Add OMAP RTC driver

Adds OMAP RTC driver.
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/char/Kconfig

@@ -761,6 +761,11 @@ config GEN_RTC_X
 config EFI_RTC
 	bool "EFI Real Time Clock Services"
 	depends on IA64
+config OMAP_RTC
+	bool "TI OMAP Real Time Clock"
+	depends on ARCH_OMAP1510 || ARCH_OMAP16XX || ARCH_OMAP730
+	help
+	  Support for TI OMAP RTC
 
 config DS1302
 	tristate "DS1302 RTC support"

drivers/char/Makefile

@@ -65,6 +65,7 @@ obj-$(CONFIG_SGI_IP27_RTC) += ip27-rtc.o
 obj-$(CONFIG_DS1302) += ds1302.o
 obj-$(CONFIG_S3C2410_RTC) += s3c2410-rtc.o
 obj-$(CONFIG_RTC_VR41XX) += vr41xx_rtc.o
+obj-$(CONFIG_OMAP_RTC)+= omap-rtc.o
 ifeq ($(CONFIG_GENERIC_NVRAM),y)
   obj-$(CONFIG_NVRAM) += generic_nvram.o
 else

drivers/char/omap-rtc.c

+/*
+ *	TI OMAP Real Time Clock interface for Linux	
+ *
+ *	Copyright (C) 2003 MontaVista Software, Inc.
+ *      Author: George G. Davis <gdavis@mvista.com> or <source@mvista.com>
+ *
+ *	Initially based on linux-2.4.20/drivers/char/rtc.c
+ *	Copyright (C) 1996 Paul Gortmaker
+ *
+ *	This driver allows use of the real time clock (built into
+ *	nearly all computers) from user space. It exports the /dev/rtc
+ *	interface supporting various ioctl() and also the
+ *	/proc/driver/rtc pseudo-file for status information.
+ *
+ *	The ioctls can be used to set the interrupt behaviour from the
+ *	RTC via IRQs. Then the /dev/rtc	interface can be used to make
+ *	use of RTC interrupts, be they time update or alarm based.
+ *
+ *	The /dev/rtc interface will block on reads until an interrupt
+ *	has been received. If a RTC interrupt has already happened,
+ *	it will output an unsigned long and then block. The output value
+ *	contains the interrupt status in the low byte and the number of
+ *	interrupts since the last read in the remaining high bytes. The 
+ *	/dev/rtc interface can also be used with the select(2) call.
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ *	Based on other minimal char device drivers, like Alan's
+ *	watchdog, Ted's random, etc. etc.
+ *
+ * Change Log :
+ *      v1.0    <gdavis@mvista.com> Initial version based on rtc.c v1.10e
+ *              <ramakrishnan@india.ti.com> Added support for 2.6 kernel, 
+ *                  - changed the return value of the interrupt handler
+ */
+
+#define RTC_VERSION		"1.0"
+
+/*
+ *	Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
+ *	interrupts disabled.
+ *	REVISIT: Elaborate on OMAP1510 TRM 15uS BUSY access rule.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/ioport.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/proc_fs.h>
+#include <linux/spinlock.h>
+#include <linux/rtc.h>
+
+#include <linux/interrupt.h>
+#include <linux/rtc.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/hardware.h>
+#include <asm/irq.h>
+#include "omap-rtc.h"
+
+extern spinlock_t rtc_lock;
+
+
+/* OMAP RTC register access macros: */
+
+#define CMOS_READ(addr)		omap_readb(addr)
+#define CMOS_WRITE(val, addr)	omap_writeb(val, addr)
+
+
+/* Local BCD/BIN conversion macros: */
+#ifdef BCD_TO_BIN
+#undef BCD_TO_BIN
+#endif
+#define BCD_TO_BIN(val)	((val)=((val)&15) + ((val)>>4)*10)
+ 
+#ifdef BIN_TO_BCD
+#undef BIN_TO_BCD
+#endif
+#define BIN_TO_BCD(val)	((val)=(((val)/10)<<4) + (val)%10)
+
+
+/*
+ *	We sponge a minor off of the misc major. No need slurping
+ *	up another valuable major dev number for this. If you add
+ *	an ioctl, make sure you don't conflict with SPARC's RTC
+ *	ioctls.
