[PATCH v8 1/4] dt-bindings: dma-engine: sifive, fu540: Add dma-channels property and modify compatible

[Zong Li]

Add dma-channels property, then we can determine how many channels there
by device tree, rather than statically defining it in PDMA driver.
In addition, we also modify the compatible for PDMA versioning scheme.

Signed-off-by: Zong Li <zong.li at sifive.com>
Reviewed-by: Rob Herring <robh at kernel.org>
Suggested-by: Palmer Dabbelt <palmer at rivosinc.com>
Reviewed-by: Palmer Dabbelt <palmer at rivosinc.com>
Acked-by: Palmer Dabbelt <palmer at rivosinc.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski at canonical.com>
---
 .../bindings/dma/sifive,fu540-c000-pdma.yaml  | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml b/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml
index 47c46af25536..3271755787b4 100644
--- a/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml
+++ b/Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml
@@ -28,7 +28,15 @@ allOf:
 properties:
   compatible:
     items:
-      - const: sifive,fu540-c000-pdma
+      - enum:
+          - sifive,fu540-c000-pdma
+      - const: sifive,pdma0
+    description:
+      Should be "sifive,<chip>-pdma" and "sifive,pdma<version>".
+      Supported compatible strings are -
+      "sifive,fu540-c000-pdma" for the SiFive PDMA v0 as integrated onto the
+      SiFive FU540 chip resp and "sifive,pdma0" for the SiFive PDMA v0 IP block
+      with no chip integration tweaks.
 
   reg:
     maxItems: 1
@@ -37,6 +45,12 @@ properties:
     minItems: 1
     maxItems: 8
 
+  dma-channels:
+    description: For backwards-compatibility, the default value is 4
+    minimum: 1
+    maximum: 4
+    default: 4
+
   '#dma-cells':
     const: 1
 
@@ -50,8 +64,9 @@ unevaluatedProperties: false
 examples:
   - |
     dma-controller at 3000000 {
-      compatible = "sifive,fu540-c000-pdma";
+      compatible = "sifive,fu540-c000-pdma", "sifive,pdma0";
       reg = <0x3000000 0x8000>;
+      dma-channels = <4>;
       interrupts = <23>, <24>, <25>, <26>, <27>, <28>, <29>, <30>;
       #dma-cells = <1>;
     };
-- 
2.35.1