Re: [PATCH] gpiolib: introduce for_each_gpio_in_chip macro

[Jaya Kumar <jayakumar.lkml@gmail.com>]

On Thu, Aug 6, 2009 at 11:31 AM, Ben Nizette <bn@niasdigital.com> wrote:
> On Tue, 2009-08-04 at 20:48 -0400, H Hartley Sweeten wrote:
>
>> For the record. The reason I sent this is I'm trying to work out an
>> extension to gpiolib that adds gpio_port_* access to the API.  Most
>> of the gpiolib drivers already the necessary logic since the raw I/O
>> is performed on the entire 'chip'.  The API just needs the extensions
>> added to request/free the port, set the direction and get/set the value.
>>
>> Is this a worthwhile addition?
>
> Plenty of people seem to think so.  Personally I haven't seen a great
> use case except "'coz I can", but if you've got one I'd love to hear.

Yes, you're right that there has been no major demand for it. There
are (luckily?) only a moderate number of devices that are using gpio
as their parallel bus interface. I've been supporting the batch-gpio
patchset below out-of-the-tree because it has come in handy with a few
e-paper display controllers and LCD 8080-IO that I've been developing
with.

>
> Have you seen http://lkml.org/lkml/2009/1/25/10 ?  Donno what ended up
> happening to that patchset..
>

I didn't pursue it further and have maintained it out-of-tree. I felt
that David had concerns about the API I implemented so it was unlikely
to get merged and I didn't have the motivation to implement another.
:-)

Thanks,
jaya

ps: I'm in Portland for the festival of linux conferences this week
and would be happy to work on this/discuss alternate APIs if it is of
interest.