feat: audio stack working — pulseaudio + x6200_control + voice_rec

- Add pulseaudio in system mode
- Add alsactl restore with correct mixer state from Aether
- Add x6200-control package (I2C hardware control library)
- Audio chain: pulseaudio -> x6200_control_init -> voice_rec -> speaker

br2_external/board/x6200/rootfs-overlay/etc/init.d/S50alsa

@@ -0,0 +1,40 @@
+#!/bin/sh
+#
+# Alsa config
+#
+
+source /etc/profile
+
+start() {
+    printf "Restore alsa"
+    alsactl restore
+    echo "OK"
+}
+
+stop() {
+    printf "Store alsa"
+#   alsactl store
+    echo "OK"
+}
+
+restart() {
+    stop
+    start
+}
+
+case "$1" in
+  start)
+    start
+    ;;
+  stop)
+    stop
+    ;;
+  restart|reload)
+    restart
+    ;;
+  *)
+    echo "Usage: $0 {start|stop|restart}"
+    exit 1
+esac
+
+exit $?

br2_external/board/x6200/rootfs-overlay/etc/init.d/S50pulseaudio

@@ -0,0 +1,45 @@
+#!/bin/sh
+#
+# Starts pulseaudio.
+#
+
+
+start() {
+	printf "Starting pulseaudio: "
+	umask 007
+	/usr/bin/pulseaudio \
+		--system \
+		--daemonize \
+		--disallow-exit \
+		--exit-idle-time=-1 \
+		--use-pid-file \
+		--disable-shm
+	echo "OK"
+}
+stop() {
+	printf "Stopping pulseaudio: "
+	PULSE_RUNTIME_PATH=/var/run/pulse /usr/bin/pulseaudio --kill
+	echo "OK"
+}
+restart() {
+	stop
+	start
+}
+
+case "$1" in
+  start)
+	start
+	;;
+  stop)
+	stop
+	;;
+  restart|reload)
+	restart
+	;;
+  *)
+	echo "Usage: $0 {start|stop|restart}"
+	exit 1
+esac
+
+exit $?
+

br2_external/board/x6200/rootfs-overlay/etc/init.d/S70mestre-audio

@@ -0,0 +1,59 @@
+#!/bin/sh
+# S70mestre-audio — X6200 audio hardware init
+#
+# Initializes the X6200's audio routing via I2C:
+#   1. Calls x6200_control_init() to establish MCU state
+#   2. Sets speaker volume
+#   3. Switches audio routing from RX-radio to SoC DAC (voice_rec)
+#
+# Must run after S50pulseaudio (pulseaudio must hold PCM open first
+# to keep ALSA clocks active).
+#
+# The voice_rec bit (0x00008 in sple_atue_trx register, cmd 12)
+# switches the X6200's internal audio mux from the RF receiver
+# to the SoC DAC — allowing piHPSDR/aplay to be heard in the speaker.
+
+VOLUME=50
+
+do_init() {
+    python3 << EOF
+import ctypes
+lib = ctypes.CDLL("libaether_x6200_control.so")
+lib.x6200_control_init.restype = ctypes.c_bool
+lib.x6200_control_rxvol_set.argtypes = [ctypes.c_uint8]
+lib.x6200_control_spmode_set.argtypes = [ctypes.c_bool]
+
+if not lib.x6200_control_init():
+    raise SystemExit("x6200_control_init() failed")
+
+lib.x6200_control_rxvol_set($VOLUME)
+lib.x6200_control_spmode_set(False)  # Speaker mode (not headphone)
+EOF
+}
+
+do_voice_rec() {
+    # Switch audio routing: RX-radio -> SoC DAC (voice_rec bit = 0x00008)
+    i2ctransfer -y 0 w6@0x72 0x00 0x30 0x08 0x00 0x00 0x00
+}
+
+case "$1" in
+    start)
+        echo "Starting mestre-audio"
+        do_init && do_voice_rec && echo "OK" || echo "FAILED"
+        ;;
+    stop)
+        echo "Stopping mestre-audio"
+        # Switch back to RX-radio audio
+        i2ctransfer -y 0 w6@0x72 0x00 0x30 0x00 0x00 0x00 0x00
+        echo "OK"
+        ;;
+    restart)
+        $0 stop
+        sleep 1
+        $0 start
+        ;;
+    *)
+        echo "Usage: $0 {start|stop|restart}" >&2
+        exit 1
+        ;;
+esac

br2_external/board/x6200/rootfs-overlay/etc/init.d/S96keepalive

@@ -0,0 +1,23 @@
+#!/bin/sh
+# S96keepalive — X6200 PMU keepalive
+#
+# The X6200 powers itself off after ~180s unless the AXP PMU receives
+# periodic I2C traffic. This script starts the keepalive daemon at boot.
+
+case "$1" in
+    start)
+        echo "Starting keepalive"
+        /usr/sbin/i2c_keepalive.sh >/dev/null 2>&1 &
+        ;;
+    stop)
+        echo "Stopping keepalive"
+        killall i2c_keepalive.sh 2>/dev/null || true
+        ;;
+    restart)
+        $0 stop; sleep 1; $0 start
+        ;;
+    *)
+        echo "Usage: $0 {start|stop|restart}" >&2
+        exit 1
+        ;;
+esac