dt-bindings: spi: Add binding for Faraday FTSSP010

This adds a binding for the Faraday FTSSP010 SSP controller,
a pretty straight-forward syncronous serial port and SPI
controller.

The bindings are submitted separately because the one device
that has this is using it in a "nonstandard way" with regards
to the electronics, and does not make it possible to develop
or test a proper driver. However we want to be able to add
this resource to the device trees and it's not complex.

Signed-off-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260203-gemini-ssp-bindings-v1-1-6d85c9c72371@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/faraday,ftssp010.yaml

@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/faraday,ftssp010.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Faraday FTSSP010 SPI Controller
+
+maintainers:
+  - Linus Walleij <linusw@kernel.org>
+
+properties:
+  compatible:
+    const: faraday,ftssp010
+
+  interrupts:
+    maxItems: 1
+
+  reg:
+    maxItems: 1
+
+  cs-gpios: true
+
+required:
+  - compatible
+  - interrupts
+  - reg
+
+allOf:
+  - $ref: spi-controller.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    spi@4a000000 {
+        compatible = "faraday,ftssp010";
+        #address-cells = <1>;
+        #size-cells = <0>;
+        reg = <0x4a000000 0x1000>;
+        interrupts = <0>;
+    };