base-files: support parse DT LED color and function

The 'label' property in led node has been deprecated and we'd better
to avoid using it. This patch allows us to extract DT OF LED name
from the newly introduced LED properties "color", "function" and
"function-enumerator".

Signed-off-by: Shiji Yang <yangshiji66@qq.com>
(cherry picked from commit e814acc599)

package/base-files/files/lib/functions/leds.sh

@@ -11,6 +11,36 @@ get_dt_led_path() {
 	echo "$ledpath"
 }
 
+get_dt_led_color_func() {
+	local enum
+	local func
+	local idx
+	local label
+
+	[ -e "$1/function" ] && func=$(cat "$1/function")
+	[ -e "$1/color" ] && idx=$((0x$(hexdump -n 4 -e '4/1 "%02x"' "$1/color")))
+	[ -e "$1/function-enumerator" ] && \
+		enum=$((0x$(hexdump -n 4 -e '4/1 "%02x"' "$1/function-enumerator")))
+
+	[ -z "$idx" ] && [ -z "$func" ] && return 2
+
+	if [ -n "$idx" ]; then
+		for color in "white" "red" "green" "blue" "amber" \
+			     "violet" "yellow" "ir" "multicolor" "rgb" \
+			     "purple" "orange" "pink" "cyan" "lime"
+		do
+			[ $idx -eq 0 ] && label="$color" && break
+			idx=$((idx-1))
+		done
+	fi
+
+	label="$label:$func"
+	[ -n "$enum" ] && label="$label-$enum"
+	echo "$label"
+
+	return 0
+}
+
 get_dt_led() {
 	local label
 	local ledpath=$(get_dt_led_path $1)
@@ -18,6 +48,7 @@ get_dt_led() {
 	[ -n "$ledpath" ] && \
 		label=$(cat "$ledpath/label" 2>/dev/null) || \
 		label=$(cat "$ledpath/chan-name" 2>/dev/null) || \
+		label=$(get_dt_led_color_func "$ledpath") || \
 		label=$(basename "$ledpath")
 
 	echo "$label"