Re: [PATCH 2/3] dt-bindings: iio: temperature: ltc2983: support more parts

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Mon, 17 Oct 2022 11:26:56 +0100
Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:

> On Mon, 17 Oct 2022 09:53:40 +0300
> Cosmin Tanislav <demonsingur@gmail.com> wrote:
> 
> > On 10/17/22 04:59, Krzysztof Kozlowski wrote:  
> > > On 14/10/2022 08:37, Cosmin Tanislav wrote:    
> > >> From: Cosmin Tanislav <cosmin.tanislav@analog.com>
> > >>
> > >> Add support for the following parts:
> > >>   * LTC2984
> > >>   * LTC2986
> > >>   * LTM2985
> > >>
> > >> The LTC2984 is a variant of the LTC2983 with EEPROM.
> > >> The LTC2986 is a variant of the LTC2983 with only 10 channels,
> > >> EEPROM and support for active analog temperature sensors.
> > >> The LTM2985 is software-compatible with the LTC2986.
> > >>
> > >> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>  
> 
> Cosmin,
> 
> Please take care to keep things polite. Krzysztof is reviewing an
> enormous number of bindings and is very helpful indeed. We should
> respect his feedback and respond appropriately. Sometimes what is
> 'obvious' to one person may need a clarifying comment or explanation
> for another.

Note I should have said we should respect ALL reviewers for taking
the time to look at our code.  Not just the particularly active ones!

