Re: [PATCH] i2c: cadence: fix clk disable/unprepare underflow warning on remove

[Pandey, Radhey Shyam]

On 9/18/2026 10:15 PM, Cong Nguyen wrote:
> cdns_i2c_probe() enables id->clk via devm_clk_get_enabled(), which
> auto-disables/unprepares it on unbind. Runtime PM autosuspend
> separately enables/disables the same clock as the device idles and
> wakes. remove() never forces the device back active first -- if it's
> runtime-suspended at removal (routine after any idle period, not a
> rare race), the devm cleanup then disables an already-disabled clock,
> hitting the "already disabled"/"already unprepared" WARN().
>
> i2c-imx.c has the identical shape and already gets this right:
> pm_runtime_get_sync() first, balanced with pm_runtime_put_noidle()
> before the final disable. Apply the same fix here.
>
> Fixes: 3d36dd1161ca ("i2c: cadence: Simplify using devm_clk_get_enabled()")
> Assisted-by: LLM
> Signed-off-by: Cong Nguyen <congnt264@xxxxxxxxx>
> ---
>   drivers/i2c/busses/i2c-cadence.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
> index da8770182a18..d0919593456b 100644
> --- a/drivers/i2c/busses/i2c-cadence.c
> +++ b/drivers/i2c/busses/i2c-cadence.c
> @@ -1625,14 +1625,21 @@ static int cdns_i2c_probe(struct platform_device *pdev)
>   static void cdns_i2c_remove(struct platform_device *pdev)
>   {
>   	struct cdns_i2c *id = platform_get_drvdata(pdev);
> +	int ret;
> +
> +	ret = pm_runtime_get_sync(&pdev->dev);
> +	if (ret < 0)
> +		dev_err(&pdev->dev, "Failed to resume device (%pe)\n", ERR_PTR(ret));

Nit - With this error handling introduced we also need to sync remove() 
documentation.

 * Return: 0 always


With that fixed.
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>

Thanks!

>   
> -	pm_runtime_disable(&pdev->dev);
> -	pm_runtime_set_suspended(&pdev->dev);
>   	pm_runtime_dont_use_autosuspend(&pdev->dev);
>   
>   	i2c_del_adapter(&id->adap);
>   	clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
>   	reset_control_assert(id->reset);
> +
> +	pm_runtime_put_noidle(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +	pm_runtime_set_suspended(&pdev->dev);
>   }
>   
>   /**