Re: [PATCH v4] Input: gpio_keys: Add level trigger support for GPIO keys

[Andy Shevchenko]

On Thu, Mar 1, 2018 at 2:37 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Thu, Mar 1, 2018 at 1:09 PM, Andy Shevchenko
> <andy.shevchenko@xxxxxxxxx> wrote:
>> On Thu, Mar 1, 2018 at 9:36 AM, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
>>> On some platforms (such as Spreadtrum platform), the GPIO keys can only
>>> be triggered by level type. So this patch introduces one trigger_type to
>>> indicate if the button's interrupt type is level trigger or edge trigger.
>>
>>>                         button->irq =
>>>                                 irq_of_parse_and_map(to_of_node(child), 0);
>>
>> AFAIU, 0 means NO_IRQ, thus,
>>
>>> +                       if (button->irq)
>>> +                               button->trigger_type =
>>> +                                       irq_get_trigger_type(button->irq);
>>
>> irq_get_trigger_type(NO_IRQ) should return 0.
>>
>> Therefore, if (button->irq) is redundant.
>> Did I miss anything?
>
> "irq_of_parse_and_map(to_of_node(child), 0);" is the first interrupt. A
> more common way to express the same thing in modern drivers is
> 'platform_get_irq(pdev, 0)'.

Yes, though I'm talking about _returned_ value.

> However, there is one more thing I'm missing: with my suggestion
> of emulating edge-triggered interrupts in the irqchip/gpio driver, the
> trigger type here should also be 'IRQF_TRIGGER_RISING |
> IRQF_TRIGGER_FALLING' in the DT description, so I don't think
> we need to change the gpio-keys driver at all, just the gpio driver.

Sounds even better.

-- 
With Best Regards,
Andy Shevchenko