dt-bindings: spi: dspi: Add S32G support

Document S32G compatible strings. 's32g2' and 's32g3' use the same
driver so 's32g2' must follow 's32g3'. The SPI controller supports
target mode when the "spi-slave" flag is used so add an example.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@nxp.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Link: https://patch.msgid.link/20250522-james-nxp-spi-v2-12-bea884630cfb@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: ciprianmcostea

Documentation/devicetree/bindings/spi/fsl,dspi.yaml

@@ -23,6 +23,7 @@ properties:
           - fsl,ls2080a-dspi
           - fsl,ls2085a-dspi
           - fsl,lx2160a-dspi
+          - nxp,s32g2-dspi
       - items:
           - enum:
               - fsl,ls1012a-dspi
@@ -37,6 +38,9 @@ properties:
       - items:
           - const: fsl,lx2160a-dspi
           - const: fsl,ls2085a-dspi
+      - items:
+          - const: nxp,s32g3-dspi
+          - const: nxp,s32g2-dspi
 
   reg:
     maxItems: 1
@@ -114,3 +118,17 @@ examples:
             spi-cs-hold-delay-ns = <50>;
         };
     };
+  # S32G3 in target mode
+  - |
+    spi@401d4000 {
+        compatible = "nxp,s32g3-dspi", "nxp,s32g2-dspi";
+        reg = <0x401d4000 0x1000>;
+        interrupts = <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clks 26>;
+        clock-names = "dspi";
+        spi-num-chipselects = <8>;
+        bus-num = <0>;
+        dmas = <&edma0 0 7>, <&edma0 0 8>;
+        dma-names = "tx", "rx";
+        spi-slave;
+    };