从platform_device获取节点信息demo

# 加载模块
insmod xxx.ko

# 查看注册的设备号
cat /proc/devices
cat /proc/devices | grep dev_name

# 查看创建的class
ls /sys/class
ls /sys/class | grep class_dev_name

# 查看设备节点
ls /dev
ls /dev | grep device_dev_name

# 卸载模块
rmmod xxx.ko

insmod sbus_demo.ko
insmod sdriver_demo.ko
insmod sdevice_demo.ko

# 查看/修改属性的值
cat /sys/bus/bus-name/attr-file
echo data > /sys/bus/bus-name/attr-file

cat /sys/bus/bus-name/devices/device-name/attr-file
echo data > /sys/bus/bus-name/devices/device-name/attr-file

cat /sys/bus/bus-name/drivers/driver-name/attr-file
echo data > /sys/bus/bus-name/drivers/driver-name/attr-file

rmmod sdevice_demo.ko
rmmod sdriver_demo.ko
rmmod sbus_demo.ko

# 查看当前控制台的打印级别
root@alpha-imx6ull:~# cat /proc/sys/kernel/printk
7       4       1       7

# 将所有的内核打印放到后台去(敲dmesg才会显示)
root@alpha-imx6ull:~# echo 1 4 1 7 > /proc/sys/kernel/printk
# 或者
root@alpha-imx6ull:~# echo 0 4 0 7 > /proc/sys/kernel/printk

# 将内核打印显示到终端
root@alpha-imx6ull:~# echo 7 4 1 7 > /proc/sys/kernel/printk