[PATCH v2] dt-bindings: iio: adc: Convert xilinx-xadc bindings to YAML schema

[PATCH v2] dt-bindings: iio: adc: Convert xilinx-xadc bindings to YAML schema

[Pramod Maurya]

Convert the Xilinx XADC and UltraScale System Monitor device tree binding
from the legacy plain-text format to a YAML schema, enabling automated
validation with dt-schema.

The new binding covers the same hardware and compatible strings:
  - xlnx,zynq-xadc-1.00.a (ZYNQ hardmacro)
  - xlnx,axi-xadc-1.00.a  (AXI softmacro)
  - xlnx,system-management-wiz-1.3 (UltraScale System Management Wizard)

Signed-off-by: Pramod Maurya <pramod.nexgen@gmail.com>
---
Changes in v2:
- Fix patternProperties regex to use lowercase hex unit addresses
  (channel@a through channel@f) instead of decimal; correct range
  is now "^channel@([0-9a-f]|10)$"
- Add allOf/if/then conditional to enforce xlnx,external-mux-channel
  is required when xlnx,external-mux is "single" or "dual"

 .../bindings/iio/adc/xilinx-xadc.txt          | 141 ------------
 .../bindings/iio/adc/xlnx,xadc.yaml           | 204 ++++++++++++++++++
 MAINTAINERS                                   |   7 +
 3 files changed, 211 insertions(+), 141 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/iio/adc/xilinx-xadc.txt
 create mode 100644 Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/xilinx-xadc.txt b/Documentation/devicetree/bindings/iio/adc/xilinx-xadc.txt
deleted file mode 100644
index f42e18078376..000000000000
--- a/Documentation/devicetree/bindings/iio/adc/xilinx-xadc.txt
+++ /dev/null
@@ -1,141 +0,0 @@
-Xilinx XADC device driver
-
-This binding document describes the bindings for the Xilinx 7 Series XADC as well
-as the UltraScale/UltraScale+ System Monitor.
-
-The Xilinx XADC is an ADC that can be found in the Series 7 FPGAs from Xilinx.
-The XADC has a DRP interface for communication. Currently two different
-frontends for the DRP interface exist. One that is only available on the ZYNQ
-family as a hardmacro in the SoC portion of the ZYNQ. The other one is available
-on all series 7 platforms and is a softmacro with a AXI interface. This binding
-document describes the bindings for both of them since the bindings are very
-similar.
-
-The Xilinx System Monitor is an ADC that is found in the UltraScale and
-UltraScale+ FPGAs from Xilinx. The System Monitor provides a DRP interface for
-communication. Xilinx provides a standard IP core that can be used to access the
-System Monitor through an AXI interface in the FPGA fabric. This IP core is
-called the Xilinx System Management Wizard. This document describes the bindings
-for this IP.
-
-Required properties:
-	- compatible: Should be one of
-		* "xlnx,zynq-xadc-1.00.a": When using the ZYNQ device
-		  configuration interface to interface to the XADC hardmacro.
-		* "xlnx,axi-xadc-1.00.a": When using the axi-xadc pcore to
-		  interface to the XADC hardmacro.
-		* "xlnx,system-management-wiz-1.3": When using the
-		  Xilinx System Management Wizard fabric IP core to access the
-		  UltraScale and UltraScale+ System Monitor.
-	- reg: Address and length of the register set for the device
-	- interrupts: Interrupt for the XADC control interface.
-	- clocks: When using the ZYNQ this must be the ZYNQ PCAP clock,
-	  when using the axi-xadc or the axi-system-management-wizard this must be
-	  the clock that provides the clock to the AXI bus interface of the core.
-
-Optional properties:
-	- xlnx,external-mux:
-		* "none": No external multiplexer is used, this is the default
-		  if the property is omitted.
-		* "single": External multiplexer mode is used with one
-		   multiplexer.
-		* "dual": External multiplexer mode is used with two
-		  multiplexers for simultaneous sampling.
-	- xlnx,external-mux-channel: Configures which pair of pins is used to
-	  sample data in external mux mode.
-	  Valid values for single external multiplexer mode are:
-		0: VP/VN
-		1: VAUXP[0]/VAUXN[0]
