[PATCH] dt-bindings: display: bridge: nxp,tda998x: Add missing clocks

[PATCH] dt-bindings: display: bridge: nxp,tda998x: Add missing clocks

[Geert Uytterhoeven]

Some TDA998x variants (e.g. TDA19988) have an OSC_IN pin, to connect
an external oscillator circuit or clock source.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
This fixes "make dtbs_check":

    arch/arm64/boot/dts/renesas/r8a774c0-ek874-mipi-2.1.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
    arch/arm64/boot/dts/renesas/r8a774c0-cat874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
    arch/arm64/boot/dts/renesas/r8a774c0-ek874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
    arch/arm64/boot/dts/renesas/r8a774c0-ek874-idk-2121wr.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml

This patch can be considered v3 of "[PATCH v2 2/3] [RFC] arm64: dts:
renesas: cat874: Drop bogus clocks property"[1], as the pin is actually
connected to a clock source on that board.  On BeagleBone Black, it is
also connected to a clock source, but not described in DT.

The linux driver does not use this clock directly, but I suspect[2] the
use of this pin is controlled through the AP_ENA register value, as
specified in the second cell of the the audio-ports property.

[1] https://lore.kernel.org/97b949cddd7e30e9c05873800330dccd3483b12b.1663165552.git.geert+renesas@glider.be
[2] I do not have access to the programming manual.
---
 .../devicetree/bindings/display/bridge/nxp,tda998x.yaml        | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
index 3fce9e698ea1d2dd..1205c8e9de329bbc 100644
--- a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
@@ -19,6 +19,9 @@ properties:
   interrupts:
     maxItems: 1
 
+  clocks:
+    maxItems: 1
+
   video-ports:
     $ref: /schemas/types.yaml#/definitions/uint32
     default: 0x230145
-- 
2.43.0

Re: [PATCH] dt-bindings: display: bridge: nxp,tda998x: Add missing clocks

[Laurent Pinchart]

Hi Geert,

Thank you for the patch.

On Mon, Jan 12, 2026 at 05:02:40PM +0100, Geert Uytterhoeven wrote:
> Some TDA998x variants (e.g. TDA19988) have an OSC_IN pin, to connect
> an external oscillator circuit or clock source.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> This fixes "make dtbs_check":
> 
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874-mipi-2.1.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-cat874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874-idk-2121wr.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
> 
> This patch can be considered v3 of "[PATCH v2 2/3] [RFC] arm64: dts:
> renesas: cat874: Drop bogus clocks property"[1], as the pin is actually
> connected to a clock source on that board.  On BeagleBone Black, it is
> also connected to a clock source, but not described in DT.
> 
> The linux driver does not use this clock directly, but I suspect[2] the
> use of this pin is controlled through the AP_ENA register value, as
> specified in the second cell of the the audio-ports property.
> 
> [1] https://lore.kernel.org/97b949cddd7e30e9c05873800330dccd3483b12b.1663165552.git.geert+renesas@glider.be
> [2] I do not have access to the programming manual.
> ---
>  .../devicetree/bindings/display/bridge/nxp,tda998x.yaml        | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> index 3fce9e698ea1d2dd..1205c8e9de329bbc 100644
> --- a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> @@ -19,6 +19,9 @@ properties:
>    interrupts:
>      maxItems: 1
>  
> +  clocks:
> +    maxItems: 1
> +

I wonder if we should add a compatible string for the variants with a
clock pin, to let drivers manage the clock.

If the clock does not need to be controlled, an alternative would be to
drop the clocks property from
arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts.

