RTC驱动程序

drivers tc tc-s3c.c

s3c_rtc_init
platform_driver_register
s3c_rtc_probe
rtc_device_register("s3c", &pdev->dev, &s3c_rtcops, THIS_MODULE)
rtc_dev_prepare
cdev_init(&rtc->char_dev, &rtc_dev_fops);
rtc_dev_add_device
cdev_add

app: open("/dev/rtc0");

kernel: sys_open
rtc_dev_fops.open
rtc_dev_open
// 根据次设备号找到以前用"rtc_device_register"注册的rtc_device
struct rtc_device *rtc = container_of(inode->i_cdev,struct rtc_device, char_dev);
const struct rtc_class_ops *ops = rtc->ops;
err = ops->open ? ops->open(rtc->dev.parent) : 0;
s3c_rtc_open
app: ioctl(fd, RTC_RD_TIME,...)

kernel: sys_ioctl
rtc_dev_fops.ioctl
rtc_dev_ioctl
struct rtc_device *rtc = file->private_data;
rtc_read_time(rtc, &tm);
err = rtc->ops->read_time(rtc->dev.parent, tm);
s3c_rtc_gettime

测试RTC:

1. 修改archarmplat-s3c24xxcommon-smdk.c
   static struct platform_device __initdata *smdk_devs[] = {
   &s3c_device_nand,
   &smdk_led4,
   &smdk_led5,
   &smdk_led6,
   &smdk_led7,
   改为(在数组smdk_devs里加上s3c_device_rtc):
   static struct platform_device __initdata *smdk_devs[] = {
   &s3c_device_nand,
   &smdk_led4,
   &smdk_led5,
   &smdk_led6,
   &smdk_led7,
   &s3c_device_rtc,

2. make uImage, 使用新内核启动
   cp arch/arm/boot/uImage /work/nfs_root/uImage_rtc
   使用新内核启动
   nfs 30000000 192.168.31.202:/work/nfs_root/uImage_rtc
   bootm 30000000

3. ls /dev/rtc* -l
   date /* 显示系统时间 /
   date 123015402011.30 / 设置系统时间 date [MMDDhhmm[[CC]YY][.ss]] /
   hwclock -w / 把系统时间写入RTC */

   短电,重启,执行date