linux驱动31：获取当前时间

头文件<linux/time.h>

墙钟转换为jiffies：

unsigned long mktime(unsigned int year, unsigned int mon, unsigned int day, unsigned int hour, unsigned int min, unsigned int sec);

获取时间戳：

void do_gettimeofday(struct timeval *tv);        //struct timeval （秒、微妙）

struct timespec current_kernel_time(void);