Commit 71db049e authored by Alexandre Belloni's avatar Alexandre Belloni
Browse files

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: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 236b7187

Documentation/ABI/testing/sysfs-class-rtc

+8 −0
Original line number Diff line number Diff line
@@ -43,6 +43,14 @@ Contact: linux-rtc@vger.kernel.org 
Description:

		(RO) The name of the RTC corresponding to this sysfs directory



What:		/sys/class/rtc/rtcX/range

Date:		January 2018

KernelVersion:	4.16

Contact:	linux-rtc@vger.kernel.org

Description:

		Valid time range for the RTC, as seconds from epoch, formatted

		as [min, max]



What:		/sys/class/rtc/rtcX/since_epoch

Date:		March 2006

KernelVersion:	2.6.17

drivers/rtc/interface.c

+14 −0
Original line number Diff line number Diff line
@@ -70,6 +70,13 @@ int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) 
	if (err != 0)

		return err;



	if (rtc->range_min != rtc->range_max) {

		time64_t time = rtc_tm_to_time64(tm);



		if (time < rtc->range_min || time > rtc->range_max)

			return -ERANGE;

	}



	err = mutex_lock_interruptible(&rtc->ops_lock);

	if (err)

		return err;
@@ -374,6 +381,13 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 
	if (err != 0)

		return err;



	if (rtc->range_min != rtc->range_max) {

		time64_t time = rtc_tm_to_time64(&alarm->time);



		if (time < rtc->range_min || time > rtc->range_max)

			return -ERANGE;

	}



	err = mutex_lock_interruptible(&rtc->ops_lock);

	if (err)

		return err;

drivers/rtc/rtc-sysfs.c

+12 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/rtc.h

+3 −0
Original line number Diff line number Diff line
@@ -150,6 +150,9 @@ struct rtc_device { 
	bool nvram_old_abi;

	struct bin_attribute *nvram;



	time64_t range_min;

	timeu64_t range_max;



#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

	struct work_struct uie_task;

	struct timer_list uie_timer;

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