CRIS v10: Update driver for pcf8563

- Use mutex instead of spinlock, fixes kernel bugzilla report 8339.
- Make sure that pcf8563_init can be called multiple times but only setup once.
- Change RTC_VLOW_RD -> RTC_VL_READ, RTC_VLOW_SET -> RTC_VL_CLR
- Cache the voltage low value at driver init so the battery status
  information does not get 'accidentally' cleared when setting the RTC time.
- Add weekday handling.
- Correct leapyear handling to include 100 and 400 year exceptions.
- Correct whitespace and formatting errors.
- Remove useless CVS id tag.

arch/cris/arch-v10/drivers/pcf8563.c

@@ -8,14 +8,13 @@
  * low detector are also provided. All address and data are transferred
  * serially via two-line bidirectional I2C-bus. Maximum bus speed is
  * 400 kbits/s. The built-in word address register is incremented
- * automatically after each written or read bute.
+ * automatically after each written or read byte.
  *
- * Copyright (c) 2002, Axis Communications AB
+ * Copyright (c) 2002-2007, Axis Communications AB
  * All rights reserved.
  *
  * Author: Tobias Anderberg <tobiasa@axis.com>.
  *
- * $Id: pcf8563.c,v 1.11 2005/03/07 13:13:07 starvik Exp $
  */
 
 #include <linux/module.h>
@@ -27,19 +26,19 @@
 #include <linux/ioctl.h>
 #include <linux/delay.h>
 #include <linux/bcd.h>
-#include <linux/capability.h>
+#include <linux/mutex.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
 #include <asm/io.h>
-#include <asm/arch/svinto.h>
 #include <asm/rtc.h>
+
 #include "i2c.h"
 
-#define PCF8563_MAJOR 121		/* Local major number. */
-#define DEVICE_NAME "rtc"		/* Name which is registered in /proc/devices. */
+#define PCF8563_MAJOR 121	/* Local major number. */
+#define DEVICE_NAME "rtc"	/* Name which is registered in /proc/devices. */
 #define PCF8563_NAME "PCF8563"
-#define DRIVER_VERSION "$Revision: 1.11 $"
+#define DRIVER_VERSION "$Revision: 1.24 $"
 
 /* I2C bus slave registers. */
 #define RTC_I2C_READ		0xa3
@@ -49,71 +48,88 @@
 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
 
-static DEFINE_SPINLOCK(rtc_lock); /* Protect state etc */
-	
+static DEFINE_MUTEX(rtc_lock); /* Protect state etc */
+
 static const unsigned char days_in_month[] =
 	{ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 
 int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
 
+/* Cache VL bit value read at driver init since writing the RTC_SECOND
+ * register clears the VL status.
+ */
+static int voltage_low;
+
 static const struct file_operations pcf8563_fops = {
 	.owner = THIS_MODULE,
 	.ioctl = pcf8563_ioctl,
 };
 
 unsigned char
-pcf8563_readreg(int reg) 
+pcf8563_readreg(int reg)
 {
-	unsigned char res = i2c_readreg(RTC_I2C_READ, reg);
-
-	/* The PCF8563 does not return 0 for unimplemented bits */
-	switch(reg)
-	{
-		case RTC_SECONDS:
-		case RTC_MINUTES:
-		     res &= 0x7f;
-		     break;
-		case RTC_HOURS:
-		case RTC_DAY_OF_MONTH:
-		     res &= 0x3f;
-		     break;
-		case RTC_MONTH:
-		     res = (res & 0x1f) - 1;  /* PCF8563 returns month in range 1-12 */
-		     break;
+	unsigned char res = rtc_read(reg);
+
+	/* The PCF8563 does not return 0 for unimplemented bits. */
+	switch (reg) {
+	case RTC_SECONDS:
+	case RTC_MINUTES:
+		res &= 0x7F;
+		break;
+	case RTC_HOURS:
+	case RTC_DAY_OF_MONTH:
+		res &= 0x3F;
+		break;
+	case RTC_WEEKDAY:
+		res &= 0x07;
+		break;
+	case RTC_MONTH:
+		res &= 0x1F;
+		break;
+	case RTC_CONTROL1:
+		res &= 0xA8;
+		break;
+	case RTC_CONTROL2:
+		res &= 0x1F;
+		break;
+	case RTC_CLOCKOUT_FREQ:
+	case RTC_TIMER_CONTROL:
+		res &= 0x83;
+		break;
 	}
 	return res;
 }
 
