openwrt: add device option

Add the new device option to UCI. This allows configuring of the modem
device instead of the serial port.

This is helpful in case serial-enumeration is different between devices.

Signed-off-by: David Bauer <[email protected]>

README.md

@@ -19,10 +19,20 @@ Determines if the tool should operate in daemon mode on system-start.
 
 Valid values: `0` or `1`
 
+## `device`
+
+Path for the modem device to use.
+
+In case this option is set, it overrides the `path` option.
+
+Example: `/dev/cdc-wdm0`
+
 ## `path`
 
 Path for the serial interface to use.
 
+This option is overriden by the `device` option.
+
 Example: `/dev/ttyUSB4`
 
 ## `interval`

openwrt/quectel-timesync/files/quectel-timesync.config

@@ -1,3 +1,3 @@
 config quectel-timesync 'timesync'
 	option enabled '0'
-	option path '/dev/ttyUSB4'
+	option device '/dev/cdc-wdm0'

openwrt/quectel-timesync/files/quectel-timesync.init

@@ -4,10 +4,31 @@ START=60
 
 USE_PROCD=1
 
+tty_from_dev() {
+	local cdc_path tty_devpath
+
+	cdc_path="$(readlink -f /sys/class/usbmisc/$1/device/)"
+	tty_devpath="${cdc_path::-1}3"
+
+	for filepath in "$tty_devpath"/* ; do
+		filename="$(basename "${filepath}")"
+		if [[ "$filename" == "ttyUSB*" ]]; then
+			echo "$filename"
+		fi
+	done
+}
+
 start_service() {
 	local enabled="$(uci -q get quectel-timesync.@quectel-timesync[-1].enabled)"
 	local interval="$(uci -q get quectel-timesync.@quectel-timesync[-1].interval)"
 	local path="$(uci -q get quectel-timesync.@quectel-timesync[-1].path)"
+	local device="$(uci -q get quectel-timesync.@quectel-timesync[-1].device)"
+	local device_name
+
+	[ -z "$device" ] || {
+		device_name="$(basename "$device")"
+		path="/dev/$(tty_from_dev "$device_name")"
+	}
 
 	interval="${interval:-10}"