[PATCh V10 04/12] usb: ehci: ehci-mv: use PHY driver for ehci

[Chao Xie]

On Thu, Jun 13, 2013 at 11:08 PM, Alan Stern <stern at rowland.harvard.edu> wrote:
> On Thu, 13 Jun 2013, Chao Xie wrote:
>
>> >> These operations sound generic enough to be done at HCD layer, no? So no need to
>> >> replicate the same stuff in ohci, ehci, xhci, etc.
>> >
>> > The HCD layer handles suspend and resume only for PCI host controllers.
>> > Not for other types.
>> >
>> > I don't know if the acquire/start and stop/release parts can be moved
>> > into the USB core.  Maybe they can.
>> >
>> > Alan Stern
>> >
>> hi
>> The following is my understanding.
>> I think for PHY initialization and shutdown part, it is generic for
>> other parts.
>> PHY initialization need to be called before hc_driver->reset is called.
>> I think it can be added at usb_add_hcd.
>> For PHY shutdown, it can be added at usb_remove_hcd.
>
> Yes, that should work.
>
Fine, i can add a patch for that. My usb phy patches are pending on it.

>> For suspend/resume, i do not know how to add it. For our EHCI driver,
>> when system goes to deep idle states, we just directly shutdown the
>> hcd and initialize it again when the system goes back.
>
> You shut down the host controller?  Then how does it detect wakeup
> events?  And how does it know if a device was disconnected while the
> power was off?
>
Hi
I think maybe my suspend/resume is not same as what you think.
The suspend/resume i mean is the peripharal sub system suspend/resume
states. When SOC enter this low power mode,
the clock to usb, power to usb are all shut down.
When the controller is shut down, i think that usb_remove_hcd will
help to remove all the attached devices.
We do not rely on usb host controller to wake up the whole sub system.
If a device is disconnected while the power was off, when the host
controller is powered again, it will do initialization again, and all
the attached devices are susposed be removed already.


> Alan Stern
>