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rtc在linux上的测试代码 .

rtc应用很广泛，在PC机和嵌入式上面几乎都能看到。下面就用最简单的代码做一个演示。相应的分析请看linux源代码中的分析文档。代码如下：

#include

#include

#include

#include

#include

#include

#include

#include

#include

/*

* This expects the new RTC class driver framework, working with

* clocks that will often not be clones of what the PC-AT had.

* Use the command line to specify another RTC if you need one.

*/

static const char default_rtc[] = "/dev/rtc";

int main(int argc, char **argv)

{

int i, fd, retval, irqcount = 0;

unsigned long tmp, data;

struct rtc_time rtc_tm;

const char *rtc = default_rtc;

switch (argc)

{

case 2:

rtc = argv[1];

/* FALLTHROUGH */

case 1:

break;

default:

fprintf(stderr, "usage: rtctest [rtcdev]/n");

return 1;

}

fd = open(rtc, O_RDONLY);

if (fd == -1)

{

perror(rtc);

exit(errno);

}

fprintf(stderr, "/n/t/t/tRTC Driver Test Example./n/n");

/* Turn on update interrupts (one per second) */

retval = ioctl(fd, RTC_UIE_ON, 0);

if (retval == -1)

{

if (errno == ENOTTY)

{

fprintf(stderr, "/n...Update IRQs not supported./n");

goto test_READ;

}

perror("RTC_UIE_ON ioctl");

exit(errno);

}

fprintf(stderr, "Counting 5 update (1/sec) interrupts from reading %s:",rtc);

fflush(stderr);

for (i=1; i<6; i++)

{

/* This read will block */

retval = read(fd, &data, sizeof(unsigned long));

if (retval == -1)

{

perror("read");

exit(errno);

}

fprintf(stderr, " %d",i);

fflush(stderr);

irqcount++;

}

fprintf(stderr, "/nAgain, from using select(2) on /dev/rtc:");

fflush(stderr);

for (i=1; i<6; i++)

{

struct timeval tv = {5, 0}; /* 5 second timeout on select */

fd_set readfds;

FD_ZERO(&readfds);

FD_SET(fd, &readfds);

/* The select will wait until an RTC interrupt happens. */

retval = select(fd+1, &readfds, NULL, NULL, &tv);

if (retval == -1)

{

perror("select");

exit(errno);

}

/* This read won't block unlike the select-less case above. */

retval = read(fd, &data, sizeof(unsigned long));

if (retval == -1)

{

perror("read");

exit(errno);

}

fprintf(stderr, " %d",i);

fflush(stderr);

irqcount++;

}

/* Turn off update interrupts */

retval = ioctl(fd, RTC_UIE_OFF, 0);

if (retval == -1)

{

perror("RTC_UIE_OFF ioctl");

exit(errno);

}

test_READ:

/* Read the RTC time/date */

retval = ioctl(fd, RTC_RD_TIME, &rtc_tm);

if (retval == -1)

{

perror("RTC_RD_TIME ioctl");

exit(errno);

}

fprintf(stderr, "/n/nCurrent RTC date/time is %d-%d-%d, %02d:%02d:%02d./n",rtc_tm.tm_mday, rtc_tm.tm_mon + 1, rtc_tm.tm_year +

1900,rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);

/* Set the alarm to 5 sec in the future, and check for rollover */

rtc_tm.tm_sec += 5;

if (rtc_tm.tm_sec >= 60)

{

rtc_tm.tm_sec %= 60;

rtc_tm.tm_min++;

}

if (rtc_tm.tm_min == 60)

{

rtc_tm.tm_min = 0;

rtc_tm.tm_hour++;

}

if (rtc_tm.tm_hour == 24)

rtc_tm.tm_hour = 0;

retval = ioctl(fd, RTC_ALM_SET, &rtc_tm);

if (retval == -1)

{

if (errno == ENOTTY)

{

fprintf(stderr,"/n...Alarm IRQs not supported./n");

goto test_PIE;

}

perror("RTC_ALM_SET ioctl");

exit(errno);

