linux-kernel - Re: [PATCH 1/2] Input: gpio_keys - Also send release events for ABS codes

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Message-ID: <56a0750b-c0f6-1fad-c730-11213dd64a97@crapouillou.net>
Date:   Sat, 5 Nov 2016 12:58:00 +0100
From:   Paul Cercueil <paul@...pouillou.net>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Laxman Dewangan <ldewangan@...dia.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        Maarten ter Huurne <maarten@...ewalker.org>
Subject: Re: [PATCH 1/2] Input: gpio_keys - Also send release events for ABS
 codes

On 03/11/2016 17:21, Dmitry Torokhov wrote:
> On Tue, Nov 01, 2016 at 11:25:03AM +0100, Paul Cercueil wrote:
>> Right now, the gpio-keys driver is mostly used with EV_KEY event types.
>> However, this driver (and its devicetree bindings) support specifying
>> a different input type, like EV_ABS, even though this doesn't work in
>> practice: "key pressed" events are correctly received and treated, but
>> "key released" are silently ignored.
>>
>> With this commit, keys configured as EV_ABS will inject an event with
>> the value 0 when released.
> No, this will break setups like this:
>
> gpio0 - ABS_X - 0
> gpio1 - ABS_X - 1
> gpio2 - ABS_X - 2
> ...
> gpio7 - ABS_X - 7
>
> - something like a slider built on top of gpios.

So what would you suggest for the implementation of a hat / d-pad on top 
of GPIOs?

Thanks,
- Paul