[PATCH v2] dt-bindings: serial: 8250: allow "main" and "uart" as clock names

[PATCH v2] dt-bindings: serial: 8250: allow "main" and "uart" as clock names

[Alex Elder]

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.

Change that logic, so that an additional condition for (only) the
SpacemiT platform similarly restricts the two clocks to have the
names "core" and "bus".

Finally, 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@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202507160314.wrC51lXX-lkp@intel.com/
Signed-off-by: Alex Elder <elder@riscstar.com>
---
 Documentation/devicetree/bindings/serial/8250.yaml | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/serial/8250.yaml b/Documentation/devicetree/bindings/serial/8250.yaml
index e46bee8d25bf0..0a05a1647b5cc 100644
--- a/Documentation/devicetree/bindings/serial/8250.yaml
+++ b/Documentation/devicetree/bindings/serial/8250.yaml
@@ -60,7 +60,12 @@ allOf:
           items:
             - const: uartclk
             - const: reg
-    else:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: spacemit,k1-uart
+    then:
       properties:
         clock-names:
           items:
@@ -162,6 +167,9 @@ properties:
     minItems: 1
     maxItems: 2
     oneOf:
+      - enum:
+          - main
+          - uart
       - items:
           - const: core
           - const: bus

base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
-- 
2.48.1


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Re: [PATCH v2] dt-bindings: serial: 8250: allow "main" and "uart" as clock names

[Conor Dooley]

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On Tue, Aug 12, 2025 at 10:13:35PM -0500, 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.
> 
> Change that logic, so that an additional condition for (only) the
> SpacemiT platform similarly restricts the two clocks to have the
> names "core" and "bus".
> 
> Finally, 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@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202507160314.wrC51lXX-lkp@intel.com/
> Signed-off-by: Alex Elder <elder@riscstar.com>

Acked-by: Conor Dooley <conor.dooley@microchip.com>

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