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

Jernej Škrabec
2022-11-17T20:32:59Z

Dne četrtek, 17. november 2022 ob 14:13:00 CET je Krzysztof Kozlowski
napisal(a):
> On 17/11/2022 07:07, Jernej Skrabec wrote:
> > 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.

Best regards,
Jernej