hwrng: imx-rngc: Disable clock on registration failure

[PATCH v1] hwrng: imx-rngc: Disable clock on registration failure

Posted by Yuho Choi 2 months ago

The RNGC clock is enabled manually before runtime PM is configured. If
devm_hwrng_register() fails, probe returns without disabling the clock.
The devm_pm_runtime_enable() cleanup only disables runtime PM and does not
call imx_rngc_suspend().

Disable the clock before returning from this failure path.

Fixes: 7a96a64e8689 ("hwrng: imx-rngc - add runtime pm")
Signed-off-by: Yuho Choi <dbgh9129@gmail.com>
---
 drivers/char/hw_random/imx-rngc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
index 28c56c2d1bf6..a2db26d7f790 100644
--- a/drivers/char/hw_random/imx-rngc.c
+++ b/drivers/char/hw_random/imx-rngc.c
@@ -313,8 +313,10 @@ static int __init imx_rngc_probe(struct platform_device *pdev)
 	devm_pm_runtime_enable(&pdev->dev);
 
 	ret = devm_hwrng_register(&pdev->dev, &rngc->rng);
-	if (ret)
+	if (ret) {
+		clk_disable_unprepare(rngc->clk);
 		return dev_err_probe(&pdev->dev, ret, "hwrng registration failed\n");
+	}
 
 	dev_info(&pdev->dev,
 		"Freescale RNG%c registered (HW revision %d.%02d)\n",
-- 
2.43.0

Re: [PATCH v1] hwrng: imx-rngc: Disable clock on registration failure

Posted by Herbert Xu 1 month, 3 weeks ago

On Sun, Aug 02, 2026 at 06:22:59PM -0400, Yuho Choi wrote:
> The RNGC clock is enabled manually before runtime PM is configured. If
> devm_hwrng_register() fails, probe returns without disabling the clock.
> The devm_pm_runtime_enable() cleanup only disables runtime PM and does not
> call imx_rngc_suspend().
> 
> Disable the clock before returning from this failure path.
> 
> Fixes: 7a96a64e8689 ("hwrng: imx-rngc - add runtime pm")
> Signed-off-by: Yuho Choi <dbgh9129@gmail.com>
> ---
>  drivers/char/hw_random/imx-rngc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH v1] hwrng: imx-rngc: Disable clock on registration failure

Posted by Martin Kaiser 1 month, 3 weeks ago

Thus wrote Yuho Choi (dbgh9129@gmail.com):

> The RNGC clock is enabled manually before runtime PM is configured. If
> devm_hwrng_register() fails, probe returns without disabling the clock.
> The devm_pm_runtime_enable() cleanup only disables runtime PM and does not
> call imx_rngc_suspend().

> Disable the clock before returning from this failure path.

> Fixes: 7a96a64e8689 ("hwrng: imx-rngc - add runtime pm")
> Signed-off-by: Yuho Choi <dbgh9129@gmail.com>
> ---
>  drivers/char/hw_random/imx-rngc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

> diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
> index 28c56c2d1bf6..a2db26d7f790 100644
> --- a/drivers/char/hw_random/imx-rngc.c
> +++ b/drivers/char/hw_random/imx-rngc.c
> @@ -313,8 +313,10 @@ static int __init imx_rngc_probe(struct platform_device *pdev)
>  	devm_pm_runtime_enable(&pdev->dev);

>  	ret = devm_hwrng_register(&pdev->dev, &rngc->rng);
> -	if (ret)
> +	if (ret) {
> +		clk_disable_unprepare(rngc->clk);
>  		return dev_err_probe(&pdev->dev, ret, "hwrng registration failed\n");
> +	}

>  	dev_info(&pdev->dev,
>  		"Freescale RNG%c registered (HW revision %d.%02d)\n",
> -- 
> 2.43.0

Good catch, thanks.

Reviewed-by: Martin Kaiser <martin@kaiser.cx>