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

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Date:   Mon, 12 Dec 2016 13:21:34 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Robert Foss <robert.foss@...labora.com>
Cc:     mathias.nyman@...el.com, Greg KH <gregkh@...uxfoundation.org>,
        Julius Werner <jwerner@...omium.org>,
        Andrew Bresticker <abrestic@...omium.org>,
        Felipe Balbi <felipe.balbi@...ux.intel.com>,
        Brian Norris <briannorris@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 1/2] usb: xhci: plat: Enable runtime PM

Hi Robert,

On 2 December 2016 at 05:46, Robert Foss <robert.foss@...labora.com> 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@...labora.com>
>
> Tested-by: Robert Foss <robert.foss@...labora.com>
> ---
>  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

> +
>         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
>



-- 
Baolin.wang
Best Regards