[PATCH 2/3] dt-bindings: mailbox: starfive: Add StarFive Meu Mailbox Driver

[Joshua Yeong <joshua.yeong@starfivetech.com>]

The StarFive Meu Mailbox allow communication between AP and SCP cores
through mailbox doorbell.

Co-developed-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Signed-off-by: Joshua Yeong <joshua.yeong@starfivetech.com>
Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
---
 .../bindings/mailbox/starfive-meu.yaml        | 66 +++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/starfive-meu.yaml

diff --git a/Documentation/devicetree/bindings/mailbox/starfive-meu.yaml b/Documentation/devicetree/bindings/mailbox/starfive-meu.yaml
new file mode 100644
index 000000000000..dbc5cfdb90ff
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/starfive-meu.yaml
@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/starfive-meu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive MEU Mailbox Controller
+
+maintainers:
+  - Jee Heng Sia <jeeheng.sia@starfivetech.com>
+  - Joshua Yeong <joshua.yeong@starfivetech.com>
+
+description: |
+  StarFive's Message-Exchange-Unit (MEU) is a mailbox controller that has 62
+  independent doorbells. Each MEU channel consist of 31 doorbells and consist of
+  a pair of Tx/Rx links that shall communicates with remote processor. The
+  sender set the bit in the SET register to indicate data readiness for the
+  receiver. An interrupt will be raised whenever receiving notification doorbell
+  from remote processor. The receiver will clear the bit in the CLR register
+  upon handling the doorbell notification. The sender should poll the STAT
+  register before starting any transaction to ensure all on-going doorbells are
+  processed.
+
+properties:
+  compatible:
+    enum:
+      - starfive,jh8100-meu
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    items:
+      - description: mailbox0
+      - description: mailbox1
+
+  '#mbox-cells':
+    description: represents index of the mailbox/doorbell paired channel
+      channel  0 - 30 for mailbox0 doorbell
+      channel 31 - 61 for mailbox1 doorbell
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - '#mbox-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        meu: mailbox@1f370000 {
+            compatible = "starfive,jh8100-meu";
+            reg = <0x0 0x1f370000 0 0x8000>;
+            interrupts = <170>, /* Mailbox0 */
+                         <171>; /* Mailbox1 */
+            #mbox-cells = <1>;
+        };
+    };
+
+...
-- 
2.25.1