linux-kernel - Re: [PATCH 06/11] iio: adc: Add QCOM PMIC5 Gen3 ADC bindings

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Message-ID: <c4ef9cac-15ac-4c2c-9f9a-cb9e740e2900@linaro.org>
Date:   Mon, 23 Oct 2023 08:36:48 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Jishnu Prakash <quic_jprakash@...cinc.com>, agross@...nel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linus.walleij@...aro.org, Jonathan.Cameron@...wei.com,
        sboyd@...nel.org, dmitry.baryshkov@...aro.org,
        quic_subbaram@...cinc.com, quic_collinsd@...cinc.com,
        quic_kamalw@...cinc.com, marijn.suijten@...ainline.org,
        andriy.shevchenko@...ux.intel.com,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Luca Weiss <luca@...tu.xyz>, linux-iio@...r.kernel.org,
        linux-arm-msm@...r.kernel.org
Cc:     linux-arm-msm-owner@...r.kernel.org
Subject: Re: [PATCH 06/11] iio: adc: Add QCOM PMIC5 Gen3 ADC bindings

On 23/10/2023 08:14, Jishnu Prakash wrote:
> Hi Krzysztof,
> 
> On 7/9/2023 10:53 PM, Krzysztof Kozlowski wrote:
>> On 08/07/2023 09:28, Jishnu Prakash wrote:
>>> For the PMIC5-Gen3 type PMICs, ADC peripheral is present in HW for the
>>> following PMICs: PMK8550, PM8550, PM8550B and PM8550VX PMICs.
>>> It is similar to PMIC5-Gen2, with SW communication to ADCs on all PMICs
>>> going through PBS firmware through a single register interface. This
>>> interface is implemented on an SDAM peripheral on the master PMIC PMK8550
>>> rather than a dedicated ADC peripheral.
>>>
>>> Signed-off-by: Jishnu Prakash <quic_jprakash@...cinc.com>
>>> ---
>>>   properties:
>>>     compatible:
>>> @@ -27,10 +27,11 @@ properties:
>>>             - qcom,spmi-adc5
>>>             - qcom,spmi-adc-rev2
>>>             - qcom,spmi-adc5-gen2
>>> +          - qcom,spmi-adc5-gen3
>>
>> This could be ordered...
> 
> 
> Yes, will do that in the next patchset.
> 
> 
>>>   
>>>     reg:
>>>       description: VADC base address in the SPMI PMIC register map
>>> -    maxItems: 1
>>> +    minItems: 1
>> Why? This does not make any sense. With previous patches it looks like
>> random set of changes.
> 
> 
> The idea here is to convey that reg can have multiple values for ADC5 
> Gen3 as there can be more than one peripheral used for ADC, so there can 
> be multiple base addresses. I'll try to make this more clear in the next 
> patchset.

You cannot remove constraints from an entry.

> 
> 
>>
>>
>>>   
>>>     '#address-cells':
>>>       const: 1
>>> @@ -38,6 +39,12 @@ properties:
>>>     '#size-cells':
>>>       const: 0
>>>   
>>>   
>>> +      qcom,adc-tm-type:
>>> +        description: |
>>> +            Indicates if ADC_TM monitoring is done on this channel.
>> Description does not match property name.
> 
> 
> You mean it sounds more like an enum which can take several values 
> rather than just a boolean? I can update it to "qcom,adc-tm" if that 
> looks better.

The property name suggests this is type of monitoring. Property
description says this will enable ADC_TM monitoring. These two do not match.

Except that I wonder now whether this is a property of hardware at
all... What is this monitoring? By the driver?

...

>>>       then:
>>>         patternProperties:
>>> @@ -299,7 +315,7 @@ examples:
>>>                   label = "xo_therm";
>>>               };
>>>   
>>> -            channel@47 {
>>> +            channel@147 {
>> Why?
> 
> 
> It would be needed if this channel number was supposed to be the virtual 
> channel number made by combining PMIC SID and actual channel 
> number....but I could drop it for now and do it in a separate fix as 
> Jonathan suggested.
> 
> 
>>
>>>                   reg = <PM8350_ADC5_GEN2_AMUX_THM4_100K_PU(1)>;
>>>                   qcom,ratiometric;
>>>                   qcom,hw-settle-time = <200>;
>>> @@ -307,3 +323,80 @@ examples:
>>>               };
>>>           };
>>>       };
>>> +
>>> +  - |
>>> +    #include <dt-bindings/iio/qcom,spmi-adc5-gen3-pmk8550.h>
>>> +    #include <dt-bindings/iio/qcom,spmi-adc5-gen3-pm8550.h>
>>> +    #include <dt-bindings/iio/qcom,spmi-adc5-gen3-pm8550b.h>
>>> +    #include <dt-bindings/iio/qcom,spmi-adc5-gen3-pm8550vx.h>
>>> +
>>> +    pmic {
>>> +      #address-cells = <1>;
>>> +      #size-cells = <0>;
>>> +
>>> +      /* VADC node */
>>> +      pmk8550_vadc: vadc@...0 {
>>> +        compatible = "qcom,spmi-adc5-gen3";
>> Don't add new examples which differ only in compatible.
> 
> 
> This example does have differences unique to ADC5 Gen3 such as use of 
> "#thermal-sensor-cells" and "qcom,adc-tm-type" properties....to make it 
> clearer, I'll delete some of the excess nodes which don't highlight 
> these differences.
> 
> 
>>
>>
>>> diff --git a/include/dt-bindings/iio/qcom,spmi-adc5-gen3-pm8550.h b/include/dt-bindings/iio/qcom,spmi-adc5-gen3-pm8550.h
>>> new file mode 100644
>>> index 000000000000..74e6e2f6f9ed
>>> --- /dev/null
>>> +++ b/include/dt-bindings/iio/qcom,spmi-adc5-gen3-pm8550.h
>>> @@ -0,0 +1,48 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> Dual license.
> 
> 
> I think we do have an internal rule by which we do have to add these two 
> licenses....I'll check again and update them if required.

Just to be clear: your internal rules are your internal affair. We
expect here dual license.

Best regards,
Krzysztof