linux-kernel - Re: [PATCH v2 1/2] dt-bindings: input: touchscreen: goodix: Add no-reset-pull-up property

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <67e9e989-b3e2-4a2c-9332-760b79f4fb15@redhat.com>
Date: Tue, 29 Apr 2025 17:42:46 +0200
From: Hans de Goede <hdegoede@...hat.com>
To: Conor Dooley <conor@...nel.org>, Esben Haabendal <esben@...nix.com>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>, Rob Herring
 <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, linux-input@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] dt-bindings: input: touchscreen: goodix: Add
 no-reset-pull-up property

Hi,

On 29-Apr-25 17:31, Conor Dooley wrote:
> On Tue, Apr 29, 2025 at 11:56:11AM +0200, Esben Haabendal wrote:
>> This should be added for boards where there is no pull-up on the reset pin,
>> as the driver will otherwise switch the reset signal to high-impedance to
>> save power, which obviously not safe without pull-up.
>>
>> Signed-off-by: Esben Haabendal <esben@...nix.com>
>> ---
>>  Documentation/devicetree/bindings/input/touchscreen/goodix.yaml | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml b/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml
>> index eb4992f708b70fef93bd4b59b9565123f7c6ad5d..21ac13046b6e021eeb403d854aabc945801dd29f 100644
>> --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml
>> +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml
>> @@ -45,6 +45,10 @@ properties:
>>    reset-gpios:
>>      maxItems: 1
>>  
>> +  goodix,no-reset-pull-up:
>> +    type: boolean
>> +    description: There is no pull-up on reset pin
> 
> I have to wonder, why are these system using the reset property if the
> reset is not usable? Shouldn't the property be omitted?

The reset is usable, but it lacks an external pull-up resistor, so
the driver cannot switch the gpio output on the CPU going to
the touchscreen controller to input to save power as it does by default.

Regards,

Hans




> 
>> +
>>    AVDD28-supply:
>>      description: Analog power supply regulator on AVDD28 pin
>>  
>>
>> -- 
>> 2.49.0
>>