dt-bindings: soc: renesas: Document RZ/N1 GPIO Interrupt Multiplexer

On the Renesas RZ/N1 SoC, GPIOs can generate interruptions. Those
interruption lines are multiplexed by the GPIO Interrupt Multiplexer in
order to map 32 * 3 GPIO interrupt lines to 8 GIC interrupt lines.

The GPIO interrupt multiplexer IP does nothing but select 8 GPIO
IRQ lines out of the 96 available to wire them to the GIC input lines.

Signed-off-by: Herve Codina (Schneider Electric) <herve.codina@bootlin.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260114093938.1089936-7-herve.codina@bootlin.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: hcodina

Documentation/devicetree/bindings/soc/renesas/renesas,rzn1-gpioirqmux.yaml

@@ -0,0 +1,87 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/renesas/renesas,rzn1-gpioirqmux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/N1 SoCs GPIO Interrupt Multiplexer
+
+description: |
+   The Renesas RZ/N1 GPIO Interrupt Multiplexer multiplexes GPIO interrupt
+   lines to the interrupt controller available in the SoC.
+
+   It selects up to 8 of the 96 GPIO interrupt lines available and connect them
+   to 8 output interrupt lines.
+
+maintainers:
+  - Herve Codina <herve.codina@bootlin.com>
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,r9a06g032-gpioirqmux
+      - const: renesas,rzn1-gpioirqmux
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 0
+
+  "#interrupt-cells":
+    const: 1
+
+  interrupt-map-mask:
+    items:
+      - const: 0x7f
+
+  interrupt-map:
+    description: |
+      Specifies the mapping from external GPIO interrupt lines to the output
+      interrupts. The array has up to 8 items defining the mapping related to
+      the output line 0 (GIC 103) up to the output line 7 (GIC 110).
+
+      The child interrupt number set in arrays items is computed using the
+      following formula:
+          gpio_bank * 32 + gpio_number
+      with:
+        - gpio_bank: The GPIO bank number
+            - 0 for GPIO0A,
+            - 1 for GPIO1A,
+            - 2 for GPIO2A
+        - gpio_number: Number of the gpio in the bank (0..31)
+    minItems: 1
+    maxItems: 8
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#interrupt-cells"
+  - interrupt-map-mask
+  - interrupt-map
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    gic: interrupt-controller {
+        interrupt-controller;
+        #address-cells = <0>;
+        #interrupt-cells = <3>;
+    };
+
+    interrupt-controller@51000480 {
+        compatible = "renesas,r9a06g032-gpioirqmux", "renesas,rzn1-gpioirqmux";
+        reg = <0x51000480 0x20>;
+        #address-cells = <0>;
+        #interrupt-cells = <1>;
+        interrupt-map-mask = <0x7f>;
+        interrupt-map =
+            <32 &gic GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>, /* line 0, GPIO1A.0 */
+            <89 &gic GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>, /* line 1, GPIO2A.25 */
+            <9 &gic GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH>; /* line 3, GPIO0A.9 */
+    };