Re: [PATCH 4/4] CI13xxx: Add USB host interrupt notifier

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On Wed, May 16, 2012 at 05:39:07PM +0200, Marek Vasut wrote:
> Dear Alan Stern,
> 
> > On Tue, 15 May 2012, Marek Vasut wrote:
> > > Dear Alan Stern,
> > > 
> > > > On Tue, 15 May 2012, Marek Vasut wrote:
> > > > > > I'm not sure I really understand the purpose of all this.  Why does
> > > > > > the PHY driver need to know about every IRQ the host driver
> > > > > > receives?
> > > > > 
> > > > > I use the .notify_event in ci13xxx to filter out this kind of event,
> > > > > read the EHCI host register and then notify the PHY about the state
> > > > > of USB PCD.
> > > > 
> > > > Which state changes are you interested in?
> > > 
> > > The PCD bit getting flipped.
> > 
> > I presume you are referring to the Port Change Detect bit (STS_PCD) in
> > the USBSTS register.  Does this controller have only one port?
> 
> Yes. Peter hinted me to use this bit to detect host connect/disconnect events.
> 
> > > > Could the ehci-hcd driver include a hook to call the appropriate PHY
> > > > driver at the right times?
> > > 
> > > But that sounds like quite unsystematic hack. I'd like to avoid poluting
> > > the code only because one stupid controller needs it.
> > 
> > It's reasonable to assume that other controllers in the future may have
> > similar needs -- they may even require multiple PHYs to be notified
> > about connect changes on multiple ports.  I see nothing wrong with
> > implementing a callback just for this purpose.  Something like:
> > 
> > 	void (*phy_connect_change)(unsigned port, int connected);
> > 
> > Then in the port loop in ehci_irq(), you could do:
> > 
> > 	if (unlikely(ehci->phy_connect_change && (pstatus & PORT_CSC)))
> > 		(ehci->phy_connect_change)(i, pstatus & PORT_CONNECT);
> 
> Ok Alan, I'll add it into the next series of the ci13xxx stuff we'll craft 
> together with Richard. Thanks for your guidance!
How about define a interface to let hcd or udc driver to pass message
to phy driver?
My work:
https://github.com/riczhao/kernel-imx/commit/693b09a41abfb07d97fe0251325576cdcc9e3606

Thanks
Richard
> 
> > 
> > Alan Stern
> 
> Best regards,
> Marek Vasut
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