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

[Hans de Goede <hdegoede@redhat.com>]

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@geanix.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
>>