[PATCH v3 2/4] dt-bindings: serial: snps-dw-apb-uart: add Allwinner H616

[James Hilliard <james.hilliard1@gmail.com>]

The H616 UART has 256-byte transmit and receive FIFOs, but its DesignWare
component parameter register does not report the FIFO depth. Its optional
register layout also differs from the generic DesignWare integration.

Add a specific compatible for the integration and allow the standard
fifo-size property to describe the capacity. Require the documented
256-byte size for H616, retaining snps,dw-apb-uart as a fallback.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
 .../devicetree/bindings/serial/snps-dw-apb-uart.yaml    | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
index e2ca126d58ba..0f8fd0485879 100644
--- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
+++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.yaml
@@ -13,6 +13,18 @@ allOf:
   - $ref: serial.yaml#
   - $ref: rs485.yaml#
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: allwinner,sun50i-h616-uart
+    then:
+      properties:
+        fifo-size:
+          const: 256
+      required:
+        - fifo-size
+
   - if:
       properties:
         compatible:
@@ -60,6 +72,7 @@ properties:
           - const: renesas,rzn1-uart
       - items:
           - enum:
+              - allwinner,sun50i-h616-uart
               - anlogic,dr1v90-uart
               - brcm,bcm11351-dw-apb-uart
               - brcm,bcm21664-dw-apb-uart
@@ -120,6 +133,10 @@ properties:
       - const: tx
       - const: rx
 
+  fifo-size:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Transmit and receive FIFO capacity in bytes.
+
   snps,uart-16550-compatible:
     description: reflects the value of UART_16550_COMPATIBLE configuration
       parameter. Define this if your UART does not implement the busy functionality.

-- 
2.53.0