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>
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@ -43,6 +43,14 @@ Contact: linux-rtc@vger.kernel.org
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Description:
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(RO) The name of the RTC corresponding to this sysfs directory
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What: /sys/class/rtc/rtcX/range
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Date: January 2018
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KernelVersion: 4.16
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Contact: linux-rtc@vger.kernel.org
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Description:
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Valid time range for the RTC, as seconds from epoch, formatted
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as [min, max]
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What: /sys/class/rtc/rtcX/since_epoch
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Date: March 2006
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KernelVersion: 2.6.17
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@ -70,6 +70,13 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
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if (err != 0)
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return err;
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if (rtc->range_min != rtc->range_max) {
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time64_t time = rtc_tm_to_time64(tm);
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if (time < rtc->range_min || time > rtc->range_max)
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return -ERANGE;
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}
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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@ -374,6 +381,13 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
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if (err != 0)
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return err;
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if (rtc->range_min != rtc->range_max) {
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time64_t time = rtc_tm_to_time64(&alarm->time);
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if (time < rtc->range_min || time > rtc->range_max)
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return -ERANGE;
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}
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return err;
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@ -248,6 +248,14 @@ offset_store(struct device *dev, struct device_attribute *attr,
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}
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static DEVICE_ATTR_RW(offset);
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static ssize_t
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range_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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return sprintf(buf, "[%lld,%llu]\n", to_rtc_device(dev)->range_min,
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to_rtc_device(dev)->range_max);
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}
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static DEVICE_ATTR_RO(range);
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static struct attribute *rtc_attrs[] = {
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&dev_attr_name.attr,
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&dev_attr_date.attr,
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@ -257,6 +265,7 @@ static struct attribute *rtc_attrs[] = {
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&dev_attr_hctosys.attr,
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&dev_attr_wakealarm.attr,
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&dev_attr_offset.attr,
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&dev_attr_range.attr,
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NULL,
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};
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@ -286,6 +295,9 @@ static umode_t rtc_attr_is_visible(struct kobject *kobj,
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} else if (attr == &dev_attr_offset.attr) {
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if (!rtc->ops->set_offset)
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mode = 0;
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} else if (attr == &dev_attr_range.attr) {
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if (!(rtc->range_max - rtc->range_min))
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mode = 0;
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}
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return mode;
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@ -150,6 +150,9 @@ struct rtc_device {
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bool nvram_old_abi;
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struct bin_attribute *nvram;
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time64_t range_min;
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timeu64_t range_max;
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#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
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struct work_struct uie_task;
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struct timer_list uie_timer;
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