Re: [PATCH v3 7/8] dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983

Re: [PATCH v3 7/8] dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983

[Liviu Stan]

On Thu, 21 May 2026 18:23:07 +0000 sashiko-bot@kernel.org wrote:

> Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
> - [Low] The new compatible string 'adi,adt7604' is omitted from the existing conditional block that disables '^temp@' nodes, violating subsystem guidelines.
> - [Low] The schema allows invalid 'adi,sensor-type' values in '^rtd@' and '^thermistor@' nodes for the ADT7604.
> --
> 
> commit fbbcd3bcbfbb106e48a6545868dd2b27a56b39b5
> Author: Liviu Stan <liviu.stan@analog.com>
> 
> dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983
> 
> This commit adds support for the ADT7604 to the LTC2983 binding schema. It
> introduces the adi,adt7604 compatible string and adds two new sensor node
> types: copper-trace@ and leak-detector@. It also adds conditional checks to
> restrict unsupported nodes for the ADT7604 device.
> 
> > diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > index a22725f7619b7..14cfa28809edd 100644
> > --- a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > +++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> [ ... ]
> > @@ -477,6 +597,22 @@ allOf:
> >        patternProperties:
> >          '^temp@': false
> >  
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            const: adi,adt7604
> > +    then:
> > +      patternProperties:
> > +        '^thermocouple@': false
> > +        '^diode@': false
> > +        '^adc@': false
> > +        '^temp@': false
> 
> [Severity: Low]
> Since ADT7604 shares the ^temp@: false constraint with the existing devices,
> should adi,adt7604 be added to the existing compatible enum block instead of
> duplicating the ^temp@ restriction in this new conditional?

I think keeping all ADT7604 related constraints in one block is more readable.
For the block above it's different because ltc2984 and ltc2983 share the same
constraints.

> 
> [Severity: Low]
> The commit message mentions that ADT7604 repurposes the custom RTD sensor type
> (18) and custom thermistor type (27).
> 
> However, the schema doesn't restrict adi,sensor-type = <18> inside ^rtd@ nodes
> or adi,sensor-type = <27> inside ^thermistor@ nodes for the adi,adt7604
> compatible.
> 
> Should these restrictions be added to this block to prevent invalid device
> tree configurations from passing validation?
> 

This makes sense, we could restrict sensor type 18 and 27 for the ADT7604, even
though the driver's supported_sensors bitmask already rejects them.

I could add something like:

- if:
    properties:
      compatible:
        contains:
          const: adi,adt7604
  then:
    patternProperties:
      '^thermocouple@': false
      '^diode@': false
      '^adc@': false
      '^temp@': false
      '^rtd@':
        properties:
          adi,sensor-type:
            not:
              const: 18
      '^thermistor@':
        properties:
          adi,sensor-type:
            not:
              const: 27

What do you think?

Thanks,
Liviu

Re: [PATCH v3 7/8] dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983

[Jonathan Cameron]

On Fri, 22 May 2026 14:42:53 +0300
Liviu Stan <liviu.stan@analog.com> wrote:

> On Thu, 21 May 2026 18:23:07 +0000 sashiko-bot@kernel.org wrote:
> 
> > Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
> > - [Low] The new compatible string 'adi,adt7604' is omitted from the existing conditional block that disables '^temp@' nodes, violating subsystem guidelines.
> > - [Low] The schema allows invalid 'adi,sensor-type' values in '^rtd@' and '^thermistor@' nodes for the ADT7604.
> > --
> > 
> > commit fbbcd3bcbfbb106e48a6545868dd2b27a56b39b5
> > Author: Liviu Stan <liviu.stan@analog.com>
> > 
> > dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983
> > 
> > This commit adds support for the ADT7604 to the LTC2983 binding schema. It
> > introduces the adi,adt7604 compatible string and adds two new sensor node
> > types: copper-trace@ and leak-detector@. It also adds conditional checks to
> > restrict unsupported nodes for the ADT7604 device.
> >   
> > > diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > > index a22725f7619b7..14cfa28809edd 100644
> > > --- a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > > +++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml  
> > [ ... ]  
> > > @@ -477,6 +597,22 @@ allOf:
> > >        patternProperties:
> > >          '^temp@': false
> > >  
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            const: adi,adt7604
> > > +    then:
> > > +      patternProperties:
> > > +        '^thermocouple@': false
> > > +        '^diode@': false
> > > +        '^adc@': false
> > > +        '^temp@': false  
> > 
> > [Severity: Low]
> > Since ADT7604 shares the ^temp@: false constraint with the existing devices,
> > should adi,adt7604 be added to the existing compatible enum block instead of
> > duplicating the ^temp@ restriction in this new conditional?  
> 
> I think keeping all ADT7604 related constraints in one block is more readable.
> For the block above it's different because ltc2984 and ltc2983 share the same
> constraints.

