dt-bindings: trigger-source: add ADI Util Sigma-Delta SPI

Add new binding for the ADI Util Sigma-Delta SPI FPGA IP Core.

This is used to trigger a SPI offload based on a RDY signal from the
ADC while masking out other signals on the same line.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250627-iio-adc-ad7173-add-spi-offload-support-v2-8-f49c55599113@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/trigger-source/adi,util-sigma-delta-spi.yaml

@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (c) 2025 Analog Devices, Inc.
+# Copyright (c) 2025 BayLibre, SAS
+
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/trigger-source/adi,util-sigma-delta-spi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices Util Sigma-Delta SPI IP Core
+
+maintainers:
+  - David Lechner <dlechner@baylibre.com>
+
+description:
+  The Util Sigma-Delta SPI is an FPGA IP core from Analog Devices that provides
+  a SPI offload trigger from the RDY signal of the combined DOUT/RDY pin of
+  the sigma-delta family of ADCs.
+  https://analogdevicesinc.github.io/hdl/library/util_sigma_delta_spi/index.html
+
+properties:
+  compatible:
+    const: adi,util-sigma-delta-spi
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  '#trigger-source-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - '#trigger-source-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    trigger@40000 {
+        reg = <0x40000 0x1000>;
+        compatible = "adi,util-sigma-delta-spi";
+        clocks = <&clk 0>;
+        #trigger-source-cells = <0>;
+    };

MAINTAINERS

@@ -25235,6 +25235,11 @@ W:	https://github.com/srcres258/linux-doc
 T:	git git://github.com/srcres258/linux-doc.git doc-zh-tw
 F:	Documentation/translations/zh_TW/
 
+TRIGGER SOURCE - ADI UTIL SIGMA DELTA SPI
+M:	David Lechner <dlechner@baylibre.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/trigger-source/adi,util-sigma-delta-spi.yaml
+
 TRIGGER SOURCE - PWM
 M:	David Lechner <dlechner@baylibre.com>
 S:	Maintained