Re: [PATCH v2 1/2] media: dt-bindings: allwinner: video-engine: Fix number of IOMMU channels

On 17/11/2022 21:31, Jernej Škrabec wrote:

Dne četrtek, 17. november 2022 ob 14:13:00 CET je Krzysztof Kozlowski 
napisal(a):

quoted

On 17/11/2022 07:07, Jernej Skrabec wrote:

quoted

Cedrus (video engine) on Allwinner H6 actually uses two IOMMU channel,
not just one. However, Cedrus on SoCs like D1 only uses one channel.

Allow up to 2 IOMMU channels.

Fixes: 62a8ccf3a248 ("arm64: dts: allwinner: h6: Fix Cedrus IOMMU usage")
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
---

 .../bindings/media/allwinner,sun4i-a10-video-engine.yaml       | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git
a/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-video-engin
e.yaml
b/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-video-engin
e.yaml index 541325f900a1..6446004d59d9 100644
---
a/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-video-engin
e.yaml +++
b/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-video-engin
e.yaml> 

@@ -55,7 +55,8 @@ properties:
     description: Phandle to the device SRAM
   
   iommus:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2

You have several compatibles in the file, so usually this is further
constrained per each variant in allOf:if:then:.

Usually, yes. But this whole binding would need update. It has a few optional 
properties and none of them is tied to any compatible. Additionally, if I do 
it as you suggest, then Robs automatic test will report the issue, because 
existing H6 based boards won't match this binding anymore. I would much rather 
send follow up patch which clears up all optional properties.

I don't understand last argument. It's basically like saying - I keep
bindings not really correct, because otherwise I would see warnings and
I would need to fix them.

If this can be constrained per variant, constrain it and then fix the
boards.
Best regards,
Krzysztof