[PATCH v2 3/3] ARM: dts: imx6q-apalis: Add VGA overlay

[Leonardo Costa]

From: Leonardo Costa <leonardo.costa at 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 non-programmable video DAC consists of a simple resistor ladder that
converts the digital 16-bit RGB signal to VGA. The VGA output is gated by
an active-low data-enable signal.

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 at toradex.com>
---
 arch/arm/boot/dts/nxp/imx/Makefile                 | 21 ++++++
 .../boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso    | 80 ++++++++++++++++++++++
 2 files changed, 101 insertions(+)

diff --git a/arch/arm/boot/dts/nxp/imx/Makefile b/arch/arm/boot/dts/nxp/imx/Makefile
index b5fad2ba764c..9c218260fdcb 100644
--- a/arch/arm/boot/dts/nxp/imx/Makefile
+++ b/arch/arm/boot/dts/nxp/imx/Makefile
@@ -60,6 +60,22 @@ 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
@@ -186,11 +202,16 @@ 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..991c2b7c2777
--- /dev/null
+++ b/arch/arm/boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso
@@ -0,0 +1,80 @@
+// 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 at 0 {
+			reg = <0>;
+
+			vga_display_in: endpoint {
+				remote-endpoint = <&ipu2_di0_disp0>;
+			};
+		};
+
+		port at 1 {
+			reg = <1>;
+
+			vga_display_out: endpoint {
+				remote-endpoint = <&vga_enc_in>;
+			};
+		};
+	};
+
+	vga-encoder {
+		compatible = "dumb-vga-dac";
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port at 0 {
+				reg = <0>;
+
+				vga_enc_in: endpoint {
+					data-enable-active = <0>;
+					remote-endpoint = <&vga_display_out>;
+				};
+			};
+
+			port at 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