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From e8a650fc27bf1e7d858c997fddd9944e6c222260 Mon Sep 17 00:00:00 2001
From: Aaron Shaw <shawaj@gmail.com>
Date: Thu, 4 Jan 2018 15:02:16 +0000
Subject: [PATCH 157/454] add gpio-key overlay (#2329)
An overlay that allows a Linux key to be bound to a GPIO.
---
arch/arm/boot/dts/overlays/Makefile | 1 +
arch/arm/boot/dts/overlays/README | 21 ++++++++
.../boot/dts/overlays/gpio-key-overlay.dts | 48 +++++++++++++++++++
3 files changed, 70 insertions(+)
create mode 100644 arch/arm/boot/dts/overlays/gpio-key-overlay.dts
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -31,6 +31,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
googlevoicehat-soundcard.dtbo \
gpio-ir.dtbo \
gpio-ir-tx.dtbo \
+ gpio-key.dtbo \
gpio-poweroff.dtbo \
gpio-shutdown.dtbo \
hifiberry-amp.dtbo \
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -515,6 +515,27 @@ Params: gpio_pin Output G
Default is "0" (active-high).
+Name: gpio-key
+Info: This is a generic overlay for activating GPIO keypresses using
+ the gpio-keys library and this dtoverlay. Multiple keys can be
+ set up using multiple calls to the overlay for configuring
+ additional buttons or joysticks. You can see available keycodes
+ at https://github.com/torvalds/linux/blob/v4.12/include/uapi/
+ linux/input-event-codes.h#L64
+Load: dtoverlay=gpio-key,<param>=<val>
+Params: gpio GPIO pin to trigger on (default 3)
+ active_low When this is 1 (active low), a falling
+ edge generates a key down event and a
+ rising edge generates a key up event.
+ When this is 0 (active high), this is
+ reversed. The default is 1 (active low)
+ gpio_pull Desired pull-up/down state (off, down, up)
+ Default is "up". Note that the default pin
+ (GPIO3) has an external pullup
+ label Set a label for the key
+ keycode Set the key code for the button
+
+
Name: gpio-poweroff
Info: Drives a GPIO high or low on poweroff (including halt). Enabling this
overlay will prevent the ability to boot by driving GPIO3 low.
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/gpio-key-overlay.dts
@@ -0,0 +1,48 @@
+// Definitions for gpio-key module
+/dts-v1/;
+/plugin/;
+
+/ {
+ compatible = "brcm,bcm2708";
+
+ fragment@0 {
+ // Configure the gpio pin controller
+ target = <&gpio>;
+ __overlay__ {
+ pin_state: button_pins@0 {
+ brcm,pins = <3>; // gpio number
+ brcm,function = <0>; // 0 = input, 1 = output
+ brcm,pull = <2>; // 0 = none, 1 = pull down, 2 = pull up
+ };
+ };
+ };
+ fragment@1 {
+ target-path = "/";
+ __overlay__ {
+ button: button@0 {
+ compatible = "gpio-keys";
+ pinctrl-names = "default";
+ pinctrl-0 = <&pin_state>;
+ status = "okay";
+
+ key: key {
+ linux,code = <116>;
+ gpios = <&gpio 3 1>;
+ label = "KEY_POWER";
+ };
+ };
+ };
+ };
+
+ __overrides__ {
+ gpio = <&key>,"gpios:4",
+ <&button>,"reg:0",
+ <&pin_state>,"brcm,pins:0",
+ <&pin_state>,"reg:0";
+ label = <&key>,"label";
+ keycode = <&key>,"linux,code:0";
+ gpio_pull = <&pin_state>,"brcm,pull:0";
+ active_low = <&key>,"gpios:8";
+ };
+
+};
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