+ */
+
+static struct fasync_struct *rtc_async_queue;
+
+static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
+
+static ssize_t rtc_read(struct file *file, char *buf,
+			size_t count, loff_t *ppos);
+
+static int rtc_ioctl(struct inode *inode, struct file *file,
+		     unsigned int cmd, unsigned long arg);
+
+static unsigned int rtc_poll(struct file *file, poll_table *wait);
+
+static void get_rtc_time (struct rtc_time *rtc_tm);
+static void get_rtc_alm_time (struct rtc_time *alm_tm);
+
+static void set_rtc_irq_bit(unsigned char bit);
+static void mask_rtc_irq_bit(unsigned char bit);
+
+static inline unsigned char rtc_is_updating(void);
+
+static int rtc_read_proc(char *page, char **start, off_t off,
+                         int count, int *eof, void *data);
+
+/*
+ *	Bits in rtc_status. (7 bits of room for future expansion)
+ */
+
+#define RTC_IS_OPEN		0x01	/* means /dev/rtc is in use	*/
+
+/*
+ * REVISIT: fix this comment:
+ * rtc_status is never changed by rtc_interrupt, and ioctl/open/close is
+ * protected by the big kernel lock.
+ */
+static unsigned long rtc_status = 0;	/* bitmapped status byte.	*/
+static unsigned long rtc_irq_data = 0;	/* our output to the world	*/
+
+/*
+ *	If this driver ever becomes modularised, it will be really nice
+ *	to make the epoch retain its value across module reload...
+ */
+
+static unsigned long epoch = 1900;	/* year corresponding to 0x00	*/
+
+static const unsigned char days_in_mo[] = 
+{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+
+/*
+ *	A very tiny interrupt handler. It runs with SA_INTERRUPT set.
+ */
+
+static irqreturn_t rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	/*
+	 *	Either an alarm interrupt or update complete interrupt.
+	 *	We store the status in the low byte and the number of
+	 *	interrupts received since the last read in the remainder
+	 *	of rtc_irq_data.
+	 */
+
+	spin_lock (&rtc_lock);
+
+	rtc_irq_data += 0x100;
+	rtc_irq_data &= ~0xff;
+	rtc_irq_data |= CMOS_READ(OMAP_RTC_STATUS_REG);
+
+	if (rtc_irq_data & OMAP_RTC_STATUS_ALARM)
+		CMOS_WRITE(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
+
+	spin_unlock (&rtc_lock);
+
+	/* Now do the rest of the actions */
+	wake_up_interruptible(&rtc_wait);	
+
+	kill_fasync (&rtc_async_queue, SIGIO, POLL_IN);
+	return IRQ_HANDLED;
+}
+
+/*
+ *	Now all the various file operations that we export.
+ */
+
+static ssize_t rtc_read(struct file *file, char *buf,
+			size_t count, loff_t *ppos)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	unsigned long data;
+	ssize_t retval;
+	
+	if (count < sizeof(unsigned long))
+		return -EINVAL;
+
+	add_wait_queue(&rtc_wait, &wait);
+	set_current_state(TASK_INTERRUPTIBLE);
+
+	for (;;) {
+		spin_lock_irq (&rtc_lock);
+		data = rtc_irq_data;
+		if (data != 0) {
+			rtc_irq_data = 0;
+			break;
+		}
+		spin_unlock_irq (&rtc_lock);
+
+		if (file->f_flags & O_NONBLOCK) {
+			retval = -EAGAIN;
+			goto out;
+		}
+		if (signal_pending(current)) {
+			retval = -ERESTARTSYS;
+			goto out;
+		}
+		schedule();
+	}
+
+	spin_unlock_irq (&rtc_lock);
+	retval = put_user(data, (unsigned long *)buf); 
+	if (!retval)
+		retval = sizeof(unsigned long); 
+ out:
+	set_current_state(TASK_RUNNING);
+	remove_wait_queue(&rtc_wait, &wait);
+
+	return retval;
+}
+
+static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+		     unsigned long arg)
+{
+	struct rtc_time wtime; 
+
+	switch (cmd) {
+	case RTC_AIE_OFF:	/* Mask alarm int. enab. bit	*/
+	{
+		mask_rtc_irq_bit(OMAP_RTC_INTERRUPTS_IT_ALARM);
+		return 0;
+	}
+	case RTC_AIE_ON:	/* Allow alarm interrupts.	*/
+	{
+		set_rtc_irq_bit(OMAP_RTC_INTERRUPTS_IT_ALARM);
+		return 0;
+	}
+	case RTC_UIE_OFF:	/* Mask ints from RTC updates.	*/
+	{
+		mask_rtc_irq_bit(OMAP_RTC_INTERRUPTS_IT_TIMER);
+		return 0;
+	}
+	case RTC_UIE_ON:	/* Allow ints for RTC updates.	*/
+	{
+		set_rtc_irq_bit(OMAP_RTC_INTERRUPTS_IT_TIMER);
+		return 0;
+	}
+	case RTC_ALM_READ:	/* Read the present alarm time */
+	{
+		/*
+		 * This returns a struct rtc_time. Reading >= 0xc0
+		 * means "don't care" or "match all". Only the tm_hour,
+		 * tm_min, and tm_sec values are filled in.
