Re: [PATCH] dt-bindings: ufs: amd,versal2-ufs: Add ref_clk clock property

[Conor Dooley <conor@kernel.org>]

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On Wed, Nov 11, 2026 at 10:08:40AM +0530, Ajay Neeli wrote:
> Add ref_clk clock property to specify the reference clock frequency
> supplied to the UFS device.
> 
> The AMD Versal2 UFS controller operates with a 26 MHz reference clock.
> UFS 3.x devices default their bRefClkFreq attribute to 26 MHz, matching
> the controller, so no explicit configuration is needed. However, UFS 4.0
> and later devices default bRefClkFreq to 52 MHz, expecting a 52 MHz
> reference clock. This mismatch causes timing violations and link
> instability.
> 
> Adding the ref_clk property allows the UFS driver to read the actual
> reference clock frequency from the devicetree and program the device
> bRefClkFreq attribute accordingly during initialization.
> 
> Signed-off-by: Ajay Neeli <ajay.neeli@amd.com>
> ---
>  .../devicetree/bindings/ufs/amd,versal2-ufs.yaml         | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/ufs/amd,versal2-ufs.yaml b/Documentation/devicetree/bindings/ufs/amd,versal2-ufs.yaml
> index c00ec342d574..e294c0f1b0ce 100644
> --- a/Documentation/devicetree/bindings/ufs/amd,versal2-ufs.yaml
> +++ b/Documentation/devicetree/bindings/ufs/amd,versal2-ufs.yaml
> @@ -20,11 +20,12 @@ properties:
>      maxItems: 1
>  
>    clocks:
> -    maxItems: 1
> +    maxItems: 2

Please add an items list here.

>  
>    clock-names:
>      items:
>        - const: core
> +      - const: ref_clk

its a clock by nature, don't restate that in the name.
pw-bot: changes-requested

Thanks,
Conor.

>  
>    power-domains:
>      maxItems: 1
> @@ -52,10 +53,10 @@ examples:
>      ufs@f10b0000 {
>          compatible = "amd,versal2-ufs";
>          reg = <0xf10b0000 0x1000>;
> -        clocks = <&ufs_core_clk>;
> -        clock-names = "core";
> +        clocks = <&ufs_core_clk>, <&ufs_ref_clk>;
> +        clock-names = "core", "ref_clk";
>          resets = <&scmi_reset 4>, <&scmi_reset 35>;
>          reset-names = "host", "phy";
>          interrupts = <GIC_SPI 234 IRQ_TYPE_LEVEL_HIGH>;
> -        freq-table-hz = <0 0>;
> +        freq-table-hz = <0 0>, <26000000 26000000>;
>      };
> -- 
> 2.43.7
> 
> 

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