[PATCH v4 2/3] dt-bindings: mailbox: Add thead,th1520-mailbox bindings

[Michal Wilczynski]

Add bindings for the mailbox controller. This work is based on the vendor
kernel. [1]

Link: https://github.com/revyos/thead-kernel.git [1]

Signed-off-by: Michal Wilczynski <m.wilczynski@xxxxxxxxxxx>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
---
 .../bindings/mailbox/thead,th1520-mbox.yaml   | 80 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 81 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml

diff --git a/Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml b/Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml
new file mode 100644
index 000000000000..12507c426691
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml
@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/thead,th1520-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-head TH1520 Mailbox Controller
+
+description:
+  The T-head mailbox controller enables communication and coordination between
+  cores within the SoC by passing messages (e.g., data, status, and control)
+  through mailbox channels. It also allows one core to signal another processor
+  using interrupts via the Interrupt Controller Unit (ICU).
+
+maintainers:
+  - Michal Wilczynski <m.wilczynski@xxxxxxxxxxx>
+
+properties:
+  compatible:
+    const: thead,th1520-mbox
+
+  reg:
+    items:
+      - description: Mailbox local base address
+      - description: Remote ICU 0 base address
+      - description: Remote ICU 1 base address
+      - description: Remote ICU 2 base address
+
+  reg-names:
+    items:
+      - const: local
+      - const: remote-icu0
+      - const: remote-icu1
+      - const: remote-icu2
+
+  interrupts:
+    maxItems: 1
+
+  '#mbox-cells':
+    const: 2
+    description: |
+      Specifies the number of cells needed to encode the mailbox specifier.
+      The mailbox specifier consists of two cells:
+        - Destination CPU ID.
+        - Type, which can be one of the following:
+            - 0:
+                - TX & RX channels share the same channel.
+                - Equipped with 7 info registers to facilitate data sharing.
+                - Supports IRQ for signaling.
+            - 1:
+                - TX & RX operate as doorbell channels.
+                - Does not have dedicated info registers.
+                - Lacks ACK support.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - '#mbox-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+      mailbox@ffffc38000 {
+        compatible = "thead,th1520-mbox";
+        reg = <0xff 0xffc38000 0x0 0x4000>,
+              <0xff 0xffc44000 0x0 0x1000>,
+              <0xff 0xffc4c000 0x0 0x1000>,
+              <0xff 0xffc54000 0x0 0x1000>;
+        reg-names = "local", "remote-icu0", "remote-icu1", "remote-icu2";
+        interrupts = <28>;
+        #mbox-cells = <2>;
+      };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 0655c6ba5435..7401c7cb6533 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19951,6 +19951,7 @@ L:	linux-riscv@xxxxxxxxxxxxxxxxxxx
 S:	Maintained
 T:	git https://github.com/pdp7/linux.git
 F:	Documentation/devicetree/bindings/clock/thead,th1520-clk-ap.yaml
+F:	Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml
 F:	arch/riscv/boot/dts/thead/
 F:	drivers/clk/thead/clk-th1520-ap.c
 F:	drivers/mailbox/mailbox-th1520.c
-- 
2.34.1