Boards that use the STM32F{4,7} series have limited amounts of RAM. The
added property allows to size, within certain limits, the memory footprint
required by the framebuffer.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

(no changes since v1)

 .../devicetree/bindings/display/st,stm32-ltdc.yaml          | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
index d6ea4d62a2cf..1c3a3653579f 100644
--- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
+++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
@@ -42,6 +42,12 @@ properties:
       - for internal dpi input of the MIPI DSI host controller.
       Note: These 2 endpoints cannot be activated simultaneously.
 
+  st,fb-bpp:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      bit depth of framebuffer (8, 16 or 32)
+    maxItems: 1
+
 required:
   - compatible
   - reg
-- 
2.32.0

Hey,

On Mon, Jun 19, 2023 at 06:55:23PM +0200, Dario Binacchi wrote:
> Boards that use the STM32F{4,7} series have limited amounts of RAM. The
> added property allows to size, within certain limits, the memory footprint
> required by the framebuffer.

Hmm, this sounds quite a lot like "software policy", since the actual
display doesn't have these limitations. Rob, Krzysztof?

> 
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> ---
> 
> (no changes since v1)

Really?
https://lore.kernel.org/all/?q=dfn:st,stm32-ltdc.yaml%20

You sure this shouldn't be "new in v4"?

>  .../devicetree/bindings/display/st,stm32-ltdc.yaml          | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> index d6ea4d62a2cf..1c3a3653579f 100644
> --- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> +++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> @@ -42,6 +42,12 @@ properties:
>        - for internal dpi input of the MIPI DSI host controller.
>        Note: These 2 endpoints cannot be activated simultaneously.
>  
> +  st,fb-bpp:

Is there not a more understandable property name than this?
Maybe I just had to think about it because fbdev stuff aint something
I've worked with...

> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      bit depth of framebuffer (8, 16 or 32)
> +    maxItems: 1

Why not make it an enum, since there are only 4 values?

Cheers,
Conor.

> +
>  required:
>    - compatible
>    - reg
> -- 
> 2.32.0
> 

On Mon, Jun 19, 2023 at 09:18:25PM +0100, Conor Dooley wrote:
> Hey,
> 
> On Mon, Jun 19, 2023 at 06:55:23PM +0200, Dario Binacchi wrote:
> > Boards that use the STM32F{4,7} series have limited amounts of RAM. The
> > added property allows to size, within certain limits, the memory footprint
> > required by the framebuffer.
> 
> Hmm, this sounds quite a lot like "software policy", since the actual
> display doesn't have these limitations. Rob, Krzysztof?

Indeed. This doesn't belong in DT.

Rob

On Mon, 19 Jun 2023 18:55:23 +0200, Dario Binacchi wrote:
> Boards that use the STM32F{4,7} series have limited amounts of RAM. The
> added property allows to size, within certain limits, the memory footprint
> required by the framebuffer.
> 
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> ---
> 
> (no changes since v1)
> 
>  .../devicetree/bindings/display/st,stm32-ltdc.yaml          | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml: properties:st,fb-bpp:maxItems: False schema does not allow 1
	from schema $id: http://devicetree.org/meta-schemas/core.yaml#

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20230619165525.1035243-5-dario.binacchi@amarulasolutions.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.