dt-bindings: bus: document the IMX AIPSTZ bridge

Add documentation for IMX AIPSTZ bridge.

Co-developed-by: Daniel Baluta <[e-mail]>
Signed-off-by: Daniel Baluta <[e-mail]>
Signed-off-by: Laurentiu Mihalcea <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

Documentation/devicetree/bindings/bus/fsl,imx8mp-aipstz.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/bus/fsl,imx8mp-aipstz.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Secure AHB to IP Slave bus (AIPSTZ) bridge
+
+description:
+  The secure AIPS bridge (AIPSTZ) acts as a bridge for AHB masters issuing
+  transactions to IP Slave peripherals. Additionally, this module offers access
+  control configurations meant to restrict which peripherals a master can
+  access.
+
+maintainers:
+  - Laurentiu Mihalcea <[e-mail]>
+
+properties:
+  compatible:
+    const: fsl,imx8mp-aipstz
+
+  reg:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 1
+
+  "#access-controller-cells":
+    const: 3
+    description:
+      First cell - consumer ID
+      Second cell - consumer type (master or peripheral)
+      Third cell - configuration value
+
+  ranges: true
+
+# borrowed from simple-bus.yaml, no additional requirements for children
+patternProperties:
+  "@(0|[1-9a-f][0-9a-f]*)$":
+    type: object
+    additionalProperties: true
+    properties:
+      reg:
+        items:
+          minItems: 2
+          maxItems: 4
+        minItems: 1
+        maxItems: 1024
+      ranges:
+        oneOf:
+          - items:
+              minItems: 3
+              maxItems: 7
+            minItems: 1
+            maxItems: 1024
+          - $ref: /schemas/types.yaml#/definitions/flag
+    anyOf:
+      - required:
+          - reg
+      - required:
+          - ranges
+
+required:
+  - compatible
+  - reg
+  - power-domains
+  - "#address-cells"
+  - "#size-cells"
+  - "#access-controller-cells"
+  - ranges
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/imx8mp-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    bus@30df0000 {
+        compatible = "fsl,imx8mp-aipstz";
+        reg = <0x30df0000 0x10000>;
+        ranges = <0x30c00000 0x30c00000 0x400000>;
+        power-domains = <&pgc_audio>;
+        #address-cells = <1>;
+        #size-cells = <1>;
+        #access-controller-cells = <3>;
+
+        dma-controller@30e00000 {
+            compatible = "fsl,imx8mp-sdma", "fsl,imx8mq-sdma";
+            reg = <0x30e00000 0x10000>;
+            #dma-cells = <3>;
+            clocks = <&audio_blk_ctrl IMX8MP_CLK_AUDIOMIX_SDMA3_ROOT>,
+                     <&clk IMX8MP_CLK_AUDIO_ROOT>;
+            clock-names = "ipg", "ahb";
+            interrupts = <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
+            fsl,sdma-ram-script-name = "imx/sdma/sdma-imx7d.bin";
+        };
+    };