[RFC PATCH 1/3] watchdog: renesas_wdt: consistently use RuntimePM for clock management

[Wolfram Sang]

On Renesas R-Car archs, RuntimePM does all the clock handling. So, use
it consistently to enable/disable the clocks. Also make sure that clocks
are really enabled around clk_get_rate(). clk_summary looks proper now:

                clock   enable_cnt      prepare_cnt     rate ...
Before this commit:

At boot:        rwdt    1               1               32768 0 0
WDT running:    rwdt    2               2               32768 0 0

After this commit:

At boot:        rwdt    0               1               32768 0 0
WDT running     rwdt    1               1               32768 0 0

Signed-off-by: Wolfram Sang <wsa+rene...@sang-engineering.com>
---
 drivers/watchdog/renesas_wdt.c | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index e3f204bb8802aa..a03997b418ba9c 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -76,7 +76,7 @@ static int rwdt_start(struct watchdog_device *wdev)
 {
        struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
 
-       clk_prepare_enable(priv->clk);
+       pm_runtime_get_sync(wdev->parent);
 
        rwdt_write(priv, 0, RWTCSRB);
        rwdt_write(priv, priv->cks, RWTCSRA);
@@ -95,7 +95,7 @@ static int rwdt_stop(struct watchdog_device *wdev)
        struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
 
        rwdt_write(priv, priv->cks, RWTCSRA);
-       clk_disable_unprepare(priv->clk);
+       pm_runtime_put(wdev->parent);
 
        return 0;
 }
@@ -141,9 +141,16 @@ static int rwdt_probe(struct platform_device *pdev)
        if (IS_ERR(priv->clk))
                return PTR_ERR(priv->clk);
 
+       pm_runtime_enable(&pdev->dev);
+
+       pm_runtime_get_sync(&pdev->dev);
        priv->clk_rate = clk_get_rate(priv->clk);
-       if (!priv->clk_rate)
-               return -ENOENT;
+       pm_runtime_put(&pdev->dev);
+
+       if (!priv->clk_rate) {
+               ret = -ENOENT;
+               goto out_pm_disable;
+       }
 
        for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) {
                clks_per_sec = priv->clk_rate / clk_divs[i];
@@ -155,12 +162,10 @@ static int rwdt_probe(struct platform_device *pdev)
 
        if (i < 0) {
                dev_err(&pdev->dev, "Can't find suitable clock divider\n");
-               return -ERANGE;
+               ret = -ERANGE;
+               goto out_pm_disable;
        }
 
-       pm_runtime_enable(&pdev->dev);
-       pm_runtime_get_sync(&pdev->dev);
-
        priv->wdev.info = &rwdt_ident,
        priv->wdev.ops = &rwdt_ops,
        priv->wdev.parent = &pdev->dev;
@@ -178,13 +183,14 @@ static int rwdt_probe(struct platform_device *pdev)
                dev_warn(&pdev->dev, "Specified timeout value invalid, using 
default\n");
 
        ret = watchdog_register_device(&priv->wdev);
-       if (ret < 0) {
-               pm_runtime_put(&pdev->dev);
-               pm_runtime_disable(&pdev->dev);
-               return ret;
-       }
+       if (ret < 0)
+               goto out_pm_disable;
 
        return 0;
+
+ out_pm_disable:
+       pm_runtime_disable(&pdev->dev);
+       return ret;
 }
 
 static int rwdt_remove(struct platform_device *pdev)
@@ -192,7 +198,6 @@ static int rwdt_remove(struct platform_device *pdev)
        struct rwdt_priv *priv = platform_get_drvdata(pdev);
 
        watchdog_unregister_device(&priv->wdev);
-       pm_runtime_put(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
 
        return 0;
-- 
2.11.0