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Date:   Tue, 5 Dec 2023 11:22:46 +0100
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Subject: Re: [RFC PATCH v3 4/5] arm64: dts: mediatek: mt8173-elm-hana: Mark
 touchscreens and trackpads as fail
To:     Doug Anderson <dianders@chromium.org>,
        Chen-Yu Tsai <wenst@chromium.org>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Wolfram Sang <wsa@kernel.org>,
        Benson Leung <bleung@chromium.org>,
        Tzung-Bi Shih <tzungbi@kernel.org>,
        chrome-platform@lists.linux.dev, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        Johan Hovold <johan@kernel.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        andriy.shevchenko@linux.intel.com, Jiri Kosina <jikos@kernel.org>,
        linus.walleij@linaro.org, broonie@kernel.org,
        gregkh@linuxfoundation.org, hdegoede@redhat.com,
        james.clark@arm.com, james@equiv.tech, keescook@chromium.org,
        rafael@kernel.org, tglx@linutronix.de,
        Jeff LaBundy <jeff@labundy.com>, linux-input@vger.kernel.org,
        linux-i2c@vger.kernel.org
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 <20231128084236.157152-5-wenst@chromium.org>
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From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
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Il 04/12/23 17:50, Doug Anderson ha scritto:
> Hi,
> 
> On Sun, Dec 3, 2023 at 10:59 PM Chen-Yu Tsai <wenst@chromium.org> wrote:
>>
>> On Sat, Dec 2, 2023 at 8:58 AM Doug Anderson <dianders@chromium.org> wrote:
>>>
>>> Hi,
>>>
>>> On Tue, Nov 28, 2023 at 12:45 AM Chen-Yu Tsai <wenst@chromium.org> wrote:
>>>>
>>>> @@ -44,6 +46,7 @@ trackpad2: trackpad@2c {
>>>>                  reg = <0x2c>;
>>>>                  hid-descr-addr = <0x0020>;
>>>>                  wakeup-source;
>>>> +               status = "fail-needs-probe";
>>>
>>> While doing this, you could also remove the hack where the trackpad
>>> IRQ pinctrl is listed under i2c4.
>>
>> Sure. I do think we can do away with it though. According to at least one
>> schematic, the interrupt line has pull-ups on both sides of the voltage
>> shifter.
>>
>> BTW, The touchscreen doesn't have pinctrl entries. This has pull-ups on
>> both sides of the voltage shifter as well.
> 
> I dunno if the convention is different on Mediatek boards, but at
> least on boards I've been involved with in the past we've always put
> pinctrl entries just to make things explicit. This meant that we
> didn't rely on the firmware/bootrom/defaults to leave pulls in any
> particular state. ...otherwise those external pull-ups could be
> fighting with internal pull-downs, right?
> 

MediaTek boards aren't special and there's no good reason for those to rely on
firmware/bootrom/defaults - so there is no good reason to avoid declaring any
relevant pinctrl entry.

Cheers,
Angelo