-		2: VAUXP[1]/VAUXN[1]
-		...
-		16: VAUXP[15]/VAUXN[15]
-	  Valid values for dual external multiplexer mode are:
-		1: VAUXP[0]/VAUXN[0] - VAUXP[8]/VAUXN[8]
-		2: VAUXP[1]/VAUXN[1] - VAUXP[9]/VAUXN[9]
-		...
-		8: VAUXP[7]/VAUXN[7] - VAUXP[15]/VAUXN[15]
-
-	  This property needs to be present if the device is configured for
-	  external multiplexer mode (either single or dual). If the device is
-	  not using external multiplexer mode the property is ignored.
-	- xnlx,channels: List of external channels that are connected to the ADC
-	  Required properties:
-		* #address-cells: Should be 1.
-		* #size-cells: Should be 0.
-
-	  The child nodes of this node represent the external channels which are
-	  connected to the ADC. If the property is no present no external
-	  channels will be assumed to be connected.
-
-	  Each child node represents one channel and has the following
-	  properties:
-		Required properties:
-			* reg: Pair of pins the channel is connected to.
-				0: VP/VN
-				1: VAUXP[0]/VAUXN[0]
-				2: VAUXP[1]/VAUXN[1]
-				...
-				16: VAUXP[15]/VAUXN[15]
-			  Note each channel number should only be used at most
-			  once.
-		Optional properties:
-			* xlnx,bipolar: If set the channel is used in bipolar
-			  mode.
-
-
-Examples:
-	xadc@f8007100 {
-		compatible = "xlnx,zynq-xadc-1.00.a";
-		reg = <0xf8007100 0x20>;
-		interrupts = <0 7 4>;
-		interrupt-parent = <&gic>;
-		clocks = <&pcap_clk>;
-
-		xlnx,channels {
-			#address-cells = <1>;
-			#size-cells = <0>;
-			channel@0 {
-				reg = <0>;
-			};
-			channel@1 {
-				reg = <1>;
-			};
-			channel@8 {
-				reg = <8>;
-			};
-		};
-	};
-
-	xadc@43200000 {
-		compatible = "xlnx,axi-xadc-1.00.a";
-		reg = <0x43200000 0x1000>;
-		interrupts = <0 53 4>;
-		interrupt-parent = <&gic>;
-		clocks = <&fpga1_clk>;
-
-		xlnx,channels {
-			#address-cells = <1>;
-			#size-cells = <0>;
-			channel@0 {
-				reg = <0>;
-				xlnx,bipolar;
-			};
-		};
-	};
-
-	adc@80000000 {
-		compatible = "xlnx,system-management-wiz-1.3";
-		reg = <0x80000000 0x1000>;
-		interrupts = <0 81 4>;
-		interrupt-parent = <&gic>;
-		clocks = <&fpga1_clk>;
-
-		xlnx,channels {
-			#address-cells = <1>;
-			#size-cells = <0>;
-			channel@0 {
-				reg = <0>;
-				xlnx,bipolar;
-			};
-		};
-	};
diff --git a/Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml b/Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml
new file mode 100644
index 000000000000..cfe753e3e8d1
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml
@@ -0,0 +1,204 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/xlnx,xadc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xilinx XADC and UltraScale System Monitor
+
+maintainers:
+  - Lars-Peter Clausen <lars@metafoo.de>
+
+description: |
+  The Xilinx XADC is an ADC found in the Series 7 FPGAs. It has a DRP
+  (Dynamic Reconfiguration Port) interface for communication. Two different
+  frontends for the DRP interface are supported:
+
+    - ZYNQ hardmacro: available only on the ZYNQ family as a hardmacro in
+      the SoC portion of the ZYNQ device.
+    - AXI softmacro: available on all Series 7 platforms as a softmacro
+      with an AXI interface (PG019).
+
+  The Xilinx System Monitor is an ADC found in UltraScale and UltraScale+
+  FPGAs. It is accessed through the Xilinx System Management Wizard IP core
+  via an AXI interface in the FPGA fabric.
+
+properties:
+  compatible:
+    enum:
+      - xlnx,zynq-xadc-1.00.a
+      - xlnx,axi-xadc-1.00.a
+      - xlnx,system-management-wiz-1.3
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: |
+      When using the ZYNQ this must be the ZYNQ PCAP clock.
+      When using the axi-xadc or system-management-wiz this must be
+      the clock that provides the clock to the AXI bus interface.
+    maxItems: 1
+
+  xlnx,external-mux:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      Selects the external multiplexer mode.
+    enum:
+      - none
+      - single
