[PATCH v2] dt-bindings: display: mediatek: split: add clocks count constraint for MT8195

[Moudy Ho (何宗原)]

Hi CK,

On Fri, 2024-09-27 at 09:01 +0000, CK Hu (胡俊光) wrote:
> Hi, Moudy:
> 
> On Fri, 2024-09-27 at 13:51 +0800, Moudy Ho wrote:
> > From: Moudy Ho <moudy.ho at mediatek.corp-partner.google.com>
> > 
> > The display node in mt8195.dtsi was triggering a CHECK_DTBS error
> > due
> > to an excessively long 'clocks' property:
> >   display at 14f06000: clocks: [[31, 14], [31, 43], [31, 44]] is too
> > long
> > 
> > To resolve this issue, apply the limit by setting 'maxItems: 3' in
> > MT8195
> > additional condition.
> 
> I think the main purpose of this patch is not to add limitation.
> The main purpose is that you add HDMI RX Clock and HDMI Metadata
> Clock.
> Could you describe more about these two clock?
> mt8173-disp-split could work without these two clocks. Why mt8195-
> mdp3-split need these two clocks?
> 

Thanks for the reminder.
In hardware design, SPLIT must enable additional clocks based on its
front-end signal source, and this also implies its position in the
display pipeline.
I will elaborate further on this part of the description.

> > 
> > Fixes: 4ed545e7d100 ("dt-bindings: display: mediatek: disp: split
> > each block to individual yaml")
> 
> The fixes patch should be 739058a9c5c3 ("dt-bindings: display:
> mediatek: split: add compatible for MT8195")
> 
> Regards,
> CK
> 

It will be corrected in the next version.

Sincerely,
Moudy Ho
> > Signed-off-by: Macpaul Lin <macpaul.lin at mediatek.com>
> > Signed-off-by: Moudy Ho <moudy.ho at mediatek.com>
> > --
> > The purpose of this patch is to separate the corrections for
> > MediaTek SPLIT CHECK_DTBS error from the original mailing list
> > mentioned below:
> > 
https://lore.kernel.org/all/20240924103156.13119-2-macpaul.lin@mediatek.com/
> > 
> > Changes since v1:
> >   - Adding functional descriptions and quantity restrictions.
> > ---
> >  .../bindings/display/mediatek/mediatek,split.yaml           | 6
> > ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/display/mediatek/mediatek,split
> > .yaml
> > b/Documentation/devicetree/bindings/display/mediatek/mediatek,split
> > .yaml
> > index e4affc854f3d..bce1b8b866ce 100644
> > ---
> > a/Documentation/devicetree/bindings/display/mediatek/mediatek,split
> > .yaml
> > +++
> > b/Documentation/devicetree/bindings/display/mediatek/mediatek,split
> > .yaml
> > @@ -57,6 +57,9 @@ properties:
> >    clocks:
> >      items:
> >        - description: SPLIT Clock
> > +      - description: HDMI RX Clock
> > +      - description: HDMI Metadata Clock
> > +    minItems: 1
> >  
> >  required:
> >    - compatible
> > @@ -72,6 +75,9 @@ allOf:
> >              const: mediatek,mt8195-mdp3-split
> >  
> >      then:
> > +      properties:
> > +        clocks:
> > +          maxItems: 3
> >        required:
> >          - mediatek,gce-client-reg
> >