[PATCH v4 1/4] dt-bindings: usb: Add CIX Sky1 USBSSP RCSU system controller

[Hongliang Yang <hongliang.yang@cixtech.com>]

Add device tree binding for the per-controller RCSU register regions
of the CIX Sky1 USBSSP controllers. The regions are exposed as syscon
nodes; USBSSP glue nodes reference their per-controller registers
through the cix,usb-rcsu phandle with register offsets.

The per-controller RCSU control and status registers live in a shared
RCSU region described by the cix,sky1-usbss-rcsu binding and are
referenced through the cix,usb-rcsu phandle.
Signed-off-by: Hongliang Yang <hongliang.yang@cixtech.com>
---
 .../bindings/usb/cix,sky1-usbss-rcsu.yaml     | 46 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 47 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/cix,sky1-usbss-rcsu.yaml

diff --git a/Documentation/devicetree/bindings/usb/cix,sky1-usbss-rcsu.yaml b/Documentation/devicetree/bindings/usb/cix,sky1-usbss-rcsu.yaml
new file mode 100644
index 000000000000..d0c54fd2cd5f
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/cix,sky1-usbss-rcsu.yaml
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/cix,sky1-usbss-rcsu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CIX Sky1 USBSSP RCSU system controller
+
+maintainers:
+  - Hongliang Yang <hongliang.yang@cixtech.com>
+
+description:
+  The CIX Sky1 USBSSP controllers integrate their per-instance glue
+  registers (AXI bus attribute configuration and controller status)
+  inside a shared RCSU register region in the SoC system control
+  aperture. This binding describes that region as a syscon, so USBSSP
+  glue nodes can reference their register offsets through the
+  cix,usb-rcsu phandle (see cix,sky1-usbssp.yaml).
+
+properties:
+  compatible:
+    items:
+      - const: cix,sky1-usbss-rcsu
+      - const: syscon
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        syscon@91c0300 {
+            compatible = "cix,sky1-usbss-rcsu", "syscon";
+            reg = <0x00 0x091c0300 0x00 0x200>;
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 15011f5752a9..1408b89607ff 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2775,6 +2775,7 @@ S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/peter.chen/cix.git
 F:	Documentation/devicetree/bindings/arm/cix.yaml
 F:	Documentation/devicetree/bindings/mailbox/cix,sky1-mbox.yaml
+F:	Documentation/devicetree/bindings/usb/cix,sky1-usbss-rcsu.yaml
 F:	arch/arm64/boot/dts/cix/
 F:	drivers/mailbox/cix-mailbox.c
 K:	\bcix\b
-- 
2.54.0