[PATCH 0/3] Add VGA support for Apalis iMX6

[PATCH 0/3] Add VGA support for Apalis iMX6

[Leonardo Costa]

This series adds a device tree overlay that enables the VGA output on Apalis
iMX6, which is driven from a parallel RGB interface passing through a
non-programmable video DAC.

The video DAC is a simple resistor network gated by an active-low
data-enable signal. For the bridge to work properly, this series also
changes the following in the dt-bindings and simple-bridge driver:

- dt-bindings: Add a new compatible for the bridge in the simple-bridge
  binding. This is necessary because the existing dumb-vga-dac compatible
  doesn't describe a data-enable signal polarity.

- simple-bridge: Add the VGA bridge match-table entry and timings
  struct, setting the DRM_BUS_FLAG_DE_LOW flag for the bridge.

This change depends on another patch, and should be applied after it:

- https://lore.kernel.org/all/20261002-v1-simple-bridge-atomic-check-v1-1-ef5d8332b078@toradex.com/T/#u

  Adds the atomic_check function to the simple-bridge driver, which
  allows the data-enable bus flag to be propagated through the DRM
  pipeline. This is necessary for the VGA to work correctly on the
  Apalis iMX6.

Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
---
Leonardo Costa (3):
      dt-bindings: display: bridge: simple: Add the Toradex Apalis iMX6 VGA DAC bridge
      drm/bridge: simple-bridge: Add Toradex RGB to VGA DAC bridge
      ARM: dts: imx6q-apalis: Add VGA overlay

 .../bindings/display/bridge/simple-bridge.yaml     |  1 +
 arch/arm/boot/dts/nxp/imx/Makefile                 | 21 ++++++
 .../boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso    | 79 ++++++++++++++++++++++
 drivers/gpu/drm/bridge/simple-bridge.c             | 10 +++
 4 files changed, 111 insertions(+)
---
base-commit: f5f84daefcd92d7a630066635ecea1433ed5eac7
change-id: 20260928-v1-apalis-imx6-enable-vga-5c7ba6b358fe

Best regards,
-- 
Leonardo Costa <leonardo.costa@toradex.com>

[PATCH 1/3] dt-bindings: display: bridge: simple: Add the Toradex Apalis iMX6 VGA DAC bridge

[Leonardo Costa]

From: Leonardo Costa <leonardo.costa@toradex.com>

The VGA bridge on Apalis iMX6 consists of a simple resistor ladder that
converts a digital 16-bit RGB signal to VGA. The VGA output is gated by
an active-low data-enable signal.

Add a dedicated compatible for the bridge, since the generic
dumb-vga-dac doesn't describe a data-enable signal.

Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
---
 Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml b/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
index 7636c24906ba..a86231a4a908 100644
--- a/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
@@ -37,6 +37,7 @@ properties:
           - ti,opa362
           - ti,ths8134
           - ti,ths8135
+          - toradex,apalis-imx6-vga-dac
 
   ports:
     $ref: /schemas/graph.yaml#/properties/ports

-- 
2.43.0

[PATCH 2/3] drm/bridge: simple-bridge: Add Toradex RGB to VGA DAC bridge

[Leonardo Costa]

From: Leonardo Costa <leonardo.costa@toradex.com>

The VGA bridge on Apalis iMX6 consists of a simple resistor ladder that
converts a digital 16-bit RGB signal to VGA. The VGA output is gated by
an active-low data-enable signal.

Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
---
 drivers/gpu/drm/bridge/simple-bridge.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
index 3fba7002322e..3f88fcdfa214 100644
--- a/drivers/gpu/drm/bridge/simple-bridge.c
+++ b/drivers/gpu/drm/bridge/simple-bridge.c
@@ -253,6 +253,10 @@ static const struct drm_bridge_timings ti_ths8135_bridge_timings = {
 	.hold_time_ps = 500,
 };
 
+static const struct drm_bridge_timings toradex_apalis_imx6_vga_dac_timings = {
+	.input_bus_flags = DRM_BUS_FLAG_DE_LOW,
+};
+
 static const struct of_device_id simple_bridge_match[] = {
 	{
 		.compatible = "dumb-vga-dac",
@@ -312,6 +316,12 @@ static const struct of_device_id simple_bridge_match[] = {
 			.timings = &ti_ths8134_bridge_timings,
 			.connector_type = DRM_MODE_CONNECTOR_VGA,
 		},
+	}, {
+		.compatible = "toradex,apalis-imx6-vga-dac",
+		.data = &(const struct simple_bridge_info) {
+			.timings = &toradex_apalis_imx6_vga_dac_timings,
+			.connector_type = DRM_MODE_CONNECTOR_VGA,
+		},
 	},
 	{},
 };

