hilink: control WFB lifecycle and power from CH6 knob

devices/ssc338q_fpv_openipc-urllc-aio/general/overlay/usr/bin/channels.sh

@@ -3,20 +3,23 @@
 CHANNEL="${1:-}"
 VALUE="${2:-}"
 
+# CH6 is the GX12 WFB knob. Betaflight exposes it as 1000..2000 PWM.
 [ "$CHANNEL" = "6" ] || exit 0
 
 case "$VALUE" in
-    ''|*[!0-9]*) exit 2 ;;
+  ''|*[!0-9]*) exit 2 ;;
 esac
 
-if [ "$VALUE" -le 1250 ]; then
-    logger -t channels "AUX2=$VALUE -> management"
-    exec /usr/bin/link-mode management
+# First 5% is an explicit OFF detent. Above it WFB starts at 5% and the
+# remaining travel maps continuously to 100%. This is a UI-range guard, not a
+# regulatory EIRP cap.
+if [ "$VALUE" -le 1050 ]; then
+  rm -f /run/wfb-power
+  logger -t channels "CH6=$VALUE -> management"
+  exec /usr/bin/link-mode management
 fi
 
-if [ "$VALUE" -ge 1350 ]; then
-    logger -t channels "AUX2=$VALUE -> preflight"
-    exec /usr/bin/link-mode preflight
-fi
-
-exit 0
+POWER=$((5 + (VALUE - 1051) * 95 / 949))
+[ "$POWER" -gt 100 ] && POWER=100
+logger -t channels "CH6=$VALUE -> WFB txpower=$POWER"
+exec /usr/bin/wfb-power "$POWER"

devices/ssc338q_fpv_openipc-urllc-aio/general/overlay/usr/bin/wfb-power

@@ -0,0 +1,28 @@
+#!/bin/sh
+
+POWER="${1:-}"
+LOCK=/run/wfb-power.lock
+STATE=/run/wfb-power
+
+case "$POWER" in
+  ''|*[!0-9]*) exit 2 ;;
+esac
+[ "$POWER" -ge 5 ] && [ "$POWER" -le 100 ] || exit 2
+
+# The runtime state is tmpfs. Do not rewrite /etc/wfb.yaml while a knob moves.
+printf '%s\n' "$POWER" >"$STATE"
+
+if ! mkdir "$LOCK" 2>/dev/null; then
+  exit 0
+fi
+trap 'rmdir "$LOCK" 2>/dev/null || true' EXIT HUP INT TERM
+
+if pidof wfb_tx wfb_rx wfb_tun wifilink >/dev/null; then
+  # RTL8812EU expects the OpenIPC scalar multiplied by 50 mBm.
+  iw wlan0 set txpower fixed $((POWER * 50))
+  logger -t wfb-power "runtime txpower=$POWER"
+  exit 0
+fi
+
+logger -t wfb-power "txpower=$POWER -> WFB preflight"
+/usr/bin/link-mode preflight

devices/ssc338q_fpv_openipc-urllc-aio/general/overlay/usr/bin/wifibroadcast

@@ -20,6 +20,12 @@ wfb_yaml() {
 load_config() {
 	wfb_yaml /rom"$wfb_cfg"
 	wfb_yaml "$wfb_cfg"
+	if [ -r /run/wfb-power ]; then
+		runtime_txpower=$(cat /run/wfb-power)
+		case "$runtime_txpower" in
+			[5-9]|[1-9][0-9]|100) txpower="$runtime_txpower" ;;
+		esac
+	fi
 	[ ! -e "$wfb_key" ] && wfb_key=/rom"$wfb_key"
 }