dt-bindings: net: add st,stlc4560/p54spi binding

The SPI version of Prism54 was sold under a couple of different
names and supported by the Linux p54spi driver, but there was
never a DT binding for it.

Document the four known names of this device and the properties
that are sufficient for its use on the Nokia N8x0 tablet.

As I don't have this hardware or documentation for it, this is
purely based on existing usage in the driver.

Link: https://lore.kernel.org/all/e8dc9acb-6f85-e0a9-a145-d101ca6da201@gmail.com/
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260507212451.3333185-2-arnd@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Documentation/devicetree/bindings/net/wireless/st,stlc4560.yaml

@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/wireless/st,stlc4560.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ST/Intersil/Conexant stlc45xx/p54spi/cx3110x SPI wireless device
+
+maintainers:
+  - Christian Lamparter <chunkeey@gmail.com>
+
+description:
+  The SPI variant of the Intersil Prism54 wireless device was sold
+  under a variety of names, including Conexant CX3110x and
+  ST Microelectronics STLC5460.
+
+allOf:
+  - $ref: ieee80211.yaml#
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      - const: st,stlc4560
+      - items:
+          - enum:
+              - cnxt,3110x
+              - isil,p54spi
+              - st,stlc4550
+          - const: st,stlc4560
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  powerdown-gpios:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        wifi@0 {
+            compatible = "st,stlc4560";
+            reg = <0>;
+            spi-max-frequency = <48000000>;
+            interrupts-extended = <&gpio 23>;
+            powerdown-gpios = <&gpio 1>;
+        };
+    };

MAINTAINERS

@@ -20131,6 +20131,7 @@ M:	Christian Lamparter <chunkeey@googlemail.com>
 L:	linux-wireless@vger.kernel.org
 S:	Maintained
 W:	https://wireless.wiki.kernel.org/en/users/Drivers/p54
+F:	Documentation/devicetree/bindings/net/wireless/st,stlc4560.yaml
 F:	drivers/net/wireless/intersil/
 
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