From 729a4f56f3db3ad4ec5dbc740312abf8d44c183d Mon Sep 17 00:00:00 2001
From: Phil Elwell <pelwell@users.noreply.github.com>
Date: Mon, 12 Sep 2016 13:46:56 +0100
Subject: [PATCH] overlays: Add dpi18 overlay (#1634)

Add support for 18-bit DPI displays. Although the dpi24 overlay could
be used, this overlay leaves GPIOs 22-27 free for other uses.
---
 arch/arm/boot/dts/overlays/Makefile          |  1 +
 arch/arm/boot/dts/overlays/README            |  8 +++++++
 arch/arm/boot/dts/overlays/dpi18-overlay.dts | 31 ++++++++++++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 arch/arm/boot/dts/overlays/dpi18-overlay.dts

--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -22,6 +22,7 @@ dtbo-$(RPI_DT_OVERLAYS) += audremap.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += bmp085_i2c-sensor.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += dht11.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += dionaudio-loco.dtbo
+dtbo-$(RPI_DT_OVERLAYS) += dpi18.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += dpi24.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += dwc-otg.dtbo
 dtbo-$(RPI_DT_OVERLAYS) += dwc2.dtbo
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -283,6 +283,14 @@ Load:   dtoverlay=dionaudio-loco
 Params: <None>
 
 
+Name:   dpi18
+Info:   Overlay for a generic 18-bit DPI display
+        This uses GPIOs 0-21 (so no I2C, uart etc.), and activates the output
+        2-3 seconds after the kernel has started.
+Load:   dtoverlay=dpi18
+Params: <None>
+
+
 Name:   dpi24
 Info:   Overlay for a generic 24-bit DPI display
         This uses GPIOs 0-27 (so no I2C, uart etc.), and activates the output
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/dpi18-overlay.dts
@@ -0,0 +1,31 @@
+/dts-v1/;
+/plugin/;
+
+/{
+	compatible = "brcm,bcm2708";
+
+	// There is no DPI driver module, but we need a platform device
+	// node (that doesn't already use pinctrl) to hang the pinctrl
+	// reference on - leds will do
+
+	fragment@0 {
+		target = <&leds>;
+		__overlay__ {
+			pinctrl-names = "default";
+			pinctrl-0 = <&dpi18_pins>;
+		};
+	};
+
+	fragment@1 {
+		target = <&gpio>;
+		__overlay__ {
+			dpi18_pins: dpi18_pins {
+				brcm,pins = <0 1 2 3 4 5 6 7 8 9 10 11
+					     12 13 14 15 16 17 18 19 20
+					     21>;
+				brcm,function = <6>; /* alt2 */
+				brcm,pull = <0>; /* no pull */
+			};
+		};
+	};
+};