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From 99f2ab0dad947049e0fa62e88c1e4c1feb7ab379 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Thu, 4 Feb 2021 14:41:10 +0000
Subject: [PATCH] dtoverlays: Add an overlay for the VGA666 when used
with vc4-kms-v3d
Includes optional use of GPIOs 0&1 / BSC0 for DDC to read the EDID
from the display.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
arch/arm/boot/dts/overlays/Makefile | 1 +
arch/arm/boot/dts/overlays/README | 10 ++
.../dts/overlays/vc4-kms-vga666-overlay.dts | 100 ++++++++++++++++++
3 files changed, 111 insertions(+)
create mode 100644 arch/arm/boot/dts/overlays/vc4-kms-vga666-overlay.dts
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -211,6 +211,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
vc4-kms-kippah-7inch.dtbo \
vc4-kms-v3d.dtbo \
vc4-kms-v3d-pi4.dtbo \
+ vc4-kms-vga666.dtbo \
vga666.dtbo \
w1-gpio.dtbo \
w1-gpio-pullup.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -3120,10 +3120,20 @@ Params: cma-512 CMA is 5
outputs)
+Name: vc4-kms-vga666
+Info: Enable the VGA666 (resistor ladder ADC) for the vc4-kms-v3d driver.
+ Requires vc4-kms-v3d to be loaded.
+Load: dtoverlay=vc4-kms-vga666,<param>
+Params: ddc Enables GPIOs 0&1 as the I2C to read the EDID
+ from the display. NB These are NOT 5V tolerant
+ GPIOs, therefore level shifters are required.
+
+
Name: vga666
Info: Overlay for the Fen Logic VGA666 board
This uses GPIOs 2-21 (so no I2C), and activates the output 2-3 seconds
after the kernel has started.
+ NOT for use with vc4-kms-v3d.
Load: dtoverlay=vga666
Params: <None>
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/vc4-kms-vga666-overlay.dts
@@ -0,0 +1,100 @@
+/*
+ * vc4-kms-vga666-overlay.dts
+ * Configures a FenLogic or similar VGA666 DPI adapter when using the
+ * vc4-kms-v3d driver.
+ * If a suitable I2C level shifter is connected to GPIOs 0&1 and the VGA
+ * ID1/SDA (pin 12) and ID3/SCL (pin 15) lines, then there is the option to
+ * enable reading the EDID from the display.
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/pinctrl/bcm2835.h>
+
+/ {
+ compatible = "brcm,bcm2835";
+
+ fragment@0 {
+ target-path = "/";
+ __overlay__ {
+ vga_connector: vga_connector {
+ compatible = "vga-connector";
+ label = "vga";
+
+ port {
+ vga_con_in: endpoint {
+ remote-endpoint = <&vga666_out>;
+ };
+ };
+ };
+
+ vga_dac {
+ compatible = "dumb-vga-dac";
+
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ port@0 {
+ reg = <0>;
+
+ vga666_in: endpoint {
+ remote-endpoint = <&dpi_out>;
+ };
+ };
+
+ port@1 {
+ reg = <1>;
+
+ vga666_out: endpoint {
+ remote-endpoint = <&vga_con_in>;
+ };
+ };
+ };
+ };
+
+ };
+ };
+
+ fragment@1 {
+ target = <&dpi>;
+ __overlay__ {
+ status = "okay";
+
+ pinctrl-names = "default";
+ pinctrl-0 = <&dpi_18bit_gpio2>;
+
+ port {
+ dpi_out: endpoint@0 {
+ remote-endpoint = <&vga666_in>;
+ };
+ };
+ };
+ };
+
+ fragment@2 {
+ target = <&vga_connector>;
+ __dormant__ {
+ ddc-i2c-bus = <&i2c_vc>;
+ };
+ };
+
+ fragment@3 {
+ target = <&i2c0if>;
+ __dormant__ {
+ status = "okay";
+ };
+ };
+
+ fragment@4 {
+ target = <&i2c0mux>;
+ __dormant__ {
+ status = "okay";
+ };
+ };
+
+ __overrides__ {
+ ddc = <0>,"=2", <0>,"=3", <0>,"=4";
+ };
+};
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