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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Thu, 1 Mar 2018 15:29:41 +0100
Message-ID: <CAK8P3a3q8QdpXKGw2TtRnCXpnUcRubDZp8ok2=F6evw86O+nSA@mail.gmail.com>
Subject: Re: [PATCH v4] Input: gpio_keys: Add level trigger support for GPIO keys
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Baolin Wang <baolin.wang@linaro.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stephen lu <lumotuwe@gmail.com>,
        Arvind Yadav <arvind.yadav.cs@gmail.com>,
        Joseph Lo <josephl@nvidia.com>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-input <linux-input@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mark Brown <broonie@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>
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On Thu, Mar 1, 2018 at 2:59 PM, Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Thu, Mar 1, 2018 at 2:37 PM, Arnd Bergmann <arnd@arndb.de> wrote:
>> On Thu, Mar 1, 2018 at 1:09 PM, Andy Shevchenko
>> <andy.shevchenko@gmail.com> wrote:
>>> On Thu, Mar 1, 2018 at 9:36 AM, Baolin Wang <baolin.wang@linaro.org> 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.

Got it, yes you are right.

      Arnd