[PATCH] arm64: dts: Add no-hpd property for all ti-sn65dsi86 bridge consumers

[PATCH] arm64: dts: Add no-hpd property for all ti-sn65dsi86 bridge consumers

[Jayesh Choudhary]

In the SN65DSI86 DSI-2-eDP bridge, HPD is not supported as of now.
But DisplayPort connector_type usecases does need hpd to be enabled.
In order not to break any platform from those driver changes, add
"no-hpd" property to all the existing sn65dsi86 nodes (that don't
have it already) as hpd is not being used there anyways.

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
---

Upcoming driver changes that will break platforms if we do not have this
property in all the existing sn65dsi86 nodes that assumes hpd is disabled:
<https://lore.kernel.org/all/20250529110418.481756-1-j-choudhary@ti.com/>

(sc7180-trogdor-ti-sn65dsi86.dtsi, sdm850-lenovo-yoga-c630.dts and
sdm845-cheza.dtsi already have this property.)

NOTE: Grouping the logical changes together in a single patch even though
we have multiple vendor dts. I hope that is not an issue.

 .../boot/dts/amlogic/meson-g12b-bananapi-cm4-mnt-reform2.dts     | 1 +
 arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts             | 1 +
 arch/arm64/boot/dts/qcom/sc7180-acer-aspire1.dts                 | 1 +
 arch/arm64/boot/dts/renesas/r8a779a0-falcon-cpu.dtsi             | 1 +
 arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts            | 1 +
 arch/arm64/boot/dts/renesas/r8a779h0-gray-hawk-single.dts        | 1 +
 arch/arm64/boot/dts/renesas/white-hawk-cpu-common.dtsi           | 1 +
 7 files changed, 7 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-bananapi-cm4-mnt-reform2.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-bananapi-cm4-mnt-reform2.dts
index 0f48c32bec97..6a7d7db3ef8f 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12b-bananapi-cm4-mnt-reform2.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-g12b-bananapi-cm4-mnt-reform2.dts
@@ -292,6 +292,7 @@ edp_bridge: bridge@2c {
 		vpll-supply = <&reg_main_1v8>;
 		vcca-supply = <&reg_main_1v2>;
 		vcc-supply = <&reg_main_1v2>;
+		no-hpd;
 
 		ports {
 			#address-cells = <1>;
diff --git a/arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts b/arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts
index 3ae3824be027..599a53969326 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts
@@ -147,6 +147,7 @@ edp_bridge: bridge@2c {
 		vpll-supply = <&reg_main_1v8>;
 		vcca-supply = <&reg_main_1v2>;
 		vcc-supply = <&reg_main_1v2>;
+		no-hpd;
 
 		ports {
 			#address-cells = <1>;
diff --git a/arch/arm64/boot/dts/qcom/sc7180-acer-aspire1.dts b/arch/arm64/boot/dts/qcom/sc7180-acer-aspire1.dts
index 672ac4c3afa3..8fa18273684f 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-acer-aspire1.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-acer-aspire1.dts
@@ -384,6 +384,7 @@ sn65dsi86_bridge: bridge@2c {
 
 		clocks = <&rpmhcc RPMH_LN_BB_CLK3>;
 		clock-names = "refclk";
+		no-hpd;
 
 		ports {
 			#address-cells = <1>;
diff --git a/arch/arm64/boot/dts/renesas/r8a779a0-falcon-cpu.dtsi b/arch/arm64/boot/dts/renesas/r8a779a0-falcon-cpu.dtsi
index 0916fd57d1f1..a115e3fc4cb9 100644
--- a/arch/arm64/boot/dts/renesas/r8a779a0-falcon-cpu.dtsi
+++ b/arch/arm64/boot/dts/renesas/r8a779a0-falcon-cpu.dtsi
@@ -214,6 +214,7 @@ bridge@2c {
 		vpll-supply = <&reg_1p8v>;
 		vcca-supply = <&reg_1p2v>;
 		vcc-supply = <&reg_1p2v>;
+		no-hpd;
 
 		ports {
 			#address-cells = <1>;
diff --git a/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts
index 6955eafd8d6a..fcc2d8edd464 100644
--- a/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts
+++ b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts
@@ -349,6 +349,7 @@ bridge@2c {
 				vpll-supply = <&reg_1p8v>;
 				vcca-supply = <&reg_1p2v>;
 				vcc-supply = <&reg_1p2v>;
+				no-hpd;
 
