From 5cadb52401f99028ebe566cccf18235d9d820b15 Mon Sep 17 00:00:00 2001
From: "Alex A. Naanou" <alex.nanou@gmail.com>
Date: Sun, 7 Apr 2024 14:26:06 +0300
Subject: [PATCH] fixed an issue with the sensor returning 0 randomly...

Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>
---
 Makefile                             | 27 ++++++++++++++--
 thinkpad-keyboard-brightness         | 46 ++++++++++++++++++++++++++++
 thinkpad-keyboard-brightness.conf    | 11 +++++++
 thinkpad-keyboard-brightness.service |  6 +---
 4 files changed, 82 insertions(+), 8 deletions(-)
 create mode 100755 thinkpad-keyboard-brightness
 create mode 100644 thinkpad-keyboard-brightness.conf

diff --git a/Makefile b/Makefile
index 8a00115..19a1bb6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,16 +1,30 @@
 
 NAME := thinkpad-keyboard-brightness
 
+SBIN_DIR := /usr/sbin
+CONFIG_DIR := /etc/
 SERVICE_DIR := /etc/systemd/system/
 
+SCRIPT := $(NAME)
+CONFIG := $(NAME).conf
 TIMER := $(NAME).timer
 UNIT := $(NAME).service
 
+SERVICE_FILES := \
+	$(TIMER) \
+	$(UNIT)
+
+FILES := \
+	$(SERVICE_FILES) \
+	$(SCRIPT) \
+	$(CONFIG)
 
 
 .PHONY:install
-install: $(TIMER) $(UNIT)
-	cp -f $? $(SERVICE_DIR) 
+install: $(FILES)
+	cp -f $(SERVICE_FILES) $(SERVICE_DIR) 
+	cp -f $(SCRIPT) $(SBIN_DIR) 
+	cp -f $(CONFIG) $(CONFIG_DIR) 
 	systemctl daemon-reload
 	systemctl enable ${UNIT}
 	systemctl enable ${TIMER}
@@ -26,14 +40,21 @@ disable: $(TIMER) $(UNIT)
 	systemctl disable ${UNIT}
 
 
+# NOTE: this will not remove user config files...
 .PHONY:uninstall
 uninstall: disable $(TIMER) $(UNIT)
 	rm -f \
 		$(SERVICE_DIR)/$(TIMER) \
-		$(SERVICE_DIR)/$(UNIT)
+		$(SERVICE_DIR)/$(UNIT) \
+		$(SBIN_DIR)/$(SCRIPT)
 	systemctl daemon-reload
 
 
+.PHONY:full-uninstall
+full-uninstall: uninstall
+	rm -f $(CONFIG_DIR)/$(CONFIG)
+
+
 .PHONY:reinstall
 reinstall: uninstall install 
 
diff --git a/thinkpad-keyboard-brightness b/thinkpad-keyboard-brightness
new file mode 100755
index 0000000..762a757
--- /dev/null
+++ b/thinkpad-keyboard-brightness
@@ -0,0 +1,46 @@
+#!/usr/bin/bash
+
+if [ -e /etc/thinkpad-keyboard-brightness.conf ] ; then
+	source /etc/thinkpad-keyboard-brightness.conf
+fi
+
+if [ -z $SENSOR ] ; then
+	SENSOR=(/sys/bus/iio/devices/iio:device*/in_illuminance_raw)
+fi
+SENSOR=${SENSOR[0]}
+
+if [ -z $TRIGGER ] ; then
+	TRIGGER=(/sys/class/leds/*::kbd_backlight/brightness)
+fi
+TRIGGER=${TRIGGER[0]}
+
+THRESHOLD=${THRESHOLD:-2000}
+HYSTERESIS=${HYSTERESIS:-200}
+ATTEMPTS=${ATTEMPTS:-3}
+VALUE=${VALUE:-1}
+
+
+
+# read the illuminance value...
+# NOTE: the sensor sometimes randomly returns 0, this will make this 
+# 	less probabble to retult in backlight turning on/off randomly...
+ATTEMPT=0
+ILLUMINANCE=0
+while (( $ATTEMPT < $ATTEMPTS )) && (( $ILLUMINANCE == 0 )) ; do
+	ILLUMINANCE=$(cat ${SENSOR})
+	ATTEMPT=$((ATTEMPT + 1))
+done
+
+#echo "ILLUMINANCE: $ILLUMINANCE (attempt: $ATTEMPT)"
+
+STATE=$(cat "$TRIGGER")
+
+# NOTE: this needs root...
+if (( $ILLUMINANCE < $THRESHOLD )) && (( $STATE == 0 )) ; then
+	echo "$VALUE" > "$TRIGGER"
+
+elif (( $ILLUMINANCE > $THRESHOLD + $HYSTERESIS )) ; then
+	echo 0 > "$TRIGGER"
+fi
+
+
diff --git a/thinkpad-keyboard-brightness.conf b/thinkpad-keyboard-brightness.conf
new file mode 100644
index 0000000..bf54899
--- /dev/null
+++ b/thinkpad-keyboard-brightness.conf
@@ -0,0 +1,11 @@
+#
+# SENSOR=/sys/bus/iio/devices/iio:device*/in_illuminance_raw
+#
+# TRIGGER=/sys/class/leds/tpacpi::kbd_backlight/brightness
+#
+# THRESHOLD=2000
+#
+# HESTERISYS=200
+#
+# VALUE=1
+#
diff --git a/thinkpad-keyboard-brightness.service b/thinkpad-keyboard-brightness.service
index 94480b1..c091f4d 100644
--- a/thinkpad-keyboard-brightness.service
+++ b/thinkpad-keyboard-brightness.service
@@ -3,12 +3,8 @@ Description="Turn keyboard backlight on/off based on light sensor"
 
 [Service]
 Type=exec
-Environment=SENSOR=/sys/bus/iio/devices/iio:device*/in_illuminance_raw
-Environment=TRIGGER=/sys/class/leds/tpacpi::kbd_backlight/brightness
-Environment=THRESHOLD=2000
-Environment=VALUE=1
 User=root
-ExecStart=bash -c "(( $(cat ${SENSOR}) < ${THRESHOLD} )) && echo ${VALUE} > ${TRIGGER} || echo 0 > ${TRIGGER}"
+ExecStart=/usr/sbin/thinkpad-keyboard-brightness
 
 [Install]
 WantedBy=multi-user.target