On Thu, Apr 07, 2016 at 01:40:21PM +0300, Roger Quadros wrote: > On 07/04/16 12:42, Peter Chen wrote: > > On Wed, Apr 06, 2016 at 09:32:22AM +0300, Roger Quadros wrote: > >> On 06/04/16 09:09, Felipe Balbi wrote: > >>> > >>> Hi, > >>> > >>> Roger Quadros <rogerq@xxxxxx> writes: > >>>> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c > >>>> index 2ca2cef..6b1930d 100644 > >>>> --- a/drivers/usb/core/hcd.c > >>>> +++ b/drivers/usb/core/hcd.c > >>>> @@ -2706,6 +2706,7 @@ int usb_add_hcd(struct usb_hcd *hcd, > >>>> int retval; > >>>> struct usb_device *rhdev; > >>>> > >>>> + hcd->flags = 0; > >>> > > > > I am not sure if this usb_add(remove)_hcd pair is safe and clean enough > > for start/stop host role. From my point, we may need to do like > > .probe/.remove host platform driver interface. In that case, we can make > > probe and remove are meant to be called from bus layer. > I do not see a way how OTG framework can call probe/remove of HCD driver. > Some HCDs may be platform devices, some PCI, so different entities are calling > the HCD .probe hook. > > > sure the clocks and regulators are off, and hcd will be zero-initialized > > why can't we make that sure that is taken care of within the hcd_ops? > Why should some driver keep its regulators and clocks enabled when hcd is stopped? > It doesn't need to. If it is doing so now, it needs to be fixed. > Well, you may misunderstand me. I mean your hcd_ops->start or ->stop is hard to be a general one which only calls usb_hcd_add or usb_hcd_remove. It needs to implement like .probe or .remove at platform driver, some example code like host_start and host_stop at drivers/usb/chipidea/host.c. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