 void
-pcf8563_writereg(int reg, unsigned char val) 
+pcf8563_writereg(int reg, unsigned char val)
 {
-#ifdef CONFIG_ETRAX_RTC_READONLY
-	if (reg == RTC_CONTROL1 || (reg >= RTC_SECONDS && reg <= RTC_YEAR))
-		return;
-#endif
-
 	rtc_write(reg, val);
 }
 
 void
 get_rtc_time(struct rtc_time *tm)
 {
-	tm->tm_sec = rtc_read(RTC_SECONDS);
-	tm->tm_min = rtc_read(RTC_MINUTES);
+	tm->tm_sec  = rtc_read(RTC_SECONDS);
+	tm->tm_min  = rtc_read(RTC_MINUTES);
 	tm->tm_hour = rtc_read(RTC_HOURS);
 	tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
-	tm->tm_mon = rtc_read(RTC_MONTH);
+	tm->tm_wday = rtc_read(RTC_WEEKDAY);
+	tm->tm_mon  = rtc_read(RTC_MONTH);
 	tm->tm_year = rtc_read(RTC_YEAR);
 
-	if (tm->tm_sec & 0x80)
-		printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
+	if (tm->tm_sec & 0x80) {
+		printk(KERN_ERR "%s: RTC Voltage Low - reliable date/time "
+		       "information is no longer guaranteed!\n", PCF8563_NAME);
+	}
 
-	tm->tm_year = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
-	tm->tm_sec &= 0x7f;
-	tm->tm_min &= 0x7f;
-	tm->tm_hour &= 0x3f;
-	tm->tm_mday &= 0x3f;
-	tm->tm_mon &= 0x1f;
+	tm->tm_year  = BCD_TO_BIN(tm->tm_year) +
+		       ((tm->tm_mon & 0x80) ? 100 : 0);
+	tm->tm_sec  &= 0x7F;
+	tm->tm_min  &= 0x7F;
+	tm->tm_hour &= 0x3F;
+	tm->tm_mday &= 0x3F;
+	tm->tm_wday &= 0x07; /* Not coded in BCD. */
+	tm->tm_mon  &= 0x1F;
 
 	BCD_TO_BIN(tm->tm_sec);
 	BCD_TO_BIN(tm->tm_min);
@@ -126,17 +142,24 @@ get_rtc_time(struct rtc_time *tm)
 int __init
 pcf8563_init(void)
 {
-	int ret;
-
-	if ((ret = i2c_init())) {
-		printk(KERN_CRIT "pcf8563_init: failed to init i2c\n");
-		return ret;
+	static int res;
+	static int first = 1;
+
+	if (!first)
+		return res;
+	first = 0;
+
+	/* Initiate the i2c protocol. */
+	res = i2c_init();
+	if (res < 0) {
+		printk(KERN_CRIT "pcf8563_init: Failed to init i2c.\n");
+		return res;
 	}
 
 	/*
 	 * First of all we need to reset the chip. This is done by
-	 * clearing control1, control2 and clk freq, clear the 
-	 * Voltage Low bit, and resetting all alarms.
+	 * clearing control1, control2 and clk freq and resetting
+	 * all alarms.
 	 */
 	if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 		goto err;
@@ -147,34 +170,36 @@ pcf8563_init(void)
 	if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 		goto err;
 
-	/* Clear the VL bit in the seconds register. */
-	ret = rtc_read(RTC_SECONDS);
-	
-	if (rtc_write(RTC_SECONDS, (ret & 0x7f)) < 0)
+	if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
 		goto err;
-		
+
 	/* Reset the alarms. */
-	if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
+	if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
 		goto err;
-	
-	if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
+
+	if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
 		goto err;
-	
-	if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
+
+	if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
 		goto err;
-	
-	if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 0)
+
+	if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
 		goto err;
-        
-	/* Check for low voltage, and warn about it.. */
-	if (rtc_read(RTC_SECONDS) & 0x80)
-		printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
-	
-	return 0;
+
+	/* Check for low voltage, and warn about it. */
+	if (rtc_read(RTC_SECONDS) & 0x80) {
+		voltage_low = 1;
+		printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
+		       "date/time information is no longer guaranteed!\n",
+		       PCF8563_NAME);
+	}
+
+	return res;
 
 err:
 	printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
-	return -1;
+	res = -1;
+	return res;
 }
 