-- 
2.43.0

[PATCH 3/3] ARM: dts: imx6q-apalis: Add VGA overlay

[Leonardo Costa]

From: Leonardo Costa <leonardo.costa@toradex.com>

Add a device tree overlay for the VGA output available on the Apalis
Evaluation Board, which is driven from a parallel RGB interface passing
through a non-programmable video DAC to a VGA connector, without VESA
DDC I2C signals.

The overlay is also combined with the various Apalis Evaluation Board
device trees to provide ready-to-use DTBs.

Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
---
 arch/arm/boot/dts/nxp/imx/Makefile                 | 21 ++++++
 .../boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso    | 79 ++++++++++++++++++++++
 2 files changed, 100 insertions(+)

diff --git a/arch/arm/boot/dts/nxp/imx/Makefile b/arch/arm/boot/dts/nxp/imx/Makefile
index c5caca92ea10..b5ad9172e1f4 100644
--- a/arch/arm/boot/dts/nxp/imx/Makefile
+++ b/arch/arm/boot/dts/nxp/imx/Makefile
@@ -59,6 +59,22 @@ dtb-$(CONFIG_SOC_IMX53) += \
 imx53-qsb-hdmi-dtbs := imx53-qsb.dtb imx53-qsb-hdmi.dtbo
 imx53-qsrb-hdmi-dtbs := imx53-qsrb.dtb imx53-qsb-hdmi.dtbo
 
+imx6q-apalis-eval-v1.2-vga-dtbs := \
+	imx6q-apalis-eval-v1.2.dtb \
+	imx6q-apalis-eval-vga.dtbo
+
+imx6q-apalis-eval-vga-dtbs := \
+	imx6q-apalis-eval.dtb \
+	imx6q-apalis-eval-vga.dtbo
+
+imx6q-apalis-v1.2-eval-v1.2-vga-dtbs := \
+	imx6q-apalis-v1.2-eval-v1.2.dtb \
+	imx6q-apalis-eval-vga.dtbo
+
+imx6q-apalis-v1.2-eval-vga-dtbs := \
+	imx6q-apalis-v1.2-eval.dtb \
+	imx6q-apalis-eval-vga.dtbo
+
 imx6qdl-dhcom-pdk2-overlay-497-200-x12-dtbs := \
 	imx6q-dhcom-pdk2.dtb \
 	imx6qdl-dhcom-pdk2-overlay-497-200-x12.dtbo
@@ -184,11 +200,16 @@ dtb-$(CONFIG_SOC_IMX6Q) += \
 	imx6dl-yapp4-ursa.dtb \
 	imx6q-apalis-eval.dtb \
 	imx6q-apalis-eval-v1.2.dtb \
+	imx6q-apalis-eval-v1.2-vga.dtb \
+	imx6q-apalis-eval-vga.dtb \
+	imx6q-apalis-eval-vga.dtbo \
 	imx6q-apalis-ixora.dtb \
 	imx6q-apalis-ixora-v1.1.dtb \
 	imx6q-apalis-ixora-v1.2.dtb \
 	imx6q-apalis-v1.2-eval.dtb \
 	imx6q-apalis-v1.2-eval-v1.2.dtb \
+	imx6q-apalis-v1.2-eval-v1.2-vga.dtb \
+	imx6q-apalis-v1.2-eval-vga.dtb \
 	imx6q-apalis-v1.2-ixora.dtb \
 	imx6q-apalis-v1.2-ixora-v1.1.dtb \
 	imx6q-apalis-v1.2-ixora-v1.2.dtb \
diff --git a/arch/arm/boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso b/arch/arm/boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso
new file mode 100644
index 000000000000..a449ef9fbfaf
--- /dev/null
+++ b/arch/arm/boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Copyright (c) Toradex
+ *
+ * VGA output connected to a parallel RGB LCD interface through a
+ * non-programmable video DAC with a VGA connector.
+ *
+ * The VGA output is available on the Apalis Evaluation Board without VESA DDC
+ * I2C signals.
+ */
+
+/dts-v1/;
+/plugin/;
+
+&{/} {
+	disp1 {
+		compatible = "fsl,imx-parallel-display";
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_ipu2_vdac>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		interface-pix-fmt = "rgb565";
+
+		port@0 {
+			reg = <0>;
+
+			vga_display_in: endpoint {
+				remote-endpoint = <&ipu2_di0_disp0>;
+			};
+		};
+
+		port@1 {
+			reg = <1>;
+
+			vga_display_out: endpoint {
+				remote-endpoint = <&vga_enc_in>;
+			};
+		};
+	};
+
+	vga-encoder {
+		compatible = "toradex,apalis-imx6-vga-dac";
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 {
+				reg = <0>;
+
+				vga_enc_in: endpoint {
+					remote-endpoint = <&vga_display_out>;
+				};
+			};
+
+			port@1 {
+				reg = <1>;
+
+				vga_enc_out: endpoint {
+					remote-endpoint = <&vga_connector_in>;
+				};
+			};
+		};
+	};
+
+	vga-connector {
+		compatible = "vga-connector";
+
+		port {
+			vga_connector_in: endpoint {
+				remote-endpoint = <&vga_enc_out>;
+			};
+		};
+	};
+};
+
+&ipu2_di0_disp0 {
+	remote-endpoint = <&vga_display_in>;
+};

