串口驱动一开始根据platform总线以及tty驱动和tty设备创建如下设备节点
/sys/devices/platform/serial8250/tty/ttyS0
/sys/devices/platform/serial8250/tty/ttyS1
来源于
serial8250_isa_devs = platform_device_alloc("serial8250", PLAT8250_DEV_LEGACY);
但是正是初始化之后将上述节点删除,在serial8250.0重新创建。猜测如果platform的id为-1则没有编号,如果有编号则为.编号
/sys/devices/platform/serial8250.0/tty/ttyS0
/sys/devices/platform/serial8250.0/tty/ttyS1
来源于
static struct platform_device serial_device = {
.name = "serial8250",
.id = PLAT8250_DEV_PLATFORM,
.dev = {
.platform_data = legacy_serial_ports,
},
};
enum {
PLAT8250_DEV_LEGACY = -1,
PLAT8250_DEV_PLATFORM,
PLAT8250_DEV_PLATFORM1,
PLAT8250_DEV_PLATFORM2,
PLAT8250_DEV_FOURPORT,
PLAT8250_DEV_ACCENT,
PLAT8250_DEV_BOCA,
PLAT8250_DEV_EXAR_ST16C554,
PLAT8250_DEV_HUB6,
PLAT8250_DEV_MCA,
PLAT8250_DEV_AU1X00,
PLAT8250_DEV_SM501,
};
对于sys文件系统devices和driver的纠缠不休
cd /sys/bus/platform/drivers/serial8250
ls -l //查看回显
bind
serial8250->../../../../devices/platform/serial8250
serial8250.0->../../../../devices/platform/serial8250.0
uevent
unbind
纠缠不休的详细代码可以查看
linux设备驱动模型一上层容器之device
https://blog.csdn.net/new_abc/article/details/7582215