 				ports {
 					#address-cells = <1>;
diff --git a/arch/arm64/boot/dts/renesas/r8a779h0-gray-hawk-single.dts b/arch/arm64/boot/dts/renesas/r8a779h0-gray-hawk-single.dts
index 4d890e0617af..8b9592b87366 100644
--- a/arch/arm64/boot/dts/renesas/r8a779h0-gray-hawk-single.dts
+++ b/arch/arm64/boot/dts/renesas/r8a779h0-gray-hawk-single.dts
@@ -460,6 +460,7 @@ bridge@2c {
 		vpll-supply = <&reg_1p8v>;
 		vcca-supply = <&reg_1p2v>;
 		vcc-supply = <&reg_1p2v>;
+		no-hpd;
 
 		ports {
 			#address-cells = <1>;
diff --git a/arch/arm64/boot/dts/renesas/white-hawk-cpu-common.dtsi b/arch/arm64/boot/dts/renesas/white-hawk-cpu-common.dtsi
index b4024e85ae5a..686a37a8680f 100644
--- a/arch/arm64/boot/dts/renesas/white-hawk-cpu-common.dtsi
+++ b/arch/arm64/boot/dts/renesas/white-hawk-cpu-common.dtsi
@@ -256,6 +256,7 @@ bridge@2c {
 		vpll-supply = <&reg_1p8v>;
 		vcca-supply = <&reg_1p2v>;
 		vcc-supply = <&reg_1p2v>;
+		no-hpd;
 
 		ports {
 			#address-cells = <1>;
-- 
2.34.1

Re: [PATCH] arm64: dts: Add no-hpd property for all ti-sn65dsi86 bridge consumers

[Geert Uytterhoeven]

Hi Jayesh,

Thanks for your patch!

On Thu, 29 May 2025 at 13:24, Jayesh Choudhary <j-choudhary@ti.com> wrote:
> In the SN65DSI86 DSI-2-eDP bridge, HPD is not supported as of now.
> But DisplayPort connector_type usecases does need hpd to be enabled.
> In order not to break any platform from those driver changes, add
> "no-hpd" property to all the existing sn65dsi86 nodes (that don't
> have it already) as hpd is not being used there anyways.
>
> Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>

DT bindings day:

  no-hpd:
    type: boolean
    description:
      Set if the HPD line on the bridge isn't hooked up to anything or is
      otherwise unusable.

On all Renesas platforms listed below, the DP bridge's HPD pin is wired
to the HPD pin on the mini-DP connector.  What am I missing?

> Upcoming driver changes that will break platforms if we do not have this
> property in all the existing sn65dsi86 nodes that assumes hpd is disabled:
> <https://lore.kernel.org/all/20250529110418.481756-1-j-choudhary@ti.com/>

Breaking backwards-compatibility with existing DTBs is definitely a no-go.
I'll reply there, too...

>  .../boot/dts/amlogic/meson-g12b-bananapi-cm4-mnt-reform2.dts     | 1 +
>  arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts             | 1 +
>  arch/arm64/boot/dts/qcom/sc7180-acer-aspire1.dts                 | 1 +
>  arch/arm64/boot/dts/renesas/r8a779a0-falcon-cpu.dtsi             | 1 +
>  arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts            | 1 +
>  arch/arm64/boot/dts/renesas/r8a779h0-gray-hawk-single.dts        | 1 +
>  arch/arm64/boot/dts/renesas/white-hawk-cpu-common.dtsi           | 1 +
>  7 files changed, 7 insertions(+)

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] arm64: dts: Add no-hpd property for all ti-sn65dsi86 bridge consumers

[Krzysztof Kozlowski]

On 29/05/2025 13:24, Jayesh Choudhary wrote:
> In the SN65DSI86 DSI-2-eDP bridge, HPD is not supported as of now.
> But DisplayPort connector_type usecases does need hpd to be enabled.
> In order not to break any platform from those driver changes, add
> "no-hpd" property to all the existing sn65dsi86 nodes (that don't
> have it already) as hpd is not being used there anyways.
> 
> Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
> ---
> 
> Upcoming driver changes that will break platforms if we do not have this
> property in all the existing sn65dsi86 nodes that assumes hpd is disabled:
> <https://lore.kernel.org/all/20250529110418.481756-1-j-choudhary@ti.com/>

That's obviously a NAK.

Best regards,
Krzysztof