spi: spi-st-ssc: convert to DT schema

Convert spi-st-ssc.txt into st,ssc-spi.yaml for the
ST Microelectronics SSC SPI driver.

Signed-off-by: Alain Volmat <avolmat@me.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230213192349.17101-1-avolmat@me.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/st,ssc-spi.yaml

@@ -0,0 +1,61 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/st,ssc-spi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics SSC SPI Controller
+
+description: |
+  The STMicroelectronics SSC SPI controller can be found on STi platforms
+  and it used to communicate with external devices using the
+  Serial Peripheral Interface.
+
+maintainers:
+  - Patrice Chotard <patrice.chotard@foss.st.com>
+
+allOf:
+  - $ref: spi-controller.yaml#
+
+properties:
+  compatible:
+    const: st,comms-ssc4-spi
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: ssc
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/stih407-clks.h>
+    spi@9840000 {
+      compatible = "st,comms-ssc4-spi";
+      reg = <0x9840000 0x110>;
+      interrupts = <GIC_SPI 112 IRQ_TYPE_LEVEL_HIGH>;
+      clocks = <&clk_s_c0_flexgen CLK_EXT2F_A9>;
+      clock-names = "ssc";
+      pinctrl-0 = <&pinctrl_spi0_default>;
+      pinctrl-names = "default";
+      #address-cells = <1>;
+      #size-cells = <0>;
+    };
+
+...

MAINTAINERS

@@ -2925,6 +2925,7 @@ M:	Patrice Chotard <patrice.chotard@foss.st.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Maintained
 W:	http://www.stlinux.com
+F:	Documentation/devicetree/bindings/spi/st,ssc-spi.yaml
 F:	Documentation/devicetree/bindings/i2c/i2c-st.txt
 F:	arch/arm/boot/dts/sti*
 F:	arch/arm/mach-sti/