Agreed

> 
> > 
> > [Severity: Low]
> > The commit message mentions that ADT7604 repurposes the custom RTD sensor type
> > (18) and custom thermistor type (27).
> > 
> > However, the schema doesn't restrict adi,sensor-type = <18> inside ^rtd@ nodes
> > or adi,sensor-type = <27> inside ^thermistor@ nodes for the adi,adt7604
> > compatible.
> > 
> > Should these restrictions be added to this block to prevent invalid device
> > tree configurations from passing validation?
> >   
> 
> This makes sense, we could restrict sensor type 18 and 27 for the ADT7604, even
> though the driver's supported_sensors bitmask already rejects them.
> 
> I could add something like:
> 
> - if:
>     properties:
>       compatible:
>         contains:
>           const: adi,adt7604
>   then:
>     patternProperties:
>       '^thermocouple@': false
>       '^diode@': false
>       '^adc@': false
>       '^temp@': false
>       '^rtd@':
>         properties:
>           adi,sensor-type:
>             not:
>               const: 18
>       '^thermistor@':
>         properties:
>           adi,sensor-type:
>             not:
>               const: 27
> 
> What do you think?
> 
Seems like a nice to have.

> Thanks,
> Liviu
> 

[PATCH v3 0/8] iio: temperature: ltc2983: Add support for ADT7604

[Liviu Stan]

This series adds support for the ADT7604 multi-sensor temperature
measurement and leak detection system to the existing ltc2983 driver.

The ADT7604 shares the same die as the LTC2984, reusing its register
map and SPI interface. It repurposes the custom RTD sensor type (18)
as a copper trace resistance sensor and the custom thermistor type (27)
as a leak detector, removing thermocouple, diode and direct ADC support.

Patches 1-5 fix pre-existing bugs in the ltc2983 driver: macro
parenthesization and renaming, inconsistent use of the local device
pointer, inconsistent channel wording in log messages, missing
fwnode_property_present() guards for optional properties, and an
n_wires default that silently bypassed the current-rotate validation.

Patch 6 adds IIO_COVERAGE, a new channel type for sensors reporting
fractional surface coverage as a percentage.

Patch 7 updates the device tree bindings: adds adi,adt7604 compatible,
copper-trace@ and leak-detector@ sensor node types with their respective
properties, and an ADT7604 example.

Patch 8 updates the driver: introduces two new software sensor type
values (LTC2983_SENSOR_COPPER_TRACE = 32, LTC2983_SENSOR_LEAK_DETECTOR
= 33) with dedicated structs and parser functions rather than extending
the existing RTD and thermistor paths. The hardware configuration bits
are fully hardcoded for both sensor types, and several RTD/thermistor
DT properties have no meaning for them. A u64 supported_sensors bitmask
in ltc2983_chip_info gates sensor type validation per chip, replacing
the has_temp bool pattern. BIT_ULL() is used for the new type values
at bits 32 and 33 to avoid shifting beyond 32 bits on 32-bit builds.

Tested on EVAL-ADT7604-AZ connected to Raspberry Pi 5 via SPI.

