linux-kernel - Re: [PATCH 2/2] usb: dwc3: imx8mp: disable auto suspend for host role

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Message-ID: <20251113230541.wbzt6xbine5gdmpp@synopsys.com>
Date: Thu, 13 Nov 2025 23:05:43 +0000
From: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To: Xu Yang <xu.yang_2@....com>
CC: Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "imx@...ts.linux.dev" <imx@...ts.linux.dev>,
        "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
        "jun.li@....com" <jun.li@....com>
Subject: Re: [PATCH 2/2] usb: dwc3: imx8mp: disable auto suspend for host role

On Wed, Nov 05, 2025, Xu Yang wrote:
> Do dwc3 core auto suspend enable for device and disable for host
> , this can make sure dwc3 core device auto suspend setting is
> correct all the time, the background of disable dwc3 core device
> auto suspend is to make its parent device suspend immediately
> (so wakeup enable can be enabled) after xhci-plat device suspended,
> for device mode, we keep the dwc3 core device auto suspend is to
> give some wait for gadget to be enumerated.
> 
> Signed-off-by: Xu Yang <xu.yang_2@....com>
> ---
>  drivers/usb/dwc3/dwc3-imx8mp.c | 31 +++++++++++++++++++++++++++++++
>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-imx8mp.c b/drivers/usb/dwc3/dwc3-imx8mp.c
> index bce6af82f54c..80a431cb6fed 100644
> --- a/drivers/usb/dwc3/dwc3-imx8mp.c
> +++ b/drivers/usb/dwc3/dwc3-imx8mp.c
> @@ -158,11 +158,31 @@ static irqreturn_t dwc3_imx8mp_interrupt(int irq, void *_dwc3_imx)
>  	return IRQ_HANDLED;
>  }
>  
> +static void dwc3_imx_pre_set_role(struct dwc3 *dwc, enum usb_role role)
> +{
> +	if (role == USB_ROLE_HOST)
> +		/*
> +		 * For xhci host, we need disable dwc core auto
> +		 * suspend, because during this auto suspend delay(5s),
> +		 * xhci host RUN_STOP is cleared and wakeup is not
> +		 * enabled, if device is inserted, xhci host can't
> +		 * response the connection.
> +		 */
> +		pm_runtime_dont_use_autosuspend(dwc->dev);
> +	else
> +		pm_runtime_use_autosuspend(dwc->dev);

Would this override the user setting everytime there's a role switch?

> +}
> +
> +struct dwc3_glue_ops dwc3_imx_glue_ops = {
> +	.pre_set_role   = dwc3_imx_pre_set_role,
> +};
> +
>  static int dwc3_imx8mp_probe(struct platform_device *pdev)
>  {
>  	struct device		*dev = &pdev->dev;
>  	struct device_node	*node = dev->of_node;
>  	struct dwc3_imx8mp	*dwc3_imx;
> +	struct dwc3		*dwc3;
>  	struct resource		*res;
>  	int			err, irq;
>  
> @@ -240,6 +260,17 @@ static int dwc3_imx8mp_probe(struct platform_device *pdev)
>  		goto depopulate;
>  	}
>  
> +	dwc3 = platform_get_drvdata(dwc3_imx->dwc3);

It's confusing how dwc3_imx->dwc3 is also named dwc3...

> +	if (!dwc3) {
> +		err = dev_err_probe(dev, -EPROBE_DEFER, "failed to get dwc3 platform data\n");
> +		goto depopulate;
> +	}
> +
> +	dwc3->glue_ops = &dwc3_imx_glue_ops;

If you want to use glue_ops, please use the new flatten model. I
don't want dwc3 to be initialized again after of_platform_populate().

BR,
Thinh

> +
> +	if (dwc3->dr_mode == USB_DR_MODE_HOST)
> +		pm_runtime_dont_use_autosuspend(dwc3->dev);
> +
>  	err = devm_request_threaded_irq(dev, irq, NULL, dwc3_imx8mp_interrupt,
>  					IRQF_ONESHOT, dev_name(dev), dwc3_imx);
>  	if (err) {
> -- 
> 2.34.1
>