The MediaTek MT8196 SoC includes an embedded MCU referred to as "GPUEB",
acting as glue logic to control power and frequency of the Mali GPU.
This MCU runs special-purpose firmware for this use, and the main
application processor communicates with it through a mailbox.

Add a binding that describes this mailbox.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
 .../mailbox/mediatek,mt8196-gpueb-mbox.yaml        | 64 ++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,mt8196-gpueb-mbox.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,mt8196-gpueb-mbox.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..ab5b780cb83a708a3897ca1a440131d97b56c3a6
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/mediatek,mt8196-gpueb-mbox.yaml
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/mediatek,mt8196-gpueb-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek MFlexGraphics GPUEB Mailbox Controller
+
+maintainers:
+  - Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt8196-gpueb-mbox
+
+  reg:
+    items:
+      - description: mailbox data registers
+      - description: mailbox control registers
+
+  reg-names:
+    items:
+      - const: data
+      - const: ctl
+
+  clocks:
+    items:
+      - description: main clock of the GPUEB MCU
+
+  interrupts:
+    items:
+      - description: fires when a new message is received
+
+  "#mbox-cells":
+    const: 1
+    description:
+      The number of the mailbox channel.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - interrupts
+  - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/mediatek,mt8196-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    mailbox@4b09fd80 {
+        compatible = "mediatek,mt8196-gpueb-mbox";
+        reg = <0x4b09fd80 0x280>,
+              <0x4b170000 0x7c>;
+        reg-names = "data", "ctl";
+        clocks = <&topckgen CLK_TOP_MFG_EB>;
+        interrupts = <GIC_SPI 608 IRQ_TYPE_LEVEL_HIGH 0>;
+        #mbox-cells = <1>;
+    };

-- 
2.51.0