rtc: Add RTC range
Add a way for drivers to inform the core of the supported date/time range.
The core can then check whether the date/time or alarm is in the range
before calling ->set_time, ->set_mmss or ->set_alarm. It returns -ERANGE
when the time is out of range.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
index 92ff2ed..454da38 100644
--- a/drivers/rtc/rtc-sysfs.c
+++ b/drivers/rtc/rtc-sysfs.c
@@ -248,6 +248,14 @@ offset_store(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RW(offset);
+static ssize_t
+range_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "[%lld,%llu]\n", to_rtc_device(dev)->range_min,
+ to_rtc_device(dev)->range_max);
+}
+static DEVICE_ATTR_RO(range);
+
static struct attribute *rtc_attrs[] = {
&dev_attr_name.attr,
&dev_attr_date.attr,
@@ -257,6 +265,7 @@ static struct attribute *rtc_attrs[] = {
&dev_attr_hctosys.attr,
&dev_attr_wakealarm.attr,
&dev_attr_offset.attr,
+ &dev_attr_range.attr,
NULL,
};
@@ -286,6 +295,9 @@ static umode_t rtc_attr_is_visible(struct kobject *kobj,
} else if (attr == &dev_attr_offset.attr) {
if (!rtc->ops->set_offset)
mode = 0;
+ } else if (attr == &dev_attr_range.attr) {
+ if (!(rtc->range_max - rtc->range_min))
+ mode = 0;
}
return mode;