From 6f922f7ae9c58f359cbacbcf0c35a3bf3262f5c5 Mon Sep 17 00:00:00 2001
From: David Bauer <mail@david-bauer.net>
Date: Sun, 8 Oct 2023 22:21:28 +0200
Subject: [PATCH] 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 <mail@david-bauer.net>
---
 README.md                                     | 10 +++++++++
 .../files/quectel-timesync.config             |  2 +-
 .../files/quectel-timesync.init               | 21 +++++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index ff90e16..800cb75 100644
--- a/README.md
+++ b/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`
diff --git a/openwrt/quectel-timesync/files/quectel-timesync.config b/openwrt/quectel-timesync/files/quectel-timesync.config
index c92d606..9baac80 100644
--- a/openwrt/quectel-timesync/files/quectel-timesync.config
+++ b/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'
diff --git a/openwrt/quectel-timesync/files/quectel-timesync.init b/openwrt/quectel-timesync/files/quectel-timesync.init
index 98102bb..18aba34 100644
--- a/openwrt/quectel-timesync/files/quectel-timesync.init
+++ b/openwrt/quectel-timesync/files/quectel-timesync.init
@@ -4,10 +4,31 @@ START=60
 
 USE_PROCD=1
 
+tty_from_dev() {
+	local cdc_path tty_devpath filepath filename
+
+	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}"