+		 */
+		memset(&wtime, 0, sizeof(struct rtc_time));
+		get_rtc_alm_time(&wtime);
+		break; 
+	}
+	case RTC_ALM_SET:	/* Store a time into the alarm */
+	{
+		struct rtc_time alm_tm;
+		unsigned char mon, day, hrs, min, sec, leap_yr;
+		unsigned int yrs;
+
+		if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
+				   sizeof(struct rtc_time)))
+			return -EFAULT;
+
+		yrs = alm_tm.tm_year + 1900;
+		mon = alm_tm.tm_mon + 1;
+		day = alm_tm.tm_mday;
+		hrs = alm_tm.tm_hour;
+		min = alm_tm.tm_min;
+		sec = alm_tm.tm_sec;
+
+		if (yrs < 1970)
+			return -EINVAL;
+
+		leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
+
+		if ((mon > 12) || (day == 0))
+			return -EINVAL;
+
+		if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
+			return -EINVAL;
+			
+		if ((hrs >= 24) || (min >= 60) || (sec >= 60))
+			return -EINVAL;
+
+		if ((yrs -= epoch) > 255)    /* They are unsigned */
+			return -EINVAL;
+
+		if (yrs > 169) {
+			return -EINVAL;
+		}
+
+		if (yrs >= 100)
+			yrs -= 100;
+
+		BIN_TO_BCD(sec);
+		BIN_TO_BCD(min);
+		BIN_TO_BCD(hrs);
+		BIN_TO_BCD(day);
+		BIN_TO_BCD(mon);
+		BIN_TO_BCD(yrs);
+
+		spin_lock_irq(&rtc_lock);
+		CMOS_WRITE(yrs, OMAP_RTC_ALARM_YEARS_REG);
+		CMOS_WRITE(mon, OMAP_RTC_ALARM_MONTHS_REG);
+		CMOS_WRITE(day, OMAP_RTC_ALARM_DAYS_REG);
+		CMOS_WRITE(hrs, OMAP_RTC_ALARM_HOURS_REG);
+		CMOS_WRITE(min, OMAP_RTC_ALARM_MINUTES_REG);
+		CMOS_WRITE(sec, OMAP_RTC_ALARM_SECONDS_REG);
+		spin_unlock_irq(&rtc_lock);
+
+		return 0;
+	}
+	case RTC_RD_TIME:	/* Read the time/date from RTC	*/
+	{
+		memset(&wtime, 0, sizeof(struct rtc_time));
+		get_rtc_time(&wtime);
+		break;
+	}
+	case RTC_SET_TIME:	/* Set the RTC */
+	{
+		struct rtc_time rtc_tm;
+		unsigned char mon, day, hrs, min, sec, leap_yr;
+		unsigned char save_control;
+		unsigned int yrs;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
+				   sizeof(struct rtc_time)))
+			return -EFAULT;
+
+		yrs = rtc_tm.tm_year + 1900;
+		mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
+		day = rtc_tm.tm_mday;
+		hrs = rtc_tm.tm_hour;
+		min = rtc_tm.tm_min;
+		sec = rtc_tm.tm_sec;
+
+		if (yrs < 1970)
+			return -EINVAL;
+
+		leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
+
+		if ((mon > 12) || (day == 0))
+			return -EINVAL;
+
+		if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
+			return -EINVAL;
+
+		if ((hrs >= 24) || (min >= 60) || (sec >= 60))
+			return -EINVAL;
+
+		if ((yrs -= epoch) > 255)    /* They are unsigned */
+			return -EINVAL;
