Re: [PATCH 1/5] USB: Make usb_hcd_irq work for multi-role USB controllers w/ shared irq

["Grant Likely" <grant.likely@secretlab.ca>]

On 11/24/07, David Brownell <david-b@pacbell.net> wrote:
> On Friday 23 November 2007, Grant Likely wrote:
> > Some multi-role (host/peripheral) USB controllers use a shared interrupt
> > line for all parts of the chip.
>
> Like the musb_hdrc code ... soonish to go upstream (it needs some
> updates to catch up to usbcore urb->status changes), this is used
> by the Nokia 800 and 810.  In terms of chips with Linux support:
> DaVinci, TUSB60x0, OMAP 2430, OMAP 3430, Blackfin BF527; and ISTR
> a few less-publicised ones (including, yes, some PPC SOCs).
>
> That driver hasn't needed to change usbcore for IRQ handling though.
>
>
> > Export usb_hcd_irq so drivers can call it
> > from their interrupt handler instead of duplicating code.
>
> This seems to be the main point of this patch.  I'd rather just
> make that "static" though; it should already be marked that way.
>
> That routine doesn't do enough to make me like it any more; and
> with dual-role controllers, the driver lifecycle is more complex
> than usbcore can be expected to mediate.  Best to just call the
> host side IRQ logic directly from your toplevel IRQ handler.
>
>
> > Drivers pass an irqnum of 0 to usb_add_hcd to signal that the interrupt handler
> > shouldn't be registerred by the core.
>
> The current way to get that behavior is to leave hcd->driver->irq
> as zero; then "irqnum" is ignored, and your dual role driver can
> register its own handler.

Okay, I'll make that change.

Cheers,
g.

-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
grant.likely@secretlab.ca
(403) 399-0195