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-rw-r--r--drivers/usb/serial/bus.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index a47a24f8820..0b14aea8ebd 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -36,6 +36,16 @@ static int usb_serial_device_match (struct device *dev, struct device_driver *dr
return 0;
}
+static ssize_t show_port_number(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct usb_serial_port *port = to_usb_serial_port(dev);
+
+ return sprintf(buf, "%d\n", port->number - port->serial->minor);
+}
+
+static DEVICE_ATTR(port_number, S_IRUGO, show_port_number, NULL);
+
static int usb_serial_device_probe (struct device *dev)
{
struct usb_serial_driver *driver;
@@ -62,6 +72,10 @@ static int usb_serial_device_probe (struct device *dev)
goto exit;
}
+ retval = device_create_file(dev, &dev_attr_port_number);
+ if (retval)
+ goto exit;
+
minor = port->number;
tty_register_device (usb_serial_tty_driver, minor, dev);
dev_info(&port->serial->dev->dev,
@@ -84,6 +98,8 @@ static int usb_serial_device_remove (struct device *dev)
return -ENODEV;
}
+ device_remove_file(&port->dev, &dev_attr_port_number);
+
driver = port->serial->type;
if (driver->port_remove) {
if (!try_module_get(driver->driver.owner)) {