Re: [PATCH RESEND 04/22] dt-bindings: clock: sun8i de2 clock: Add a100/a133 compatible

[Andre Przywara <andre.przywara@arm.com>]

On Fri, 27 Dec 2024 18:30:53 +0530
Parthiban Nallathambi <parthiban@linumiz.com> wrote:

Hi,

> A100/A133 uses one mixer without rotation support, which is same
> as sun8i v3s. Add it with fallback to v3s compatible.
> 
> Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>
> ---
>  .../devicetree/bindings/clock/allwinner,sun8i-a83t-de2-clk.yaml       | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/clock/allwinner,sun8i-a83t-de2-clk.yaml b/Documentation/devicetree/bindings/clock/allwinner,sun8i-a83t-de2-clk.yaml
> index 3e00905b66ca..ed038967929b 100644
> --- a/Documentation/devicetree/bindings/clock/allwinner,sun8i-a83t-de2-clk.yaml
> +++ b/Documentation/devicetree/bindings/clock/allwinner,sun8i-a83t-de2-clk.yaml
> @@ -23,6 +23,7 @@ properties:
>        - const: allwinner,sun8i-h3-de2-clk
>        - const: allwinner,sun8i-v3s-de2-clk
>        - const: allwinner,sun50i-a64-de2-clk
> +      - const: allwinner,sun50i-a100-de2-clk
>        - const: allwinner,sun50i-h5-de2-clk
>        - const: allwinner,sun50i-h6-de3-clk
>        - items:
> @@ -31,6 +32,9 @@ properties:
>        - items:
>            - const: allwinner,sun20i-d1-de2-clk
>            - const: allwinner,sun50i-h5-de2-clk
> +      - items:
> +          - const: allwinner,sun50i-a100-de2-clk
> +          - const: allwinner,sun8i-v3s-de2-clk

Wait, does this add the same compatible string twice, once as a
standalone, once with a fallback? This doesn't look right.

If you positively know already about an incompatibility, just provide the
single string. If you suspect there *might* be something, use the fallback
version for now, and we can revisit that later.

Also please note that the semantics of the fallback is:
"Any driver supporting only the V3s can also support the A100 version of
the clock, as the new device is either fully compatible or a subset of the
old one."

So what would it be then here? The driver patch [16/22] suggests it's
compatible, but that might just cover the part that the Linux driver
implements? If it is compatible, you wouldn't need any change to the
driver code at all, the DT core code takes care of matching the driver
using the fallback.

Cheers,
Andre

>  
>    reg:
>      maxItems: 1
>