Re: [PATCH] usb: dwc3-am62: shut down refclk on remove

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Sat, Sep 12, 2026, Myeonghun Pak wrote:
> dwc3_ti_remove() relies on pm_runtime_put_sync() to invoke the
> runtime-suspend callback and disable the USB2 reference clock.  The
> callback is not guaranteed to run: autosuspend may defer it, and a
> reference held by pm_runtime_forbid() keeps the usage count above zero.
> The following pm_runtime_disable() then cancels pending work while the
> clock remains enabled.
> 
> Balance only the reference acquired by remove without requesting a suspend,
> then disable runtime PM to drain any operation in progress.  Disable the
> clock explicitly when the stable runtime status shows that the device was
> not already suspended.  This also handles CONFIG_PM=n, where the runtime-PM
> calls are stubs, without double-disabling the clock after a failed resume.
> 
> This issue was identified during our ongoing static-analysis research while
> reviewing kernel code.
> 
> Fixes: 6661befe4100 ("usb: dwc3-am62: fix module unload/reload behavior")
> Assisted-by: OpenAI:GPT-5.6
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
> ---
>  drivers/usb/dwc3/dwc3-am62.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
> index 632634d6e..2fb9e088f 100644
> --- a/drivers/usb/dwc3/dwc3-am62.c
> +++ b/drivers/usb/dwc3/dwc3-am62.c
> @@ -319,9 +319,11 @@ static void dwc3_ti_remove(struct platform_device *pdev)
>  	reg &= ~USBSS_MODE_VALID;
>  	dwc3_ti_writel(am62, USBSS_MODE_CONTROL, reg);
>  
> -	pm_runtime_put_sync(dev);
> +	pm_runtime_put_noidle(dev);
>  	pm_runtime_disable(dev);
>  	pm_runtime_dont_use_autosuspend(dev);
> +	if (!pm_runtime_status_suspended(dev))
> +		clk_disable_unprepare(am62->usb2_refclk);
>  	pm_runtime_set_suspended(dev);
>  }
>  
> -- 
> 2.47.1
> 

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

Please also add Cc stable.

Thanks,
Thinh