linux-kernel - Re: [PATCH v3 1/5] usb: dwc3: core: Host wake up support from system suspend

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Message-ID: <20200929181745.GB1621304@google.com>
Date:   Tue, 29 Sep 2020 11:17:45 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Sandeep Maheswaram <sanm@...eaurora.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Felipe Balbi <balbi@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Manu Gautam <mgautam@...eaurora.org>
Subject: Re: [PATCH v3 1/5] usb: dwc3: core: Host wake up support from system
 suspend

On Tue, Sep 29, 2020 at 04:17:28PM +0530, Sandeep Maheswaram wrote:
> Avoiding phy powerdown in host mode so that it can be wake up by devices.
> Added hs_phy_flags and ss_phy_flags to check connection status and
> set phy mode and configure interrupts.
> 
> Signed-off-by: Sandeep Maheswaram <sanm@...eaurora.org>
> ---
>  drivers/usb/dwc3/core.c | 14 +++-----------
>  drivers/usb/dwc3/core.h |  3 +++
>  2 files changed, 6 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 385262f..c32ed10 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1663,10 +1663,6 @@ 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)) {
> -			dwc3_core_exit(dwc);
> -			break;
> -		}
>  
>  		/* Let controller to suspend HSPHY before PHY driver suspends */
>  		if (dwc->dis_u2_susphy_quirk ||
> @@ -1724,13 +1720,9 @@ 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)) {
> -			ret = dwc3_core_init_for_resume(dwc);
> -			if (ret)
> -				return ret;
> -			dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
> -			break;
> -		}
> +
> +		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
> +
>  		/* Restore GUSB2PHYCFG bits that were modified in suspend */
>  		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
>  		if (dwc->dis_u2_susphy_quirk)
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 83b6c87..cd385a8 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -1096,6 +1096,9 @@ struct dwc3 {
>  
>  	bool			phys_ready;
>  
> +	unsigned int            hs_phy_flags;
> +	unsigned int            ss_phy_flags;
> +

It doesn't seem ss_phy_flags is really needed, it is only used
in dwc3_set_phy_speed_flags(), a local variable could be used
instead.

The 'flags' are passed as 'mode' to phy_set_mode(), I think it
would be clearer to reflect that in the name, i.e. 'hs_phy_mode'
instead of 'hs_phy_flags'.