+      - dual
+
+  xlnx,external-mux-channel:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Configures which pair of pins is used to sample data in external
+      multiplexer mode. This property is required when the device is
+      configured for external multiplexer mode.
+
+      Valid values for single external multiplexer mode:
+        0: VP/VN
+        1-16: VAUXP[0]/VAUXN[0] through VAUXP[15]/VAUXN[15]
+
+      Valid values for dual external multiplexer mode:
+        1: VAUXP[0]/VAUXN[0] - VAUXP[8]/VAUXN[8]
+        2: VAUXP[1]/VAUXN[1] - VAUXP[9]/VAUXN[9]
+        ...
+        8: VAUXP[7]/VAUXN[7] - VAUXP[15]/VAUXN[15]
+    minimum: 0
+    maximum: 16
+
+  xlnx,channels:
+    type: object
+    description:
+      List of external channels connected to the ADC. If this property is
+      absent, no external channels are assumed to be connected.
+
+    properties:
+      '#address-cells':
+        const: 1
+
+      '#size-cells':
+        const: 0
+
+    patternProperties:
+      "^channel@([0-9a-f]|10)$":
+        type: object
+        description:
+          Represents an external channel connected to the ADC.
+
+        properties:
+          reg:
+            description: |
+              Pair of pins the channel is connected to.
+                0: VP/VN
+                1: VAUXP[0]/VAUXN[0]
+                2: VAUXP[1]/VAUXN[1]
+                ...
+                16: VAUXP[15]/VAUXN[15]
+            minimum: 0
+            maximum: 16
+
+          xlnx,bipolar:
+            $ref: /schemas/types.yaml#/definitions/flag
+            type: boolean
+            description:
+              If set, the channel is used in bipolar mode.
+
+        required:
+          - reg
+
+        additionalProperties: false
+
+    required:
+      - '#address-cells'
+      - '#size-cells'
+
+    additionalProperties: false
+
+allOf:
+  - if:
+      properties:
+        xlnx,external-mux:
+          enum:
+            - single
+            - dual
+      required:
+        - xlnx,external-mux
+    then:
+      required:
+        - xlnx,external-mux-channel
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    /* ZYNQ hardmacro example */
+    adc@f8007100 {
+        compatible = "xlnx,zynq-xadc-1.00.a";
+        reg = <0xf8007100 0x20>;
+        interrupts = <0 7 4>;
+        interrupt-parent = <&gic>;
+        clocks = <&pcap_clk>;
+
+        xlnx,channels {
+            #address-cells = <1>;
+            #size-cells = <0>;
+            channel@0 {
+                reg = <0>;
+            };
+            channel@1 {
+                reg = <1>;
+            };
+            channel@8 {
+                reg = <8>;
+            };
+        };
+    };
+
+  - |
+    /* AXI softmacro example */
+    adc@43200000 {
+        compatible = "xlnx,axi-xadc-1.00.a";
+        reg = <0x43200000 0x1000>;
+        interrupts = <0 53 4>;
+        interrupt-parent = <&gic>;
+        clocks = <&fpga1_clk>;
+
+        xlnx,channels {
+            #address-cells = <1>;
+            #size-cells = <0>;
+            channel@0 {
+                reg = <0>;
+                xlnx,bipolar;
+            };
+        };
+    };
+
+  - |
+    /* UltraScale System Management Wizard example */
+    adc@80000000 {
+        compatible = "xlnx,system-management-wiz-1.3";
+        reg = <0x80000000 0x1000>;
+        interrupts = <0 81 4>;
+        interrupt-parent = <&gic>;
+        clocks = <&fpga1_clk>;
+
+        xlnx,channels {
+            #address-cells = <1>;
+            #size-cells = <0>;
+            channel@0 {
+                reg = <0>;
+                xlnx,bipolar;
+            };
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 2fb1c75afd16..9b107057ad8c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -29226,6 +29226,13 @@ F:	Documentation/devicetree/bindings/watchdog/xlnx,xps-timebase-wdt.yaml
 F:	drivers/watchdog/of_xilinx_wdt.c
 F:	drivers/watchdog/xilinx_wwdt.c
 
