需求：3368的老主板更换为3568的新主板，为了app兼容两款主板，要求串口号一致。有个ttyS0的口，需要对应改为ttySWK0
跟踪驱动代码：
dw8250_probe(drivers\tty\serial\8250\8250_dw.c) -->serial8250_register_8250_port(drivers\tty\serial\8250\8250_core.c) -->uart_add_one_port(drivers\tty\serial\serial_core.c) -->tty_port_register_device_attr_serdev(drivers\tty\tty_port.c) -->tty_register_device_attr -->tty_line_name(drivers\tty\tty_io.c)
tty_line_name函数：
static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p) { if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE) return sprintf(p, "%s", driver->name); else return sprintf(p, "%s%d", driver->name, index + driver->name_base); }
可知ttySx串口节点设备名称是由驱动名称 driver->name和串口序号index 组成的。
这里做一个判断，index是0，串口节点设备名称则为ttySWK0即可满足需求：
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index b6f42d0ee626..fb6750ad356d 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1135,9 +1135,14 @@ static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
{
if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
return sprintf(p, "%s", driver->name);
- else
+ else{
+ if(index == 0){
+ return sprintf(p, "ttySWK%d",index);
+ }else
return sprintf(p, "%s%d", driver->name,
index + driver->name_base);
+ }
+
}
编译好重新烧录，ttyS改为ttySWK0：
参考：
https://www.jianshu.com/p/c345576b94a1?ivk_sa=1024320u
https://www.ngui.cc/article/show-884649.html?action=onClick