Re: [PATCH v2 4/5] iio: trigger: add support for STM32 EXTI triggers

[Linus Walleij <linus.walleij@linaro.org>]

On Sat, Feb 4, 2017 at 12:39 PM, Jonathan Cameron <jic23@kernel.org> wrote:
> On 03/02/17 19:40, Linus Walleij wrote:

>>> +               if (ret) {
>>> +                       dev_err(&pdev->dev, "request IRQ %d failed\n", irq);
>>> +                       return ret;
>>> +               }
>>
>> Here you need some elaborate trigger edge handling.
>>
>> The flags that you define as "0" here, how do we say that we
>> want to handle rising or falling edges, for example?
>>
>> I think you might want to establish these DT properties for
>> GPIO triggers:
>>
>> gpio-trigger-rising-edge;
>> gpio-trigger-falling-edge;
>>
>> Then:
>>
>> int irq_flags = 0;
>>
>> if (of_property_read_bool(np, "gpio-trigger-rising-edge")
>>    irq_flags |= IRQF_TRIGGER_RISING;
>> else if (of_property_read_bool(np, "gpio-trigger-falling-edge")
>>    irq_flags |= IRQF_TRIGGER_FALLING;
>
> Should this not all be part of the interrupt specification rather
> than down here in the specific driver?

I might be thinking a bit too generic here actually.

I was thinking we need to support something that has
gpio-controller; so a consumer can get a GPIO line reference
but would not also be an interrupt-controller; so it can't
serve interrupts through the device tree bindings but
may still do so from the driver using gpiolibs .to_irq().

So the specifier would need to come in someplace else.

But I think that is maybe not at all realistic.

If there is an interrupt trigger, that can be used with
a gpio-controller that is also an interrupt-controller,
that should be fine, and then we can use the standard
DT bindings to specify the interrupt type.

Yours,
Linus Walleij