linux通过usb端口绑定到固定的串口号

我们在安卓设备上经常会用到usb转串口的设备，而usb转串口的设备生成的设备号是按usb枚举的顺序生成的，所以同一个usb设备每次开机之后生成的串口序号可能不相同，通过下面的补丁可以解决这个问题。

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;
 	}