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authorRoman Kagan <rkagan@sw.ru>2007-08-24 20:22:52 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-10-12 14:55:20 -0700
commitce0d9325b19555f05b08cbb1ea4c2393eec188ec (patch)
tree8e7da899788b3a5e0c266b94bd9c3549f9f5df9d /drivers/usb
parentfdf99c9ec10cb9cd44be3ac0bd007a49ac6dc751 (diff)
usb-serial: show port number in sysfs
Some usb-serial devices (e.g. certain Edgeport models) have more than one serial port on the same USB device/interface. Currently the only way to distinguish these ports in userspace is by their minor device number: the driver makes them consecutive and in stable order. However, for the purpose of stable naming with udev this is insufficient: when udev handles the ADD event for one of the ports it doesn't know what minor number the other one has. To make stable naming easier, export the port number via sysfs. Signed-off-by: Roman Kagan <rkagan@sw.ru> Signed-off-by: Dmitry Guryanov <dimak@dgap.mipt.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-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)) {