[PATCH v3 4/5] dt-bindings: iio: adc: ad4080: add AD4880 support

[PATCH v3 4/5] dt-bindings: iio: adc: ad4080: add AD4880 support

[Antoniu Miclaus]

Add support for the AD4880, a dual-channel 20-bit 40MSPS SAR ADC
with integrated fully differential amplifiers (FDA).

The AD4880 has two independent ADC channels, each with its own SPI
configuration interface. This requires:
- Two entries in reg property for primary and secondary channel
  chip selects
- Two io-backends entries for the two data channels

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
Changes in v3:
  - Add items descriptions for io-backends entries
  - Fix reg example format: reg = <0 1> -> reg = <0>, <1>

 .../bindings/iio/adc/adi,ad4080.yaml          | 54 ++++++++++++++++++-
 1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4080.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4080.yaml
index ccd6a0ac1539..871bbdd7e1ce 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad4080.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4080.yaml
@@ -18,7 +18,11 @@ description: |
   service a wide variety of precision, wide bandwidth data acquisition
   applications.
 
+  The AD4880 is a dual-channel variant with two independent ADC channels,
+  each with its own SPI configuration interface.
+
   https://www.analog.com/media/en/technical-documentation/data-sheets/ad4080.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ad4880.pdf
 
 $ref: /schemas/spi/spi-peripheral-props.yaml#
 
@@ -31,9 +35,15 @@ properties:
       - adi,ad4084
       - adi,ad4086
       - adi,ad4087
+      - adi,ad4880
 
   reg:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
+    description:
+      SPI chip select(s). For single-channel devices, one chip select.
+      For multi-channel devices like AD4880, two chip selects are required
+      as each channel has its own SPI configuration interface.
 
   spi-max-frequency:
     description: Configuration of the SPI bus.
@@ -57,7 +67,11 @@ properties:
   vrefin-supply: true
 
   io-backends:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
+    items:
+      - description: Backend for channel A (primary)
+      - description: Backend for channel B (secondary)
 
   adi,lvds-cnv-enable:
     description: Enable the LVDS signal type on the CNV pin. Default is CMOS.
@@ -78,6 +92,25 @@ required:
   - vdd33-supply
   - vrefin-supply
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: adi,ad4880
+    then:
+      properties:
+        reg:
+          minItems: 2
+        io-backends:
+          minItems: 2
+    else:
+      properties:
+        reg:
+          maxItems: 1
+        io-backends:
+          maxItems: 1
+
 additionalProperties: false
 
 examples:
@@ -98,4 +131,21 @@ examples:
           io-backends = <&iio_backend>;
         };
     };
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+          compatible = "adi,ad4880";
+          reg = <0>, <1>;
+          spi-max-frequency = <10000000>;
+          vdd33-supply = <&vdd33>;
+          vddldo-supply = <&vddldo>;
+          vrefin-supply = <&vrefin>;
+          clocks = <&cnv>;
+          clock-names = "cnv";
+          io-backends = <&iio_backend_cha>, <&iio_backend_chb>;
+        };
+    };
 ...
-- 
2.43.0

Re: [PATCH v3 4/5] dt-bindings: iio: adc: ad4080: add AD4880 support

[Rob Herring (Arm)]

On Fri, 13 Feb 2026 16:47:36 +0200, Antoniu Miclaus wrote:
> Add support for the AD4880, a dual-channel 20-bit 40MSPS SAR ADC
> with integrated fully differential amplifiers (FDA).
> 
> The AD4880 has two independent ADC channels, each with its own SPI
> configuration interface. This requires:
> - Two entries in reg property for primary and secondary channel
>   chip selects
> - Two io-backends entries for the two data channels
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
> Changes in v3:
>   - Add items descriptions for io-backends entries
>   - Fix reg example format: reg = <0 1> -> reg = <0>, <1>
> 
>  .../bindings/iio/adc/adi,ad4080.yaml          | 54 ++++++++++++++++++-
>  1 file changed, 52 insertions(+), 2 deletions(-)
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/iio/adc/adi,ad4080.yaml: properties:io-backends: {'minItems': 1, 'maxItems': 2, 'items': [{'description': 'Backend for channel A (primary)'}, {'description': 'Backend for channel B (secondary)'}]} should not be valid under {'required': ['maxItems']}
	hint: "maxItems" is not needed with an "items" list
	from schema $id: http://devicetree.org/meta-schemas/items.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.kernel.org/project/devicetree/patch/20260213144742.16394-5-antoniu.miclaus@analog.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH v3 4/5] dt-bindings: iio: adc: ad4080: add AD4880 support

[kernel test robot]

