rtc: add max_user_freq to sysfs (06c65eb4) · Commits · 戴 / test

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:

Bryan Kadzban <bryan@kdzbn.homelinux.net> Acked-by:

Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

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),
		{ },
		};

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