Re: [PATCH v4 1/4] dt-bindings: dmaengine: Add MediaTek Command-Queue DMA controller bindings

On Thu, May 28, 2020 at 05:57:09PM +0800, EastL wrote:

Document the devicetree bindings for MediaTek Command-Queue DMA controller
which could be found on MT6779 SoC or other similar Mediatek SoCs.

Signed-off-by: EastL <redacted>

Need a full name.

Dual license new bindings:

(GPL-2.0-only OR BSD-2-Clause)

+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/mtk-cqdma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek Command-Queue DMA controller Device Tree Binding
+
+maintainers:
+  - EastL [off-list ref]
+
+description:
+  MediaTek Command-Queue DMA controller (CQDMA) on Mediatek SoC
+  is dedicated to memory-to-memory transfer through queue based
+  descriptor management.
+

Need a $ref to dma-controller.yaml

+properties:
+  "#dma-cells":
+    minimum: 1
+    # Should be enough
+    maximum: 255
+    description:
+      Used to provide DMA controller specific information.
+
+  compatible:
+    const: mediatek,cqdma

Needs SoC specific compatible string(s).

+
+  reg:
+    minItems: 1
+    maxItems: 255

You can have 255 register regions?

You need to define what each region is if more than 1.

+
+  interrupts:
+    minItems: 1
+    maxItems: 255

255 interrupts?

+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: cqdma
+
+  dma-channel-mask:
+    description:
+      Bitmask of available DMA channels in ascending order that are
+      not reserved by firmware and are available to the
+      kernel. i.e. first channel corresponds to LSB.
+      The first item in the array is for channels 0-31, the second is for
+      channels 32-63, etc.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32-array
+    items:
+      minItems: 1
+      # Should be enough
+      maxItems: 255

This already has a definition in dma-common.yaml. Don't copy-n-paste 
it. Just add any constraints you have. Like what is the max number of 
channels?

+
+  dma-channels:
+    $ref: /schemas/types.yaml#definitions/uint32
+    description:
+      Number of DMA channels supported by the controller.
+
+  dma-requests:
+    $ref: /schemas/types.yaml#definitions/uint32
+    description:
+      Number of DMA request signals supported by the controller.

Same comment on these 2.

+
+required:
+  - "#dma-cells"
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - dma-channel-mask
+  - dma-channels
+  - dma-requests
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/mt6779-clk.h>
+    cqdma: dma-controller@10212000 {
+        compatible = "mediatek,cqdma";
+        reg = <0 0x10212000 0 0x80>,
+            <0 0x10212080 0 0x80>,
+            <0 0x10212100 0 0x80>;

Examples default to 1 cell each for address and size.

+        interrupts = <GIC_SPI 139 IRQ_TYPE_LEVEL_LOW>,
+            <GIC_SPI 140 IRQ_TYPE_LEVEL_LOW>,
+            <GIC_SPI 141 IRQ_TYPE_LEVEL_LOW>;
+        clocks = <&infracfg_ao CLK_INFRA_CQ_DMA>;
+        clock-names = "cqdma";
+        dma-channel-mask = <63>;
+        dma-channels = <3>;
+        dma-requests = <32>;
+        #dma-cells = <1>;
+    };
+
+...
-- 
1.9.1