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

Cosmin Tanislav
2022-10-17T07:01:15Z

On 10/14/22 18:37, Jonathan Cameron wrote:
> On Fri, 14 Oct 2022 15:37:23 +0300
> Cosmin Tanislav <demonsingur@gmail.com> 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.
>
> 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@analog.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@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
>
> 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:
>