Re: [PATCH 1/6] media: dt-bindings: Document SC8280XP/SM8350 Venus

On 7.08.2023 20:44, Bryan O'Donoghue wrote:

On 07/08/2023 16:02, Konrad Dybcio wrote:

quoted

On 7.08.2023 16:04, Krzysztof Kozlowski wrote:

quoted

On 07/08/2023 14:41, Konrad Dybcio wrote:

quoted

On 5.08.2023 21:29, Krzysztof Kozlowski wrote:

quoted

On 04/08/2023 22:09, Konrad Dybcio wrote:

quoted

Both of these SoCs implement an IRIS2 block, with SC8280XP being able
to clock it a bit higher.

...

quoted

+
+  iommus:
+    maxItems: 1
+
+  video-decoder:
+    type: object
+
+    properties:
+      compatible:
+        const: venus-decoder

That's not how compatibles are constructed... missing vendor prefix, SoC
or IP block name.

quoted

+
+    required:
+      - compatible
+
+    additionalProperties: false

Why do you need this child node? Child nodes without properties are
usually useless.

For both comments: I aligned with what was there..

The driver abuses these compats to probe enc/dec submodules, even though
every Venus implementation (to my knowledge) is implicitly enc/dec capable..

Holy crap, I see...

quoted

Perhaps a bigger clean-up is due. I guess I could just create the venc/vdec
devices from the venus core probe and get rid of this fake stuff?

Few devices (qcom,msm8996-venus.yaml, sdm660, sdm845) have clocks there,
so we actually could stay with these subnodes, just correct the
compatibles to a list with correct prefixes:

qcom,sc8280xp-venus-decoder + qcom,venus-decoder

Hm.. looks like pre-845-v2 (with the v2 being "v2 binding" and not
"v2 chip" or "v2 hardware") these were used to look up clocks but
then they were moved to the root node.

I am not quite sure if it makes sense to distinguish e.g.
sc8280xp-venus-decoder within sc8280xp-venus..

Perhaps deprecating the "8916 way" (clocks under subnodes), adding
some boilerplate to look up clocks/pds in both places and converting
everybody to the "7180 way" way of doing things (clocks under venus),
and then getting rid of venus encoder/decoder completely (by calling
device creation from venus probe) would be better. WDYT?

Konrad

As I understand it though, for some classes of venus hardware - earlier, it was possible to have two encoders or two decoders and it really didn't - perhaps still doesn't matter which order they are declared in.

That's the logic behind having a compat string that assigns either encoder or decoder to one of the logical blocks.

You can have any mixture of
- encoder
- decoder

- encoder
- encoder

- decoder
- decoder

- decoder
- encoder

- encoder

- decoder

I think it should *still* be the case - whether it is a practical reality or not, that any of those mapping can be selected and supported.

That can be taken care of with match data.

Konrad