linux如何通過usb端口綁定到固定的串口號

更新時間：2025年09月08日 11:31:44 作者：技術求索者

文章討論了在安卓設備使用USB轉串口時,由于設備號隨USB枚舉順序變化導致串口無法被系統(tǒng)識別的問題,最初通過修改串口號解決,但發(fā)現(xiàn)直接修改串口號無法被系統(tǒng)正確映射,最終解決方法是不修改串口號,而是通過調整串口配置或延長串口可用長度,確保系統(tǒng)能夠正確識別和映射串口

linux通過usb端口綁定到固定的串口號

我們在安卓設備上經常會用到usb轉串口的設備，而usb轉串口的設備生成的設備號是按usb枚舉的順序生成的，所以同一個usb設備每次開機之后生成的串口序號可能不相同，通過下面的補丁可以解決這個問題。

Index: kernel/drivers/usb/serial/usb-serial.c
===================================================================
--- kernel/drivers/usb/serial/usb-serial.c	(revision 1851)
+++ kernel/drivers/usb/serial/usb-serial.c	(working copy)
@@ -85,20 +85,74 @@
 	return port;
 }
 
-static int allocate_minors(struct usb_serial *serial, int num_ports)
+static int allocate_minors(struct usb_serial *serial, int num_ports,char * dev_name)
 {
 	struct usb_serial_port *port;
 	unsigned int i, j;
-	int minor;
+	int minor,tmpmiior;
 
 	dev_dbg(&serial->interface->dev, "%s %d\n", __func__, num_ports);
 
 	mutex_lock(&table_lock);
+printk("dev_name = %s\n",dev_name);
 	for (i = 0; i < num_ports; ++i) {
 		port = serial->port[i];
-		minor = idr_alloc(&serial_minors, port, 0, 0, GFP_KERNEL);
-		if (minor < 0)
-			goto error;
+      
+	   printk("num_ports = %d\n",num_ports);
+
+	   if(!strcmp(dev_name,"2-1.7")) //USB0
+		 {
+		 minor = idr_alloc(&serial_minors, port, 0, 4, GFP_KERNEL);
+			 if (minor < 0)
+			   goto error;
+		 }
+      else
+      	{
+	   
+	   if(!strcmp(dev_name,"1-1.1")) //USB0
+	   {
+			   minor = 5;
+	   }
+		 else if(!strcmp(dev_name,"2-1.6.1")) //USB0
+		{
+				minor = 6;
+		}
+
+		else if(!strcmp(dev_name,"2-1.5.1")) //USB0
+	   {
+			   minor = 7;
+	   }
+
+		else if(!strcmp(dev_name,"2-1.4.1")) //USB0
+ 	   {
+ 			   minor = 8;
+ 	   }
+ 	   else if(!strcmp(dev_name,"2-1.3.1"))
+ 	   {
+ 			   minor = 9; 
+ 	   }
+ 	   else if(!strcmp(dev_name,"2-1.2.1"))
+ 		{
+ 				minor = 10;
+ 		}
+	    else if(!strcmp(dev_name,"2-1.1.1"))
+ 		{
+ 				minor = 11;
+ 		}
+	  
+		 tmpmiior=idr_alloc(&serial_minors, port, 5, 20, GFP_KERNEL);
+		 if (minor < 0)
+	   		goto error;
+
+	   }
+ 	/*   else if(!strcmp(dev_name,"2-1.7"))
+ 	   {
+ 				i = 7;
+ 	   }*/
+		//minor = idr_alloc(&serial_minors, port, 0, 0, GFP_KERNEL);
+		//if (minor < 0)
+		//	goto error;
+
 		port->minor = minor;
 		port->port_number = i;
 	}
@@ -1058,7 +1112,7 @@
 	 */
 	serial->disconnected = 1;
 
-	if (allocate_minors(serial, num_ports)) {
+	if (allocate_minors(serial, num_ports,dev_name(&port->serial->dev->dev))) {
 		dev_err(ddev, "No more free serial minor numbers\n");
 		goto probe_error;
 	}

后來發(fā)現(xiàn)以上方法有問題，串口好是改了，系統(tǒng)沒費配到改的串口號就是手動改的串口號并不是idr_alloc 分配出來的串口號，導致去打開的時候經常打不開

終極解決方法

如下所示：

#!/system/bin/sh

creat_tty_symlink(){
	tty0=$(ls -l /sys/class/tty/$1)
	hastty=$(ls  /sys/class/tty*)
	#goal="2-1.1"
	echo "parameter1 is "$1
	echo "hastty is "$hastty
	if [[ $tty0 == *"2-1.1"* ]] ; then
	     if [[ $hastty == *"ttyXRUSB1"* ]] ; then
		    echo "ttyXRUSB1 exsit"
		 else
			 echo "creat ttyXRUSB1"
			 rm  /dev/ttyXRUSB1
			 ln -s /dev/$1 /dev/ttyXRUSB1
			 chown system:system /dev/ttyXRUSB1
		 fi
		 
	elif  [[ $tty0 == *"2-1.2"* ]] ; then
	     if [[ $hastty == *"ttyXRUSB2"* ]] ; then
			echo "ttyXRUSB2 exsit"
		 else
		 echo "creat ttyXRUSB2"
			 rm  /dev/ttyXRUSB2
			 ln -s /dev/$1 /dev/ttyXRUSB2
			 chown system:system /dev/ttyXRUSB2
		 fi
	elif  [[ $tty0 == *"2-1.3"* ]] ; then 
	     if [[ $hastty == *"ttyXRUSB3"* ]] ; then
			echo "ttyXRUSB3 exsit"
		 else
			 echo "creat ttyXRUSB3"
			 rm  /dev/ttyXRUSB3
			 ln -s /dev/$1 /dev/ttyXRUSB3
			 chown system:system /dev/ttyXRUSB3
	     fi
	elif  [[ $tty0 == *"2-1.4"* ]] ; then 
		 if [[ $hastty == *"ttyXRUSB4"* ]] ; then
			echo "ttyXRUSB4 exsit"
		 else
			 echo "creat ttyXRUSB4"
			 rm  /dev/ttyXRUSB4
			 ln -s /dev/$1  /dev/ttyXRUSB4
			 chown system:system /dev/ttyXRUSB4			 
		fi
     else
	    echo "end"
	 fi



}


while true
do
    creat_tty_symlink ttyUSB0
	sleep 1
	creat_tty_symlink ttyUSB1
	sleep 1
    creat_tty_symlink ttyUSB2
	sleep 1
	creat_tty_symlink ttyUSB3
	sleep 1
	creat_tty_symlink ttyUSB4
	sleep 2
done