-- 
2.43.0

Re: [PATCH 1/3] dt-bindings: display: bridge: simple: Add the Toradex Apalis iMX6 VGA DAC bridge

[Frank Li]

On Mon, Oct 12, 2026 at 04:25:23AM -0300, Leonardo Costa wrote:
> From: Leonardo Costa <leonardo.costa@toradex.com>
>
> The VGA bridge on Apalis iMX6 consists of a simple resistor ladder that
> converts a digital 16-bit RGB signal to VGA. The VGA output is gated by
> an active-low data-enable signal.
>
> Add a dedicated compatible for the bridge, since the generic
> dumb-vga-dac doesn't describe a data-enable signal.
>
> Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml b/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
> index 7636c24906ba..a86231a4a908 100644
> --- a/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/simple-bridge.yaml
> @@ -37,6 +37,7 @@ properties:
>            - ti,opa362
>            - ti,ths8134
>            - ti,ths8135
> +          - toradex,apalis-imx6-vga-dac
>
>    ports:
>      $ref: /schemas/graph.yaml#/properties/ports
>
> --
> 2.43.0
>
>

Re: [PATCH 2/3] drm/bridge: simple-bridge: Add Toradex RGB to VGA DAC bridge

[Frank Li]

On Mon, Oct 12, 2026 at 04:25:24AM -0300, Leonardo Costa wrote:
> From: Leonardo Costa <leonardo.costa@toradex.com>
>
> The VGA bridge on Apalis iMX6 consists of a simple resistor ladder that
> converts a digital 16-bit RGB signal to VGA. The VGA output is gated by
> an active-low data-enable signal.
>
> Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  drivers/gpu/drm/bridge/simple-bridge.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
> index 3fba7002322e..3f88fcdfa214 100644
> --- a/drivers/gpu/drm/bridge/simple-bridge.c
> +++ b/drivers/gpu/drm/bridge/simple-bridge.c
> @@ -253,6 +253,10 @@ static const struct drm_bridge_timings ti_ths8135_bridge_timings = {
>  	.hold_time_ps = 500,
>  };
>
> +static const struct drm_bridge_timings toradex_apalis_imx6_vga_dac_timings = {
> +	.input_bus_flags = DRM_BUS_FLAG_DE_LOW,
> +};
> +
>  static const struct of_device_id simple_bridge_match[] = {
>  	{
>  		.compatible = "dumb-vga-dac",
> @@ -312,6 +316,12 @@ static const struct of_device_id simple_bridge_match[] = {
>  			.timings = &ti_ths8134_bridge_timings,
>  			.connector_type = DRM_MODE_CONNECTOR_VGA,
>  		},
> +	}, {
> +		.compatible = "toradex,apalis-imx6-vga-dac",
> +		.data = &(const struct simple_bridge_info) {
> +			.timings = &toradex_apalis_imx6_vga_dac_timings,
> +			.connector_type = DRM_MODE_CONNECTOR_VGA,
> +		},
>  	},
>  	{},
>  };
>
> --
> 2.43.0
>
>

