[PATCH] watchdog: of_xilinx_wdt: Remove unnecessary clock disable call in the remove path

[PATCH] watchdog: of_xilinx_wdt: Remove unnecessary clock disable call in the remove path

[Srinivas Neeli]

There is a mismatch in axi clock enable and disable calls.
The axi clock is enabled and disabled by the probe function,
then it is again disabled in the remove path.
So observed the call trace while removing the module.
Use the clk_enable() and devm_clk_get_prepared() functions
instead of devm_clk_get_enable() to avoid an extra clock disable
call from the remove path.

 Call trace:
  clk_core_disable+0xb0/0xc0
  clk_disable+0x30/0x4c
  clk_disable_unprepare+0x18/0x30
  devm_clk_release+0x24/0x40
  devres_release_all+0xc8/0x190
  device_unbind_cleanup+0x18/0x6c
  device_release_driver_internal+0x20c/0x250
  device_release_driver+0x18/0x24
  bus_remove_device+0x124/0x130
  device_del+0x174/0x440

Fixes: 4de0224c6fbe ("watchdog: of_xilinx_wdt: Use devm_clk_get_enabled() helper")
Signed-off-by: Srinivas Neeli <srinivas.neeli@amd.com>
---
 drivers/watchdog/of_xilinx_wdt.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
index 05657dc1d36a..777272f7d326 100644
--- a/drivers/watchdog/of_xilinx_wdt.c
+++ b/drivers/watchdog/of_xilinx_wdt.c
@@ -187,7 +187,7 @@ static int xwdt_probe(struct platform_device *pdev)
 
 	watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);
 
-	xdev->clk = devm_clk_get_enabled(dev, NULL);
+	xdev->clk = devm_clk_get_prepared(dev, NULL);
 	if (IS_ERR(xdev->clk)) {
 		if (PTR_ERR(xdev->clk) != -ENOENT)
 			return PTR_ERR(xdev->clk);
@@ -218,18 +218,24 @@ static int xwdt_probe(struct platform_device *pdev)
 	spin_lock_init(&xdev->spinlock);
 	watchdog_set_drvdata(xilinx_wdt_wdd, xdev);
 
+	rc = clk_enable(xdev->clk);
+	if (rc) {
+		dev_err(dev, "unable to enable clock\n");
+		return rc;
+	}
+
 	rc = xwdt_selftest(xdev);
 	if (rc == XWT_TIMER_FAILED) {
 		dev_err(dev, "SelfTest routine error\n");
 		return rc;
 	}
 
+	clk_disable(xdev->clk);
+
 	rc = devm_watchdog_register_device(dev, xilinx_wdt_wdd);
 	if (rc)
 		return rc;
 
-	clk_disable(xdev->clk);
-
 	dev_info(dev, "Xilinx Watchdog Timer with timeout %ds\n",
 		 xilinx_wdt_wdd->timeout);
 
-- 
2.25.1

Re: [PATCH] watchdog: of_xilinx_wdt: Remove unnecessary clock disable call in the remove path

[Guenter Roeck]

On 8/28/23 02:20, Srinivas Neeli wrote:
> There is a mismatch in axi clock enable and disable calls.
> The axi clock is enabled and disabled by the probe function,
> then it is again disabled in the remove path.
> So observed the call trace while removing the module.
> Use the clk_enable() and devm_clk_get_prepared() functions
> instead of devm_clk_get_enable() to avoid an extra clock disable
> call from the remove path.
> 
>   Call trace:
>    clk_core_disable+0xb0/0xc0
>    clk_disable+0x30/0x4c
>    clk_disable_unprepare+0x18/0x30
>    devm_clk_release+0x24/0x40
>    devres_release_all+0xc8/0x190
>    device_unbind_cleanup+0x18/0x6c
>    device_release_driver_internal+0x20c/0x250
>    device_release_driver+0x18/0x24
>    bus_remove_device+0x124/0x130
>    device_del+0x174/0x440
> 
> Fixes: 4de0224c6fbe ("watchdog: of_xilinx_wdt: Use devm_clk_get_enabled() helper")
> Signed-off-by: Srinivas Neeli <srinivas.neeli@amd.com>
> ---
>   drivers/watchdog/of_xilinx_wdt.c | 12 +++++++++---
>   1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
> index 05657dc1d36a..777272f7d326 100644
> --- a/drivers/watchdog/of_xilinx_wdt.c
> +++ b/drivers/watchdog/of_xilinx_wdt.c
> @@ -187,7 +187,7 @@ static int xwdt_probe(struct platform_device *pdev)
>   
>   	watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);
>   
> -	xdev->clk = devm_clk_get_enabled(dev, NULL);
> +	xdev->clk = devm_clk_get_prepared(dev, NULL);
>   	if (IS_ERR(xdev->clk)) {
>   		if (PTR_ERR(xdev->clk) != -ENOENT)
>   			return PTR_ERR(xdev->clk);
> @@ -218,18 +218,24 @@ static int xwdt_probe(struct platform_device *pdev)
>   	spin_lock_init(&xdev->spinlock);
>   	watchdog_set_drvdata(xilinx_wdt_wdd, xdev);
>   
> +	rc = clk_enable(xdev->clk);
> +	if (rc) {
> +		dev_err(dev, "unable to enable clock\n");
> +		return rc;
> +	}
> +
>   	rc = xwdt_selftest(xdev);
>   	if (rc == XWT_TIMER_FAILED) {
>   		dev_err(dev, "SelfTest routine error\n");

Needs clk_disable() here as well.

Guenter

>   		return rc;
>   	}
>   
> +	clk_disable(xdev->clk);
> +
>   	rc = devm_watchdog_register_device(dev, xilinx_wdt_wdd);
>   	if (rc)
>   		return rc;
>   
> -	clk_disable(xdev->clk);
> -
>   	dev_info(dev, "Xilinx Watchdog Timer with timeout %ds\n",
>   		 xilinx_wdt_wdd->timeout);
>