Changes in v3:

Patch 1 - macro parenthesization and rename:
- Dropped the Fixes: tag
- Removed the "base" parameter from ADT7604_RES_RES_ADDR(); the resistance
  result memory region is (currently) ADT7604-specific so the macro's
  modification belongs in the driver patch

Patch 2 - use local device pointer consistently:
- Dropped the Fixes: tag
- Fixed one remaining dev_dbg() call in __ltc2983_chan_assign_common()
  that was still using the raw device pointer instead of the dev local
  variable introduced by this patch

Patch 3 - fix inconsistent channel wording in messages:
- Dropped both Fixes: tags
- Removed the "all" from "all occurrences" in the commit message
- Fixed some missed "chan" / "chann" occurrences

Patch 4 - use fwnode_property_present() for optional properties:
- Dropped the Fixes: tag
- Fixed other occurrences brought up by sashiko

Patch 5 - Fix n_wires default bypassing rotation check:
- New patch

Patch 6 - IIO_COVERAGE channel type:
- Renamed the sysfs attribute from in_coveragepercentX_raw to
  in_coverageX_raw
- Added a _scale ABI documentation entry
- Corrected KernelVersion in the ABI documentation from 6.15 to 7.2
- Added IIO_COVERAGE to the event_is_known() switch in
  tools/iio/iio_event_monitor.c

Patch 7 - DT bindings:
- Changed the custom leak detector table encoding, users now specify
  plain coverage percentage values (0-100) in the device tree and the
  driver applies the +273.15 C offset internally before writing the
  hardware table
- Changed custom-rtd to custom-copper-trace to better represent the
  copper trace custom table, and made it required for > 1 ohm variants
- Made custom-leak-detector required for leak detector sensors
- Updated commit message to reflect the changes
- Updated leak detector node description
- Updated adi,custom-leak-detector description
- Modified the example leak detector custom table to match the datasheet

Patch 8 - driver:
- Relocated the "base" parameter addition from patch 1 to this one since
  the resistance result memory region is (currently) ADT7604-specific
- Updated the commit message to mention the base and base_reg parameters
  added to the result-bank read helpers
- Stacked the IIO_RESISTANCE and IIO_COVERAGE case labels in
  ltc2983_read_raw()
- Added LTC2983_SENSOR_NUM sentinel at the end of the sensor-type enum
- Changed the sensor-type bounds check from > LTC2983_SENSOR_LEAK_DETECTOR
  to >= LTC2983_SENSOR_NUM
- Reordered the ltm2985_chip_info_data struct initializer so has_eeprom
  doesn't look like it was added to the ltm2985 in the diff
- Changed the custom leak detector table encoding, users now specify
  plain coverage percentage values (0-100) in the device tree and the
  driver applies the +273.15 C offset internally before writing the
  hardware table
- Changed custom-rtd to custom-copper-trace to better represent the
  copper trace custom table, and made it required for > 1 ohm variants
- Made custom-leak-detector required for leak detector sensors, _new
  and _assign_chan functions were updated for both sensor types
- Updated commit message to reflect the changes
- Removed "..." from "rsense channel must be configured" error message
  from ltc2983_leak_detector_new()
- Removed blank line before hw_type declaration in
  __ltc2983_chan_assign_common

Liviu Stan (8):
  iio: temperature: ltc2983: Fix macro parenthesization and rename
  iio: temperature: ltc2983: Use local device pointer consistently
  iio: temperature: ltc2983: Fix inconsistent channel wording in
    messages
  iio: temperature: ltc2983: Use fwnode_property_present() for optional
    properties
  iio: temperature: ltc2983: Fix n_wires default bypassing rotation
    check
  iio: core: Add IIO_COVERAGE channel type
  dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983
  iio: temperature: ltc2983: Add support for ADT7604