Re: [PATCH 3/3] ARM: dts: imx6q-apalis: Add VGA overlay

[Frank Li]

On Mon, Oct 12, 2026 at 04:25:25AM -0300, Leonardo Costa wrote:
> From: Leonardo Costa <leonardo.costa@toradex.com>
>
> Add a device tree overlay for the VGA output available on the Apalis
> Evaluation Board, which is driven from a parallel RGB interface passing
> through a non-programmable video DAC to a VGA connector, without VESA
> DDC I2C signals.
>
> The overlay is also combined with the various Apalis Evaluation Board
> device trees to provide ready-to-use DTBs.
>
> Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
> ---
>  arch/arm/boot/dts/nxp/imx/Makefile                 | 21 ++++++
>  .../boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso    | 79 ++++++++++++++++++++++
>  2 files changed, 100 insertions(+)
>
> diff --git a/arch/arm/boot/dts/nxp/imx/Makefile b/arch/arm/boot/dts/nxp/imx/Makefile
> index c5caca92ea10..b5ad9172e1f4 100644
> --- a/arch/arm/boot/dts/nxp/imx/Makefile
> +++ b/arch/arm/boot/dts/nxp/imx/Makefile
> @@ -59,6 +59,22 @@ dtb-$(CONFIG_SOC_IMX53) += \
>  imx53-qsb-hdmi-dtbs := imx53-qsb.dtb imx53-qsb-hdmi.dtbo
>  imx53-qsrb-hdmi-dtbs := imx53-qsrb.dtb imx53-qsb-hdmi.dtbo
>
> +imx6q-apalis-eval-v1.2-vga-dtbs := \
> +	imx6q-apalis-eval-v1.2.dtb \
> +	imx6q-apalis-eval-vga.dtbo
> +
> +imx6q-apalis-eval-vga-dtbs := \
> +	imx6q-apalis-eval.dtb \
> +	imx6q-apalis-eval-vga.dtbo
> +
> +imx6q-apalis-v1.2-eval-v1.2-vga-dtbs := \
> +	imx6q-apalis-v1.2-eval-v1.2.dtb \
> +	imx6q-apalis-eval-vga.dtbo
> +
> +imx6q-apalis-v1.2-eval-vga-dtbs := \
> +	imx6q-apalis-v1.2-eval.dtb \
> +	imx6q-apalis-eval-vga.dtbo
> +

Thank you using one overlay cover difference boards

Frank

Re: [PATCH 0/3] Add VGA support for Apalis iMX6

[Laurent Pinchart]

On Mon, Oct 12, 2026 at 04:25:22AM -0300, Leonardo Costa wrote:
> This series adds a device tree overlay that enables the VGA output on Apalis
> iMX6, which is driven from a parallel RGB interface passing through a
> non-programmable video DAC.
> 
> The video DAC is a simple resistor network gated by an active-low
> data-enable signal. For the bridge to work properly, this series also
> changes the following in the dt-bindings and simple-bridge driver:
> 
> - dt-bindings: Add a new compatible for the bridge in the simple-bridge
>   binding. This is necessary because the existing dumb-vga-dac compatible
>   doesn't describe a data-enable signal polarity.
> 
> - simple-bridge: Add the VGA bridge match-table entry and timings
>   struct, setting the DRM_BUS_FLAG_DE_LOW flag for the bridge.

Is there schematics available anywhere ? That would help reviewing the
series ?

> 
> This change depends on another patch, and should be applied after it:
> 
> - https://lore.kernel.org/all/20261002-v1-simple-bridge-atomic-check-v1-1-ef5d8332b078@toradex.com/T/#u
> 
>   Adds the atomic_check function to the simple-bridge driver, which
>   allows the data-enable bus flag to be propagated through the DRM
>   pipeline. This is necessary for the VGA to work correctly on the
>   Apalis iMX6.
> 
> Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
> ---
> Leonardo Costa (3):
>       dt-bindings: display: bridge: simple: Add the Toradex Apalis iMX6 VGA DAC bridge
>       drm/bridge: simple-bridge: Add Toradex RGB to VGA DAC bridge
>       ARM: dts: imx6q-apalis: Add VGA overlay
> 
>  .../bindings/display/bridge/simple-bridge.yaml     |  1 +
>  arch/arm/boot/dts/nxp/imx/Makefile                 | 21 ++++++
>  .../boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso    | 79 ++++++++++++++++++++++
>  drivers/gpu/drm/bridge/simple-bridge.c             | 10 +++
>  4 files changed, 111 insertions(+)
> ---
> base-commit: f5f84daefcd92d7a630066635ecea1433ed5eac7
> change-id: 20260928-v1-apalis-imx6-enable-vga-5c7ba6b358fe