+
+		if (yrs > 169) {
+			return -EINVAL;
+		}
+
+		if (yrs >= 100)
+			yrs -= 100;
+
+		BIN_TO_BCD(sec);
+		BIN_TO_BCD(min);
+		BIN_TO_BCD(hrs);
+		BIN_TO_BCD(day);
+		BIN_TO_BCD(mon);
+		BIN_TO_BCD(yrs);
+
+		spin_lock_irq(&rtc_lock);
+		save_control = CMOS_READ(OMAP_RTC_CTRL_REG);
+		CMOS_WRITE((save_control & ~OMAP_RTC_CTRL_STOP),
+			   OMAP_RTC_CTRL_REG);
+		CMOS_WRITE(yrs, OMAP_RTC_YEARS_REG);
+		CMOS_WRITE(mon, OMAP_RTC_MONTHS_REG);
+		CMOS_WRITE(day, OMAP_RTC_DAYS_REG);
+		CMOS_WRITE(hrs, OMAP_RTC_HOURS_REG);
+		CMOS_WRITE(min, OMAP_RTC_MINUTES_REG);
+		CMOS_WRITE(sec, OMAP_RTC_SECONDS_REG);
+		CMOS_WRITE((save_control | OMAP_RTC_CTRL_STOP),
+			   OMAP_RTC_CTRL_REG);
+		spin_unlock_irq(&rtc_lock);
+
+		return 0;
+	}
+	case RTC_EPOCH_READ:	/* Read the epoch.	*/
+	{
+		return put_user (epoch, (unsigned long *)arg);
+	}
+	case RTC_EPOCH_SET:	/* Set the epoch.	*/
+	{
+		/* 
+		 * There were no RTC clocks before 1900.
+		 */
+		if (arg < 1900)
+			return -EINVAL;
+
+		if (!capable(CAP_SYS_TIME))
+			return -EACCES;
+
+		epoch = arg;
+		return 0;
+	}
+	default:
+#if	!defined(CONFIG_ARCH_OMAP)
+		return -ENOTTY;
+#else
+		return -EINVAL;
+#endif
+	}
+	return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 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
+ *	up things on a close.
+ */
+
+/* We use rtc_lock to protect against concurrent opens. So the BKL is not
+ * needed here. Or anywhere else in this driver. */
+static int rtc_open(struct inode *inode, struct file *file)
+{
+	spin_lock_irq (&rtc_lock);
+
+	if(rtc_status & RTC_IS_OPEN)
+		goto out_busy;
+
+	rtc_status |= RTC_IS_OPEN;
+
+	rtc_irq_data = 0;
+	spin_unlock_irq (&rtc_lock);
+	return 0;
+
+out_busy:
+	spin_unlock_irq (&rtc_lock);
+	return -EBUSY;
+}
+
+static int rtc_fasync (int fd, struct file *filp, int on)
+
+{
+	return fasync_helper (fd, filp, on, &rtc_async_queue);
+}
+
+static int rtc_release(struct inode *inode, struct file *file)
+{
+	unsigned char tmp;
+
+	/*
+	 * Turn off all interrupts once the device is no longer
+	 * in use, and clear the data.
+	 */
+
+	spin_lock_irq(&rtc_lock);
+	tmp = CMOS_READ(OMAP_RTC_INTERRUPTS_REG);
+	tmp &=  ~OMAP_RTC_INTERRUPTS_IT_ALARM;
+	tmp &=  ~OMAP_RTC_INTERRUPTS_IT_TIMER;
+	CMOS_WRITE(tmp, OMAP_RTC_INTERRUPTS_REG);
+	spin_unlock_irq(&rtc_lock);
+
+	if (file->f_flags & FASYNC) {
+		rtc_fasync (-1, file, 0);
+	}
+
+	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 we don't implement timer support in omap-rtc.
