linux-kernel - Re: [PATCH v2] Input: gpio_keys: Add level trigger support for GPIO keys

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Date:   Mon, 26 Feb 2018 14:24:09 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     Rob Herring <robh@...nel.org>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Greg KH <gregkh@...uxfoundation.org>,
        stephen lu <lumotuwe@...il.com>,
        Arvind Yadav <arvind.yadav.cs@...il.com>,
        Joseph Lo <josephl@...dia.com>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-input@...r.kernel.org, DTML <devicetree@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Mark Brown <broonie@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH v2] Input: gpio_keys: Add level trigger support for GPIO keys

Hi Rob,

On 21 February 2018 at 19:35, Baolin Wang <baolin.wang@...aro.org> wrote:
> Hi Rob,
>
> On 20 February 2018 at 02:11, Rob Herring <robh@...nel.org> wrote:
>> On Sun, Feb 11, 2018 at 02:55:04PM +0800, Baolin Wang wrote:
>>> On some platforms (such as Spreadtrum platform), the GPIO keys can only
>>> be triggered by level type. So this patch introduces one property to
>>> indicate if the GPIO trigger type is level trigger or edge trigger.
>>
>> If the parent interrupt controller only supports a certain trigger, then
>> it should ignore setting the trigger type.
>
> We still need to set high level type trigger or low level type trigger
> if it only supports level trigger.
>
>>
>>>
>>> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
>>> ---
>>> Changes since v1:
>>>  - Diable the GPIO irq until reversing the GPIO level type.
>>> ---
>>>  .../devicetree/bindings/input/gpio-keys.txt        |    2 ++
>>>  drivers/input/keyboard/gpio_keys.c                 |   26 +++++++++++++++++++-
>>>  include/linux/gpio_keys.h                          |    1 +
>>>  3 files changed, 28 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/input/gpio-keys.txt b/Documentation/devicetree/bindings/input/gpio-keys.txt
>>> index a949404..e3104bd 100644
>>> --- a/Documentation/devicetree/bindings/input/gpio-keys.txt
>>> +++ b/Documentation/devicetree/bindings/input/gpio-keys.txt
>>> @@ -29,6 +29,8 @@ Optional subnode-properties:
>>>       - linux,can-disable: Boolean, indicates that button is connected
>>>         to dedicated (not shared) interrupt which can be disabled to
>>>         suppress events from the button.
>>> +     - gpio-key,level-trigger: Boolean, indicates that button's interrupt
>>> +       type is level trigger. Otherwise it is edge trigger as default.
>>
>> No. Just use 'interrupts' instead of 'gpios' and specify the trigger
>> type. Or put both if you need to read the state.
>
> Okay, so something as below to get the level type from the
> 'interrupts' property.
> if (fwnode_property_read_u32(child, "interrupts", &button->level_type))
>         button->level_type = IRQ_TYPE_NONE;

After more thinking, if we use 'interrupts' to indicate the irq type
for this case, we cannot specify the irq number due to the irq number
should be get by gpiod_to_irq(). So the device nodes look weird, since
we should define the index of the interrupt controller instead of the
irq type if the #interrupt_cells is set to 1 according to the
interrupt controller documentation. What do you think about this?
Thanks.

gpio-keys {
            compatible = "gpio-keys";

            key-volumedown {
                label = "Volume Down Key";
                linux,code = <KEY_VOLUMEDOWN>;
                gpios = <&ap_eic_debounce 2 GPIO_ACTIVE_LOW>;
                debounce-interval = <2>;
                wakeup-source;
                interrupts = <IRQ_TYPE_LEVEL_LOW>;
            };

            key-volumeup {
                label = "Volume Up Key";
                linux,code = <KEY_VOLUMEUP>;
                gpios = <&pmic_eic 10 GPIO_ACTIVE_HIGH>;
                debounce-interval = <2>;
                wakeup-source;
                interrupts = <IRQ_TYPE_LEVEL_HIGH>;
            };

            key-power {
                label = "Power Key";
                linux,code = <KEY_POWER>;
                gpios = <&pmic_eic 1 GPIO_ACTIVE_HIGH>;
                wakeup-source;
                interrupts = <IRQ_TYPE_LEVEL_HIGH>;
            };
};

-- 
Baolin Wang
Best Regards