Re: [PATCH] usb: dwc3: qcom: Add support to skip phy management by USB core

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

On Mon, Sep 14, 2026, Krishna Kurapati wrote:
> DWC3 driver does manage phys itself sufficiently for Qualcomm platforms.
> If xhci-skip-phy-init is not set, the HCD core does a phy_init and phy_
> exit is done only when roothub is being destroyed. Due to this, during
> system suspend in host mode, although phy_exit is done by DWC3 core, the
> init_count on phy is never down to zero since HCD core also did an init.
> consequently causing phy's exit routine to not be called. Hence, add
> support to skip phy management by USB core.
> 
> Some Exynos platforms still do rely on USB core for phy_calibrate calls,
> hence disable USB core management for Qualcomm platforms only.
> 
> Signed-off-by: Krishna Kurapati <krishna.kurapati@oss.qualcomm.com>
> ---
> Initially, a patch was sent adding software_node properties [1]. But it
> was causing a bootup issue as mentioned in [2]. Hence a revert was sent
> to fix it [3]. This patch uses a different approach as opposed to adding
> sofware node properties and was tested on sm8750 mtp.
> 
> [1]: https://urldefense.com/v3/__https://lore.kernel.org/all/20260723-dwc3-skip-init-quirk-v1-1-97682bb44ebd@oss.qualcomm.com/__;!!A4F2R9G_pg!ftg4gg9oGl2AtD94fdRRqDIoquKIgH6nl9w9IbKomj-QO2yB9Y43pLHCT2fXhQ0ISAjTHaNeQHIeJqzRmMNc41v91pW218JaadHg0w$ 
> [2]: https://urldefense.com/v3/__https://lore.kernel.org/all/cbb4ae94-7862-4d91-b01d-0d7f18d49a45@packett.cool/__;!!A4F2R9G_pg!ftg4gg9oGl2AtD94fdRRqDIoquKIgH6nl9w9IbKomj-QO2yB9Y43pLHCT2fXhQ0ISAjTHaNeQHIeJqzRmMNc41v91pW218KCWX4GOA$ 
> [3]: https://urldefense.com/v3/__https://lore.kernel.org/all/20260909-xhci-fixes-revert-v1-1-7cc97fa0f307@oss.qualcomm.com/__;!!A4F2R9G_pg!ftg4gg9oGl2AtD94fdRRqDIoquKIgH6nl9w9IbKomj-QO2yB9Y43pLHCT2fXhQ0ISAjTHaNeQHIeJqzRmMNc41v91pW218JTBr_EyQ$ 
> ---
>  drivers/usb/dwc3/core.c      | 3 +++
>  drivers/usb/dwc3/core.h      | 1 +
>  drivers/usb/dwc3/dwc3-qcom.c | 1 +
>  drivers/usb/dwc3/glue.h      | 2 ++
>  drivers/usb/dwc3/host.c      | 5 ++++-
>  5 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index fd5c2cd36c59..d9f4e4109abb 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1694,6 +1694,9 @@ static void dwc3_get_software_properties(struct dwc3 *dwc,
>  	if (properties->needs_full_reinit)
>  		dwc->needs_full_reinit = true;
>  
> +	if (properties->skip_phy_init)
> +		dwc->skip_phy_init = true;
> +
>  	dwc->gsbuscfg0_reqinfo = DWC3_GSBUSCFG0_REQINFO_UNSPECIFIED;
>  
>  	if (properties->gsbuscfg0_reqinfo !=
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 608daeb7ef10..b72869380933 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1420,6 +1420,7 @@ struct dwc3 {
>  	unsigned		wakeup_configured:1;
>  	unsigned		suspended:1;
>  	unsigned		susphy_state:1;
> +	unsigned		skip_phy_init:1;
>  
>  	u16			imod_interval;
>  
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index e6b6beb38fcb..5387658dd38d 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -738,6 +738,7 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
>  	probe_data.res = &res;
>  	probe_data.ignore_clocks_and_resets = true;
>  	probe_data.properties = DWC3_DEFAULT_PROPERTIES;
> +	probe_data.properties.skip_phy_init = true;
>  	ret = dwc3_core_probe(&probe_data);
>  	if (ret)  {
>  		ret = dev_err_probe(dev, ret, "failed to register DWC3 Core\n");
> diff --git a/drivers/usb/dwc3/glue.h b/drivers/usb/dwc3/glue.h
> index d738e1739ae0..72c5593e657a 100644
> --- a/drivers/usb/dwc3/glue.h
> +++ b/drivers/usb/dwc3/glue.h
> @@ -14,10 +14,12 @@
>   * @gsbuscfg0_reqinfo: Value to be programmed in the GSBUSCFG0.REQINFO field
>   * @needs_full_reinit: indicate the controller may not remain power during system
>   *			pm and need full initialization
> + * @skip_phy_init: skip xHCI PHY initialization on host init
>   */
>  struct dwc3_properties {
>  	u32 gsbuscfg0_reqinfo;
>  	unsigned needs_full_reinit:1;
> +	unsigned skip_phy_init:1;
>  };
>  
>  #define DWC3_DEFAULT_PROPERTIES ((struct dwc3_properties){		\
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index c5674161b2b0..3fb8be8be590 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -130,7 +130,7 @@ static int dwc3_host_get_irq(struct dwc3 *dwc)
>  
>  int dwc3_host_init(struct dwc3 *dwc)
>  {
> -	struct property_entry	props[6];
> +	struct property_entry	props[7];
>  	struct platform_device	*xhci;
>  	int			ret, irq;
>  	int			prop_idx = 0;
> @@ -174,6 +174,9 @@ int dwc3_host_init(struct dwc3 *dwc)
>  	if (dwc->usb2_lpm_disable)
>  		props[prop_idx++] = PROPERTY_ENTRY_BOOL("usb2-lpm-disable");
>  
> +	if (dwc->skip_phy_init)
> +		props[prop_idx++] = PROPERTY_ENTRY_BOOL("xhci-skip-phy-init-quirk");
> +
>  	/**
>  	 * WORKAROUND: dwc3 revisions <=3.00a have a limitation
>  	 * where Port Disable command doesn't work.
> 
> ---
> base-commit: 7f69cecb6098fada87b010c911aa736a5af8f679
> change-id: 20260914-xhci-skip-phy-init-d0a6bd96b13f
> 
> Best regards,
> --  
> Krishna Kurapati <krishna.kurapati@oss.qualcomm.com>
> 

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

Thanks,
Thinh