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Message-ID: <de87d6ae-3449-5581-3e17-4aae72e8197a@wolfvision.net>
Date:   Thu, 27 Apr 2023 13:11:25 +0200
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Subject: Re: [RFC v1 0/4] Input: support virtual objects on touchscreens
Content-Language: en-US
To:     Pavel Machek <pavel@ucw.cz>,
        Javier Carrasco <javier.carrasco@wolfvision.net>,
        phone-devel@vger.kernel.org
Cc:     linux-input@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Henrik Rydberg <rydberg@bitmath.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Stephen Boyd <sboyd@kernel.org>,
        Sebastian Reichel <sre@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Uwe Kleine-g <u.kleine-koenig@pengutronix.de>,
        Bastian Hecht <hechtb@gmail.com>
References: <20230425115049.870003-1-javier.carrasco@wolfvision.net>
 <ZEpWrWpzkI9kNTkr@duo.ucw.cz>
From:   Michael Riesch <michael.riesch@wolfvision.net>
Organization: WolfVision GmbH
In-Reply-To: <ZEpWrWpzkI9kNTkr@duo.ucw.cz>
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Hi Pavel,

On 4/27/23 13:04, Pavel Machek wrote:
> Hi!
> 
>> Some touchscreens are shipped with a physical layer on top of them where
>> a number of buttons and a resized touchscreen surface might be
>> available.
> 
> Yes, it is quite comon, for example Motorola Droid 4 has 4 virtual
> buttons below touchscreen.

Are those buttons configurable in some way? Or do they have a fixed purpose?

How does Android handle those buttons, BTW?

> One question is if this should be handled inside the kernel. It will
> make it compatible with existing software, but it will also reduce
> flexibility.

I would say that it should be described in device tree if the purpose is
fixed. For example, if there is no display behind the touch screen at a
certain point but a printed sheet (e.g., with a home or return symbol)
then it is clear that this button is not going to change. In such a case
I doubt that flexibility is required.

Best regards, Michael

> 
> Best regards,
> 								Pavel