+	 */
+	rtc_status &= ~RTC_IS_OPEN;
+	return 0;
+}
+
+/* Called without the kernel lock - fine */
+static unsigned int rtc_poll(struct file *file, poll_table *wait)
+{
+	unsigned long l;
+
+	poll_wait(file, &rtc_wait, wait);
+
+	spin_lock_irq (&rtc_lock);
+	l = rtc_irq_data;
+	spin_unlock_irq (&rtc_lock);
+
+	if (l != 0)
+		return POLLIN | POLLRDNORM;
+	return 0;
+}
+
+/*
+ *	The various file operations we support.
+ */
+
+static struct file_operations rtc_fops = {
+	owner:		THIS_MODULE,
+	llseek:		no_llseek,
+	read:		rtc_read,
+	poll:		rtc_poll,
+	ioctl:		rtc_ioctl,
+	open:		rtc_open,
+	release:	rtc_release,
+	fasync:		rtc_fasync,
+};
+
+static struct miscdevice rtc_dev=
+{
+	RTC_MINOR,
+	"rtc",
+	&rtc_fops
+};
+
+static int __init rtc_init(void)
+{
+	if (!request_region(OMAP_RTC_VIRT_BASE, OMAP_RTC_SIZE,
+			    rtc_dev.name)) {
+		printk(KERN_ERR "%s: RTC I/O port %d is not free.\n",
+		       rtc_dev.name, OMAP_RTC_VIRT_BASE);
+		return -EIO;
+	}
+
+	if (CMOS_READ(OMAP_RTC_STATUS_REG) & OMAP_RTC_STATUS_POWER_UP) {
+		printk(KERN_WARNING "%s: RTC power up reset detected.\n",
+		       rtc_dev.name);
+		/* Clear OMAP_RTC_STATUS_POWER_UP */
+		CMOS_WRITE(OMAP_RTC_STATUS_POWER_UP, OMAP_RTC_STATUS_REG);
+	}
+
+	if (CMOS_READ(OMAP_RTC_STATUS_REG) & OMAP_RTC_STATUS_ALARM) {
+		printk(KERN_WARNING "%s: Clearing RTC ALARM interrupt.\n",
+		       rtc_dev.name);
+		/* Clear OMAP_RTC_STATUS_ALARM */
+		CMOS_WRITE(OMAP_RTC_STATUS_ALARM, OMAP_RTC_STATUS_REG);
+	}
+
+	if (!(CMOS_READ(OMAP_RTC_CTRL_REG) & OMAP_RTC_CTRL_STOP)) {
+		printk(KERN_INFO "%s: Enabling RTC.\n", rtc_dev.name);
+		CMOS_WRITE(OMAP_RTC_CTRL_STOP, OMAP_RTC_CTRL_REG);
+	}
+
+	if (request_irq(INT_RTC_TIMER, rtc_interrupt, SA_INTERRUPT,
+			rtc_dev.name, NULL)) {
+		printk(KERN_ERR "%s: RTC timer interrupt IRQ%d is not free.\n",
+		       rtc_dev.name, INT_RTC_TIMER);
+		release_region(OMAP_RTC_VIRT_BASE, OMAP_RTC_SIZE);
+		return -EIO;
+	}
+
+	if (request_irq(INT_RTC_ALARM, rtc_interrupt, SA_INTERRUPT,
+	                "omap-rtc alarm", NULL)) {
+		printk(KERN_ERR "%s: RTC alarm interrupt IRQ%d is not free.\n",
+		       rtc_dev.name, INT_RTC_ALARM);
+		release_region(OMAP_RTC_VIRT_BASE, OMAP_RTC_SIZE);
+		return -EIO;
+	}
+
+	spin_lock_init(&rtc_lock);
+	misc_register(&rtc_dev);
+	create_proc_read_entry ("driver/rtc", 0, 0, rtc_read_proc, NULL);
+
+	printk(KERN_INFO "Real Time Clock Driver v" RTC_VERSION "\n");
+
+	return 0;
+}
+
+static void __exit rtc_exit (void)
+{
+	free_irq (INT_RTC_TIMER, NULL);
+	free_irq (INT_RTC_ALARM, NULL);
+
+	remove_proc_entry ("driver/rtc", NULL);
+	misc_deregister(&rtc_dev);
+
+	release_region (OMAP_RTC_VIRT_BASE, OMAP_RTC_SIZE);
+}
+
+/*
+ *	Info exported via "/proc/driver/rtc".