>    video-ports:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      default: 0x230145

-- 
Regards,

Laurent Pinchart

Re: [PATCH] dt-bindings: display: bridge: nxp,tda998x: Add missing clocks

[Geert Uytterhoeven]

Hi Laurent,

On Mon, 12 Jan 2026 at 18:50, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> On Mon, Jan 12, 2026 at 05:02:40PM +0100, Geert Uytterhoeven wrote:
> > Some TDA998x variants (e.g. TDA19988) have an OSC_IN pin, to connect
> > an external oscillator circuit or clock source.
> >
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > ---
> > This fixes "make dtbs_check":
> >
> >     arch/arm64/boot/dts/renesas/r8a774c0-ek874-mipi-2.1.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> >           from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
> >     arch/arm64/boot/dts/renesas/r8a774c0-cat874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> >           from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
> >     arch/arm64/boot/dts/renesas/r8a774c0-ek874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> >           from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
> >     arch/arm64/boot/dts/renesas/r8a774c0-ek874-idk-2121wr.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> >           from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
> >
> > This patch can be considered v3 of "[PATCH v2 2/3] [RFC] arm64: dts:
> > renesas: cat874: Drop bogus clocks property"[1], as the pin is actually
> > connected to a clock source on that board.  On BeagleBone Black, it is
> > also connected to a clock source, but not described in DT.
> >
> > The linux driver does not use this clock directly, but I suspect[2] the
> > use of this pin is controlled through the AP_ENA register value, as
> > specified in the second cell of the the audio-ports property.
> >
> > [1] https://lore.kernel.org/97b949cddd7e30e9c05873800330dccd3483b12b.1663165552.git.geert+renesas@glider.be
> > [2] I do not have access to the programming manual.
> > ---
> >  .../devicetree/bindings/display/bridge/nxp,tda998x.yaml        | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> > index 3fce9e698ea1d2dd..1205c8e9de329bbc 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> > +++ b/Documentation/devicetree/bindings/display/bridge/nxp,tda998x.yaml
> > @@ -19,6 +19,9 @@ properties:
> >    interrupts:
> >      maxItems: 1
> >
> > +  clocks:
> > +    maxItems: 1
> > +
>
> I wonder if we should add a compatible string for the variants with a
> clock pin, to let drivers manage the clock.

I am not sure if that is necessary, as the clock is optional, and thus
devm_clk_get_optional() can just be added to the driver.

> If the clock does not need to be controlled, an alternative would be to

I think the driver should control the clock. Currently it works by
accident, as on (at least) cat874 and boneblack the external clock is
a fixed clock that is always running.

A simple solution would be to use e.g. devm_clk_get_optional_enabled().
A more complex solution would probably involve using the AP_ENA
register value.  Anyone who has the programming manual for tda998x?

> drop the clocks property from
> arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts.

Cfr. my RFC v2 linked above[1] ;-)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] dt-bindings: display: bridge: nxp,tda998x: Add missing clocks

[Rob Herring (Arm)]

On Mon, 12 Jan 2026 17:02:40 +0100, Geert Uytterhoeven wrote:
> Some TDA998x variants (e.g. TDA19988) have an OSC_IN pin, to connect
> an external oscillator circuit or clock source.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> This fixes "make dtbs_check":
> 
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874-mipi-2.1.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-cat874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
>     arch/arm64/boot/dts/renesas/r8a774c0-ek874-idk-2121wr.dtb: tda19988@70 (nxp,tda998x): Unevaluated properties are not allowed ('clocks' was unexpected)
> 	    from schema $id: http://devicetree.org/schemas/display/bridge/nxp,tda998x.yaml
> 
> This patch can be considered v3 of "[PATCH v2 2/3] [RFC] arm64: dts:
> renesas: cat874: Drop bogus clocks property"[1], as the pin is actually
> connected to a clock source on that board.  On BeagleBone Black, it is
> also connected to a clock source, but not described in DT.
> 
> The linux driver does not use this clock directly, but I suspect[2] the
> use of this pin is controlled through the AP_ENA register value, as
> specified in the second cell of the the audio-ports property.
> 
> [1] https://lore.kernel.org/97b949cddd7e30e9c05873800330dccd3483b12b.1663165552.git.geert+renesas@glider.be
> [2] I do not have access to the programming manual.
> ---
>  .../devicetree/bindings/display/bridge/nxp,tda998x.yaml        | 3 +++
>  1 file changed, 3 insertions(+)
> 

Applied, thanks!