feat: CANable 2.0 bringup with udev rule and systemd service (Issue #643)

- udev: 70-canable.rules — gs_usb VID/PID 1d50:606f, names iface can0 and brings it up at 500 kbps on plug-in
- systemd: can-bringup.service — oneshot service bound to sys-subsystem-net-devices-can0.device
- scripts: can_setup.sh — manual up/down/verify helper; candump verify for VESC IDs 61 (0x3D) and 79 (0x4F)
- install_systemd.sh updated to install can-bringup.service and all udev rules

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

jetson/ros2_ws/src/saltybot_bringup/systemd/can-bringup.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=CANable 2.0 CAN bus bringup (can0, 500 kbps)
+Documentation=https://gitea.vayrette.com/seb/saltylab-firmware/issues/643
+# Wait until the gs_usb net device appears; udev fires After=sys-subsystem-net-devices-can0.device
+After=network.target sys-subsystem-net-devices-can0.device
+Requires=sys-subsystem-net-devices-can0.device
+BindsTo=sys-subsystem-net-devices-can0.device
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+
+ExecStart=/usr/sbin/ip link set can0 up type can bitrate 500000
+ExecStop=/usr/sbin/ip link set can0 down
+
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=can-bringup
+
+[Install]
+WantedBy=multi-user.target

jetson/ros2_ws/src/saltybot_bringup/udev/70-canable.rules

@@ -0,0 +1,19 @@
+# CANable 2.0 USB-CAN adapter (gs_usb driver)
+# Exposes the adapter as can0 via the SocketCAN subsystem.
+# Issue: https://gitea.vayrette.com/seb/saltylab-firmware/issues/643
+#
+# Install:
+#   sudo cp 70-canable.rules /etc/udev/rules.d/
+#   sudo udevadm control --reload && sudo udevadm trigger
+#
+# CANable 2.0 USB IDs (Geschwister Schneider / candleLight firmware):
+#   idVendor  = 1d50  (OpenMoko)
+#   idProduct = 606f  (candleLight / gs_usb)
+#
+# Verify with: lsusb | grep -i candl
+#              ip link show can0
+
+SUBSYSTEM=="net", ACTION=="add", \
+    ATTRS{idVendor}=="1d50", ATTRS{idProduct}=="606f", \
+    NAME="can0", \
+    RUN+="/sbin/ip link set can0 up type can bitrate 500000"

jetson/scripts/can_setup.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+# can_setup.sh — Bring up CANable 2.0 (gs_usb) as can0 at 500 kbps
+# Issue: https://gitea.vayrette.com/seb/saltylab-firmware/issues/643
+#
+# Usage:
+#   sudo ./can_setup.sh          # bring up
+#   sudo ./can_setup.sh down     # bring down
+#   sudo ./can_setup.sh verify   # candump one-shot check (Ctrl-C to stop)
+#
+# VESCs on bus: CAN ID 61 (0x3D) and CAN ID 79 (0x4F), 500 kbps
+set -euo pipefail
+
+IFACE="${CAN_IFACE:-can0}"
+BITRATE="${CAN_BITRATE:-500000}"
+
+log() { echo "[can_setup] $*"; }
+die() { echo "[can_setup] ERROR: $*" >&2; exit 1; }
+
+cmd="${1:-up}"
+
+case "$cmd" in
+  up)
+    # Verify the interface exists (gs_usb module loaded by kernel on plug-in)
+    if ! ip link show "$IFACE" &>/dev/null; then
+        die "$IFACE not found — is CANable 2.0 plugged in and gs_usb loaded?"
+    fi
+
+    log "Bringing up $IFACE at ${BITRATE} bps..."
+    ip link set "$IFACE" down 2>/dev/null || true
+    ip link set "$IFACE" up type can bitrate "$BITRATE"
+    ip link set "$IFACE" up
+    log "$IFACE is up."
+    ip -details link show "$IFACE"
+    ;;
+
+  down)
+    log "Bringing down $IFACE..."
+    ip link set "$IFACE" down
+    log "$IFACE is down."
+    ;;
+
+  verify)
+    log "Listening on $IFACE — expecting frames from VESC IDs 0x3D (61) and 0x4F (79)"
+    log "Press Ctrl-C to stop."
+    exec candump "$IFACE"
+    ;;
+
+  *)
+    echo "Usage: $0 [up|down|verify]"
+    exit 1
+    ;;
+esac

jetson/systemd/install_systemd.sh

@@ -7,6 +7,9 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 REPO_DIR="$(dirname "${SCRIPT_DIR}")"
 SYSTEMD_DIR="/etc/systemd/system"
 DEPLOY_DIR="/opt/saltybot/jetson"
+UDEV_DIR="/etc/udev/rules.d"
+BRINGUP_SYSTEMD="${REPO_DIR}/ros2_ws/src/saltybot_bringup/systemd"
+BRINGUP_UDEV="${REPO_DIR}/ros2_ws/src/saltybot_bringup/udev"
 
 log() { echo "[install_systemd] $*"; }
 
@@ -23,15 +26,30 @@ log "Installing systemd units..."
 cp "${SCRIPT_DIR}/saltybot.target"        "${SYSTEMD_DIR}/"
 cp "${SCRIPT_DIR}/saltybot-social.service" "${SYSTEMD_DIR}/"
 cp "${SCRIPT_DIR}/tailscale-vpn.service"  "${SYSTEMD_DIR}/"
+cp "${BRINGUP_SYSTEMD}/can-bringup.service" "${SYSTEMD_DIR}/"
+
+# Install udev rules
+log "Installing udev rules..."
+mkdir -p "${UDEV_DIR}"
+cp "${BRINGUP_UDEV}/70-canable.rules"    "${UDEV_DIR}/"
+cp "${BRINGUP_UDEV}/90-magedok-touch.rules" "${UDEV_DIR}/"
+udevadm control --reload
+udevadm trigger --subsystem-match=net --action=add
 
 # Reload and enable
 systemctl daemon-reload
 systemctl enable saltybot.target
 systemctl enable saltybot-social.service
 systemctl enable tailscale-vpn.service
+systemctl enable can-bringup.service
 
 log "Services installed. Start with:"
 log "  systemctl start saltybot-social"
 log "  systemctl start tailscale-vpn"
+log "  systemctl start can-bringup"
 log "  journalctl -fu saltybot-social"
 log "  journalctl -fu tailscale-vpn"
+log "  journalctl -fu can-bringup"
+log ""
+log "Verify CAN bus: candump can0"
+log "  VESC CAN IDs: 61 (0x3D) and 79 (0x4F)"