+ */
+
+static int rtc_proc_output (char *buf)
+{
+#define YN(value) ((value) ? "yes" : "no")
+#define NY(value) ((value) ? "no" : "yes")
+	char *p;
+	struct rtc_time tm;
+
+	p = buf;
+
+	get_rtc_time(&tm);
+
+	/*
+	 * There is no way to tell if the luser has the RTC set for local
+	 * time or for Universal Standard Time (GMT). Probably local though.
+	 */
+	p += sprintf(p,
+		     "rtc_time\t: %02d:%02d:%02d\n"
+		     "rtc_date\t: %04d-%02d-%02d\n"
+	 	     "rtc_epoch\t: %04lu\n",
+		     tm.tm_hour, tm.tm_min, tm.tm_sec,
+		     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
+
+	get_rtc_alm_time(&tm);
+
+	/*
+	 * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
+	 * match any value for that particular field. Values that are
+	 * greater than a valid time, but less than 0xc0 shouldn't appear.
+	 */
+	p += sprintf(p,
+		     "alarm_time\t: %02d:%02d:%02d\n"
+		     "alarm_date\t: %04d-%02d-%02d\n",
+		     tm.tm_hour, tm.tm_min, tm.tm_sec,
+		     tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
+
+	p += sprintf(p,
+		     "BCD\t\t: %s\n"
+		     "24hr\t\t: %s\n"
+		     "alarm_IRQ\t: %s\n"
+		     "update_IRQ\t: %s\n"
+		     "update_rate\t: %ud\n",
+		     YN(1),
+		     YN(1),
+		     YN(CMOS_READ(OMAP_RTC_INTERRUPTS_REG) &
+			OMAP_RTC_INTERRUPTS_IT_ALARM),
+		     YN(CMOS_READ(OMAP_RTC_INTERRUPTS_REG) &
+			OMAP_RTC_INTERRUPTS_IT_TIMER),
+		     CMOS_READ(OMAP_RTC_INTERRUPTS_REG) & 3 /* REVISIT */);
+
+	return  p - buf;
+#undef YN
+#undef NY
+}
+
+static int rtc_read_proc(char *page, char **start, off_t off,
+                         int count, int *eof, void *data)
+{
+        int len = rtc_proc_output (page);
+        if (len <= off+count) *eof = 1;
+        *start = page + off;
+        len -= off;
+        if (len>count) len = count;
+        if (len<0) len = 0;
+        return len;
+}
+
+/*
+ * Returns true if a clock update is in progress
+ */
+/* FIXME shouldn't this be above rtc_init to make it fully inlined? */
+static inline unsigned char rtc_is_updating(void)
+{
+	unsigned char uip;
+
+	spin_lock_irq(&rtc_lock);
+	uip = (CMOS_READ(OMAP_RTC_STATUS_REG) & OMAP_RTC_STATUS_BUSY);
+	spin_unlock_irq(&rtc_lock);
+	return uip;
+}
+
+static void get_rtc_time(struct rtc_time *rtc_tm)
+{
+	unsigned char ctrl;
+
+	/* REVISIT: Fix this comment!!!
+	 * read RTC once any update in progress is done. The update
+	 * can take just over 2ms. We wait 10 to 20ms. There is no need to
+	 * to poll-wait (up to 1s - eeccch) for the falling edge of OMAP_RTC_STATUS_BUSY.
+	 * If you need to know *exactly* when a second has started, enable
+	 * periodic update complete interrupts, (via ioctl) and then 
+	 * immediately read /dev/rtc which will block until you get the IRQ.
