linux-kernel - Re: [RFT PATCH v2 2/2] arm64: dts: qcom: sdm845: align TLMM pin configuration with DT schema

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Date:   Fri, 2 Dec 2022 09:15:25 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Doug Anderson <dianders@...omium.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Rob Clark <robdclark@...omium.org>,
        Fritz Koenig <frkoenig@...gle.com>
Subject: Re: [RFT PATCH v2 2/2] arm64: dts: qcom: sdm845: align TLMM pin
 configuration with DT schema

On 02/12/2022 01:50, Doug Anderson wrote:
> Hi,
> 
> On Fri, Nov 18, 2022 at 8:42 AM Krzysztof Kozlowski
> <krzysztof.kozlowski@...aro.org> wrote:
>>
>> DT schema expects TLMM pin configuration nodes to be named with
>> '-state' suffix and their optional children with '-pins' suffix.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>>
>> ---
>>
>> Cc: Doug Anderson <dianders@...omium.org>
>>
>> Tested on Qualcomm RB3. Please kndly test a bit more on other devices.
>> This should not have an functional impact.
> 
> Added Rob Clark and Fritz who are the only people I know that still do
> anything with cheza.
> 
> 
>> -       wcd_intr_default: wcd_intr_default {
>> +       wcd_intr_default: wcd-intr-default-state {
>>                 pins = <54>;
> 
> Not new to your patch, but I'm surprised it truly works to use an
> integer for a pin? How does it know that 54 is an integer and not a
> string???

Maybe it passes the checks as phandle...

Anyway, I'll fix it in separate patch, assuming this is GPIO54. On
schematics I see CODEC_INT1_N GPIO_54.

> 
> 
>>  &qup_uart3_default {
>> -       pinmux {
>> -               pins = "gpio41", "gpio42", "gpio43", "gpio44";
>> +       cts-rts-pins {
>> +               pins = "gpio41", "gpio42";
>>                 function = "qup3";
>>         };
>>  };
> 
> FWIW, I would have expected that the SoC dtsi file would get a "4-pin"
> definition (similar to what you did with qup_uart6_4pin) and then we'd
> use that here.

Sure.

> 
> 
>>                         qup_uart6_4pin: qup-uart6-4pin-state {
>> -
>> -                               cts-pins {
>> +                               qup_uart6_4pin_cts: cts-pins {
>>                                         pins = "gpio45";
>>                                         function = "qup6";
>> -                                       bias-pull-down;
> 
> After your patch, where is the above bias set for cheza, db845c,
> oneplus, shift-axolotl, ...?
> 
> 
>>                                 };
>>
>> -                               rts-tx-pins {
>> +                               qup_uart6_4pin_rts_tx: rts-tx-pins {
>>                                         pins = "gpio46", "gpio47";
>>                                         function = "qup6";
>> -                                       drive-strength = <2>;
>> -                                       bias-disable;
> 
> After your patch, where is the above bias / drive-strength set?

They don't use 4-pin setup. If they use, I would assume they will
override the entries just like sdm850 boards (where I override it to set
these).

Alternatively I can keep it in DTSI, but it is not really property of
the SoC.
> 
> 
>>                                 };
>>
>> -                               rx-pins {
>> +                               qup_uart6_4pin_rx: rx-pins {
>>                                         pins = "gpio48";
>>                                         function = "qup6";
>> -                                       bias-pull-up;
> 
> After your patch, where is the above bias set?

Best regards,
Krzysztof