+XILINX XADC DRIVER
+M:	Lars-Peter Clausen <lars@metafoo.de>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml
+F:	drivers/iio/adc/xilinx-xadc*
+
 XILINX XDMA DRIVER
 M:	Lizhi Hou <lizhi.hou@amd.com>
 M:	Brian Xu <brian.xu@amd.com>
-- 
2.52.0

Re: [PATCH v2] dt-bindings: iio: adc: Convert xilinx-xadc bindings to YAML schema

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Invalid `minimum` and `maximum` constraints applied directly to the `reg` property in `channel@...` subnodes.
--

commit 5043f94915e880a0ca171308ea2b8d199810b756
Author: Pramod Maurya <pramod.nexgen@gmail.com>

dt-bindings: iio: adc: Convert xilinx-xadc bindings to YAML schema

This commit converts the Xilinx XADC and UltraScale System Monitor device
tree binding from the legacy plain-text format to a YAML schema. The
new binding covers the ZYNQ hardmacro, AXI softmacro, and UltraScale System
Management Wizard.

> diff --git a/Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml b/Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml
> new file mode 100644
> index 0000000000000..cfe753e3e8d19
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml

[ ... ]

> +    patternProperties:
> +      "^channel@([0-9a-f]|10)$":
> +        type: object
> +        description:
> +          Represents an external channel connected to the ADC.
> +
> +        properties:
> +          reg:
> +            description: |
> +              Pair of pins the channel is connected to.
> +                0: VP/VN
> +                1: VAUXP[0]/VAUXN[0]
> +                2: VAUXP[1]/VAUXN[1]
> +                ...
> +                16: VAUXP[15]/VAUXN[15]
> +            minimum: 0
> +            maximum: 16

Will these constraints work correctly on the reg property?

In dt-schema, the reg property is intrinsically defined as a uint32-matrix
array type. According to the JSON Schema specification, the minimum and
maximum validation keywords apply exclusively to numeric types, not arrays.

Placing these keywords directly on the reg property may trigger a
meta-schema violation during dt_binding_check or be silently ignored,
allowing out-of-bounds configurations to pass validation.

Should this use maxItems: 1 with the numeric bounds placed inside items,
such as items: [ { minimum: 0, maximum: 16 } ] instead?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260509180719.53704-1-pramod.nexgen@gmail.com?part=1

Re: [PATCH v2] dt-bindings: iio: adc: Convert xilinx-xadc bindings to YAML schema

[Rob Herring (Arm)]

On Sat, 09 May 2026 14:07:14 -0400, Pramod Maurya wrote:
> Convert the Xilinx XADC and UltraScale System Monitor device tree binding
> from the legacy plain-text format to a YAML schema, enabling automated
> validation with dt-schema.
> 
> The new binding covers the same hardware and compatible strings:
>   - xlnx,zynq-xadc-1.00.a (ZYNQ hardmacro)
>   - xlnx,axi-xadc-1.00.a  (AXI softmacro)
>   - xlnx,system-management-wiz-1.3 (UltraScale System Management Wizard)
> 
> Signed-off-by: Pramod Maurya <pramod.nexgen@gmail.com>
> ---
> Changes in v2:
> - Fix patternProperties regex to use lowercase hex unit addresses
>   (channel@a through channel@f) instead of decimal; correct range
>   is now "^channel@([0-9a-f]|10)$"
> - Add allOf/if/then conditional to enforce xlnx,external-mux-channel
>   is required when xlnx,external-mux is "single" or "dual"
> 
>  .../bindings/iio/adc/xilinx-xadc.txt          | 141 ------------
>  .../bindings/iio/adc/xlnx,xadc.yaml           | 204 ++++++++++++++++++
>  MAINTAINERS                                   |   7 +
>  3 files changed, 211 insertions(+), 141 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/iio/adc/xilinx-xadc.txt
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/xlnx,xadc.yaml
> 

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/xlnx,xadc.yaml: properties:xlnx,channels:type: 'boolean' was expected
	hint: A vendor boolean property can use "type: boolean"
	from schema $id: http://devicetree.org/meta-schemas/vendor-props.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.kernel.org/project/devicetree/patch/20260509180719.53704-1-pramod.nexgen@gmail.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.