+	 * Once the read clears, read the RTC time (again via ioctl). Easy.
+	 */
+
+#if	0 /* REVISIT: This need to do as the TRM says. */
+	unsigned long uip_watchdog = jiffies;
+	if (rtc_is_updating() != 0)
+		while (jiffies - uip_watchdog < 2*HZ/100) {
+			barrier();
+			cpu_relax();
+		}
+#endif
+
+	/*
+	 * Only the values that we read from the RTC are set. We leave
+	 * tm_wday, tm_yday and tm_isdst untouched. Even though the
+	 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
+	 * by the RTC when initially set to a non-zero value.
+	 */
+	spin_lock_irq(&rtc_lock);
+	rtc_tm->tm_sec = CMOS_READ(OMAP_RTC_SECONDS_REG);
+	rtc_tm->tm_min = CMOS_READ(OMAP_RTC_MINUTES_REG);
+	rtc_tm->tm_hour = CMOS_READ(OMAP_RTC_HOURS_REG);
+	rtc_tm->tm_mday = CMOS_READ(OMAP_RTC_DAYS_REG);
+	rtc_tm->tm_mon = CMOS_READ(OMAP_RTC_MONTHS_REG);
+	rtc_tm->tm_year = CMOS_READ(OMAP_RTC_YEARS_REG);
+	ctrl = CMOS_READ(OMAP_RTC_CTRL_REG);
+	spin_unlock_irq(&rtc_lock);
+
+	BCD_TO_BIN(rtc_tm->tm_sec);
+	BCD_TO_BIN(rtc_tm->tm_min);
+	BCD_TO_BIN(rtc_tm->tm_hour);
+	BCD_TO_BIN(rtc_tm->tm_mday);
+	BCD_TO_BIN(rtc_tm->tm_mon);
+	BCD_TO_BIN(rtc_tm->tm_year);
+
+	/*
+	 * Account for differences between how the RTC uses the values
+	 * and how they are defined in a struct rtc_time;
+	 */
+	if ((rtc_tm->tm_year += (epoch - 1900)) <= 69)
+		rtc_tm->tm_year += 100;
+
+	rtc_tm->tm_mon--;
+}
+
+static void get_rtc_alm_time(struct rtc_time *alm_tm)
+{
+	unsigned char ctrl;
+
+	spin_lock_irq(&rtc_lock);
+	alm_tm->tm_sec = CMOS_READ(OMAP_RTC_ALARM_SECONDS_REG);
+	alm_tm->tm_min = CMOS_READ(OMAP_RTC_ALARM_MINUTES_REG);
+	alm_tm->tm_hour = CMOS_READ(OMAP_RTC_ALARM_HOURS_REG);
+	alm_tm->tm_mday = CMOS_READ(OMAP_RTC_ALARM_DAYS_REG);
+	alm_tm->tm_mon = CMOS_READ(OMAP_RTC_ALARM_MONTHS_REG);
+	alm_tm->tm_year = CMOS_READ(OMAP_RTC_ALARM_YEARS_REG);
+	ctrl = CMOS_READ(OMAP_RTC_CTRL_REG);
+	spin_unlock_irq(&rtc_lock);
+
+	BCD_TO_BIN(alm_tm->tm_sec);
+	BCD_TO_BIN(alm_tm->tm_min);
+	BCD_TO_BIN(alm_tm->tm_hour);
+	BCD_TO_BIN(alm_tm->tm_mday);
+	BCD_TO_BIN(alm_tm->tm_mon);
+	BCD_TO_BIN(alm_tm->tm_year);
+
+	/*
+	 * Account for differences between how the RTC uses the values
+	 * and how they are defined in a struct rtc_time;
+	 */
+	if ((alm_tm->tm_year += (epoch - 1900)) <= 69)
+		alm_tm->tm_year += 100;
+
+	alm_tm->tm_mon--;
+}
+
+/*
+ * Used to disable/enable UIE and AIE interrupts.
