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From:   Jun Li <lijun.kernel@gmail.com>
Date:   Wed, 16 Feb 2022 16:49:32 +0800
Message-ID: <CAKgpwJVwTDd40ZR3tKOgVpRTNs1OjE5ssMM+Lj-Ak0CHPSAWQQ@mail.gmail.com>
Subject: Re: [PATCH 2/2] usb: dwc: host: add xhci_plat_priv quirk XHCI_SKIP_PHY_INIT
To:     Pavan Kondeti <quic_pkondeti@quicinc.com>, Li Jun <jun.li@nxp.com>
Cc:     Sandeep Maheswaram <quic_c_sanm@quicinc.com>,
        Peter Chen <peter.chen@kernel.org>,
        Pawel Laszczak <pawell@cadence.com>,
        Roger Quadros <rogerq@kernel.org>,
        Aswath Govindraju <a-govindraju@ti.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Felipe Balbi <balbi@kernel.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Stephen Boyd <swboyd@chromium.org>,
        Doug Anderson <dianders@chromium.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        linux-arm-msm@vger.kernel.org,
        Linux USB List <linux-usb@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>, quic_ppratap@quicinc.com
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Pavan Kondeti <quic_pkondeti@quicinc.com> =E4=BA=8E2022=E5=B9=B42=E6=9C=881=
6=E6=97=A5=E5=91=A8=E4=B8=89 16:00=E5=86=99=E9=81=93=EF=BC=9A
>
> On Wed, Feb 16, 2022 at 03:16:40PM +0800, Jun Li wrote:
> > Sandeep Maheswaram <quic_c_sanm@quicinc.com> =E4=BA=8E2022=E5=B9=B42=E6=
=9C=8816=E6=97=A5=E5=91=A8=E4=B8=89 14:58=E5=86=99=E9=81=93=EF=BC=9A
> > >
> > > dwc3 manages PHY by own DRD driver, so skip the management by
> > > HCD core.
> > > During runtime suspend phy was not getting suspend because
> > > runtime_usage value is 2.
> > >
> > > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
> > > ---
> > >  drivers/usb/dwc3/host.c | 15 +++++++++++++++
> > >  1 file changed, 15 insertions(+)
> > >
> > > diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> > > index eda8719..4a035a8 100644
> > > --- a/drivers/usb/dwc3/host.c
> > > +++ b/drivers/usb/dwc3/host.c
> > > @@ -13,6 +13,14 @@
> > >  #include <linux/platform_device.h>
> > >
> > >  #include "core.h"
> > > +#include <linux/usb/hcd.h>
> > > +#include <linux/usb/xhci-plat.h>
> > > +#include <linux/usb/xhci-quirks.h>
> > > +
> > > +
> > > +static const struct xhci_plat_priv xhci_plat_dwc3_xhci =3D {
> > > +       .quirks =3D XHCI_SKIP_PHY_INIT,
> > > +};
> >
> > It's better to create this xhci_plat_priv by each dwc3 glue layer,
> > with that, we can use this priv to pass other flags and possibly
> > override APIs by each glue driver which may not apply to all dwc3
> > platforms.
> >
>
> Do you see a need for any glue driver to know about this xHC platform dat=
a?

Yes. I have some xhci quirks which are specifix to NXP iMX platforms.

> AFAICT, glue driver has no direction connection with the dwc3 core. All
> the required data is coming from dT on ARM based boards. Adding a private
> interface between dwc3 core and glue for passing xhci platform data seems
> to be overkill. If there is a pressing need, why not?

And looking at xhci_plat_priv members

-struct xhci_plat_priv {
-       const char *firmware_name;
-       unsigned long long quirks;
-       int (*plat_setup)(struct usb_hcd *);
-       void (*plat_start)(struct usb_hcd *);
-       int (*init_quirk)(struct usb_hcd *);
-       int (*suspend_quirk)(struct usb_hcd *);
-       int (*resume_quirk)(struct usb_hcd *);
-};

Are we going to share the same all those quirks and APIs
implementation across all dwc3 platforms?

Thanks
Li Jun
>
> Thanks,
> Pavan