Re: [PATCH v19 2/5] usb: dwc3: core: Host wake up support from system suspend

[Pavan Kondeti <quic_pkondeti@quicinc.com>]

Hi Krishna,

On Thu, Jun 02, 2022 at 08:41:52AM +0530, Krishna Kurapati wrote:
> From: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> 
> Check wakeup-source property for dwc3 core node to set the
> wakeup capability. Drop the device_init_wakeup call from
> runtime suspend and resume.
> 
> If the dwc3 is wakeup capable, don't power down the USB PHY(s).
> The glue drivers are expected to take care of configuring the
> additional wakeup settings if needed based on the dwc3 wakeup
> capability status. In some SOC designs, powering off the PHY is
> resulting in higher leakage, so this patch save power on such boards.
> 
> Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> Reviewed-by: Pavankumar Kondeti <quic_pkondeti@quicinc.com>
> ---
>  drivers/usb/dwc3/core.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index e027c04..c9d7fe3 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1787,6 +1787,7 @@ static int dwc3_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, dwc);
>  	dwc3_cache_hwparams(dwc);
> +	device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source"));
>  
>  	spin_lock_init(&dwc->lock);
>  	mutex_init(&dwc->mutex);
> @@ -1948,7 +1949,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>  		dwc3_core_exit(dwc);
>  		break;
>  	case DWC3_GCTL_PRTCAP_HOST:
> -		if (!PMSG_IS_AUTO(msg)) {
> +		if (!PMSG_IS_AUTO(msg) && !device_can_wakeup(dwc->dev)) {
>  			dwc3_core_exit(dwc);
>  			break;
>  		}
> @@ -2009,12 +2010,11 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
>  		spin_unlock_irqrestore(&dwc->lock, flags);
>  		break;
>  	case DWC3_GCTL_PRTCAP_HOST:
> -		if (!PMSG_IS_AUTO(msg)) {
> +		if (!PMSG_IS_AUTO(msg) && !device_can_wakeup(dwc->dev)) {
>  			ret = dwc3_core_init_for_resume(dwc);
>  			if (ret)
>  				return ret;
>  			dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
> -			break;
>  		}

We should break here for the case the device does not support wakeup and
PM transition is system suspend. See the suspend block above where we break
correctly.

Thanks,
Pavan