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

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

[PATCH v3 0/5] iio: adc: ad4080: add support for AD4880 dual-channel ADC

[Antoniu Miclaus]

Add support for the AD4880, a dual-channel 20-bit 40MSPS SAR ADC from
the same family as AD4080.

The AD4880 has two independent ADC channels, each with its own SPI
configuration interface and LVDS data output. The driver uses
spi_new_ancillary_device() for the second channel's SPI and requires
two io-backend instances for the data interfaces.

This series includes:
  - SPI core fix to allow ancillary devices to share parent's chip selects
  - New devm_spi_new_ancillary_device() managed helper
  - Refactored devm_iio_backend_get_by_index() for multi-channel backend lookup
  - DT bindings update for AD4880
  - Driver support for AD4880

Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad4880.pdf

Changes in v3:
  - Drop redundant NULL check for info->parent in spi_dev_check()
  - Add new devm_spi_new_ancillary_device() managed helper (new patch)
  - Refactor iio backend: make __devm_iio_backend_fwnode_get() reuse
    __devm_iio_backend_fwnode_get_by_index() to avoid code duplication
  - Use __free(fwnode_handle) for automatic cleanup in backend code
  - Add items descriptions for io-backends in dt-bindings
  - Fix reg example format in dt-bindings
  - Use devm_spi_new_ancillary_device() instead of manual
    spi_new_ancillary_device() + devm_add_action_or_reset()
  - Generalize ancillary device setup with loop instead of
    hardcoding channel 1


Antoniu Miclaus (5):
  spi: allow ancillary devices to share parent's chip selects
  spi: add devm_spi_new_ancillary_device()
  iio: backend: add devm_iio_backend_get_by_index()
  dt-bindings: iio: adc: ad4080: add AD4880 support
  iio: adc: ad4080: add support for AD4880 dual-channel ADC

 .../bindings/iio/adc/adi,ad4080.yaml          |  54 +++-
 drivers/iio/adc/ad4080.c                      | 248 ++++++++++++++----
 drivers/iio/industrialio-backend.c            |  61 +++--
 drivers/spi/spi.c                             |  69 ++++-
 include/linux/iio/backend.h                   |   2 +
 include/linux/spi/spi.h                       |   1 +
 6 files changed, 357 insertions(+), 78 deletions(-)

-- 
2.43.0

[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

[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