+ */
+
+static void mask_rtc_irq_bit(unsigned char bit)
+{
+	unsigned char val;
+
+	spin_lock_irq(&rtc_lock);
+	val = CMOS_READ(OMAP_RTC_INTERRUPTS_REG);
+	val &=  ~bit;
+	CMOS_WRITE(val, OMAP_RTC_INTERRUPTS_REG);
+	rtc_irq_data = 0;
+	spin_unlock_irq(&rtc_lock);
+}
+
+static void set_rtc_irq_bit(unsigned char bit)
+{
+	unsigned char val;
+
+	spin_lock_irq(&rtc_lock);
+	val = CMOS_READ(OMAP_RTC_INTERRUPTS_REG);
+	val |= bit;
+	CMOS_WRITE(val, OMAP_RTC_INTERRUPTS_REG);
+	rtc_irq_data = 0;
+	spin_unlock_irq(&rtc_lock);
+}
+
+MODULE_AUTHOR("George G. Davis");
+MODULE_LICENSE("GPL");
+
+module_init(rtc_init);
+module_exit(rtc_exit);

drivers/char/omap-rtc.h

+/*
+ *  TI OMAP Real Time Clock header file
+ *
+ *  Copyright (C) 2003 TI
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+
+#define OMAP_RTC_BASE			0xfffb4800
+#define OMAP_RTC_SIZE			128
+
+#define OMAP_RTC_VIRT_BASE		IO_ADDRESS(OMAP_RTC_BASE)
+
+/*
+ * Real-Time Clock
+ */
+
+#define OMAP_RTC_SECONDS_REG            (OMAP_RTC_BASE + 0x00)
+#define OMAP_RTC_MINUTES_REG            (OMAP_RTC_BASE + 0x04)
+#define OMAP_RTC_HOURS_REG              (OMAP_RTC_BASE + 0x08)
+#define OMAP_RTC_DAYS_REG               (OMAP_RTC_BASE + 0x0C)
+#define OMAP_RTC_MONTHS_REG             (OMAP_RTC_BASE + 0x10)
+#define OMAP_RTC_YEARS_REG              (OMAP_RTC_BASE + 0x14)
+#define OMAP_RTC_WEEKS_REG              (OMAP_RTC_BASE + 0x18)
+#define OMAP_RTC_ALARM_SECONDS_REG      (OMAP_RTC_BASE + 0x20)
+#define OMAP_RTC_ALARM_MINUTES_REG      (OMAP_RTC_BASE + 0x24)
+#define OMAP_RTC_ALARM_HOURS_REG        (OMAP_RTC_BASE + 0x28)
+#define OMAP_RTC_ALARM_DAYS_REG         (OMAP_RTC_BASE + 0x2c)
+#define OMAP_RTC_ALARM_MONTHS_REG       (OMAP_RTC_BASE + 0x30)
+#define OMAP_RTC_ALARM_YEARS_REG        (OMAP_RTC_BASE + 0x34)
+#define OMAP_RTC_CTRL_REG               (OMAP_RTC_BASE + 0x40)
+#define OMAP_RTC_STATUS_REG             (OMAP_RTC_BASE + 0x44)
+#define OMAP_RTC_INTERRUPTS_REG         (OMAP_RTC_BASE + 0x48)
+#define OMAP_RTC_COMP_LSB_REG           (OMAP_RTC_BASE + 0x4c)
+#define OMAP_RTC_COMP_MSB_REG           (OMAP_RTC_BASE + 0x50)
+
+/* RTC Control Register bit fields: */
+
+#define OMAP_RTC_CTRL_STOP              (1<<0)
+
+/* RTC Status Register bit fields: */
+
+#define OMAP_RTC_STATUS_POWER_UP        (1<<7)
+#define OMAP_RTC_STATUS_ALARM           (1<<6)
+#define OMAP_RTC_STATUS_1D_EVENT        (1<<5)
+#define OMAP_RTC_STATUS_1H_EVENT        (1<<4)
+#define OMAP_RTC_STATUS_1M_EVENT        (1<<3)
+#define OMAP_RTC_STATUS_1S_EVENT        (1<<2)
+#define OMAP_RTC_STATUS_RUN             (1<<1)
+#define OMAP_RTC_STATUS_BUSY            (1<<0)
+
+/* RTC Interrupt Register bit fields: */
+
+#define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
+#define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)