linux-kernel - Re: [PATCH v3 2/5] usb: dwc3-am62: fix error on module removal

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Message-ID: <20240223221757.ugoyugtdokcxzci7@synopsys.com>
Date: Fri, 23 Feb 2024 22:17:58 +0000
From: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To: Roger Quadros <rogerq@...nel.org>
CC: Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>, "nm@...com" <nm@...com>,
        "r-gunasekaran@...com" <r-gunasekaran@...com>,
        "afd@...com" <afd@...com>, "b-liu@...com" <b-liu@...com>,
        "srk@...com" <srk@...com>,
        "francesco@...cini.it" <francesco@...cini.it>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v3 2/5] usb: dwc3-am62: fix error on module removal

On Wed, Feb 14, 2024, Roger Quadros wrote:
> As runtime PM is enabled, the module can be runtime
> suspended when .remove() is called.
> 
> Do a pm_runtime_get_sync() to make sure module is active
> before doing any register operations.
> 
> Doing a pm_runtime_put_sync() should disable the refclk
> so no need to disable it again.
> 
> Fixes the below warning at module removel.
> 
> [   39.705310] ------------[ cut here ]------------
> [   39.710004] clk:162:3 already disabled
> [   39.713941] WARNING: CPU: 0 PID: 921 at drivers/clk/clk.c:1090 clk_core_disable+0xb0/0xb8
> 
> Signed-off-by: Roger Quadros <rogerq@...nel.org>
> ---
> Changelog:
> 
> v3: no change
> 
> v2: no change
> 	https://urldefense.com/v3/__https://lore.kernel.org/all/20240205141221.56076-3-rogerq@kernel.org/__;!!A4F2R9G_pg!b7_3vmJpNLOFy3g_wExMQSAzi949O4PoID3e4rNEvAsbgCvxxkj0DiSDFJxF7857DZM7qy9DMkH6Q5BPD-jX$ 
> 
> v1: https://urldefense.com/v3/__https://lore.kernel.org/all/20240201121220.5523-3-rogerq@kernel.org/__;!!A4F2R9G_pg!b7_3vmJpNLOFy3g_wExMQSAzi949O4PoID3e4rNEvAsbgCvxxkj0DiSDFJxF7857DZM7qy9DMkH6Q1CciylE$ 
> ---
>  drivers/usb/dwc3/dwc3-am62.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
> index 1bfc9e67614f..600ba9cfefea 100644
> --- a/drivers/usb/dwc3/dwc3-am62.c
> +++ b/drivers/usb/dwc3/dwc3-am62.c
> @@ -273,6 +273,11 @@ static void dwc3_ti_remove(struct platform_device *pdev)
>  	struct dwc3_am62 *am62 = platform_get_drvdata(pdev);
>  	u32 reg;
>  
> +	pm_runtime_get_sync(dev);
> +
> +	device_wakeup_disable(dev);
> +	device_set_wakeup_capable(dev, false);
> +

We have a more convenient function to enable/disable this
(device_init_wakeup()) if you ever want to cleanup the driver later.

>  	of_platform_depopulate(dev);
>  
>  	/* Clear mode valid bit */
> @@ -281,7 +286,6 @@ static void dwc3_ti_remove(struct platform_device *pdev)
>  	dwc3_ti_writel(am62, USBSS_MODE_CONTROL, reg);
>  
>  	pm_runtime_put_sync(dev);
> -	clk_disable_unprepare(am62->usb2_refclk);
>  	pm_runtime_disable(dev);
>  	pm_runtime_set_suspended(dev);
>  }
> 
> -- 
> 2.34.1
> 

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

Thanks,
Thinh