Re: [PATCH v7 1/2] usb: xhci: plat: Enable runtime PM

[Robert Foss]

Hey Baolin,

On 2016-12-12 12:21 AM, Baolin Wang wrote:
> Hi Robert,
>
> On 2 December 2016 at 05:46, Robert Foss <robert.foss@xxxxxxxxxxxxx> wrote:
> > Enable runtime PM for the xhci-plat device so that the parent device
> > may implement runtime PM.
> >
> > Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> >
> > Tested-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> > ---
> >  drivers/usb/host/xhci-plat.c | 29 +++++++++++++++++++++++++++--
> >  1 file changed, 27 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> > index ed56bf9ed885..ba4efe74f537 100644
> > --- a/drivers/usb/host/xhci-plat.c
> > +++ b/drivers/usb/host/xhci-plat.c
> > @@ -246,6 +246,9 @@ static int xhci_plat_probe(struct platform_device *pdev)
> >         if (ret)
> >                 goto dealloc_usb2_hcd;
> >
> > +       pm_runtime_set_active(&pdev->dev);
> > +       pm_runtime_enable(&pdev->dev);
>
> You did not implement the runtime callbacks of xHCI device, then how
> can the parent device control the resume/suspend of xHCI device by
> runtime PM mechanism? Could you see my previous patch which implement
> the runtime callbacks for xHCI device?
> https://lkml.org/lkml/2016/11/28/25

Pardon my ignorance, but which exact functions need to be implemented?
Also, does the lkml link you provided contain an example implementation 
of those functions?

> > +
> >         return 0;
> >
> >
> > @@ -274,6 +277,8 @@ static int xhci_plat_remove(struct platform_device *dev)
> >         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> >         struct clk *clk = xhci->clk;
> >
> > +       pm_runtime_disable(&dev->dev);
> > +
> >         usb_remove_hcd(xhci->shared_hcd);
> >         usb_phy_shutdown(hcd->usb_phy);
> >
> > @@ -292,6 +297,13 @@ static int xhci_plat_suspend(struct device *dev)
> >  {
> >         struct usb_hcd  *hcd = dev_get_drvdata(dev);
> >         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> > +       int ret;
> > +
> > +       ret = pm_runtime_get_sync(dev);
> > +       if (ret < 0) {
> > +               pm_runtime_put(dev);
> > +               return ret;
> > +       }
> >
> >         /*
> >          * xhci_suspend() needs `do_wakeup` to know whether host is allowed
> > @@ -301,15 +313,28 @@ static int xhci_plat_suspend(struct device *dev)
> >          * reconsider this when xhci_plat_suspend enlarges its scope, e.g.,
> >          * also applies to runtime suspend.
> >          */
> > -       return xhci_suspend(xhci, device_may_wakeup(dev));
> > +       ret = xhci_suspend(xhci, device_may_wakeup(dev));
> > +       pm_runtime_put(dev);
> > +
> > +       return ret;
> >  }
> >
> >  static int xhci_plat_resume(struct device *dev)
> >  {
> >         struct usb_hcd  *hcd = dev_get_drvdata(dev);
> >         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> > +       int ret;
> >
> > -       return xhci_resume(xhci, 0);
> > +       ret = pm_runtime_get_sync(dev);
> > +       if (ret < 0) {
> > +               pm_runtime_put(dev);
> > +               return ret;
> > +       }
> > +
> > +       ret = xhci_resume(xhci, 0);
> > +       pm_runtime_put(dev);
> > +
> > +       return ret;
> >  }
> >
> >  static const struct dev_pm_ops xhci_plat_pm_ops = {
> > --
> > 2.11.0