linux-kernel - Re: [PATCH v3] usb: host: xhci-plat: Set XHCI_SKIP_PHY

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Message-ID: <CAE-0n50sO_HcMiou7nhWTkGRiyG1-yHJmgXexMhS=j+AH2NyfA@mail.gmail.com>
Date:   Wed, 15 Dec 2021 02:02:33 +0100
From:   Stephen Boyd <swboyd@...omium.org>
To:     Doug Anderson <dianders@...omium.org>,
        Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Matthias Kaehlcke <mka@...omium.org>,
        Sandeep Maheswaram <quic_c_sanm@...cinc.com>
Cc:     linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, quic_pkondeti@...cinc.com,
        quic_ppratap@...cinc.com
Subject: Re: [PATCH v3] usb: host: xhci-plat: Set XHCI_SKIP_PHY_INIT quirk for
 DWC3 controller

Quoting Sandeep Maheswaram (2021-12-13 20:47:48)
>
> On 12/2/2021 8:47 AM, Stephen Boyd wrote:
> > Quoting Sandeep Maheswaram (2021-11-30 22:15:38)
> >> Set XHCI_SKIP_PHY_INIT quirk to avoid phy initialization twice.
> >> Runtime suspend of phy drivers was failing from DWC3 driver as
> >> runtime usage value is 2 because the phy is initialized from
> >> DWC3 core and HCD core.
> >> DWC3 manages phy in their core drivers.
> > This looks wrapped weirdly.
> >
> >> Set this quirk to avoid phy initialization in HCD core.
> >>
> >> Signed-off-by: Sandeep Maheswaram <quic_c_sanm@...cinc.com>
> > Any Fixes tag?
> Not sure about the commit id to be used here.

Maybe whenever the phy started being initialized twice?

> >
> >> ---
> >>   drivers/usb/host/xhci-plat.c | 3 +++
> >>   1 file changed, 3 insertions(+)
> >>
> >> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> >> index c1edcc9..9bbd939 100644
> >> --- a/drivers/usb/host/xhci-plat.c
> >> +++ b/drivers/usb/host/xhci-plat.c
> >> @@ -327,6 +327,9 @@ static int xhci_plat_probe(struct platform_device *pdev)
> >>                                           &xhci->imod_interval);
> >>          }
> >>
> >> +       if (of_device_is_compatible(pdev->dev.parent->of_node, "snps,dwc3"))
> > Are we sure that pdev->dev.parent isn't NULL here?
>
> +    if (of_device_is_compatible(to_of_node(sysdev->fwnode), "snps,dwc3"))
>
> Will this be ok ?

Probably? But I see this function already uses 'sysdev->of_node' so
that's probably all that's necessary assuming sysdev == pdev->dev.parent
in this case.

	if (of_device_is_compatible(sysdev->of_node, "snps,dwc3"))

>
> >
> >> +               xhci->quirks |= XHCI_SKIP_PHY_INIT;
> >> +
> >>          hcd->usb_phy = devm_usb_get_phy_by_phandle(sysdev, "usb-phy", 0);
> >>          if (IS_ERR(hcd->usb_phy)) {