:::::: 
:::::: Manual check reason: "dtcheck: binding changes may go via different trees"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20260213144742.16394-5-antoniu.miclaus@analog.com>
References: <20260213144742.16394-5-antoniu.miclaus@analog.com>
TO: Antoniu Miclaus <antoniu.miclaus@analog.com>
TO: "Lars-Peter Clausen" <lars@metafoo.de>
TO: Michael Hennerich <Michael.Hennerich@analog.com>
TO: Antoniu Miclaus <antoniu.miclaus@analog.com>
TO: Jonathan Cameron <jic23@kernel.org>
TO: David Lechner <dlechner@baylibre.com>
TO: "Nuno Sá" <nuno.sa@analog.com>
TO: Andy Shevchenko <andy@kernel.org>
TO: Rob Herring <robh@kernel.org>
TO: Krzysztof Kozlowski <krzk@kernel.org>
TO: Conor Dooley <conor+dt@kernel.org>
TO: Olivier Moysan <olivier.moysan@foss.st.com>
TO: Mark Brown <broonie@kernel.org>
TO: linux-iio@vger.kernel.org
TO: devicetree@vger.kernel.org
TO: linux-kernel@vger.kernel.org
TO: linux-spi@vger.kernel.org

Hi Antoniu,

kernel test robot noticed the following build warnings:

[auto build test WARNING on jic23-iio/togreg]
[also build test WARNING on broonie-spi/for-next linus/master v6.19 next-20260213]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Antoniu-Miclaus/spi-allow-ancillary-devices-to-share-parent-s-chip-selects/20260213-225621
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
patch link:    https://lore.kernel.org/r/20260213144742.16394-5-antoniu.miclaus%40analog.com
patch subject: [PATCH v3 4/5] dt-bindings: iio: adc: ad4080: add AD4880 support
:::::: branch date: 11 hours ago
:::::: commit date: 11 hours ago
config: arc-randconfig-2051-20260213 (https://download.01.org/0day-ci/archive/20260214/202602140208.PyZVLhoN-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 8.5.0
dtschema: 2025.13.dev7+gd16dc68b0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260214/202602140208.PyZVLhoN-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202602140208.PyZVLhoN-lkp@intel.com/

dtcheck warnings: (new ones prefixed by >>)
   Documentation/devicetree/bindings/hwmon/sensirion,shtc1.yaml: maintainers:0: 'Christopher Ruehl chris.ruehl@gtsys.com.hk' does not match '^(.+ <[\\S]+@[\\S]+>|[\\S]+@[\\S]+)$'
   	from schema $id: http://devicetree.org/meta-schemas/base.yaml
>> Documentation/devicetree/bindings/iio/adc/adi,ad4080.yaml: properties:io-backends: {'minItems': 1, 'maxItems': 2, 'items': [{'description': 'Backend for channel A (primary)'}, {'description': 'Backend for channel B (secondary)'}]} should not be valid under {'required': ['maxItems']}
   	hint: "maxItems" is not needed with an "items" list
   	from schema $id: http://devicetree.org/meta-schemas/items.yaml
   Documentation/devicetree/bindings/input/syna,rmi4.yaml: maintainers:1: 'Matthias Schiffer <matthias.schiffer@ew.tq-group.com' does not match '^(.+ <[\\S]+@[\\S]+>|[\\S]+@[\\S]+)$'
   	from schema $id: http://devicetree.org/meta-schemas/base.yaml
   Documentation/devicetree/bindings/pci/mbvl,gpex40-pcie.yaml: maintainers:0: 'Frank Li <Frank Li@nxp.com>' does not match '^(.+ <[\\S]+@[\\S]+>|[\\S]+@[\\S]+)$'
   	from schema $id: http://devicetree.org/meta-schemas/base.yaml
   Documentation/devicetree/bindings/media/samsung,exynos5250-gsc.yaml: maintainers:2: 'Seung-Woo Kim <sw0312.kim@samsung.com' does not match '^(.+ <[\\S]+@[\\S]+>|[\\S]+@[\\S]+)$'
   	from schema $id: http://devicetree.org/meta-schemas/base.yaml

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v3 4/5] dt-bindings: iio: adc: ad4080: add AD4880 support

[Krzysztof Kozlowski]

On 13/02/2026 15:47, Antoniu Miclaus wrote:
> Add support for the AD4880, a dual-channel 20-bit 40MSPS SAR ADC
> with integrated fully differential amplifiers (FDA).
> 
> The AD4880 has two independent ADC channels, each with its own SPI
> configuration interface. This requires:
> - Two entries in reg property for primary and secondary channel
>   chip selects
> - Two io-backends entries for the two data channels
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
> Changes in v3:
>   - Add items descriptions for io-backends entries
>   - Fix reg example format: reg = <0 1> -> reg = <0>, <1>

Not tested.

Best regards,
Krzysztof