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

[Cosmin Tanislav]

On 10/14/22 18:37, Jonathan Cameron wrote:
> On Fri, 14 Oct 2022 15:37:23 +0300
> Cosmin Tanislav <demonsingur@xxxxxxxxx> wrote:
>
> > From: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
> >
> > 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.
>
> If they 'work' but with fewer features, perhaps a fallback
> compatible?

10 channels vs 20 channels. Using ltc2983 compatible as fallback
would allow you to have 10 non-functional channels specified in the
dts.

> > The LTM2985 is software-compatible with the LTC2986.
>
> Fallback compatible?
>
> > Signed-off-by: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
> > ---
> >   .../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@xxxxxxxxxx>
> >   
> >   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
>
> Definitely a lesson here in avoiding device names in the descriptions!
>
> >         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@":
> > +    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
>
> Ah. This is a bit odd as it's fixed for the channel type.  However there
> is precedence in this binding so fair enough.

I think it

> > +
> > +      adi,single-ended:
> > +        description: Boolean property which sets the sensor as single-ended.
> > +        type: boolean
> > +
> > +      adi,custom-temp:
> > +        description:
> > +          This is a table, where each entry should be a pair of
> > +          voltage(mv)-temperature(K). The entries must be given in nv and uK
> > +          so that, the original values must be multiplied by 1000000. For
> > +          more details look at table 71 and 72.
> > +          Note should be signed, but dtc doesn't currently maintain the
> > +          sign.
> > +        $ref: /schemas/types.yaml#/definitions/uint64-matrix
> > +        minItems: 3
> > +        maxItems: 64
> > +        items:
> > +          minItems: 2
> > +          maxItems: 2
> > +
> > +    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: