Thread (20 messages) 20 messages, 2 authors, 2025-09-12

Re: [PATCH v3 2/9] dt-bindings: media: nxp: Add Wave6 video codec device

From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2025-08-29 13:57:29
Also in: linux-devicetree, linux-media, lkml

On 29/08/2025 10:46, Nas Chung wrote:
Add documents for the Wave6 video codec on NXP i.MX SoCs.
Pretty incomplete commit msg. Nothing explaining hardware, nothing
documenting resolution of previous discussions (where is all this
chip&media?).

...

+
+properties:
+  compatible:
+    enum:
+      - nxp,imx95-vpu
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  memory-region:
+    maxItems: 1
+
+  sram:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: phandle of the SRAM memory region node.
+
+  "#cooling-cells":
+    const: 2
+
+  "#address-cells":
+    const: 2
+
+  "#size-cells":
+    const: 2
+
+  ranges: true
+
+patternProperties:
+  "^video-core@[0-9a-f]+$":
+    type: object
Missing description.
+    additionalProperties: false
+
+    properties:
+      compatible:
+        enum:
+          - nxp,imx95-vpu-core
Why do you need here compatible? Can this child be anything else? Can it
be re-used? Is it actually a separate block?

Your example suggests that the only distinctive resource are the
interrupt and address space and that's on the edge of calling it a
separate device.

There is some tendency to call such "pseudo-cores" a separate devices in
case of video codec bindings and experience shows these are usually
fake. It's not the same as DP or HDMI sub-block of display pipeline.

That's why you should come here with strong argument what separate piece
of hardware this is.
+
+      reg:
+        maxItems: 1
+
+      clocks:
+        maxItems: 1
+
+      power-domains:
+        maxItems: 1
+
+      interrupts:
+        maxItems: 1
+
+    required:
+      - compatible
+      - reg
+      - clocks
+      - power-domains
+      - interrupts
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - power-domains
+  - memory-region
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/nxp,imx95-clock.h>
+
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+
+      vpu: video-codec@4c4c0000 {
Unused label, drop
+        compatible = "nxp,imx95-vpu";
+        reg = <0x0 0x4c4c0000 0x0 0x10000>;
+        clocks = <&vpu_blk_ctrl IMX95_CLK_VPUBLK_WAVE>;
+        power-domains = <&scmi_perf 10>;
+        memory-region = <&vpu_boot>;
+        sram = <&sram1>;
+        #cooling-cells = <2>;
+        #address-cells = <2>;
+        #size-cells = <2>;
+        ranges;
+
+        vpucore0: video-core@4c480000 {
None of these labels are used, drop.
+          compatible = "nxp,imx95-vpu-core";
+          reg = <0x0 0x4c480000 0x0 0x10000>;
+          clocks = <&scmi_clk 115>;
+          power-domains = <&scmi_devpd 21>;
+          interrupts = <GIC_SPI 299 IRQ_TYPE_LEVEL_HIGH>;
+        };
+
+        vpucore1: video-core@4c490000 {
+          compatible = "nxp,imx95-vpu-core";
+          reg = <0x0 0x4c490000 0x0 0x10000>;
+          clocks = <&scmi_clk 115>;
+          power-domains = <&scmi_devpd 21>;
+          interrupts = <GIC_SPI 300 IRQ_TYPE_LEVEL_HIGH>;
+        };
+


Best regards,
Krzysztof
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