Re: [PATCH v2] gpio: interrupt consistency check for OF GPIO IRQs

[Stephen Warren <swarren@wwwdotorg.org>]

On 08/23/2013 12:38 PM, Linus Walleij wrote:
> On Thu, Aug 22, 2013 at 10:53 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>> On 08/21/2013 05:27 PM, Linus Walleij wrote:
>>> On Thu, Aug 22, 2013 at 1:10 AM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>>>>> On Wednesday 21 of August 2013 15:38:54 Lars Poeschel wrote:
>>>
>>>>>> To solve this dilemma, perform an interrupt consistency check
>>>>>> when adding a GPIO chip: if the chip is both gpio-controller and
>>>>>> interrupt-controller, walk all children of the device tree,
>>>>
>>>> It seems a little odd to solve this only for DT. What about the non-DT case?
>>>
>>> DT is the hardware configuration system that lets you request
>>> the same resource in two ways, i.e. it allows one and the same
>>> node to be both gpio-controller and interrupt-controller, and
>>> start handing out the same line as both GPIO and IRQ
>>> independently.
>>
>> Huh? What stops systems using board files and platform data from having
>> this issue?
> 
> It can't be stopped but I consider it a bug if they do, as the proper
> way to handle such GPIO lines is the sequence:
> 
> request_gpio(gpio);
> request_irq(gpio_to_irq(gpio));

Back in the old days of ARM board files, there were many boards that
didn't do this. I guess that doesn't make it any less of a bug, but it
certainly implies to me that solving this in a way that caters to that
bug being present will be a lot more useful.