[PATCH v2 1/4] spi: dt-bindings: amlogic: spisg: Document A9-specific properties

Document the Amlogic A9 SPISG controller and its additional
Device Tree properties.

Add the "amlogic,a9-spisg" compatible string and define the
A9-specific "amlogic,mo-idle-output" and "amlogic,word-gap"
properties, which configure the MOSI idle output level and
the inter-word gap, respectively.

Signed-off-by: Xianwei Zhao <[email protected]>
---
 .../devicetree/bindings/spi/amlogic,a4-spisg.yaml  | 38 +++++++++++++++++++---
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/amlogic,a4-spisg.yaml b/Documentation/devicetree/bindings/spi/amlogic,a4-spisg.yaml
index 9bfb8089f7ea..ddef92f3f3b6 100644
--- a/Documentation/devicetree/bindings/spi/amlogic,a4-spisg.yaml
+++ b/Documentation/devicetree/bindings/spi/amlogic,a4-spisg.yaml
@@ -11,12 +11,11 @@ maintainers:
   - Xianwei Zhao <[email protected]>
   - Sunny Luo <[email protected]>
 
-allOf:
-  - $ref: spi-controller.yaml#
-
 properties:
   compatible:
-    const: amlogic,a4-spisg
+    enum:
+      - amlogic,a4-spisg
+      - amlogic,a9-spisg
 
   reg:
     maxItems: 1
@@ -35,6 +34,23 @@ properties:
   resets:
     maxItems: 1
 
+  amlogic,mo-idle-output:
+    description: |
+      Controls the MOSI output level when the controller is idle.
+      0 - Drive MOSI low
+      1 - Drive MOSI high
+      2 - Follow the last transmitted bit
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1, 2]
+    default: 0
+
+  amlogic,word-gap:
+    description: |
+      Number of idle clock cycles inserted between consecutive SPI words.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1, 2, 3]
+    default: 1
+
 required:
   - compatible
   - reg
@@ -42,6 +58,20 @@ required:
   - clocks
   - clock-names
 
+allOf:
+  - $ref: spi-controller.yaml#
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              enum:
+                - amlogic,a9-spisg
+    then:
+      properties:
+        amlogic,mo-idle-output: false
+        amlogic,word-gap: false
+
 unevaluatedProperties: false
 
 examples:

-- 
2.52.0