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

[Svyatoslav Ryhel]

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.

> 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