Re: [PATCH v4 8/9] dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983

[Liviu Stan]

On Tue, 26 May 2026 17:55:49 +0100 Conor Dooley <conor@xxxxxxxxxx> wrote:

> On Mon, May 25, 2026 at 07:39:35PM +0300, Liviu Stan wrote:
> > The ADT7604 shares the same die as the LTC2984. It repurposes the
> > custom RTD sensor type (18) as a copper trace resistance sensor
> > and the custom thermistor type (27) as a leak detector, and
> > removes thermocouple, diode and direct ADC sensor types.
> > 
> > Add adi,adt7604 to the compatible list and introduce two new
> > sensor node types specific to this device:
> > 
> > - copper-trace@: maps to the custom RTD sensor type (18). Two
> > variants: sub-ohm (< 1 ohm, adi,copper-trace-sub-ohm boolean,
> > no custom table and excitation current) and standard (> 1 ohm,
> > required adi,custom-copper-trace table, optional excitation current
> > defaulting to the datasheet recommended value). Primary output
> > is resistance in ohms. For > 1 ohm copper traces with a custom table,
> > the chip also outputs temperature in millidegrees Celsius.
> > 
> > - leak-detector@: maps to the custom thermistor sensor type (27).
> > Takes a required adi,custom-leak-detector lookup table encoding
> > resistance (uOhm) against coverage data (%). Two outputs:
> > resistance in ohms and coverage in percent.
> > 
> > Separate node types are used rather than extending the existing
> > rtd@ and thermistor@ nodes because adi,custom-rtd is required
> > for sensor type 18, and several properties (adi,number-of-wires,
> > adi,rtd-curve, adi,rsense-share, adi,single-ended,
> > adi,current-rotate) have no meaning for the new sensor types, since
> > the configuration is hardcoded, and would need to be explicitly
> > forbidden or ignored in the driver.
> > 
> > allOf conditions are added to restrict thermocouple, diode, direct
> > ADC and active temperature nodes to non-ADT7604 devices, and to
> > restrict copper-trace and leak-detector nodes to the ADT7604
> > (some parts only).
> > 
> > Signed-off-by: Liviu Stan <liviu.stan@xxxxxxxxxx>
> 
> If this approach is acceptable to Jonathan, it is acceptable to me.
> Acked-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> pw-bot: not-applicable
> 

Thank you!

> > +            leak-detector@14 {
> > +                reg = <14>;
> > +                adi,sensor-type = <33>;
> > +                adi,rsense-handle = <&r_sense>;
> > +                adi,excitation-current-nanoamp = <10000>;
> > +                adi,custom-leak-detector =
> > +                    /bits/ 64 <          0 100>,
> > +                    /bits/ 64 <  202020000  99>,
> > +                    /bits/ 64 <  285710000  70>,
> > +                    /bits/ 64 <  333330000  60>,
> > +                    /bits/ 64 <  400000000  50>,
> > +                    /bits/ 64 <  500000000  40>,
> > +                    /bits/ 64 <  666670000  30>,
> > +                    /bits/ 64 < 1000000000  20>,
> > +                    /bits/ 64 < 2000000000  10>,
> > +                    /bits/ 64 <1000000000000 0>;
> 
> My OCD hates that you have gone to some effort with alignment here, only
> for this last line's first cell to scupper it completely.
> 

Sorry for this, I can fix it if necessary.

Thanks,
Liviu