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[v6,2/9] dt-bindings: dma: dw: Add max burst transaction length property

Message ID 20200617234028.25808-3-Sergey.Semin@baikalelectronics.ru
State Not Applicable
Headers show
Series dmaengine: dw: Take Baikal-T1 SoC DW DMAC peculiarities into account | expand


Context Check Description
robh/dt-meta-schema success
robh/checkpatch success

Commit Message

Serge Semin June 17, 2020, 11:40 p.m. UTC
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>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-mips@vger.kernel.org


Changelog v2:
- Rearrange SoBs.
- Move $ref to the root level of the properties. So do with the
- Set default max-burst-len to 256 TR-WIDTH words.

Changelog v3:
- Add more details into the property description about what limitations
  snps,max-burst-len defines.
 .../bindings/dma/snps,dma-spear1340.yaml          | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
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diff --git a/Documentation/devicetree/bindings/dma/snps,dma-spear1340.yaml b/Documentation/devicetree/bindings/dma/snps,dma-spear1340.yaml
index e7611840a7cf..20870f5c14dd 100644
--- a/Documentation/devicetree/bindings/dma/snps,dma-spear1340.yaml
+++ b/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
     $ref: /schemas/types.yaml#definitions/uint32
     description: |