Re: [PATCH 1/2] dt-bindings: nvmem: imx-iim: Allow syscon fallback on i.MX5

[Conor Dooley <conor@kernel.org>]

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On Fri, Oct 16, 2026 at 08:27:59PM -0300, Fabio Estevam wrote:
> The i.MX51 and i.MX53 SoC device code reads the unique ID through
> syscon_regmap_lookup_by_compatible(). Their IIM nodes therefore need the
> syscon fallback so the syscon core can instantiate a regmap.
> 
> Allow the two-item compatible sequence for these SoCs. This prepares for
> restoring the fallback removed while making the IIM nodes conform to the
> binding.

Making it a syscon is only the right thing to do if it genuinely is a
syscon. If it's not, then don't. The nvmem driver doesn't treat this as
a syscon, so the inbuilt regmap locking doesn't actually do anything
here.
Surely the right thing to do is for the soc driver to access the efuse
through the nvmem subsystem somehow?

> 
> Cc: stable@vger.kernel.org
> Fixes: d5b55c35e033 ("ARM: dts: imx: Fix the iim compatible string")

A binding should not have a fixes tag pointing to a devicetree.

> Signed-off-by: Fabio Estevam <festevam@gmail.com>
> ---
>  .../devicetree/bindings/nvmem/imx-iim.yaml    | 20 +++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/nvmem/imx-iim.yaml b/Documentation/devicetree/bindings/nvmem/imx-iim.yaml
> index bb37d72c9eaa..ebfd947e6800 100644
> --- a/Documentation/devicetree/bindings/nvmem/imx-iim.yaml
> +++ b/Documentation/devicetree/bindings/nvmem/imx-iim.yaml
> @@ -20,13 +20,17 @@ allOf:
>  
>  properties:
>    compatible:
> -    enum:
> -      - fsl,imx25-iim
> -      - fsl,imx27-iim
> -      - fsl,imx31-iim
> -      - fsl,imx35-iim
> -      - fsl,imx51-iim
> -      - fsl,imx53-iim
> +    oneOf:
> +      - enum:
> +          - fsl,imx25-iim
> +          - fsl,imx27-iim
> +          - fsl,imx31-iim
> +          - fsl,imx35-iim
> +      - items:
> +          - enum:
> +              - fsl,imx51-iim
> +              - fsl,imx53-iim
> +          - const: syscon
>  
>    reg:
>      maxItems: 1
> @@ -50,7 +54,7 @@ examples:
>      #include <dt-bindings/clock/imx5-clock.h>
>  
>      iim: efuse@63f98000 {
> -        compatible = "fsl,imx53-iim";
> +        compatible = "fsl,imx53-iim", "syscon";
>          reg = <0x63f98000 0x4000>;
>          interrupts = <69>;
>          clocks = <&clks IMX5_CLK_IIM_GATE>;
> -- 
> 2.43.0
> 

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