Re: [PATCH v5] usb: host: xhci-plat: Set XHCI_SKIP_PHY_INIT quirk for DWC3 controller

[Sandeep Maheswaram]

Hi Greg,

On 1/7/2022 10:27 AM, Sandeep Maheswaram wrote:
> On 1/6/2022 7:55 PM, Greg Kroah-Hartman wrote:
> > On Wed, Dec 22, 2021 at 11:39:43AM +0530, Sandeep Maheswaram wrote:
> > > 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 and HCD core.
> > > DWC3 manages phy in their core drivers. Set this quirk to avoid phy
> > > initialization in HCD core.
> > >
> > > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
> > > ---
> > > v5:
> > > Added comment to explain the change done.
> > > v4:
> > > Changed pdev->dev.parent->of_node to sysdev->of_node
> > >
> > >   drivers/usb/host/xhci-plat.c | 8 ++++++++
> > >   1 file changed, 8 insertions(+)
> > >
> > > diff --git a/drivers/usb/host/xhci-plat.c 
> > > b/drivers/usb/host/xhci-plat.c
> > > index c1edcc9..e6014d4 100644
> > > --- a/drivers/usb/host/xhci-plat.c
> > > +++ b/drivers/usb/host/xhci-plat.c
> > > @@ -327,6 +327,14 @@ static int xhci_plat_probe(struct 
> > > platform_device *pdev)
> > >                        &xhci->imod_interval);
> > >       }
> > >   +    /*
> > > +     * Set XHCI_SKIP_PHY_INIT quirk to avoid phy initialization twice.
> > > +     * DWC3 manages phy in their core drivers. Set this quirk to 
> > > avoid phy
> > > +     * initialization in HCD core.
> > > +     */
> > > +    if (of_device_is_compatible(sysdev->of_node, "snps,dwc3"))
> > > +        xhci->quirks |= XHCI_SKIP_PHY_INIT;
> > > +
> > Why is this function caring about dwc3 stuff?  Shoudn't this be a
> > "generic" device property instead of this device-specific one?
> >
> > thanks,
> >
> > greg k-h
>
> This quirk is set only if required for some controllers (eg: dwc3 & 
> cdns3).
>
> Please check below commit.
>
> https://lore.kernel.org/all/20200918131752.16488-5-mathias.nyman@xxxxxxxxxxxxxxx/ 
>
>
>
> Regards
>
> Sandeep
Please let me know if anything more info needed for this patch.

Regards

Sandeep