Jonathan

> 
> Jonathan
> 
> 
> > >> ---
> > >>   .../bindings/iio/temperature/adi,ltc2983.yaml | 63 +++++++++++++++++--
> > >>   1 file changed, 59 insertions(+), 4 deletions(-)
> > >>
> > >> diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > >> index 722781aa4697..c33ab524fb64 100644
> > >> --- a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > >> +++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > >> @@ -4,19 +4,27 @@
> > >>   $id: http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
> > >>   $schema: http://devicetree.org/meta-schemas/core.yaml#
> > >>   
> > >> -title: Analog Devices LTC2983 Multi-sensor Temperature system
> > >> +title: Analog Devices LTC2983, LTC2986, LTM2985 Multi-sensor Temperature system
> > >>   
> > >>   maintainers:
> > >>     - Nuno Sá <nuno.sa@analog.com>
> > >>   
> > >>   description: |
> > >> -  Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
> > >> +  Analog Devices LTC2983, LTC2984, LTC2986, LTM2985 Multi-Sensor Digital
> > >> +  Temperature Measurement Systems
> > >> +
> > >>     https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
> > >> +  https://www.analog.com/media/en/technical-documentation/data-sheets/2984fb.pdf
> > >> +  https://www.analog.com/media/en/technical-documentation/data-sheets/29861fa.pdf
> > >> +  https://www.analog.com/media/en/technical-documentation/data-sheets/ltm2985.pdf
> > >>   
> > >>   properties:
> > >>     compatible:
> > >>       enum:
> > >>         - adi,ltc2983
> > >> +      - adi,ltc2984
> > >> +      - adi,ltc2986
> > >> +      - adi,ltm2985
> > >>   
> > >>     reg:
> > >>       maxItems: 1
> > >> @@ -26,7 +34,7 @@ properties:
> > >>   
> > >>     adi,mux-delay-config-us:
> > >>       description:
> > >> -      The LTC2983 performs 2 or 3 internal conversion cycles per temperature
> > >> +      The device performs 2 or 3 internal conversion cycles per temperature
> > >>         result. Each conversion cycle is performed with different excitation and
> > >>         input multiplexer configurations. Prior to each conversion, these
> > >>         excitation circuits and input switch configurations are changed and an
> > >> @@ -145,7 +153,7 @@ patternProperties:
> > >>         adi,three-conversion-cycles:
> > >>           description:
> > >>             Boolean property which set's three conversion cycles removing
> > >> -          parasitic resistance effects between the LTC2983 and the diode.
> > >> +          parasitic resistance effects between the device and the diode.
> > >>           type: boolean
> > >>   
> > >>         adi,average-on:
> > >> @@ -353,6 +361,41 @@ patternProperties:
> > >>           description: Boolean property which set's the adc as single-ended.
> > >>           type: boolean
> > >>   
> > >> +  "^temp@":    
> > > 
> > > There is already a property for thermocouple. Isn't a thermocouple a
> > > temperature sensor? IOW, why new property is needed?
> > >     
> > This node is needed for active analog temperature sensors.
> > It has fewer options than the thermocouple, as it only supports
> > a table to map from voltage to temperature and specifying whether
> > the measurement is differential or single-ended.
> > 
> > If you did as much as glimpsed at the datasheet you would have
> > understood.
> >   
> > >> +    type: object
> > >> +    description:
> > >> +      Represents a channel which is being used as an active analog temperature
> > >> +      sensor.
> > >> +
> > >> +    properties:
> > >> +      adi,sensor-type:
> > >> +        description:
> > >> +          Identifies the sensor as an active analog temperature sensor.
> > >> +        $ref: /schemas/types.yaml#/definitions/uint32
> > >> +        const: 31
> > >> +
> > >> +      adi,single-ended:
> > >> +        description: Boolean property which sets the sensor as single-ended.    
> > > 
> > > Drop "Boolean property which sets" - it's obvious from the type.
> > >     
> > 
> > That's how the rest of the file is written.
> >   
> > > 
> > >     
> > >> +        type: boolean
> > >> +
> > >> +      adi,custom-temp:
> > >> +        description:
> > >> +          This is a table, where each entry should be a pair of    
> > > 
> > > "This is a table" - obvious from the type.
> > >     
> > 
> > That's how the rest of the file is written.
> >   
> > >> +          voltage(mv)-temperature(K). The entries must be given in nv and uK    
> > > 
> > > mv-K or nv-uK? Confusing...    
> > 
> > That's how the rest of the file is written.
> > 
> > The chip uses mv-K, but the binding specifies nv-uK, the driver
> > translates it into the appropriate unit.
> >   
> > >     
> > >> +          so that, the original values must be multiplied by 1000000. For
> > >> +          more details look at table 71 and 72.    
> > > 
> > > There is no table 71 in the bindings... It seems you pasted it from
> > > somewhere.
> > >     
> > 
> > It's pretty obvious that "Table" in a binding refers to the datasheet.
> > But if you meant datasheet, not binding, you're looking at the wrong
> > datasheet then.
> > Also, that's how the rest of the file is written.
> >   
> > >> +          Note should be signed, but dtc doesn't currently maintain the
> > >> +          sign.    
> > > 
> > > What do you mean? "Maintain" as allow or keep when building FDT?  What's
> > > the problem of using negative numbers here and why it should be part of
> > > bindings?
> > >     
> > 
> > You're really clueless, I'll let you figure it out on your own.
> > Also, that's how the rest of the file is written.  
> 
> >   
> > >> +        $ref: /schemas/types.yaml#/definitions/uint64-matrix
> > >> +        minItems: 3
> > >> +        maxItems: 64
> > >> +        items:
> > >> +          minItems: 2
> > >> +          maxItems: 2    
> > > 
> > > Instead describe the items with "description" (and maybe constraints)
> > > like here:
> > > 
> > > https://elixir.bootlin.com/linux/v5.19/source/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml#L278
> > >     
> > 
> > That's how the rest of the file is written.
> > If you really want to use something different, you can submit a
> > patch later and fix the whole binding however you want.
> >   
> > >> +
> > >> +    required:
> > >> +      - adi,custom-temp
> > >> +
> > >>     "^rsense@":
> > >>       type: object
> > >>       description:
> > >> @@ -382,6 +425,18 @@ required:
> > >>     - reg
> > >>     - interrupts
> > >>   
> > >> +allOf:
> > >> +  - if:
> > >> +      properties:
> > >> +        compatible:
> > >> +          contains:
> > >> +            enum:
> > >> +              - adi,ltc2983
> > >> +              - adi,ltc2984
> > >> +    then:
> > >> +      patternProperties:
> > >> +        "^temp@": false
> > >> +
> > >>   additionalProperties: false
> > >>   
> > >>   examples:    
> > > 
> > > Best regards,
> > > Krzysztof
> > >     
> 
>