Re: [PATCH] usb: host: ehci-platform: add pm_runtime_xx()

[Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>]

Hi Alan, Magnus

Thank you for your reply

> >     -- probe --
> >    if (pdata->power)
> >         pdata->power(xxx, 1)
> >
> >    usb_add_hcd()
> >
> >    -- remove --
> >    usb_remove_hcd()
> >
> >    if (pdata->power)
> >         pdata->power(xxx, 0)
> 
> From my point of view this all depends on what the hardware supports.
> If the USB host controller hardware can be powered down (power domain
> off, clock off) when no USB hardware is connected, but still perform
> hotplug detection of a newly added device, then if so then I'd like to
> see more fine grained PM support in the drivers. If that's not
> possible then I believe the more static approach (on probe/remove) is
> fine. Perhaps the latter is a good first step.

Thank you.
If Alan accepted this idea (= add .power callback), I would like to use this.

>> Alan
 please let me know your opinion.

 - hotplug power down is difficult on USB host, since host should output VBUS.
 - this kind of "power ON/OFF" is a platform limited problem (at this point ?)
 - I don't want create a new confusion (= use simple solution)

Best regards
---
Kuninori Morimoto
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