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

Linus Walleij
2013-08-23T18:38:06Z

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));

But I was mainly contrasting against ACPI, where the problem appears
to not exist.

Yours,
Linus Walleij