 Documentation/ABI/testing/sysfs-bus-iio       |  17 +
 .../bindings/iio/temperature/adi,ltc2983.yaml | 207 +++++-
 drivers/iio/industrialio-core.c               |   1 +
 drivers/iio/temperature/ltc2983.c             | 614 +++++++++++++++---
 include/uapi/linux/iio/types.h                |   1 +
 tools/iio/iio_event_monitor.c                 |   2 +
 6 files changed, 741 insertions(+), 101 deletions(-)

-- 
2.43.0

[PATCH v3 7/8] dt-bindings: iio: temperature: Add ADT7604 support to adi,ltc2983

[Liviu Stan]

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@analog.com>
---
Changes in v3:
- Changed the custom leak detector table encoding, users now specify
  plain coverage percentage values (0-100) in the device tree and the
  driver applies the +273.15 C offset internally before writing the
  hardware table
- Changed custom-rtd to custom-copper-trace to better represent the
  copper trace custom table, and made it required for > 1 ohm variants
- Made custom-leak-detector required for leak detector sensors
- Updated commit message to reflect the changes
- Updated leak detector node description
- Updated adi,custom-leak-detector description
- Modified the example leak detector custom table to match the datasheet

 .../bindings/iio/temperature/adi,ltc2983.yaml | 207 +++++++++++++++++-
 1 file changed, 204 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
index a22725f7619b..14cfa28809ed 100644
--- a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
+++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
@@ -4,14 +4,18 @@
 $id: http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Analog Devices LTC2983, LTC2986, LTM2985 Multi-sensor Temperature system
+title: Analog Devices LTC2983 and similar Multi-sensor Temperature systems
 
 maintainers:
   - Nuno Sá <nuno.sa@analog.com>
 
 description: |
-  Analog Devices LTC2983, LTC2984, LTC2986, LTM2985 Multi-Sensor Digital
-  Temperature Measurement Systems
+  Analog Devices Multi-Sensor Digital Temperature Measurement Systems:
+    - ADT7604
+    - LTC2983
+    - LTC2984
+    - LTC2986
+    - LTM2985
 
   https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
   https://www.analog.com/media/en/technical-documentation/data-sheets/2984fb.pdf
@@ -43,6 +47,7 @@ properties:
   compatible:
     oneOf:
       - enum:
+          - adi,adt7604
           - adi,ltc2983
           - adi,ltc2986
           - adi,ltm2985
@@ -436,6 +441,121 @@ patternProperties:
     required:
       - adi,custom-temp
 
