Re: [PATCH v16 6/6] usb: dwc3: rockchip: fix USB-C reconnect in gadget mode

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

On Thu, Sep 24, 2026, Sebastian Reichel wrote:
> When USB-C is configured in gadget mode and the cable is unplugged
> the USB controller is suspended. After plugging in the cable again,
> the USB controller stays suspended and thus the port status remains
> not-attached.
> 
> Fix this by informing the USB core about VBUS updates when the PHY
> mode changes.

What about gadget-only mode? dwc3_pre_set_role() is only called from
drd.c, so for peripheral dr_mode, the role stays USB_ROLE_NONE and
POST_RESET never restores the gadget's vbus valid state. Perhaps we can
use dwc->current_dr_role?

Thanks,
Thinh

> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
>  drivers/usb/dwc3/Kconfig         |  1 +
>  drivers/usb/dwc3/dwc3-rockchip.c | 23 +++++++++++++++++++++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
> index 3c120ea9746d..344291daf1b2 100644
> --- a/drivers/usb/dwc3/Kconfig
> +++ b/drivers/usb/dwc3/Kconfig
> @@ -193,6 +193,7 @@ config USB_DWC3_OCTEON
>  config USB_DWC3_ROCKCHIP
>  	tristate "Rockchip DWC3 Platform Driver"
>  	depends on ARCH_ROCKCHIP || COMPILE_TEST
> +	depends on USB_GADGET || !USB_GADGET # if USB_GADGET=m, this can't be 'y'
>  	depends on OF
>  	default USB_DWC3
>  	help
> diff --git a/drivers/usb/dwc3/dwc3-rockchip.c b/drivers/usb/dwc3/dwc3-rockchip.c
> index 17b6c2ca9e19..ba8ffef2f27e 100644
> --- a/drivers/usb/dwc3/dwc3-rockchip.c
> +++ b/drivers/usb/dwc3/dwc3-rockchip.c
> @@ -25,8 +25,17 @@ struct dwc3_rockchip {
>  	struct dwc3		dwc;
>  	struct dwc3_rk_phy_nb	usb3_phy_nb[DWC3_USB3_MAX_PORTS];
>  	u8			phy_reset_active;
> +	enum usb_role		role;
>  };
>  
> +static void dwc3_rockchip_vbus_handler(struct dwc3 *dwc, bool present)
> +{
> +	if (!dwc->gadget || !dwc->gadget_driver)
> +		return;
> +
> +	usb_udc_vbus_handler(dwc->gadget, present);
> +}
> +
>  static int dwc3_usb3_phy_notify(struct notifier_block *nb,
>  				unsigned long action, void *data)
>  {
> @@ -57,6 +66,8 @@ static int dwc3_usb3_phy_notify(struct notifier_block *nb,
>  		if (!ret)
>  			return NOTIFY_OK;
>  
> +		dwc3_rockchip_vbus_handler(dwc, false);
> +
>  		/*
>  		 * Assert USB3 PHY soft reset within DWC3 before the external
>  		 * PHY resets. This disconnects the PIPE interface, preventing
> @@ -69,6 +80,7 @@ static int dwc3_usb3_phy_notify(struct notifier_block *nb,
>  		reg |= DWC3_GUSB3PIPECTL_PHYSOFTRST;
>  		dwc3_writel(dwc, DWC3_GUSB3PIPECTL(port), reg);
>  		spin_unlock_irqrestore(&dwc->lock, flags);
> +
>  		break;
>  
>  	case PHY_NOTIFY_POST_RESET:
> @@ -89,6 +101,8 @@ static int dwc3_usb3_phy_notify(struct notifier_block *nb,
>  		dwc3_writel(dwc, DWC3_GUSB3PIPECTL(port), reg);
>  		spin_unlock_irqrestore(&dwc->lock, flags);
>  
> +		dwc3_rockchip_vbus_handler(dwc, dwc_rk->role == USB_ROLE_DEVICE);
> +
>  		pm_runtime_put_autosuspend(dwc->dev);
>  		break;
>  	}
> @@ -130,7 +144,16 @@ static int dwc3_rk_phy_register_notifiers(struct dwc3 *dwc)
>  	return devm_add_action_or_reset(dwc->dev, dwc3_rk_phy_unregister_notifiers, dwc_rk);
>  }
>  
> +static void dwc3_rockchip_set_role(struct dwc3 *dwc, enum usb_role role)
> +{
> +	struct dwc3_rockchip *dwc_rk = container_of(dwc, struct dwc3_rockchip, dwc);
> +
> +	dwc_rk->role = role;
> +	dwc3_rockchip_vbus_handler(dwc, role == USB_ROLE_DEVICE);
> +}
> +
>  static struct dwc3_glue_ops dwc3_rockchip_glue_ops = {
> +	.pre_set_role = dwc3_rockchip_set_role,
>  	.post_phy_registration = dwc3_rk_phy_register_notifiers,
>  };
>  
> 
> -- 
> 2.53.0
> 
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