in drivers/line.c [362:412]
int setup_one_line(struct line *lines, int n, char *init,
const struct chan_opts *opts, char **error_out)
{
struct line *line = &lines[n];
struct tty_driver *driver = line->driver->driver;
int err = -EINVAL;
if (line->port.count) {
*error_out = "Device is already open";
goto out;
}
if (!strcmp(init, "none")) {
if (line->valid) {
line->valid = 0;
kfree(line->init_str);
tty_unregister_device(driver, n);
parse_chan_pair(NULL, line, n, opts, error_out);
err = 0;
}
} else {
char *new = kstrdup(init, GFP_KERNEL);
if (!new) {
*error_out = "Failed to allocate memory";
return -ENOMEM;
}
if (line->valid) {
tty_unregister_device(driver, n);
kfree(line->init_str);
}
line->init_str = new;
line->valid = 1;
err = parse_chan_pair(new, line, n, opts, error_out);
if (!err) {
struct device *d = tty_port_register_device(&line->port,
driver, n, NULL);
if (IS_ERR(d)) {
*error_out = "Failed to register device";
err = PTR_ERR(d);
parse_chan_pair(NULL, line, n, opts, error_out);
}
}
if (err) {
line->init_str = NULL;
line->valid = 0;
kfree(new);
}
}
out:
return err;
}