDC_WDT_CONFIG_DELAY_MASK + 1) {
-		dev_err(&pdev->dev, "invalid clock rate\n");
-		ret = -EINVAL;
-		goto disable_wdt_clk;
+		dev_err(dev, "invalid clock rate\n");
+		return -EINVAL;
 	}
 
 	if (order_base_2(clk_rate) == 0)
@@ -243,10 +255,10 @@ static int pdc_wdt_probe(struct platform_device *pdev)
 	do_div(div, clk_rate);
 	pdc_wdt->wdt_dev.max_timeout = div;
 	pdc_wdt->wdt_dev.timeout = PDC_WDT_DEF_TIMEOUT;
-	pdc_wdt->wdt_dev.parent = &pdev->dev;
+	pdc_wdt->wdt_dev.parent = dev;
 	watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
 
-	watchdog_init_timeout(&pdc_wdt->wdt_dev, heartbeat, &pdev->dev);
+	watchdog_init_timeout(&pdc_wdt->wdt_dev, heartbeat, dev);
 
 	pdc_wdt_stop(&pdc_wdt->wdt_dev);
 
@@ -257,24 +269,22 @@ static int pdc_wdt_probe(struct platform_device *pdev)
 	case PDC_WDT_TICKLE_STATUS_TICKLE:
 	case PDC_WDT_TICKLE_STATUS_TIMEOUT:
 		pdc_wdt->wdt_dev.bootstatus |= WDIOF_CARDRESET;
-		dev_info(&pdev->dev,
-			 "watchdog module last reset due to timeout\n");
+		dev_info(dev, "watchdog module last reset due to timeout\n");
 		break;
 	case PDC_WDT_TICKLE_STATUS_HRESET:
-		dev_info(&pdev->dev,
+		dev_info(dev,
 			 "watchdog module last reset due to hard reset\n");
 		break;
 	case PDC_WDT_TICKLE_STATUS_SRESET:
-		dev_info(&pdev->dev,
+		dev_info(dev,
 			 "watchdog module last reset due to soft reset\n");
 		break;
 	case PDC_WDT_TICKLE_STATUS_USER:
-		dev_info(&pdev->dev,
+		dev_info(dev,
 			 "watchdog module last reset due to user reset\n");
 		break;
 	default:
-		dev_info(&pdev->dev,
-			 "contains an illegal status code (%08x)\n", val);
+		dev_info(dev, "contains an illegal status code (%08x)\n", val);
 		break;
 	}
 
@@ -283,36 +293,9 @@ static int pdc_wdt_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, pdc_wdt);
 
-	ret = watchdog_register_device(&pdc_wdt->wdt_dev);
-	if (ret)
-		goto disable_wdt_clk;
-
-	return 0;
-
-disable_wdt_clk:
-	clk_disable_unprepare(pdc_wdt->wdt_clk);
-disable_sys_clk:
-	clk_disable_unprepare(pdc_wdt->sys_clk);
-	return ret;
-}
-
-static void pdc_wdt_shutdown(struct platform_device *pdev)
-{
-	struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
-
-	pdc_wdt_stop(&pdc_wdt->wdt_dev);
-}
-
-static int pdc_wdt_remove(struct platform_device *pdev)
-{
-	struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
-
-	pdc_wdt_stop(&pdc_wdt->wdt_dev);
-	watchdog_unregister_device(&pdc_wdt->wdt_dev);
-	clk_disable_unprepare(pdc_wdt->wdt_clk);
-	clk_disable_unprepare(pdc_wdt->sys_clk);
-
-	return 0;
+	watchdog_stop_on_reboot(&pdc_wdt->wdt_dev);
+	watchdog_stop_on_unregister(&pdc_wdt->wdt_dev);
+	return devm_watchdog_register_device(dev, &pdc_wdt->wdt_dev);
 }
 
 static const struct of_device_id pdc_wdt_match[] = {
@@ -327,8 +310,6 @@ static struct platform_driver pdc_wdt_driver = {
 		.of_match_table	= pdc_wdt_match,
 	},
 	.probe = pdc_wdt_probe,
-	.remove = pdc_wdt_remove,
-	.shutdown = pdc_wdt_shutdown,
 };
 module_platform_driver(pdc_wdt_driver);