[PATCH v2] Add interrupt handling capability to pca953x

[Eric Miao]

On Fri, Dec 25, 2009 at 2:37 AM, Mark Brown
<broonie at opensource.wolfsonmicro.com> wrote:
> On Thu, Dec 24, 2009 at 06:52:40PM +0100, Marc Zyngier wrote:
>
>> Pending problems to be solved:
>> - Modular build is broken, as handle_edge_irq, set_irq_flags and
>>   irq_to_desc are not exported, among others. First approach would be
>>   to disable the irq_chip when build modular, but I really don't like
>>   it.
>
> The other approach here is just to not support modular builds; it's what
> the IRQ core wants you to do and what I ended up doing for wm831x.  Or
> speak to Ingo and Thomas and see if they'll relax the requirement that
> interrupt controller drivers be built in.
>
>> - request_irq vs request_threaded_irq: genirq is a bit of a mess in
>>   this respect. We'd love a consistent API...
>
> What's the problem here?  Are you referring to the consumer side or
> something that the driver itself has to deal with - from the point of
> view of the interrupt controller itself this is pretty much transparent.
>
> Like I said in my previous mail a threaded interrupt context is
> fundamentally not a non-threaded one so users do need to be aware of
> which context they're running in - you can do more things in a threaded
> context but you also have more possibility for concurrency issues to
> creep in.  This means that the visible difference between the two
> handlers always seemed reasonable to me.
>
> It would be nice to have a third option for handlers which can cope with
> either context, though.  Actually, using request_threaded_irq and
> supplying the same function for both primary and secondary handler may
> DTRT in that case but I'd need to check.  This is another thing we
> really ought to bring up with Ingo and Thomas rather than discussing
> here, though.
>

Then, let's get them involved. Thomas and Ingo CC'ed.