[PATCH RFC 05/12] dt-bindings: serial: Add BL808 UART

[Kwanghoon Son]

Describe the UART register range, interrupt and baud clock input.
Initial Linux support targets the BL808 32-byte FIFO and reuses
Zephyr's bflb,uart compatible. UART3 is D0 PLIC source 20.

Link: https://docs.zephyrproject.org/latest/build/dts/api/bindings/serial/bflb,uart.html

Signed-off-by: Kwanghoon Son <asdfkwang at gmail.com>
---
 .../devicetree/bindings/serial/bflb,uart.yaml      | 57 ++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/bflb,uart.yaml b/Documentation/devicetree/bindings/serial/bflb,uart.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..df29d258f0a1c6d7bb283cf19c4157436991b64b
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/bflb,uart.yaml
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/bflb,uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bouffalo Lab UART Controller
+
+description: |
+  UART IP used by Bouffalo Lab SoCs. Initial Linux support covers the
+  BL808 controller with a 32-byte FIFO. The compatible follows Zephyr.
+
+maintainers:
+  - Kwanghoon Son <asdfkwang at gmail.com>
+
+allOf:
+  - $ref: serial.yaml#
+
+properties:
+  compatible:
+    const: bflb,uart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Baud rate generator clock
+
+  clock-names:
+    items:
+      - const: baud
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    uart3: serial at 30002000 {
+        compatible = "bflb,uart";
+        reg = <0x30002000 0x1000>;
+        interrupts = <20 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&uart_baud>;
+        clock-names = "baud";
+    };
+...

-- 
2.47.3