-- 
Regards,

Laurent Pinchart

Re: [PATCH 1/3] dt-bindings: display: bridge: simple: Add the Toradex Apalis iMX6 VGA DAC bridge

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 75 bytes --]

Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH 0/3] Add VGA support for Apalis iMX6

[Francesco Dolcini]

Hello Laurent,

On Mon, Oct 12, 2026 at 06:40:54PM +0200, Laurent Pinchart wrote:
> On Mon, Oct 12, 2026 at 04:25:22AM -0300, Leonardo Costa wrote:
> > This series adds a device tree overlay that enables the VGA output on Apalis
> > iMX6, which is driven from a parallel RGB interface passing through a
> > non-programmable video DAC.
> > 
> > The video DAC is a simple resistor network gated by an active-low
> > data-enable signal. For the bridge to work properly, this series also
> > changes the following in the dt-bindings and simple-bridge driver:
> > 
> > - dt-bindings: Add a new compatible for the bridge in the simple-bridge
> >   binding. This is necessary because the existing dumb-vga-dac compatible
> >   doesn't describe a data-enable signal polarity.
> > 
> > - simple-bridge: Add the VGA bridge match-table entry and timings
> >   struct, setting the DRM_BUS_FLAG_DE_LOW flag for the bridge.
> 
> Is there schematics available anywhere ? That would help reviewing the
> series ?

This circuit is on the SoM, and the SoM schematics are
confidential and not generally available.

I tried to extract as ascii art the relevant circuit, hope it helps

BLUE (5 bits)
=============
DISP0_DATA[4] ---[R30   348R]---+
DISP0_DATA[3] ---[R33   715R]---+
DISP0_DATA[2] ---[R36  1.47K]---+-------- VGA1_B
DISP0_DATA[1] ---[R39  2.94K]---+          |
DISP0_DATA[0] ---[R42  5.90K]---+          D
                                           |
DI0_PIN15 ------------------------------ G | T4 MMBF2201N
                                           S
                                           |
                                          GND


RED (5 bits)
============
DISP0_DATA[15] --[R31   348R]---+
DISP0_DATA[14] --[R34   715R]---+
DISP0_DATA[13] --[R37  1.47K]---+-------- VGA1_R
DISP0_DATA[12] --[R40  2.94K]---+          |
DISP0_DATA[11] --[R43  5.90K]---+          D
                                           |
DI0_PIN15 ------------------------------ G | T5 MMBF2201N
                                           S
                                           |
                                          GND


GREEN (6 bits)
==============
DISP0_DATA[10] --[R32   348R]---+
DISP0_DATA[9]  --[R35   715R]---+
DISP0_DATA[8]  --[R38  1.47K]---+
DISP0_DATA[7]  --[R41  2.94K]---+-------- VGA1_G
DISP0_DATA[6]  --[R44  5.90K]---+          |
DISP0_DATA[5]  --[R45  11.8K]---+          D
                                           |
DI0_PIN15 ------------------------------ G | T6 MMBF2201N
                                           S
                                           |
                                          GND



Francesco

Re: [PATCH 0/3] Add VGA support for Apalis iMX6

[Laurent Pinchart]

Hi Francesco,

On Tue, Oct 13, 2026 at 11:06:31AM +0200, Francesco Dolcini wrote:
> On Mon, Oct 12, 2026 at 06:40:54PM +0200, Laurent Pinchart wrote:
> > On Mon, Oct 12, 2026 at 04:25:22AM -0300, Leonardo Costa wrote:
> > > This series adds a device tree overlay that enables the VGA output on Apalis
> > > iMX6, which is driven from a parallel RGB interface passing through a
> > > non-programmable video DAC.
> > > 
> > > The video DAC is a simple resistor network gated by an active-low
> > > data-enable signal. For the bridge to work properly, this series also
> > > changes the following in the dt-bindings and simple-bridge driver:
> > > 
> > > - dt-bindings: Add a new compatible for the bridge in the simple-bridge
> > >   binding. This is necessary because the existing dumb-vga-dac compatible
> > >   doesn't describe a data-enable signal polarity.
> > > 
> > > - simple-bridge: Add the VGA bridge match-table entry and timings
> > >   struct, setting the DRM_BUS_FLAG_DE_LOW flag for the bridge.
> > 
> > Is there schematics available anywhere ? That would help reviewing the
> > series ?
> 
> This circuit is on the SoM, and the SoM schematics are
> confidential and not generally available.
> 
> I tried to extract as ascii art the relevant circuit, hope it helps

Thank you, it makes things clearer.

