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

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Message-ID: <20221017112210.00002c17@huawei.com>
Date:   Mon, 17 Oct 2022 11:22:10 +0100
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     Cosmin Tanislav <demonsingur@...il.com>
CC:     Nuno Sá <nuno.sa@...log.com>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Michael Hennerich <Michael.Hennerich@...log.com>,
        "Jonathan Cameron" <jic23@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@...aro.org>,
        <linux-iio@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Cosmin Tanislav <cosmin.tanislav@...log.com>
Subject: Re: [PATCH 2/3] dt-bindings: iio: temperature: ltc2983: support
 more parts

On Mon, 17 Oct 2022 10:01:03 +0300
Cosmin Tanislav <demonsingur@...il.com> wrote:

> On 10/14/22 18:37, Jonathan Cameron wrote:
> > On Fri, 14 Oct 2022 15:37:23 +0300
> > Cosmin Tanislav <demonsingur@...il.com> wrote:
> >   
> >> From: Cosmin Tanislav <cosmin.tanislav@...log.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.  
> > 
> > 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.

Ah. That one probably doesn't make sense then.  The 2984?

> 
> >> The LTM2985 is software-compatible with the LTC2986.  
> > 
> > Fallback compatible?
> >   
> >>
> >> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@...log.com>
> >> ---
> >>   .../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@...log.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  
> > 
> > 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:  
> >