Re: [PATCH 1/3] dt-bindings: auxdisplay: hit,hd44780: drop redundant GPIO node

[Krzysztof Kozlowski]

On 12/02/2024 09:41, Geert Uytterhoeven wrote:
> Thanks for your patch!
> 
>> --- a/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.yaml
>> +++ b/Documentation/devicetree/bindings/auxdisplay/hit,hd44780.yaml
>> @@ -99,17 +99,7 @@ examples:
>>      };
>>    - |
>>      #include <dt-bindings/gpio/gpio.h>
>> -    i2c {
>> -            #address-cells = <1>;
>> -            #size-cells = <0>;
>>
>> -            pcf8574: pcf8574@27 {
>> -                    compatible = "nxp,pcf8574";
>> -                    reg = <0x27>;
>> -                    gpio-controller;
>> -                    #gpio-cells = <2>;
>> -            };
>> -    };
> 
> This part was added delberately in commit c784e46c8445635a ("auxdisplay:
> Add I2C gpio expander example"), to aid makers who are not DT experts.
> Note that there are no other examples of this popular wiring scheme
> in upstream DTS.

Hm, I don't understand how exactly it helps. The GPIO expander has its
own example and as you pointed below, this is basically the same code,
except rw and backlight GPIOs.


> 
>>      hd44780 {
>>              compatible = "hit,hd44780";
>>              display-height-chars = <2>;
> 
> If you do want to insist on removing the i2c GPIO expander part,
> I think this node should be removed too, as it is almost identical
> to the first example.
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 

Best regards,
Krzysztof