1 files changed, 187 insertions, 46 deletions

diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
index 9418a59fb36..babd43bf3dd 100644
--- a/drivers/rtc/rtc-sysfs.c
+++ b/drivers/rtc/rtc-sysfs.c
@@ -12,20 +12,32 @@
 #include <linux/module.h>
 #include <linux/rtc.h>
 
+#include "rtc-core.h"
+
+
 /* device attributes */
 
-static ssize_t rtc_sysfs_show_name(struct class_device *dev, char *buf)
+/*
+ * NOTE:  RTC times displayed in sysfs use the RTC's timezone.  That's
+ * ideally UTC.  However, PCs that also boot to MS-Windows normally use
+ * the local time and change to match daylight savings time.  That affects
+ * attributes including date, time, since_epoch, and wakealarm.
+ */
+
+static ssize_t
+name_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
 }
-static CLASS_DEVICE_ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL);
+static DEVICE_ATTR_RO(name);
 
-static ssize_t rtc_sysfs_show_date(struct class_device *dev, char *buf)
+static ssize_t
+date_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	ssize_t retval;
 	struct rtc_time tm;
 
-	retval = rtc_read_time(dev, &tm);
+	retval = rtc_read_time(to_rtc_device(dev), &tm);
 	if (retval == 0) {
 		retval = sprintf(buf, "%04d-%02d-%02d\n",
 			tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
@@ -33,14 +45,15 @@ static ssize_t rtc_sysfs_show_date(struct class_device *dev, char *buf)
 
 	return retval;
 }
-static CLASS_DEVICE_ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL);
+static DEVICE_ATTR_RO(date);
 
-static ssize_t rtc_sysfs_show_time(struct class_device *dev, char *buf)
+static ssize_t
+time_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	ssize_t retval;
 	struct rtc_time tm;
 
-	retval = rtc_read_time(dev, &tm);
+	retval = rtc_read_time(to_rtc_device(dev), &tm);
 	if (retval == 0) {
 		retval = sprintf(buf, "%02d:%02d:%02d\n",
 			tm.tm_hour, tm.tm_min, tm.tm_sec);
@@ -48,14 +61,15 @@ static ssize_t rtc_sysfs_show_time(struct class_device *dev, char *buf)
 
 	return retval;
 }
-static CLASS_DEVICE_ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL);
+static DEVICE_ATTR_RO(time);
 
-static ssize_t rtc_sysfs_show_since_epoch(struct class_device *dev, char *buf)
+static ssize_t
+since_epoch_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	ssize_t retval;
 	struct rtc_time tm;
 
-	retval = rtc_read_time(dev, &tm);
+	retval = rtc_read_time(to_rtc_device(dev), &tm);
 	if (retval == 0) {
 		unsigned long time;
 		rtc_tm_to_time(&tm, &time);
@@ -64,61 +78,188 @@ static ssize_t rtc_sysfs_show_since_epoch(struct class_device *dev, char *buf)
 
 	return retval;
 }
-static CLASS_DEVICE_ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL);
+static DEVICE_ATTR_RO(since_epoch);
+
+static ssize_t
+max_user_freq_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
+}
+
+static ssize_t
+max_user_freq_store(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 DEVICE_ATTR_RW(max_user_freq);
+
+/**
+ * rtc_sysfs_show_hctosys - indicate if the given RTC set the system time
+ *
+ * Returns 1 if the system clock was set by this RTC at the last
+ * boot or resume event.
+ */
+static ssize_t
+hctosys_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+#ifdef CONFIG_RTC_HCTOSYS_DEVICE
+	if (rtc_hctosys_ret == 0 &&
+			strcmp(dev_name(&to_rtc_device(dev)->dev),
+				CONFIG_RTC_HCTOSYS_DEVICE) == 0)
+		return sprintf(buf, "1\n");
+	else
+#endif
+		return sprintf(buf, "0\n");
+}
+static DEVICE_ATTR_RO(hctosys);
 
 static struct attribute *rtc_attrs[] = {
-	&class_device_attr_name.attr,
-	&class_device_attr_date.attr,
-	&class_device_attr_time.attr,
-	&class_device_attr_since_epoch.attr,
+	&dev_attr_name.attr,
+	&dev_attr_date.attr,
+	&dev_attr_time.attr,
+	&dev_attr_since_epoch.attr,
+	&dev_attr_max_user_freq.attr,
+	&dev_attr_hctosys.attr,
 	NULL,
 };
+ATTRIBUTE_GROUPS(rtc);
 
-static struct attribute_group rtc_attr_group = {
-	.attrs = rtc_attrs,
-};
+static ssize_t
+rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	ssize_t retval;
+	unsigned long alarm;
+	struct rtc_wkalrm alm;
+
+	/* Don't show disabled alarms.  For uniformity, RTC alarms are
+	 * conceptually one-shot, even though some common RTCs (on PCs)
+	 * don't actually work that way.
+	 *
+	 * NOTE: RTC implementations where the alarm doesn't match an
+	 * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
+	 * alarms after they trigger, to ensure one-shot semantics.
+	 */
+	retval = rtc_read_alarm(to_rtc_device(dev), &alm);
+	if (retval == 0 && alm.enabled) {
+		rtc_tm_to_time(&alm.time, &alarm);
+		retval = sprintf(buf, "%lu\n", alarm);
+	}
+
+	return retval;
+}
 
