From 4c3e6044ce7f6764b7258f74c31d55f503723ef8 Mon Sep 17 00:00:00 2001
From: Clayton Craft <clayton@craftyguy.net>
Date: Fri, 23 Apr 2021 23:54:41 -0700
Subject: [PATCH] sxmo_brightness: add support for overriding backlight device

This uses the BACKLIGHT env var to override the device used for
controlling the backlight. My intention was to keep the default behavior
if it's unset, use the backlight/backlight path if that exists then fall
back to backlight/edp-backlight.

Finally, this changes the script to return immediately if no backlight
device is found with the given options.

Signed-off-by: Stacy Harper <contact@stacyharper.net>
---
 scripts/core/sxmo_brightness.sh | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/scripts/core/sxmo_brightness.sh b/scripts/core/sxmo_brightness.sh
index 2c7733d..3128e35 100755
--- a/scripts/core/sxmo_brightness.sh
+++ b/scripts/core/sxmo_brightness.sh
@@ -4,23 +4,27 @@
 # shellcheck source=scripts/core/sxmo_common.sh
 . "$(dirname "$0")/sxmo_common.sh"
 
-[ -e /sys/class/backlight/edp-backlight ] && DEV=/sys/class/backlight/edp-backlight
-[ -e /sys/devices/platform/backlight/backlight/backlight ] && DEV=/sys/devices/platform/backlight/backlight/backlight
+BACKLIGHT="${BACKLIGHT:-/sys/devices/platform/backlight/backlight/backlight}"
+if [ ! -e "$BACKLIGHT" ] && [ -e /sys/class/backlight/edp-backlight ]; then
+	BACKLIGHT=/sys/class/backlight/edp-backlight
+fi
 
-MAX=$(cat $DEV/max_brightness)
+[ ! -e "$BACKLIGHT" ] && echo "unable to find backlight device" && exit 1
+
+MAX=$(cat $BACKLIGHT/max_brightness)
 MIN=2
 MINSTEP=1
 STEP=$(echo "($MAX - $MIN) / 10" | bc | xargs -ISTP echo -e "$MINSTEP\nSTP" | sort -r | head -n1)
 
 setdelta() {
 	sxmo_setpinebacklight "$(
-		xargs -IB echo B "$1" < $DEV/brightness |
+		xargs -IB echo B "$1" < $BACKLIGHT/brightness |
 		bc |
 		xargs -INUM echo -e "$MIN\nNUM" | sort -n | tail -n1 |
 		xargs -INUM echo -e "$MAX\nNUM" | sort -n | head -n1
 	)"
 
-	dunstify -i 0 -u normal -r 999 "☀ $(cat $DEV/brightness)/${MAX}"
+	dunstify -i 0 -u normal -r 999 "☀ $(cat $BACKLIGHT/brightness)/${MAX}"
 }
 
 up() {