+  '^copper-trace@':
+    $ref: '#/$defs/sensor-node'
+    unevaluatedProperties: false
+    description: |
+      Copper trace resistance sensor (some parts only). Two variants exist:
+      sub-ohm (< 1 ohm, no custom table allowed) and standard (> 1 ohm,
+      required custom table).
+
+    properties:
+      reg:
+        minimum: 2
+        maximum: 20
+
+      adi,sensor-type:
+        description: Sensor type for copper trace sensors.
+        $ref: /schemas/types.yaml#/definitions/uint32
+        const: 32
+
+      adi,rsense-handle:
+        description: Associated sense resistor sensor.
+        $ref: /schemas/types.yaml#/definitions/phandle
+
+      adi,copper-trace-sub-ohm:
+        description:
+          Select the sub-ohm (< 1 ohm) copper trace variant. Custom table
+          and excitation current are not allowed in this mode.
+        type: boolean
+
+      adi,excitation-current-microamp:
+        description:
+          Excitation current applied to the copper trace. Not used in
+          sub-ohm mode. The datasheet recommends 1mA for copper trace
+          sensors due to their typically small resistance.
+        enum: [5, 10, 25, 50, 100, 250, 500, 1000]
+        default: 1000
+
+      adi,custom-copper-trace:
+        description:
+          Resistance-to-temperature table for copper trace sensors with
+          resistance > 1 ohm. Required when adi,copper-trace-sub-ohm is not
+          set. See Page 36 of the datasheet.
+        $ref: /schemas/types.yaml#/definitions/uint64-matrix
+        minItems: 3
+        maxItems: 64
+        items:
+          items:
+            - description: Resistance point in uOhms.
+            - description: Temperature point in uK.
+
+    required:
+      - adi,rsense-handle
+
+    allOf:
+      - if:
+          required:
+            - adi,copper-trace-sub-ohm
+        then:
+          properties:
+            adi,custom-copper-trace: false
+            adi,excitation-current-microamp: false
+      - if:
+          not:
+            required:
+              - adi,copper-trace-sub-ohm
+        then:
+          required:
+            - adi,custom-copper-trace
+
+  '^leak-detector@':
+    $ref: '#/$defs/sensor-node'
+    unevaluatedProperties: false
+    description: |
+      Leak detector sensor (some parts only). Outputs resistance in ohms and
+      a coverage percentage via IIO_COVERAGE (raw/1024 = coverage %).
+
+    properties:
+      reg:
+        minimum: 2
+        maximum: 20
+
+      adi,sensor-type:
+        description: Sensor type for leak detector sensors.
+        $ref: /schemas/types.yaml#/definitions/uint32
+        const: 33
+
+      adi,rsense-handle:
+        description: Associated sense resistor sensor.
+        $ref: /schemas/types.yaml#/definitions/phandle
+
+      adi,excitation-current-nanoamp:
+        description:
+          Excitation current applied to the leak detector. The correct value
+          depends on the electrical characteristics of the liquid being sensed.
+          For example, 10000 (10µA) is recommended for PG25 (see datasheet
+          Table 39).
+        enum: [250, 500, 1000, 5000, 10000, 25000, 50000, 100000, 250000,
+               500000, 1000000]
+
+      adi,custom-leak-detector:
+        description: |
+          Lookup table mapping resistance to coverage percentage. Entries must
+          be in ascending resistance order.
+        $ref: /schemas/types.yaml#/definitions/uint64-matrix
+        minItems: 3
+        maxItems: 64
+        items:
+          items:
+            - description: Resistance point in uOhms.
+            - description: Coverage data percentage (0 to 100).
+
+    required:
+      - adi,rsense-handle
+      - adi,excitation-current-nanoamp
+      - adi,custom-leak-detector
+
   '^rsense@':
     $ref: '#/$defs/sensor-node'
     unevaluatedProperties: false
@@ -477,6 +597,22 @@ allOf:
       patternProperties:
         '^temp@': false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: adi,adt7604
+    then:
+      patternProperties:
+        '^thermocouple@': false
+        '^diode@': false
+        '^adc@': false
+        '^temp@': false
+    else:
+      patternProperties:
+        '^copper-trace@': false
+        '^leak-detector@': false
+
 examples:
   - |
     #include <dt-bindings/interrupt-controller/irq.h>
@@ -556,4 +692,69 @@ examples:
             };
         };
     };
+
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        temperature-sensor@0 {
+            compatible = "adi,adt7604";
+            reg = <0>;
+            interrupt-parent = <&gpio>;
+            interrupts = <25 IRQ_TYPE_EDGE_RISING>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+            vdd-supply = <&supply>;
+
+            trace_rsense: rsense@2 {
+                reg = <2>;
+                adi,sensor-type = <29>;
+                adi,rsense-val-milli-ohms = <100000>; // 100 ohm
+            };
+
+            copper-trace@4 {
+                reg = <4>;
+                adi,sensor-type = <32>;
+                adi,rsense-handle = <&trace_rsense>;
+                adi,copper-trace-sub-ohm;
+            };
+
+            r_sense: rsense@12 {
+                reg = <12>;
+                adi,sensor-type = <29>;
+                adi,rsense-val-milli-ohms = <1000000>; // 1 kohm
+            };
+
+            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>;
+            };
+
+            rtd@18 {
+                reg = <18>;
+                adi,sensor-type = <12>; // PT100
+                adi,rsense-handle = <&r_sense>;
+                adi,number-of-wires = <2>;
+                adi,rsense-share;
+                adi,excitation-current-microamp = <500>;
+                adi,rtd-curve = <0>;
+            };
+        };
+    };
 ...
-- 
2.43.0