dt-bindings: dma: dw: Add max burst transaction length property

This array property is used to indicate the maximum burst transaction
length supported by each DMA channel.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20200723005848.31907-3-Sergey.Semin@baikalelectronics.ruSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/dma/snps,dma-spear1340.yaml

@@ -120,6 +120,21 @@ properties:
         enum: [0, 1]
         default: 1
 
+  snps,max-burst-len:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description: |
+      Maximum length of the burst transactions supported by the controller.
+      This property defines the upper limit of the run-time burst setting
+      (CTLx.SRC_MSIZE/CTLx.DST_MSIZE fields) so the allowed burst length
+      will be from 1 to max-burst-len words. It's an array property with one
+      cell per channel in the units determined by the value set in the
+      CTLx.SRC_TR_WIDTH/CTLx.DST_TR_WIDTH fields (data width).
+    items:
+      maxItems: 8
+      items:
+        enum: [4, 8, 16, 32, 64, 128, 256]
+        default: 256
+
   snps,dma-protection-control:
     $ref: /schemas/types.yaml#definitions/uint32
     description: |