-static int __devinit rtc_sysfs_add_device(struct class_device *class_dev,
-					struct class_interface *class_intf)
+static ssize_t
+rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t n)
 {
-	int err;
+	ssize_t retval;
+	unsigned long now, alarm;
+	unsigned long push = 0;
+	struct rtc_wkalrm alm;
+	struct rtc_device *rtc = to_rtc_device(dev);
+	char *buf_ptr;
+	int adjust = 0;
 
-	dev_dbg(class_dev->dev, "rtc intf: sysfs\n");
+	/* Only request alarms that trigger in the future.  Disable them
+	 * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
+	 */
+	retval = rtc_read_time(rtc, &alm.time);
+	if (retval < 0)
+		return retval;
+	rtc_tm_to_time(&alm.time, &now);
 
-	err = sysfs_create_group(&class_dev->kobj, &rtc_attr_group);
-	if (err)
-		dev_err(class_dev->dev,
-			"failed to create sysfs attributes\n");
+	buf_ptr = (char *)buf;
+	if (*buf_ptr == '+') {
+		buf_ptr++;
+		if (*buf_ptr == '=') {
+			buf_ptr++;
+			push = 1;
+		} else
+			adjust = 1;
+	}
+	alarm = simple_strtoul(buf_ptr, NULL, 0);
+	if (adjust) {
+		alarm += now;
+	}
+	if (alarm > now || push) {
+		/* Avoid accidentally clobbering active alarms; we can't
+		 * entirely prevent that here, without even the minimal
+		 * locking from the /dev/rtcN api.
+		 */
+		retval = rtc_read_alarm(rtc, &alm);
+		if (retval < 0)
+			return retval;
+		if (alm.enabled) {
+			if (push) {
+				rtc_tm_to_time(&alm.time, &push);
+				alarm += push;
+			} else
+				return -EBUSY;
+		} else if (push)
+			return -EINVAL;
+		alm.enabled = 1;
+	} else {
+		alm.enabled = 0;
+
+		/* Provide a valid future alarm time.  Linux isn't EFI,
+		 * this time won't be ignored when disabling the alarm.
+		 */
+		alarm = now + 300;
+	}
+	rtc_time_to_tm(alarm, &alm.time);
 
-	return err;
+	retval = rtc_set_alarm(rtc, &alm);
+	return (retval < 0) ? retval : n;
 }
+static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
+		rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
 
-static void rtc_sysfs_remove_device(struct class_device *class_dev,
-				struct class_interface *class_intf)
+
+/* The reason to trigger an alarm with no process watching it (via sysfs)
+ * is its side effect:  waking from a system state like suspend-to-RAM or
+ * suspend-to-disk.  So: no attribute unless that side effect is possible.
+ * (Userspace may disable that mechanism later.)
+ */
+static inline int rtc_does_wakealarm(struct rtc_device *rtc)
 {
-	sysfs_remove_group(&class_dev->kobj, &rtc_attr_group);
+	if (!device_can_wakeup(rtc->dev.parent))
+		return 0;
+	return rtc->ops->set_alarm != NULL;
 }
 
-/* interface registration */
-
-static struct class_interface rtc_sysfs_interface = {
-	.add = &rtc_sysfs_add_device,
-	.remove = &rtc_sysfs_remove_device,
-};
 
-static int __init rtc_sysfs_init(void)
+void rtc_sysfs_add_device(struct rtc_device *rtc)
 {
-	return rtc_interface_register(&rtc_sysfs_interface);
+	int err;
+
+	/* not all RTCs support both alarms and wakeup */
+	if (!rtc_does_wakealarm(rtc))
+		return;
+
+	err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
+	if (err)
+		dev_err(rtc->dev.parent,
+			"failed to create alarm attribute, %d\n", err);
 }
 
-static void __exit rtc_sysfs_exit(void)
+void rtc_sysfs_del_device(struct rtc_device *rtc)
 {
-	class_interface_unregister(&rtc_sysfs_interface);
+	/* REVISIT did we add it successfully? */
+	if (rtc_does_wakealarm(rtc))
+		device_remove_file(&rtc->dev, &dev_attr_wakealarm);
 }
 
-subsys_initcall(rtc_sysfs_init);
-module_exit(rtc_sysfs_exit);
-
-MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
-MODULE_DESCRIPTION("RTC class sysfs interface");
-MODULE_LICENSE("GPL");
+void __init rtc_sysfs_init(struct class *rtc_class)
+{
+	rtc_class->dev_groups = rtc_groups;
+}