X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=drivers%2Frtc%2Finterface.c;h=de0da545c7a107c0c967e35b9a4eb3daa4cf1c5b;hb=6f37ac793d6ba7b35d338f791974166f67fdd9ba;hp=6f11f6dfdd9dccc699b5a1a958132d55dec5daa6;hpb=463e7c7cf9aaf95dd05e97e1a47854fdf5454cdc;p=linux-2.6-omap-h63xx.git

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 6f11f6dfdd9..de0da545c7a 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -12,11 +12,11 @@
 */
 
 #include <linux/rtc.h>
+#include <linux/log2.h>
 
-int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
+int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
 {
 	int err;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
 
 	err = mutex_lock_interruptible(&rtc->ops_lock);
 	if (err)
@@ -28,7 +28,7 @@ int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
 		err = -EINVAL;
 	else {
 		memset(tm, 0, sizeof(struct rtc_time));
-		err = rtc->ops->read_time(class_dev->dev, tm);
+		err = rtc->ops->read_time(rtc->dev.parent, tm);
 	}
 
 	mutex_unlock(&rtc->ops_lock);
@@ -36,10 +36,9 @@ int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
 }
 EXPORT_SYMBOL_GPL(rtc_read_time);
 
-int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
+int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
 {
 	int err;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
 
 	err = rtc_valid_tm(tm);
 	if (err != 0)
@@ -54,17 +53,16 @@ int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
 	else if (!rtc->ops->set_time)
 		err = -EINVAL;
 	else
-		err = rtc->ops->set_time(class_dev->dev, tm);
+		err = rtc->ops->set_time(rtc->dev.parent, tm);
 
 	mutex_unlock(&rtc->ops_lock);
 	return err;
 }
 EXPORT_SYMBOL_GPL(rtc_set_time);
 
-int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
+int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
 {
 	int err;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
 
 	err = mutex_lock_interruptible(&rtc->ops_lock);
 	if (err)
@@ -73,11 +71,11 @@ int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
 	if (!rtc->ops)
 		err = -ENODEV;
 	else if (rtc->ops->set_mmss)
-		err = rtc->ops->set_mmss(class_dev->dev, secs);
+		err = rtc->ops->set_mmss(rtc->dev.parent, secs);
 	else if (rtc->ops->read_time && rtc->ops->set_time) {
 		struct rtc_time new, old;
 
-		err = rtc->ops->read_time(class_dev->dev, &old);
+		err = rtc->ops->read_time(rtc->dev.parent, &old);
 		if (err == 0) {
 			rtc_time_to_tm(secs, &new);
 
@@ -89,7 +87,8 @@ int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
 			 */
 			if (!((old.tm_hour == 23 && old.tm_min == 59) ||
 				(new.tm_hour == 23 && new.tm_min == 59)))
-				err = rtc->ops->set_time(class_dev->dev, &new);
+				err = rtc->ops->set_time(rtc->dev.parent,
+						&new);
 		}
 	}
 	else
@@ -101,10 +100,9 @@ int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
 }
 EXPORT_SYMBOL_GPL(rtc_set_mmss);
 
-int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 {
 	int err;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
 
 	err = mutex_lock_interruptible(&rtc->ops_lock);
 	if (err)
@@ -116,18 +114,102 @@ int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
 		err = -EINVAL;
 	else {
 		memset(alarm, 0, sizeof(struct rtc_wkalrm));
-		err = rtc->ops->read_alarm(class_dev->dev, alarm);
+		err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
 	}
 