The circuit seems fairly generic. Wouldn't it be better to add an
optional property ot the dumb-vga-dac instead of a new compatible string
specific to Apalis ?

> BLUE (5 bits)
> =============
> DISP0_DATA[4] ---[R30   348R]---+
> DISP0_DATA[3] ---[R33   715R]---+
> DISP0_DATA[2] ---[R36  1.47K]---+-------- VGA1_B
> DISP0_DATA[1] ---[R39  2.94K]---+          |
> DISP0_DATA[0] ---[R42  5.90K]---+          D
>                                            |
> DI0_PIN15 ------------------------------ G | T4 MMBF2201N
>                                            S
>                                            |
>                                           GND
> 
> 
> RED (5 bits)
> ============
> DISP0_DATA[15] --[R31   348R]---+
> DISP0_DATA[14] --[R34   715R]---+
> DISP0_DATA[13] --[R37  1.47K]---+-------- VGA1_R
> DISP0_DATA[12] --[R40  2.94K]---+          |
> DISP0_DATA[11] --[R43  5.90K]---+          D
>                                            |
> DI0_PIN15 ------------------------------ G | T5 MMBF2201N
>                                            S
>                                            |
>                                           GND
> 
> 
> GREEN (6 bits)
> ==============
> DISP0_DATA[10] --[R32   348R]---+
> DISP0_DATA[9]  --[R35   715R]---+
> DISP0_DATA[8]  --[R38  1.47K]---+
> DISP0_DATA[7]  --[R41  2.94K]---+-------- VGA1_G
> DISP0_DATA[6]  --[R44  5.90K]---+          |
> DISP0_DATA[5]  --[R45  11.8K]---+          D
>                                            |
> DI0_PIN15 ------------------------------ G | T6 MMBF2201N
>                                            S
>                                            |
>                                           GND

-- 
Regards,

Laurent Pinchart

Re: [PATCH 0/3] Add VGA support for Apalis iMX6

[Francesco Dolcini]

On Tue, Oct 13, 2026 at 01:11:58PM +0200, Laurent Pinchart wrote:
> On Tue, Oct 13, 2026 at 11:06:31AM +0200, Francesco Dolcini wrote:
> > On Mon, Oct 12, 2026 at 06:40:54PM +0200, Laurent Pinchart wrote:
> > > On Mon, Oct 12, 2026 at 04:25:22AM -0300, Leonardo Costa wrote:
> > > > This series adds a device tree overlay that enables the VGA output on Apalis
> > > > iMX6, which is driven from a parallel RGB interface passing through a
> > > > non-programmable video DAC.
> > > > 
> > > > The video DAC is a simple resistor network gated by an active-low
> > > > data-enable signal. For the bridge to work properly, this series also
> > > > changes the following in the dt-bindings and simple-bridge driver:
> > > > 
> > > > - dt-bindings: Add a new compatible for the bridge in the simple-bridge
> > > >   binding. This is necessary because the existing dumb-vga-dac compatible
> > > >   doesn't describe a data-enable signal polarity.
> > > > 
> > > > - simple-bridge: Add the VGA bridge match-table entry and timings
> > > >   struct, setting the DRM_BUS_FLAG_DE_LOW flag for the bridge.
> > > 
> > > Is there schematics available anywhere ? That would help reviewing the
> > > series ?
> > 
> > This circuit is on the SoM, and the SoM schematics are
> > confidential and not generally available.
> > 
> > I tried to extract as ascii art the relevant circuit, hope it helps
> 
> Thank you, it makes things clearer.
> 
> The circuit seems fairly generic. Wouldn't it be better to add an
> optional property ot the dumb-vga-dac instead of a new compatible string
> specific to Apalis ?

We discussed this internally and we were not 100% sure, so we decided to
go with this proposal that seemed easier and less controversial.

With that wrote, I let Leonardo comment on the pro/cons of the two
approaches.

Francesco