The new STMicroelectronics SoC features a display controller similar to
the one used in previous SoCs.  Because there is additional registers,
and different mandatory clocks it is incompatible with existing IPs.  On
STM32MP251, the device only needs two clocks while on STM32MP255 it
needs four.

Add the new names to the list of compatible string and handle each
quirks accordingly.

Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
---
 .../devicetree/bindings/display/st,stm32-ltdc.yaml | 50 +++++++++++++++++++++-
 1 file changed, 48 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
index d6ea4d62a2cfae26353c9f20a326a4329fed3a2f..bcedcfef5427f5725a0473c09628e70d172c8f58 100644
--- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
+++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
@@ -12,7 +12,10 @@ maintainers:
 
 properties:
   compatible:
-    const: st,stm32-ltdc
+    enum:
+      - st,stm32-ltdc
+      - st,stm32mp251-ltdc
+      - st,stm32mp255-ltdc
 
   reg:
     maxItems: 1
@@ -24,11 +27,16 @@ properties:
     minItems: 1
 
   clocks:
-    maxItems: 1
+    minItems: 1
+    maxItems: 4
 
   clock-names:
     items:
       - const: lcd
+      - const: bus
+      - const: ref
+      - const: lvds
+    minItems: 1
 
   resets:
     maxItems: 1
@@ -51,6 +59,44 @@ required:
   - resets
   - port
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - st,stm32-ltdc
+    then:
+      properties:
+        clocks:
+          maxItems: 1
+        clock-names:
+          maxItems: 1
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - st,stm32mp251-ltdc
+    then:
+      properties:
+        clocks:
+          maxItems: 2
+        clock-names:
+          maxItems: 2
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - st,stm32mp255-ltdc
+    then:
+      properties:
+        clocks:
+          minItems: 4
+        clock-names:
+          minItems: 4
+
 additionalProperties: false
 
 examples:

-- 
2.25.1

Hi Raphael,

Thanks for the patch.

Acked-by: Yannick Fertre <yannick.fertre@foss.st.com>

Le 21/08/2025 à 13:08, Raphael Gallais-Pou a écrit :
> The new STMicroelectronics SoC features a display controller similar to
> the one used in previous SoCs.  Because there is additional registers,
> and different mandatory clocks it is incompatible with existing IPs.  On
> STM32MP251, the device only needs two clocks while on STM32MP255 it
> needs four.
>
> Add the new names to the list of compatible string and handle each
> quirks accordingly.
>
> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
> ---
>   .../devicetree/bindings/display/st,stm32-ltdc.yaml | 50 +++++++++++++++++++++-
>   1 file changed, 48 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> index d6ea4d62a2cfae26353c9f20a326a4329fed3a2f..bcedcfef5427f5725a0473c09628e70d172c8f58 100644
> --- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> +++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> @@ -12,7 +12,10 @@ maintainers:
>   
>   properties:
>     compatible:
> -    const: st,stm32-ltdc
> +    enum:
> +      - st,stm32-ltdc
> +      - st,stm32mp251-ltdc
> +      - st,stm32mp255-ltdc
>   
>     reg:
>       maxItems: 1
> @@ -24,11 +27,16 @@ properties:
>       minItems: 1
>   
>     clocks:
> -    maxItems: 1
> +    minItems: 1
> +    maxItems: 4
>   
>     clock-names:
>       items:
>         - const: lcd
> +      - const: bus
> +      - const: ref
> +      - const: lvds
> +    minItems: 1
>   
>     resets:
>       maxItems: 1
> @@ -51,6 +59,44 @@ required:
>     - resets
>     - port
>   
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - st,stm32-ltdc
> +    then:
> +      properties:
> +        clocks:
> +          maxItems: 1
> +        clock-names:
> +          maxItems: 1
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - st,stm32mp251-ltdc
> +    then:
> +      properties:
> +        clocks:
> +          maxItems: 2
> +        clock-names:
> +          maxItems: 2
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - st,stm32mp255-ltdc
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 4
> +        clock-names:
> +          minItems: 4
> +
>   additionalProperties: false
>   
>   examples:
>

On Thu, Aug 21, 2025 at 01:08:51PM +0200, Raphael Gallais-Pou wrote:
> +    then:
> +      properties:
> +        clocks:
> +          maxItems: 1
> +        clock-names:
> +          maxItems: 1
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - st,stm32mp251-ltdc
> +    then:
> +      properties:
> +        clocks:

minItems: 2

> +          maxItems: 2
> +        clock-names:

minItems: 2

Best regards,
Krzysztof

On 8/22/25 10:00, Krzysztof Kozlowski wrote:
> On Thu, Aug 21, 2025 at 01:08:51PM +0200, Raphael Gallais-Pou wrote:
>> +    then:
>> +      properties:
>> +        clocks:
>> +          maxItems: 1
>> +        clock-names:
>> +          maxItems: 1
>> +  - if:
>> +      properties:
>> +        compatible:
>> +          contains:
>> +            enum:
>> +              - st,stm32mp251-ltdc
>> +    then:
>> +      properties:
>> +        clocks:
> minItems: 2
>
>> +          maxItems: 2
>> +        clock-names:
> minItems: 2
>
> Best regards,
> Krzysztof

Dumb mistakes... I'll correct it in the upcoming version.

Thanks,
Best regards,

Raphaël
>