base-files: maintain LED config state

Record the state of any hardware LED configured through UCI and use that
information to revert the state when applying updated settings while
maintaining default behaviour of system LEDs.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

diff --git a/package/base-files/files/etc/init.d/led b/package/base-files/files/etc/init.d/led
index a6be788a5e0569368b164cb62acd4a9775489b34..1d10f723d0ce11bff6828661dfa7385b825791a1 100755 (executable)
--- a/package/base-files/files/etc/init.d/led
+++ b/package/base-files/files/etc/init.d/led
@@ -37,6 +37,12 @@ load_led() {
        [ -e /sys/class/leds/${sysfs}/brightness ] && {
                echo "setting up led ${name}"
 
+               printf "%s %s %d\n" \
+                       "$sysfs" \
+                       "$(sed -ne 's/^.*\[\(.*\)\].*$/\1/p' /sys/class/leds/${sysfs}/trigger)" \
+                       "$(cat /sys/class/leds/${sysfs}/brightness)" \
+                               >> /var/run/led.state
+
                [ "$default" = 0 ] &&
                        echo 0 >/sys/class/leds/${sysfs}/brightness
 
@@ -103,11 +109,17 @@ load_led() {
 
 start() {
        [ -e /sys/class/leds/ ] && {
-               local led
-               for led in /sys/class/leds/*; do
-                       [ -e "$led/trigger" ] && echo "none" > "$led/trigger"
-                       [ -e "$led/brightness" ] && echo "0" > "$led/brightness"
-               done
+               [ -s /var/run/led.state ] && {
+                       local led trigger brightness
+                       while read led trigger brightness; do
+                               [ -e "/sys/class/leds/$led/trigger" ] && \
+                                       echo "$trigger" > "/sys/class/leds/$led/trigger"
+
+                               [ -e "/sys/class/leds/$led/brightness" ] && \
+                                       echo "$brightness" > "/sys/class/leds/$led/brightness"
+                       done < /var/run/led.state
+                       rm /var/run/led.state
+               }
 
                config_load system
                config_foreach load_led led