高精度定时器使用示例。

1
  2 #include <linux/module.h>
  3 #include <linux/kernel.h>
  4 #include <linux/hrtimer.h>
  5 #include <linux/jiffies.h>
  6
  7
  8 static struct hrtimer timer;
  9 ktime_t kt;
 10
 11 static enum hrtimer_restart hrtimer_handler(struct hrtimer *timer)
 12 {
 13     //kt = ktime_set(1, 10);
 14     printk(" ------ I am in hrtimer -----\n");
 15     hrtimer_forward(timer, timer->base->get_time(), kt);
 16     return HRTIMER_RESTART;
 17 }
 18
 19 static int __init test_init(void)
 20 {
 21
 22     pr_info("timer resolution: %lu\n", TICK_NSEC);
 23     kt = ktime_set(1, 10); /* 1 sec, 10 nsec */
 24     hrtimer_init(&timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 25     //hrtimer_set_expires(&timer, kt);
 26     hrtimer_start(&timer, kt, HRTIMER_MODE_REL);
 27     timer.function = hrtimer_handler;
 28
 29     printk("\n-------- test start ---------\n");
 30     return 0;
 31 }
 32
 33 static void __exit test_exit(void)
 34 {
 35     hrtimer_cancel(&timer);
 36     printk("-------- test over ----------\n");
 37     return;
 38 }
 39
 40 MODULE_LICENSE("GPL");
 41
 42 module_init(test_init);
 43 module_exit(test_exit);
~

编译：

  2 name = test.o
  3 #name ?= jprobe.o
  4 obj-m := $(name)
  5
  6 KERNELDIR := /home/tangyt/tmp/linux-2.6-cloud.p1020/
  7
  8 ARCH = powerpc
  9 CROSS_COMPILE = /home/tangyt/toolchain/powerpc-linux-gnu-
 10 export ARCH CROSS_COMPILE
 11 #export CC
 12
 13 default:
 14     make -C $(KERNELDIR) M=$(shell pwd) modules
 15
 16
 17 clean:
 18     make -C $(KERNELDIR) M=$(shell pwd) clean

说明：
1.  40 MODULE_LICENSE("GPL");不可少，否则找不到相应的函数
2. 为了测试需要设置了1秒10纳秒延时，此处完全可以设置纳秒级的延时