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Commit 06c65eb4 authored by Bryan Kadzban's avatar Bryan Kadzban Committed by Linus Torvalds
Browse files

rtc: add max_user_freq to sysfs 



drivers/char/rtc.c exposed a sysctl to change the maximum frequency at
which a non-root user could ask the RTC to generate interrupts (via the
RTC_IRQP_SET ioctl).  This value is no longer available under the new RTC
subsystem, so add it to sysfs for each RTC device.

Works for me on x86_64 (both reads and writes), using rtc-cmos.

Signed-off-by: default avatarBryan Kadzban <bryan@kdzbn.homelinux.net>
Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 05440dfc

drivers/rtc/rtc-sysfs.c

+24 −0
Original line number Diff line number Diff line
@@ -73,11 +73,35 @@ rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr, 
	return retval;

}



static ssize_t

rtc_sysfs_show_max_user_freq(struct device *dev, struct device_attribute *attr,

		char *buf)

{

	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);

}



static ssize_t

rtc_sysfs_set_max_user_freq(struct device *dev, struct device_attribute *attr,

		const char *buf, size_t n)

{

	struct rtc_device *rtc = to_rtc_device(dev);

	unsigned long val = simple_strtoul(buf, NULL, 0);



	if (val >= 4096 || val == 0)

		return -EINVAL;



	rtc->max_user_freq = (int)val;



	return 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(time, S_IRUGO, rtc_sysfs_show_time, 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),

	{ },

};