 	mutex_unlock(&rtc->ops_lock);
 	return err;
 }
+
+int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_time before, now;
+	int first_time = 1;
+
+	/* The lower level RTC driver may not be capable of filling
+	 * in all fields of the rtc_time struct (eg. rtc-cmos),
+	 * and so might instead return -1 in some fields.
+	 * We deal with that here by grabbing a current RTC timestamp
+	 * and using values from that for any missing (-1) values.
+	 *
+	 * But this can be racey, because some fields of the RTC timestamp
+	 * may have wrapped in the interval since we read the RTC alarm,
+	 * which would lead to us inserting inconsistent values in place
+	 * of the -1 fields.
+	 *
+	 * Reading the alarm and timestamp in the reverse sequence
+	 * would have the same race condition, and not solve the issue.
+	 *
+	 * So, we must first read the RTC timestamp,
+	 * then read the RTC alarm value,
+	 * and then read a second RTC timestamp.
+	 *
+	 * If any fields of the second timestamp have changed
+	 * when compared with the first timestamp, then we know
+	 * our timestamp may be inconsistent with that used by
+	 * the low-level rtc_read_alarm_internal() function.
+	 *
+	 * So, when the two timestamps disagree, we just loop and do
+	 * the process again to get a fully consistent set of values.
+	 *
+	 * This could all instead be done in the lower level driver,
+	 * but since more than one lower level RTC implementation needs it,
+	 * then it's probably best best to do it here instead of there..
+	 */
+
+	/* Get the "before" timestamp */
+	err = rtc_read_time(rtc, &before);
+	if (err < 0)
+		return err;
+	do {
+		if (!first_time)
+			memcpy(&before, &now, sizeof(struct rtc_time));
+		first_time = 0;
+
+		/* get the RTC alarm values, which may be incomplete */
+		err = rtc_read_alarm_internal(rtc, alarm);
+		if (err)
+			return err;
+		if (!alarm->enabled)
+			return 0;
+
+		/* get the "after" timestamp, to detect wrapped fields */
+		err = rtc_read_time(rtc, &now);
+		if (err < 0)
+			return err;
+
+		/* note that tm_sec is a "don't care" value here: */
+	} while (   before.tm_min   != now.tm_min
+		 || before.tm_hour  != now.tm_hour
+		 || before.tm_mon   != now.tm_mon
+		 || before.tm_year  != now.tm_year
+		 || before.tm_isdst != now.tm_isdst);
+
+	/* Fill in any missing alarm fields using the timestamp */
+	if (alarm->time.tm_sec == -1)
+		alarm->time.tm_sec = now.tm_sec;
+	if (alarm->time.tm_min == -1)
+		alarm->time.tm_min = now.tm_min;
+	if (alarm->time.tm_hour == -1)
+		alarm->time.tm_hour = now.tm_hour;
+	if (alarm->time.tm_mday == -1)
+		alarm->time.tm_mday = now.tm_mday;
+	if (alarm->time.tm_mon == -1)
+		alarm->time.tm_mon = now.tm_mon;
+	if (alarm->time.tm_year == -1)
+		alarm->time.tm_year = now.tm_year;
+	return 0;
+}
 EXPORT_SYMBOL_GPL(rtc_read_alarm);
 
-int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 {
 	int err;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = rtc_valid_tm(&alarm->time);
+	if (err != 0)
+		return err;
 
 	err = mutex_lock_interruptible(&rtc->ops_lock);
 	if (err)
@@ -138,7 +220,7 @@ int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
 	else if (!rtc->ops->set_alarm)
 		err = -EINVAL;
 	else
-		err = rtc->ops->set_alarm(class_dev->dev, alarm);
+		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
 
 	mutex_unlock(&rtc->ops_lock);
 	return err;
@@ -147,16 +229,14 @@ EXPORT_SYMBOL_GPL(rtc_set_alarm);
 
 /**
  * rtc_update_irq - report RTC periodic, alarm, and/or update irqs
- * @class_dev: the rtc's class device
+ * @rtc: the rtc device
  * @num: how many irqs are being reported (usually one)
  * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
  * Context: in_interrupt(), irqs blocked
  */
-void rtc_update_irq(struct class_device *class_dev,
+void rtc_update_irq(struct rtc_device *rtc,
 		unsigned long num, unsigned long events)
 {
-	struct rtc_device *rtc = to_rtc_device(class_dev);
-
 	spin_lock(&rtc->irq_lock);
 	rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
 	spin_unlock(&rtc->irq_lock);
@@ -171,43 +251,51 @@ void rtc_update_irq(struct class_device *class_dev,
 }
 EXPORT_SYMBOL_GPL(rtc_update_irq);
 
-struct class_device *rtc_class_open(char *name)
+struct rtc_device *rtc_class_open(char *name)
 {
-	struct class_device *class_dev = NULL,
-				*class_dev_tmp;
+	struct device *dev;
+	struct rtc_device *rtc = NULL;
 
 	down(&rtc_class->sem);
-	list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
-		if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
-			class_dev = class_dev_tmp;
+	list_for_each_entry(dev, &rtc_class->devices, node) {
+		if (strncmp(dev->bus_id, name, BUS_ID_SIZE) == 0) {
+			dev = get_device(dev);
+			if (dev)
+				rtc = to_rtc_device(dev);
 			break;
 		}
 	}
 
