kernel-ark/drivers/usb/serial/bus.c
Roman Kagan ce0d9325b1 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>
2007-10-12 14:55:20 -07:00

189 lines
4.2 KiB
C

/*
* USB Serial Converter Bus specific functions
*
* Copyright (C) 2002 Greg Kroah-Hartman (greg@kroah.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
static int usb_serial_device_match (struct device *dev, struct device_driver *drv)
{
struct usb_serial_driver *driver;
const struct usb_serial_port *port;
/*
* drivers are already assigned to ports in serial_probe so it's
* a simple check here.
*/
port = to_usb_serial_port(dev);
if (!port)
return 0;
driver = to_usb_serial_driver(drv);
if (driver == port->serial->type)
return 1;
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;
struct usb_serial_port *port;
int retval = 0;
int minor;
port = to_usb_serial_port(dev);
if (!port) {
retval = -ENODEV;
goto exit;
}
driver = port->serial->type;
if (driver->port_probe) {
if (!try_module_get(driver->driver.owner)) {
dev_err(dev, "module get failed, exiting\n");
retval = -EIO;
goto exit;
}
retval = driver->port_probe (port);
module_put(driver->driver.owner);
if (retval)
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,
"%s converter now attached to ttyUSB%d\n",
driver->description, minor);
exit:
return retval;
}
static int usb_serial_device_remove (struct device *dev)
{
struct usb_serial_driver *driver;
struct usb_serial_port *port;
int retval = 0;
int minor;
port = to_usb_serial_port(dev);
if (!port) {
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)) {
dev_err(dev, "module get failed, exiting\n");
retval = -EIO;
goto exit;
}
retval = driver->port_remove (port);
module_put(driver->driver.owner);
}
exit:
minor = port->number;
tty_unregister_device (usb_serial_tty_driver, minor);
dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
driver->description, minor);
return retval;
}
#ifdef CONFIG_HOTPLUG
static ssize_t store_new_id(struct device_driver *driver,
const char *buf, size_t count)
{
struct usb_serial_driver *usb_drv = to_usb_serial_driver(driver);
ssize_t retval = usb_store_new_id(&usb_drv->dynids, driver, buf, count);
if (retval >= 0 && usb_drv->usb_driver != NULL)
retval = usb_store_new_id(&usb_drv->usb_driver->dynids,
&usb_drv->usb_driver->drvwrap.driver,
buf, count);
return retval;
}
static struct driver_attribute drv_attrs[] = {
__ATTR(new_id, S_IWUSR, NULL, store_new_id),
__ATTR_NULL,
};
static void free_dynids(struct usb_serial_driver *drv)
{
struct usb_dynid *dynid, *n;
spin_lock(&drv->dynids.lock);
list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
list_del(&dynid->node);
kfree(dynid);
}
spin_unlock(&drv->dynids.lock);
}
#else
static struct driver_attribute drv_attrs[] = {
__ATTR_NULL,
};
static inline void free_dynids(struct usb_serial_driver *drv)
{
}
#endif
struct bus_type usb_serial_bus_type = {
.name = "usb-serial",
.match = usb_serial_device_match,
.probe = usb_serial_device_probe,
.remove = usb_serial_device_remove,
.drv_attrs = drv_attrs,
};
int usb_serial_bus_register(struct usb_serial_driver *driver)
{
int retval;
driver->driver.bus = &usb_serial_bus_type;
spin_lock_init(&driver->dynids.lock);
INIT_LIST_HEAD(&driver->dynids.list);
retval = driver_register(&driver->driver);
return retval;
}
void usb_serial_bus_deregister(struct usb_serial_driver *driver)
{
free_dynids(driver);
driver_unregister(&driver->driver);
}