[PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[Vishnu Saini]

The DLC0697 panel is lit by a separate backlight device, which is
referenced from the panel node through the common 'backlight'
property.

Declare 'backlight: true' so the property is explicitly allowed by the
schema.

Signed-off-by: Vishnu Saini <vishnu.saini@oss.qualcomm.com>
---
 Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml b/Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml
index ba8c5bbf8ffc..46b941c18565 100644
--- a/Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml
+++ b/Documentation/devicetree/bindings/display/panel/ilitek,ili7807s.yaml
@@ -23,6 +23,8 @@ properties:
     maxItems: 1
     description: DSI virtual channel
 
+  backlight: true
+
   vddi-supply:
     description: I/O voltage supply (1.8V)
 

---
base-commit: cf61bef3801c3c9d0d8c39026b7b2fb242898a3a
change-id: 20261025-dlc_backlight-c00d00ec8f62

Best regards,
-- 
Vishnu Saini <vishnu.saini@oss.qualcomm.com>

Re: [PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[Krzysztof Kozlowski]

On Sun, Oct 25, 2026 at 12:18:17PM +0530, Vishnu Saini wrote:
> The DLC0697 panel is lit by a separate backlight device, which is
> referenced from the panel node through the common 'backlight'
> property.
> 
> Declare 'backlight: true' so the property is explicitly allowed by the
> schema.

Why do you need to explicitly allow it? Since when?

I see no benefit of this patch and commit msg does not explain me what
that benefit would be.

Best regards,
Krzysztof

Re: [PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[Vishnu Saini]

On Tue, Oct 27, 2026 at 09:12:27AM +0100, Krzysztof Kozlowski wrote:
> On Sun, Oct 25, 2026 at 12:18:17PM +0530, Vishnu Saini wrote:
> > The DLC0697 panel is lit by a separate backlight device, which is
> > referenced from the panel node through the common 'backlight'
> > property.
> > 
> > Declare 'backlight: true' so the property is explicitly allowed by the
> > schema.
> 
> Why do you need to explicitly allow it? Since when?
> 
> I see no benefit of this patch and commit msg does not explain me what
> that benefit would be.
It is required for below DLC panel, when enabling backlight using gpio-backlight driver,
Apologies, missed to add this in dependency there.
https://lore.kernel.org/all/20261021-shikra_display_overlays-v1-2-adaea735999f@oss.qualcomm.com/
> Best regards,
> Krzysztof
> 

Re: [PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[Krzysztof Kozlowski]

On 27/10/2026 11:57, Vishnu Saini wrote:
> On Tue, Oct 27, 2026 at 09:12:27AM +0100, Krzysztof Kozlowski wrote:
>> On Sun, Oct 25, 2026 at 12:18:17PM +0530, Vishnu Saini wrote:
>>> The DLC0697 panel is lit by a separate backlight device, which is
>>> referenced from the panel node through the common 'backlight'
>>> property.
>>>
>>> Declare 'backlight: true' so the property is explicitly allowed by the
>>> schema.
>>
>> Why do you need to explicitly allow it? Since when?
>>
>> I see no benefit of this patch and commit msg does not explain me what
>> that benefit would be.
> It is required for below DLC panel, when enabling backlight using gpio-backlight driver,

How is it required? You did not really answer, so again:

Why do you need to explicitly allow it?

Answer starts "because ... " and you provide technical arguments, not
wishes.


Best regards,
Krzysztof

Re: [PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[Vishnu Saini]

On Tue, Oct 27, 2026 at 03:34:19PM +0100, Krzysztof Kozlowski wrote:
> On 27/10/2026 11:57, Vishnu Saini wrote:
> > On Tue, Oct 27, 2026 at 09:12:27AM +0100, Krzysztof Kozlowski wrote:
> >> On Sun, Oct 25, 2026 at 12:18:17PM +0530, Vishnu Saini wrote:
> >>> The DLC0697 panel is lit by a separate backlight device, which is
> >>> referenced from the panel node through the common 'backlight'
> >>> property.
> >>>
> >>> Declare 'backlight: true' so the property is explicitly allowed by the
> >>> schema.
> >>
> >> Why do you need to explicitly allow it? Since when?
> >>
> >> I see no benefit of this patch and commit msg does not explain me what
> >> that benefit would be.
> > It is required for below DLC panel, when enabling backlight using gpio-backlight driver,
> 
> How is it required? You did not really answer, so again:
> 
> Why do you need to explicitly allow it?
> 
> Answer starts "because ... " and you provide technical arguments, not
> wishes.
Because the DLC panel node references an external gpio-backlight device through the
backlight property, but the current DLC binding does not allow this property.
As a result, adding the backlight phandle to the panel node causes a dtbs_check validation error.

Adding backlight: true to the binding allows the common panel backlight property used by this DT. 
I will improve the commit message.

> 
> Best regards,
> Krzysztof

Re: [PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[Krzysztof Kozlowski]

On 27/10/2026 19:18, Vishnu Saini wrote:
>>>>> Declare 'backlight: true' so the property is explicitly allowed by the
>>>>> schema.
>>>>
>>>> Why do you need to explicitly allow it? Since when?
>>>>
>>>> I see no benefit of this patch and commit msg does not explain me what
>>>> that benefit would be.
>>> It is required for below DLC panel, when enabling backlight using gpio-backlight driver,
>>
>> How is it required? You did not really answer, so again:
>>
>> Why do you need to explicitly allow it?
>>
>> Answer starts "because ... " and you provide technical arguments, not
>> wishes.
> Because the DLC panel node references an external gpio-backlight device through the
> backlight property, but the current DLC binding does not allow this property.
> As a result, adding the backlight phandle to the panel node causes a dtbs_check validation error.

Thanks, but that's confusing or we looked at different source code,
because to my eyes it clearly lists backlight already. Can you show me
how can I reproduce the dtbs_check error?


Best regards,
Krzysztof

Re: [PATCH] dt-bindings: display: panel: ilitek,ili7807s: Allow backlight property

[Vishnu Saini]

On Tue, Oct 27, 2026 at 07:24:08PM +0100, Krzysztof Kozlowski wrote:
> On 27/10/2026 19:18, Vishnu Saini wrote:
> >>>>> Declare 'backlight: true' so the property is explicitly allowed by the
> >>>>> schema.
> >>>>
> >>>> Why do you need to explicitly allow it? Since when?
> >>>>
> >>>> I see no benefit of this patch and commit msg does not explain me what
> >>>> that benefit would be.
> >>> It is required for below DLC panel, when enabling backlight using gpio-backlight driver,
> >>
> >> How is it required? You did not really answer, so again:
> >>
> >> Why do you need to explicitly allow it?
> >>
> >> Answer starts "because ... " and you provide technical arguments, not
> >> wishes.
> > Because the DLC panel node references an external gpio-backlight device through the
> > backlight property, but the current DLC binding does not allow this property.
> > As a result, adding the backlight phandle to the panel node causes a dtbs_check validation error.
> 
> Thanks, but that's confusing or we looked at different source code,
> because to my eyes it clearly lists backlight already. Can you show me
> how can I reproduce the dtbs_check error?
You are right. I was looking at an older version of the binding which used additionalProperties: false.
The current binding uses unevaluatedProperties: false and references panel-common.yaml,
where the backlight property is already defined.
Therefore, I cannot reproduce the dtbs_check error with the current binding.
Thanks for pointing this out. This patch is redundent.
 
> 
> Best regards,
> Krzysztof