/* device attributes */
+/*
+ * NOTE: RTC times displayed in sysfs use the RTC's timezone. That's
+ * ideally UTC. However, PCs that also boot to MS-Windows normally use
+ * the local time and change to match daylight savings time. That affects
+ * attributes including date, time, since_epoch, and wakealarm.
+ */
+
static ssize_t
rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr,
char *buf)
return n;
}
+static ssize_t
+rtc_sysfs_show_hctosys(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+#ifdef CONFIG_RTC_HCTOSYS_DEVICE
+ if (rtc_hctosys_ret == 0 &&
+ strcmp(dev_name(&to_rtc_device(dev)->dev),
+ CONFIG_RTC_HCTOSYS_DEVICE) == 0)
+ return sprintf(buf, "1\n");
+ else
+#endif
+ return sprintf(buf, "0\n");
+}
+
static struct device_attribute rtc_attrs[] = {
__ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL),
__ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL),
__ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL),
__ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq,
rtc_sysfs_set_max_user_freq),
+ __ATTR(hctosys, S_IRUGO, rtc_sysfs_show_hctosys, NULL),
{ },
};
unsigned long alarm;
struct rtc_wkalrm alm;
- /* Don't show disabled alarms; but the RTC could leave the
- * alarm enabled after it's already triggered. Alarms are
- * conceptually one-shot, even though some common hardware
- * (PCs) doesn't actually work that way.
+ /* Don't show disabled alarms. For uniformity, RTC alarms are
+ * conceptually one-shot, even though some common RTCs (on PCs)
+ * don't actually work that way.
*
- * REVISIT maybe we should require RTC implementations to
- * disable the RTC alarm after it triggers, for uniformity.
+ * NOTE: RTC implementations where the alarm doesn't match an
+ * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
+ * alarms after they trigger, to ensure one-shot semantics.
*/
retval = rtc_read_alarm(to_rtc_device(dev), &alm);
if (retval == 0 && alm.enabled) {
unsigned long now, alarm;
struct rtc_wkalrm alm;
struct rtc_device *rtc = to_rtc_device(dev);
+ char *buf_ptr;
+ int adjust = 0;
/* Only request alarms that trigger in the future. Disable them
* by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
return retval;
rtc_tm_to_time(&alm.time, &now);
- alarm = simple_strtoul(buf, NULL, 0);
+ buf_ptr = (char *)buf;
+ if (*buf_ptr == '+') {
+ buf_ptr++;
+ adjust = 1;
+ }
+ alarm = simple_strtoul(buf_ptr, NULL, 0);
+ if (adjust) {
+ alarm += now;
+ }
if (alarm > now) {
/* Avoid accidentally clobbering active alarms; we can't
* entirely prevent that here, without even the minimal
err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
if (err)
- dev_err(rtc->dev.parent, "failed to create "
- "alarm attribute, %d",
- err);
+ dev_err(rtc->dev.parent,
+ "failed to create alarm attribute, %d\n", err);
}
void rtc_sysfs_del_device(struct rtc_device *rtc)