usb-serial: show port number in sysfs (ce0d9325) · Commits · 戴 / test

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>

drivers/usb/serial/bus.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -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)) {

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