[PATCH v1 2/6] usb: chipidea: tegra: Avoid controller/PHY init if bus is externally controlled

[Svyatoslav Ryhel]

вт, 12 трав. 2026 р. о 10:51 Peter Chen (CIX) <peter.chen at kernel.org> пише:
>
> On 26-05-12 09:13:40, Svyatoslav Ryhel wrote:
> > вт, 12 трав. 2026 р. о 04:16 Peter Chen (CIX) <peter.chen at kernel.org> пише:
> > >
> > > On 26-05-11 16:56:57, Svyatoslav Ryhel wrote:
> > > > If the USB controller and PHY are externally controlled, then the
> > > > registration of the controller and the PHY initialization should be
> > > > skipped, since these configurations must be done by the device that
> > > > controls the bus to work correctly.
> > > >
> > >
> > > I find you only control USB controller device add at PHY driver, most of USB drivers
> > > has PHY control, for chipidea, it has PHY control at core.c, would please try to
> > > adapt for it?
> > >
> >
> > Usually yes, but this is not the case for Tegra unfortunately. As you
> > can see Tegra specific section of Chipidea driver specifically
> > describes why it has to set PHY manually.
> >
> > /*
> >  * USB controller registers shouldn't be touched before PHY is
> >  * initialized, otherwise CPU will hang because clocks are gated.
> >  * PHY driver controls gating of internal USB clocks on Tegra.
> >  */
> >
> > So in order to provide correct work of USB when set by an external
> > device, both PHY and controller init/add must be skipped.
>
> You could call generic PHY APIs at ci_hdrc_tegra.c, after PHY init or power on,
> call controller initialization.
>

And what it will give? Modem used in Tegra devices exposes its output
as USB device on an HSIC line. At the same time modem requires a
precise control when USB should be registered, to be able to register
and unregister it. This cannot be done by linking modem's phy to usb
controller, quite the opposite, controller must be linked to modem's
phy.

> >
> > > Peter
> > >
> > > > Signed-off-by: Svyatoslav Ryhel <clamor95 at gmail.com>
> > > > ---
> > > >  drivers/usb/chipidea/ci_hdrc_tegra.c | 36 +++++++++++++++++-----------
> > > >  1 file changed, 22 insertions(+), 14 deletions(-)
> > > >
> > > > diff --git a/drivers/usb/chipidea/ci_hdrc_tegra.c b/drivers/usb/chipidea/ci_hdrc_tegra.c
> > > > index 372788f0f970..593390a818d1 100644
> > > > --- a/drivers/usb/chipidea/ci_hdrc_tegra.c
> > > > +++ b/drivers/usb/chipidea/ci_hdrc_tegra.c
> > > > @@ -32,6 +32,7 @@ struct tegra_usb {
> > > >       struct clk *clk;
> > > >
> > > >       bool needs_double_reset;
> > > > +     bool externally_controlled;
> > > >  };
> > > >
> > > >  struct tegra_usb_soc_info {
> > > > @@ -312,20 +313,25 @@ static int tegra_usb_probe(struct platform_device *pdev)
> > > >       if (device_property_present(&pdev->dev, "nvidia,needs-double-reset"))
> > > >               usb->needs_double_reset = true;
> > > >
> > > > +     if (device_property_present(&pdev->dev, "nvidia,external-control"))
> > > > +             usb->externally_controlled = true;
> > > > +
> > > >       err = tegra_usb_reset_controller(&pdev->dev);
> > > >       if (err) {
> > > >               dev_err_probe(&pdev->dev, err, "failed to reset controller");
> > > >               goto fail_power_off;
> > > >       }
> > > >
> > > > -     /*
> > > > -      * USB controller registers shouldn't be touched before PHY is
> > > > -      * initialized, otherwise CPU will hang because clocks are gated.
> > > > -      * PHY driver controls gating of internal USB clocks on Tegra.
> > > > -      */
> > > > -     err = usb_phy_init(usb->phy);
> > > > -     if (err)
> > > > -             goto fail_power_off;
> > > > +     if (!usb->externally_controlled) {
> > > > +             /*
> > > > +              * USB controller registers shouldn't be touched before PHY is
> > > > +              * initialized, otherwise CPU will hang because clocks are gated.
> > > > +              * PHY driver controls gating of internal USB clocks on Tegra.
> > > > +              */
> > > > +             err = usb_phy_init(usb->phy);
> > > > +             if (err)
> > > > +                     goto fail_power_off;
> > > > +     }
> > > >
> > > >       /* setup and register ChipIdea HDRC device */
> > > >       usb->soc = soc;
> > > > @@ -342,12 +348,14 @@ static int tegra_usb_probe(struct platform_device *pdev)
> > > >       if (of_usb_get_phy_mode(pdev->dev.of_node) == USBPHY_INTERFACE_MODE_ULPI)
> > > >               usb->data.flags &= ~CI_HDRC_SUPPORTS_RUNTIME_PM;
> > > >
> > > > -     usb->dev = ci_hdrc_add_device(&pdev->dev, pdev->resource,
> > > > -                                   pdev->num_resources, &usb->data);
> > > > -     if (IS_ERR(usb->dev)) {
> > > > -             err = dev_err_probe(&pdev->dev, PTR_ERR(usb->dev),
> > > > -                                 "failed to add HDRC device");
> > > > -             goto phy_shutdown;
> > > > +     if (!usb->externally_controlled) {
> > > > +             usb->dev = ci_hdrc_add_device(&pdev->dev, pdev->resource,
> > > > +                                           pdev->num_resources, &usb->data);
> > > > +             if (IS_ERR(usb->dev)) {
> > > > +                     err = dev_err_probe(&pdev->dev, PTR_ERR(usb->dev),
> > > > +                                         "failed to add HDRC device");
> > > > +                     goto phy_shutdown;
> > > > +             }
> > > >       }
> > > >
> > > >       return 0;
> > > > --
> > > > 2.51.0
> > > >
> > >
> > > --
> > >
> > > Best regards,
> > > Peter
>
> --
>
> Best regards,
> Peter