[PATCH] RTC subsystem: class

Add the basic RTC subsystem infrastructure to the kernel.

rtc/class.c - registration facilities for RTC drivers
rtc/interface.c - kernel/rtc interface functions
rtc/hctosys.c - snippet of code that copies hw clock to sw clock
		at bootup, if configured to do so.

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 277 insertions, 0 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
new file mode 100644
index 000000000000..56e490709b87
--- /dev/null
+++ b/drivers/rtc/interface.c
@@ -0,0 +1,277 @@
+/*
+ * RTC subsystem, interface functions
+ *
+ * Copyright (C) 2005 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/rtc.h>
+
+int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->read_time)
+		err = -EINVAL;
+	else {
+		memset(tm, 0, sizeof(struct rtc_time));
+		err = rtc->ops->read_time(class_dev->dev, tm);
+	}
+
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_time);
+
+int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = rtc_valid_tm(tm);
+	if (err != 0)
+		return err;
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->set_time)
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_time(class_dev->dev, 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 err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (rtc->ops->set_mmss)
+		err = rtc->ops->set_mmss(class_dev->dev, 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);
+		if (err == 0) {
+			rtc_time_to_tm(secs, &new);
+
+			/*
+			 * avoid writing when we're going to change the day of
+			 * the month. We will retry in the next minute. This
+			 * basically means that if the RTC must not drift
+			 * by more than 1 minute in 11 minutes.
+			 */
+			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);
+		}
+	}
+	else
+		err = -EINVAL;
+
+	mutex_unlock(&rtc->ops_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_mmss);
+
+int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (rtc->ops == NULL)
+		err = -ENODEV;
+	else if (!rtc->ops->read_alarm)
+		err = -EINVAL;
+	else {
+		memset(alarm, 0, sizeof(struct rtc_wkalrm));
+		err = rtc->ops->read_alarm(class_dev->dev, alarm);
+	}
+
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_read_alarm);
+
+int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
+{
+	int err;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	err = mutex_lock_interruptible(&rtc->ops_lock);
+	if (err)
+		return -EBUSY;
+
+	if (!rtc->ops)
+		err = -ENODEV;
+	else if (!rtc->ops->set_alarm)
+		err = -EINVAL;
+	else
+		err = rtc->ops->set_alarm(class_dev->dev, alarm);
+
+	mutex_unlock(&rtc->ops_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(rtc_set_alarm);
+
+void rtc_update_irq(struct class_device *class_dev,
+		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);
+
+	spin_lock(&rtc->irq_task_lock);
+	if (rtc->irq_task)
+		rtc->irq_task->func(rtc->irq_task->private_data);
+	spin_unlock(&rtc->irq_task_lock);
+
+	wake_up_interruptible(&rtc->irq_queue);
+	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
+}
+EXPORT_SYMBOL_GPL(rtc_update_irq);
+
+struct class_device *rtc_class_open(char *name)
+{
+	struct class_device *class_dev = NULL,
+				*class_dev_tmp;
+
+	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;
+			break;
+		}
+	}
+
+	if (class_dev) {
+		if (!try_module_get(to_rtc_device(class_dev)->owner))
+			class_dev = NULL;
+	}
+	up(&rtc_class->sem);
+
+	return class_dev;
+}
+EXPORT_SYMBOL_GPL(rtc_class_open);
+
+void rtc_class_close(struct class_device *class_dev)
+{
+	module_put(to_rtc_device(class_dev)->owner);
+}
+EXPORT_SYMBOL_GPL(rtc_class_close);
+
+int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
+{
+	int retval = -EBUSY;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	if (task == NULL || task->func == NULL)
+		return -EINVAL;
+
+	spin_lock(&rtc->irq_task_lock);
+	if (rtc->irq_task == NULL) {
+		rtc->irq_task = task;
+		retval = 0;
+	}
+	spin_unlock(&rtc->irq_task_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(rtc_irq_register);
+
+void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
+{
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	spin_lock(&rtc->irq_task_lock);
+	if (rtc->irq_task == task)
+		rtc->irq_task = NULL;
+	spin_unlock(&rtc->irq_task_lock);
+}
+EXPORT_SYMBOL_GPL(rtc_irq_unregister);
+
+int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
+{
+	int err = 0;
+	unsigned long flags;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	spin_lock_irqsave(&rtc->irq_task_lock, flags);
+	if (rtc->irq_task != task)
+		err = -ENXIO;
+	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
+
+	if (err == 0)
+		err = rtc->ops->irq_set_state(class_dev->dev, 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)
+{
+	int err = 0, tmp = 0;
+	unsigned long flags;
+	struct rtc_device *rtc = to_rtc_device(class_dev);
+
+	/* allowed range is 2-8192 */
+	if (freq < 2 || freq > 8192)
+		return -EINVAL;
+/*
+	FIXME: this does not belong here, will move where appropriate
+	at a later stage. It cannot hurt right now, trust me :)
+	if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
+		return -EACCES;
+*/
+	/* check if freq is a power of 2 */
+	while (freq > (1 << tmp))
+		tmp++;
+
+	if (freq != (1 << tmp))
+		return -EINVAL;
+
+	spin_lock_irqsave(&rtc->irq_task_lock, flags);
+	if (rtc->irq_task != task)
+		err = -ENXIO;
+	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
+
+	if (err == 0) {
+		err = rtc->ops->irq_set_freq(class_dev->dev, freq);
+		if (err == 0)
+			rtc->irq_freq = freq;
+	}
+	return err;
+}