[PATCH] dt-bindings: serial: 8250: allow "main" and "uart" as clock names

Yixun Lan dlan at gentoo.org
Mon Jul 28 15:53:19 PDT 2025


Hi Alex,

On 17:00 Mon 28 Jul     , Alex Elder wrote:
> There are two compatible strings defined in "8250.yaml" that require
> two clocks to be specified, along with their names:
>   - "spacemit,k1-uart", used in "spacemit/k1.dtsi"
>   - "nxp,lpc1850-uart", used in "lpc/lpc18xx.dtsi"
> 
> When only one clock is used, the name is not required.  However there
> are two places that do specify a name:
>   - In "mediatek/mt7623.dtsi", the clock for the "mediatek,mtk-btif"
>     compatible serial device is named "main"
>   - In "qca/ar9132.dtsi", the clock for the "ns8250" compatible
>     serial device is named "uart"
> 
> In commit d2db0d7815444 ("dt-bindings: serial: 8250: allow clock 'uartclk'
> and 'reg' for nxp,lpc1850-uart"), Frank Li added the restriction that two
> named clocks be used for the NXP platform mentioned above.  Extend that
> so that the two named clocks used by the SpacemiT platform are similarly
> restricted.
> 
> Add "main" and "uart" as allowed names when a single clock is specified.
> 
> Fixes: 2c0594f9f0629 ("dt-bindings: serial: 8250: support an optional second clock")
> Reported-by: kernel test robot <lkp at intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202507160314.wrC51lXX-lkp@intel.com/
> Signed-off-by: Alex Elder <elder at riscstar.com>
> ---
>  .../devicetree/bindings/serial/8250.yaml      | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/serial/8250.yaml b/Documentation/devicetree/bindings/serial/8250.yaml
> index e46bee8d25bf0..cef52ebd8f7da 100644
> --- a/Documentation/devicetree/bindings/serial/8250.yaml
> +++ b/Documentation/devicetree/bindings/serial/8250.yaml
> @@ -61,11 +61,17 @@ allOf:
>              - const: uartclk
>              - const: reg
..
>      else:
would it be better to drop this 'else', and moving following 'if' block
to the same level with "nxp,lpc1850-uart"?

the reason here would avoid too many indentions if add more constraint in
the future if other SoC uart need different clock-names..

> -      properties:
> -        clock-names:
> -          items:
> -            - const: core
> -            - const: bus
> +      if:
> +        properties:
> +          compatible:
> +            contains:
> +              const: spacemit,k1-uart
> +      then:
> +        properties:
> +          clock-names:
> +            items:
> +              - const: core
> +              - const: bus
>  
>  properties:
>    compatible:
> @@ -162,6 +168,9 @@ properties:
>      minItems: 1
>      maxItems: 2
>      oneOf:
> +      - enum:
> +          - main
> +          - uart
>        - items:
>            - const: core
>            - const: bus
> 
> base-commit: 0b90c3b6d76ea512dc3dac8fb30215e175b0019a
> -- 
> 2.48.1
> 

-- 
Yixun Lan (dlan)



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