--- linux/drivers/char/rtc.c	Mon Nov 26 14:39:31 2001
+++ linux/drivers/char/rtc.c	Mon Nov 26 14:40:09 2001
@@ -139,6 +139,11 @@
 static unsigned long rtc_freq = 0;	/* Current periodic IRQ rate	*/
 static unsigned long rtc_irq_data = 0;	/* our output to the world	*/
 
+#if RTC_IRQ
+static spinlock_t rtc_task_lock = SPIN_LOCK_UNLOCKED;
+static rtc_task_t *rtc_callback = NULL;
+#endif
+
 /*
  *	If this driver ever becomes modularised, it will be really nice
  *	to make the epoch retain its value across module reload...
@@ -180,6 +185,10 @@
 	spin_unlock (&rtc_lock);
 
 	/* Now do the rest of the actions */
+	spin_lock(&rtc_task_lock);
+	if (rtc_callback)
+		rtc_callback->func(rtc_callback->private_data);
+	spin_unlock(&rtc_task_lock);
 	wake_up_interruptible(&rtc_wait);	
 
 	kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
@@ -244,8 +253,7 @@
 #endif
 }
 
-static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
-		     unsigned long arg)
+static int rtc_do_ioctl(unsigned int cmd, unsigned long arg, int kernel)
 {
 	struct rtc_time wtime; 
 
@@ -295,7 +303,7 @@
 		 * We don't really want Joe User enabling more
 		 * than 64Hz of interrupts on a multi-user machine.
 		 */
-		if ((rtc_freq > rtc_max_user_freq) && 
+		if (!kernel && (rtc_freq > rtc_max_user_freq) && 
 		    (!capable(CAP_SYS_RESOURCE)))
 			return -EACCES;
 
@@ -493,7 +501,7 @@
 		 * We don't really want Joe User generating more
 		 * than 64Hz of interrupts on a multi-user machine.
 		 */
-		if ((arg > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
+		if (!kernel && (arg > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
 			return -EACCES;
 
 		while (arg > (1<<tmp))
@@ -539,6 +547,12 @@
 	return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
 }
 
+static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+		     unsigned long arg)
+{
+	return rtc_do_ioctl(cmd, arg, 0);
+}
+
 /*
  *	We enforce only one user at a time here with the open/close.
  *	Also clear the previous interrupt data on an open, and clean
@@ -606,11 +620,8 @@
 
 	spin_lock_irq (&rtc_lock);
 	rtc_irq_data = 0;
-	spin_unlock_irq (&rtc_lock);
-
-	/* No need for locking -- nobody else can do anything until this rmw is
-	 * committed, and no timer is running. */
 	rtc_status &= ~RTC_IS_OPEN;
+	spin_unlock_irq (&rtc_lock);
 	return 0;
 }
 
@@ -636,6 +647,88 @@
 #endif
 
 /*
+ * exported stuffs
+ */
+
+EXPORT_SYMBOL(rtc_register);
+EXPORT_SYMBOL(rtc_unregister);
+EXPORT_SYMBOL(rtc_control);
+
+int rtc_register(rtc_task_t *task)
+{
+#if !RTC_IRQ
+	return -EIO;
+#else
+	if (task == NULL || task->func == NULL)
+		return -EINVAL;
+	spin_lock_irq(&rtc_lock);
+	if (rtc_status & RTC_IS_OPEN) {
+		spin_unlock_irq(&rtc_lock);
+		return -EBUSY;
+	}
+	spin_lock(&rtc_task_lock);
+	if (rtc_callback) {
+		spin_unlock(&rtc_task_lock);
+		spin_unlock_irq(&rtc_lock);
+		return -EBUSY;
+	}
+	rtc_status |= RTC_IS_OPEN;
+	rtc_callback = task;
+	spin_unlock(&rtc_task_lock);
+	spin_unlock_irq(&rtc_lock);
+	return 0;
+#endif
+}
+
+int rtc_unregister(rtc_task_t *task)
+{
+#if !RTC_IRQ
+	return -EIO;
+#else
+	unsigned char tmp;
+
+	spin_lock_irq(&rtc_task_lock);
+	if (rtc_callback != task) {
+		spin_unlock_irq(&rtc_task_lock);
+		return -ENXIO;
+	}
+	rtc_callback = NULL;
+	spin_lock(&rtc_lock);
+	/* disable controls */
+	tmp = CMOS_READ(RTC_CONTROL);
+	tmp &= ~RTC_PIE;
+	tmp &= ~RTC_AIE;
+	tmp &= ~RTC_UIE;
+	CMOS_WRITE(tmp, RTC_CONTROL);
+	CMOS_READ(RTC_INTR_FLAGS);
+	if (rtc_status & RTC_TIMER_ON) {
+		rtc_status &= ~RTC_TIMER_ON;
+		del_timer(&rtc_irq_timer);
+	}
+	rtc_status &= ~RTC_IS_OPEN;
+	spin_unlock(&rtc_lock);
+	spin_unlock_irq(&rtc_task_lock);
+	return 0;
+#endif
+}
+
+int rtc_control(rtc_task_t *task, unsigned int cmd, unsigned long arg)
+{
+#if !RTC_IRQ
+	return -EIO;
+#else
+	spin_lock_irq(&rtc_task_lock);
+	if (rtc_callback != task) {
+		spin_unlock_irq(&rtc_task_lock);
+		return -ENXIO;
+	}
+	spin_unlock_irq(&rtc_task_lock);
+	return rtc_do_ioctl(cmd, arg, 1);
+#endif
+}
+
+
+/*
  *	The various file operations we support.
  */
 
@@ -818,7 +911,6 @@
 
 module_init(rtc_init);
 module_exit(rtc_exit);
-EXPORT_NO_SYMBOLS;
 
 #if RTC_IRQ
 /*
--- linux-2.4.20/drivers/char/Makefile.orig2	2003-04-22 17:32:19.000000000 +0200
+++ linux-2.4.20/drivers/char/Makefile	2003-04-22 17:32:33.000000000 +0200
@@ -24,7 +24,7 @@
 export-objs     :=	vt.o vt_proc.o keyboard.o sysrq.o \
 			misc.o pty.o random.o selection.o serial.o \
 			sonypi.o tty_io.o tty_ioctl.o generic_serial.o \
-			au1000_gpio.o hp_psaux.o nvram.o scx200.o
+			au1000_gpio.o hp_psaux.o nvram.o scx200.o rtc.o
 
 mod-subdirs	:=	ftape drm drm-4.0 pcmcia
 
--- linux-2.4.20/include/linux/rtc.h.dc09.orig	2003-05-07 21:00:57.000000000 +0200
+++ linux-2.4.20/include/linux/rtc.h	2003-05-07 21:07:00.000000000 +0200
@@ -90,4 +90,18 @@
 
 #define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */
 #define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */
+
+/* Exported functions to other kernel drivers */
+
+#ifdef __KERNEL__
+typedef struct rtc_task {
+	void (*func)(void *private_data);
+	void *private_data;
+} rtc_task_t;
+
+int rtc_register(rtc_task_t *task);
+int rtc_unregister(rtc_task_t *task);
+int rtc_control(rtc_task_t *t, unsigned int cmd, unsigned long arg);
+#endif
+
 #endif /* _LINUX_RTC_H_ */