[PATCH 12/23] watchdog: qcom-wdt: Convert to use device managed functions and other improvements

[Guenter Roeck <linux@roeck-us.net>]

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

Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/watchdog/qcom-wdt.c | 55 +++++++++++++++++++++------------------------
 1 file changed, 25 insertions(+), 30 deletions(-)

diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
index 5dfd604477a4..6d29c33b1316 100644
--- a/drivers/watchdog/qcom-wdt.c
+++ b/drivers/watchdog/qcom-wdt.c
@@ -142,22 +142,28 @@ static const struct watchdog_info qcom_wdt_info = {
 	.identity	= KBUILD_MODNAME,
 };
 
+static void qcom_clk_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
 static int qcom_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct qcom_wdt *wdt;
 	struct resource *res;
-	struct device_node *np = pdev->dev.of_node;
+	struct device_node *np = dev->of_node;
 	const u32 *regs;
 	u32 percpu_offset;
 	int ret;
 
-	regs = of_device_get_match_data(&pdev->dev);
+	regs = of_device_get_match_data(dev);
 	if (!regs) {
-		dev_err(&pdev->dev, "Unsupported QCOM WDT module\n");
+		dev_err(dev, "Unsupported QCOM WDT module\n");
 		return -ENODEV;
 	}
 
-	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 	if (!wdt)
 		return -ENOMEM;
 
@@ -172,21 +178,25 @@ static int qcom_wdt_probe(struct platform_device *pdev)
 	res->start += percpu_offset;
 	res->end += percpu_offset;
 
-	wdt->base = devm_ioremap_resource(&pdev->dev, res);
+	wdt->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
-	wdt->clk = devm_clk_get(&pdev->dev, NULL);
+	wdt->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(wdt->clk)) {
-		dev_err(&pdev->dev, "failed to get input clock\n");
+		dev_err(dev, "failed to get input clock\n");
 		return PTR_ERR(wdt->clk);
 	}
 
 	ret = clk_prepare_enable(wdt->clk);
 	if (ret) {
-		dev_err(&pdev->dev, "failed to setup clock\n");
+		dev_err(dev, "failed to setup clock\n");
 		return ret;
 	}
+	ret = devm_add_action_or_reset(dev, qcom_clk_disable_unprepare,
+				       wdt->clk);
+	if (ret)
+		return ret;
 
 	/*
 	 * We use the clock rate to calculate the max timeout, so ensure it's
@@ -199,16 +209,15 @@ static int qcom_wdt_probe(struct platform_device *pdev)
 	wdt->rate = clk_get_rate(wdt->clk);
 	if (wdt->rate == 0 ||
 	    wdt->rate > 0x10000000U) {
-		dev_err(&pdev->dev, "invalid clock rate\n");
-		ret = -EINVAL;
-		goto err_clk_unprepare;
+		dev_err(dev, "invalid clock rate\n");
+		return -EINVAL;
 	}
 
 	wdt->wdd.info = &qcom_wdt_info;
 	wdt->wdd.ops = &qcom_wdt_ops;
 	wdt->wdd.min_timeout = 1;
 	wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
-	wdt->wdd.parent = &pdev->dev;
+	wdt->wdd.parent = dev;
 	wdt->layout = regs;
 
 	if (readl(wdt_addr(wdt, WDT_STS)) & 1)
@@ -220,29 +229,16 @@ static int qcom_wdt_probe(struct platform_device *pdev)
 	 * the max instead.
 	 */
 	wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
-	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+	watchdog_init_timeout(&wdt->wdd, 0, dev);
 
-	ret = watchdog_register_device(&wdt->wdd);
+	ret = devm_watchdog_register_device(dev, &wdt->wdd);
 	if (ret) {
-		dev_err(&pdev->dev, "failed to register watchdog\n");
-		goto err_clk_unprepare;
+		dev_err(dev, "failed to register watchdog\n");
+		return ret;
 	}
 
 	platform_set_drvdata(pdev, wdt);
 	return 0;
-
-err_clk_unprepare:
-	clk_disable_unprepare(wdt->clk);
-	return ret;
-}
-
-static int qcom_wdt_remove(struct platform_device *pdev)
-{
-	struct qcom_wdt *wdt = platform_get_drvdata(pdev);
-
-	watchdog_unregister_device(&wdt->wdd);
-	clk_disable_unprepare(wdt->clk);
-	return 0;
 }
 
 static int __maybe_unused qcom_wdt_suspend(struct device *dev)
@@ -277,7 +273,6 @@ MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
 
 static struct platform_driver qcom_watchdog_driver = {
 	.probe	= qcom_wdt_probe,
-	.remove	= qcom_wdt_remove,
 	.driver	= {
 		.name		= KBUILD_MODNAME,
 		.of_match_table	= qcom_wdt_of_table,
-- 
2.7.4