}

/* Read the current alarm settings */

retval = ioctl(fd, RTC_ALM_READ, &rtc_tm);

if (retval == -1)

{

perror("RTC_ALM_READ ioctl");

exit(errno);

}

fprintf(stderr, "Alarm time now set to %02d:%02d:%02d./n",rtc_tm.tm_hour, rtc_tm.tm_min, rtc_tm.tm_sec);

/* Enable alarm interrupts */

retval = ioctl(fd, RTC_AIE_ON, 0);

if (retval == -1)

{

perror("RTC_AIE_ON ioctl");

exit(errno);

}

fprintf(stderr, "Waiting 5 seconds for alarm...");

fflush(stderr);

/* This blocks until the alarm ring causes an interrupt */

retval = read(fd, &data, sizeof(unsigned long));

if (retval == -1)

{

perror("read");

exit(errno);

}

irqcount++;

fprintf(stderr, " okay. Alarm rang./n");

/* Disable alarm interrupts */

retval = ioctl(fd, RTC_AIE_OFF, 0);

if (retval == -1)

{

perror("RTC_AIE_OFF ioctl");

exit(errno);

}

test_PIE:

/* Read periodic IRQ rate */

retval = ioctl(fd, RTC_IRQP_READ, &tmp);

if (retval == -1)

{

/* not all RTCs support periodic IRQs */

if (errno == ENOTTY)

{

fprintf(stderr, "/nNo periodic IRQ support/n");

goto done;

}

perror("RTC_IRQP_READ ioctl");

exit(errno);

}

fprintf(stderr, "/nPeriodic IRQ rate is %ldHz./n", tmp);

fprintf(stderr, "Counting 20 interrupts at:");

fflush(stderr);

/* The frequencies 128Hz, 256Hz, ... 8192Hz are only allowed for root. */

for (tmp=2; tmp<=1024; tmp*=2)

{

retval = ioctl(fd, RTC_IRQP_SET, tmp);

if (retval == -1)

{

/* not all RTCs can change their periodic IRQ rate */

if (errno == ENOTTY)

{

fprintf(stderr,"/n...Periodic IRQ rate is fixed/n");

goto done;

}

perror("RTC_IRQP_SET ioctl");

exit(errno);

}

fprintf(stderr, "/n%ldHz:/t", tmp);

fflush(stderr);

/* Enable periodic interrupts */

retval = ioctl(fd, RTC_PIE_ON, 0);

if (retval == -1)

{

perror("RTC_PIE_ON ioctl");

exit(errno);

}

for (i=1; i<21; i++)

{

/* This blocks */

retval = read(fd, &data, sizeof(unsigned long));

if (retval == -1)

{

perror("read");

exit(errno);

}

fprintf(stderr, " %d",i);

fflush(stderr);

irqcount++;

}

/* Disable periodic interrupts */

retval = ioctl(fd, RTC_PIE_OFF, 0);

if (retval == -1)

{

perror("RTC_PIE_OFF ioctl");

exit(errno);

}

}

done:

fprintf(stderr, "/n/n/t/t/t *** Test complete ***/n");

close(fd);

return 0;

}

这个是linux文档中的说明代码，希望能给你做RTC程序提供相应的思路。

2.6.24.3 smdk2440的rtc驱动测试

2.6.24.3 内核已经有支援RTC，只要选择就可以在Device Driver –>Real Time Clock -> 选中s3c rtc就可以。

主设备号应该是kernel动态分配的，我的板子上254，mknode一个/dev/rtc

同时加入s3c_device_rtc:

static struct platform_device *smdk2440_devices[] __initdata = {

&s3c_device_usb,

&s3c_device_lcd,

&s3c_device_wdt,

&s3c_device_i2c,

&s3c_device_iis,

&s3c_device_sdi,   //creator added

&s3c_device_rtc,   //add device。

};

可以通过date设定时间

假如配置系统时间为2008年8月9日，10：11分，能够这样配置

1>     date 080910112008

2>     hwclock –w      //写入了

反复执行hwclock ，看看是否时间在变化。