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

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Date:   Wed, 14 Dec 2016 17:26:58 +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 14 December 2016 at 14:43, Robert Foss <robert.foss@...labora.com> wrote:
> 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@...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
>>
>
> 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?

Please check below link:
https://lkml.org/lkml/2016/12/13/32
https://lkml.org/lkml/2016/12/13/34

>
>
>>> +
>>>         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