[openwrt/openwrt] base-files: add new application led trigger backend

[LEDE Commits]

aparcar pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/dec14ac436325abddd0ded06f34e95425fc9a75e

commit dec14ac436325abddd0ded06f34e95425fc9a75e
Author: Florian Eckert <fe at dev.tdt.de>
AuthorDate: Wed Feb 5 09:23:27 2020 +0100

    base-files: add new application led trigger backend
    
    For now we have only kernel LED trigger support. With this change it is now
    possible to use application triggers.
    
    If we configure a LED with a non kernel trigger, then we check on every
    restart and boot of the LED service if we have this trigger as an application
    in "/usr/libexec/led-trigger". If this file with the name is found, then we
    execute this to init the LED.
    
    Possible use cases are:
    
    - Start/Stop/Restart an application led trigger service for this led
    - Init a LED that is configured by a hotplug script (VPN tunnel established)
    
    Signed-off-by: Florian Eckert <fe at dev.tdt.de>
---
 package/base-files/files/etc/init.d/led | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/package/base-files/files/etc/init.d/led b/package/base-files/files/etc/init.d/led
index 277fb4e76f..51cb8b5178 100755
--- a/package/base-files/files/etc/init.d/led
+++ b/package/base-files/files/etc/init.d/led
@@ -31,10 +31,11 @@ load_led() {
 	config_get gpio $1 gpio "0"
 	config_get inverted $1 inverted "0"
 
-	if [ "$trigger" = "rssi" ]; then
-		# handled by rssileds userspace process
-		return
-	fi
+	# execute application led trigger
+	[ -f "/usr/libexec/led-trigger/${trigger}" ] && {
+		. "/usr/libexec/led-trigger/${trigger}"
+		return 0
+	}
 
 	[ "$trigger" = "usbdev" ] && {
 		# Backward compatibility: translate to the new trigger