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From b5ec75dab38af2429278df48121642cb5605e318 Mon Sep 17 00:00:00 2001
From: Jasper Boomer <jasperboomer@gmail.com>
Date: Sun, 24 Jun 2018 12:20:27 -0400
Subject: [PATCH] Add device tree overlay for HD44780
---
arch/arm/boot/dts/overlays/Makefile | 1 +
arch/arm/boot/dts/overlays/README | 25 ++++++++++
.../boot/dts/overlays/hd44780-lcd-overlay.dts | 46 +++++++++++++++++++
3 files changed, 72 insertions(+)
create mode 100644 arch/arm/boot/dts/overlays/hd44780-lcd-overlay.dts
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -38,6 +38,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
gpio-no-irq.dtbo \
gpio-poweroff.dtbo \
gpio-shutdown.dtbo \
+ hd44780-lcd.dtbo \
hifiberry-amp.dtbo \
hifiberry-dac.dtbo \
hifiberry-dacplus.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -639,6 +639,31 @@ Params: gpio_pin GPIO pin
external pullup.
+Name: hd44780-lcd
+Info: Configures an HD44780 compatible LCD display. Uses 4 gpio pins for
+ data, 2 gpio pins for enable and register select and 1 optional pin
+ for enabling/disabling the backlight display.
+Load: dtoverlay=hd44780-lcd,<param>=<val>
+Params: pin_d4 GPIO pin for data pin D4 (default 6)
+
+ pin_d5 GPIO pin for data pin D5 (default 13)
+
+ pin_d6 GPIO pin for data pin D6 (default 19)
+
+ pin_d7 GPIO pin for data pin D7 (default 26)
+
+ pin_en GPIO pin for "Enable" (default 21)
+
+ pin_rs GPIO pin for "Register Select" (default 20)
+
+ pin_bl Optional pin for enabling/disabling the
+ display backlight. (default disabled)
+
+ display_height Height of the display in characters
+
+ display_width Width of the display in characters
+
+
Name: hifiberry-amp
Info: Configures the HifiBerry Amp and Amp+ audio cards
Load: dtoverlay=hifiberry-amp
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/hd44780-lcd-overlay.dts
@@ -0,0 +1,46 @@
+/dts-v1/;
+/plugin/;
+
+/ {
+ compatible = "brcm,bcm2835";
+
+ fragment@0 {
+ target-path = "/";
+ __overlay__ {
+ lcd_screen: auxdisplay {
+ compatible = "hit,hd44780";
+
+ data-gpios = <&gpio 6 0>,
+ <&gpio 13 0>,
+ <&gpio 19 0>,
+ <&gpio 26 0>;
+ enable-gpios = <&gpio 21 0>;
+ rs-gpios = <&gpio 20 0>;
+
+ display-height-chars = <2>;
+ display-width-chars = <16>;
+ };
+
+ };
+ };
+
+ fragment@1 {
+ target = <&lcd_screen>;
+ __dormant__ {
+ backlight-gpios = <&gpio 12 0>;
+ };
+ };
+
+ __overrides__ {
+ pin_d4 = <&lcd_screen>,"data-gpios:4";
+ pin_d5 = <&lcd_screen>,"data-gpios:16";
+ pin_d6 = <&lcd_screen>,"data-gpios:28";
+ pin_d7 = <&lcd_screen>,"data-gpios:40";
+ pin_en = <&lcd_screen>,"enable-gpios:4";
+ pin_rs = <&lcd_screen>,"rs-gpios:4";
+ pin_bl = <0>,"+1", <&lcd_screen>,"backlight-gpios:4";
+ display_height = <&lcd_screen>,"display-height-chars:0";
+ display_width = <&lcd_screen>,"display-width-chars:0";
+ };
+
+};
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