-	if (class_dev) {
-		if (!try_module_get(to_rtc_device(class_dev)->owner))
-			class_dev = NULL;
+	if (rtc) {
+		if (!try_module_get(rtc->owner)) {
+			put_device(dev);
+			rtc = NULL;
+		}
 	}
 	up(&rtc_class->sem);
 
-	return class_dev;
+	return rtc;
 }
 EXPORT_SYMBOL_GPL(rtc_class_open);
 
-void rtc_class_close(struct class_device *class_dev)
+void rtc_class_close(struct rtc_device *rtc)
 {
-	module_put(to_rtc_device(class_dev)->owner);
+	module_put(rtc->owner);
+	put_device(&rtc->dev);
 }
 EXPORT_SYMBOL_GPL(rtc_class_close);
 
-int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
+int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
 {
 	int retval = -EBUSY;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
 
 	if (task == NULL || task->func == NULL)
 		return -EINVAL;
 
+	/* Cannot register while the char dev is in use */
+	if (!(mutex_trylock(&rtc->char_lock)))
+		return -EBUSY;
+
 	spin_lock_irq(&rtc->irq_task_lock);
 	if (rtc->irq_task == NULL) {
 		rtc->irq_task = task;
@@ -215,14 +303,14 @@ int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
 	}
 	spin_unlock_irq(&rtc->irq_task_lock);
 
+	mutex_unlock(&rtc->char_lock);
+
 	return retval;
 }
 EXPORT_SYMBOL_GPL(rtc_irq_register);
 
-void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
+void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
 {
-	struct rtc_device *rtc = to_rtc_device(class_dev);
-
 	spin_lock_irq(&rtc->irq_task_lock);
 	if (rtc->irq_task == task)
 		rtc->irq_task = NULL;
@@ -230,43 +318,68 @@ void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
 }
 EXPORT_SYMBOL_GPL(rtc_irq_unregister);
 
-int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
+/**
+ * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
+ * @rtc: the rtc device
+ * @task: currently registered with rtc_irq_register()
+ * @enabled: true to enable periodic IRQs
+ * Context: any
+ *
+ * Note that rtc_irq_set_freq() should previously have been used to
+ * specify the desired frequency of periodic IRQ task->func() callbacks.
+ */
+int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
 {
 	int err = 0;
 	unsigned long flags;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
 
 	if (rtc->ops->irq_set_state == NULL)
 		return -ENXIO;
 
 	spin_lock_irqsave(&rtc->irq_task_lock, flags);
+	if (rtc->irq_task != NULL && task == NULL)
+		err = -EBUSY;
 	if (rtc->irq_task != task)
-		err = -ENXIO;
+		err = -EACCES;
 	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 
 	if (err == 0)
-		err = rtc->ops->irq_set_state(class_dev->dev, enabled);
+		err = rtc->ops->irq_set_state(rtc->dev.parent, enabled);
 
 	return err;
 }
 EXPORT_SYMBOL_GPL(rtc_irq_set_state);
 
-int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq)
+/**
+ * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
+ * @rtc: the rtc device
+ * @task: currently registered with rtc_irq_register()
+ * @freq: positive frequency with which task->func() will be called
+ * Context: any
+ *
+ * Note that rtc_irq_set_state() is used to enable or disable the
+ * periodic IRQs.
+ */
+int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
 {
 	int err = 0;
 	unsigned long flags;
-	struct rtc_device *rtc = to_rtc_device(class_dev);
 
 	if (rtc->ops->irq_set_freq == NULL)
 		return -ENXIO;
 
+	if (!is_power_of_2(freq))
+		return -EINVAL;
+
 	spin_lock_irqsave(&rtc->irq_task_lock, flags);
+	if (rtc->irq_task != NULL && task == NULL)
+		err = -EBUSY;
 	if (rtc->irq_task != task)
-		err = -ENXIO;
+		err = -EACCES;
 	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
 
 	if (err == 0) {
-		err = rtc->ops->irq_set_freq(class_dev->dev, freq);
+		err = rtc->ops->irq_set_freq(rtc->dev.parent, freq);
 		if (err == 0)
 			rtc->irq_freq = freq;
 	}