 void __exit
@@ -187,8 +212,8 @@ pcf8563_exit(void)
  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
  * POSIX says so!
  */
-int
-pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
+int pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
+	unsigned long arg)
 {
 	/* Some sanity checks. */
 	if (_IOC_TYPE(cmd) != RTC_MAGIC)
@@ -198,124 +223,146 @@ pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned
 		return -ENOTTY;
 
 	switch (cmd) {
-		case RTC_RD_TIME:
-			{
-				struct rtc_time tm;
-
-				spin_lock(&rtc_lock);
-				get_rtc_time(&tm);
-
-				if (copy_to_user((struct rtc_time *) arg, &tm, sizeof(struct rtc_time))) {
-					spin_unlock(&rtc_lock);
-					return -EFAULT;
-				}
-
-				spin_unlock(&rtc_lock);
-				return 0;
-			}
-			break;
-		case RTC_SET_TIME:
-			{
-#ifdef CONFIG_ETRAX_RTC_READONLY
-				return -EPERM;
-#else
-				int leap;
-				int century;
-				struct rtc_time tm;
-
-				memset(&tm, 0, sizeof (struct rtc_time));
-				if (!capable(CAP_SYS_TIME))
-					return -EPERM;
-
-				if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
-					return -EFAULT;
-
-				/* Convert from struct tm to struct rtc_time. */
-				tm.tm_year += 1900;
-				tm.tm_mon += 1;
-				
-				leap = ((tm.tm_mon == 2) && ((tm.tm_year % 4) == 0)) ? 1 : 0;
-
-				/* Perform some sanity checks. */
-				if ((tm.tm_year < 1970) ||
-				    (tm.tm_mon > 12) ||
-				    (tm.tm_mday == 0) ||
-				    (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
-				    (tm.tm_hour >= 24) ||
-				    (tm.tm_min >= 60) ||
-				    (tm.tm_sec >= 60))
-					return -EINVAL;
-
-				century = (tm.tm_year >= 2000) ? 0x80 : 0;
-				tm.tm_year = tm.tm_year % 100;
-
-				BIN_TO_BCD(tm.tm_year);
-				BIN_TO_BCD(tm.tm_mday);
-				BIN_TO_BCD(tm.tm_hour);
-				BIN_TO_BCD(tm.tm_min);
-				BIN_TO_BCD(tm.tm_sec);
-				tm.tm_mon |= century;
-
-				spin_lock(&rtc_lock);
-				
-				rtc_write(RTC_YEAR, tm.tm_year);
-				rtc_write(RTC_MONTH, tm.tm_mon);
-				rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
-				rtc_write(RTC_HOURS, tm.tm_hour);
-				rtc_write(RTC_MINUTES, tm.tm_min);
-				rtc_write(RTC_SECONDS, tm.tm_sec);
-
-				spin_unlock(&rtc_lock);
-
-				return 0;
-#endif /* !CONFIG_ETRAX_RTC_READONLY */
-			}
-
-		case RTC_VLOW_RD:
-		{
-			int vl_bit = 0;
-
-			if (rtc_read(RTC_SECONDS) & 0x80) {
-				vl_bit = 1;
-				printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
-				       "date/time information is no longer guaranteed!\n",
-				       PCF8563_NAME);
-			}
-			if (copy_to_user((int *) arg, &vl_bit, sizeof(int)))
-				return -EFAULT;
-
-			return 0;
-		}
+	case RTC_RD_TIME:
+	{
+		struct rtc_time tm;
 
-		case RTC_VLOW_SET:
-		{
-			/* Clear the VL bit in the seconds register */
-			int ret = rtc_read(RTC_SECONDS);
+		mutex_lock(&rtc_lock);
+		memset(&tm, 0, sizeof tm);
+		get_rtc_time(&tm);
 
-			rtc_write(RTC_SECONDS, (ret & 0x7F));
+		if (copy_to_user((struct rtc_time *) arg, &tm,
+				 sizeof tm)) {
+			spin_unlock(&rtc_lock);
+			return -EFAULT;
+		}
+
+		mutex_unlock(&rtc_lock);
 
-			return 0;
+		return 0;
+	}
+	case RTC_SET_TIME:
+	{
+		int leap;
+		int year;
+		int century;
+		struct rtc_time tm;
+
+		memset(&tm, 0, sizeof tm);
+		if (!capable(CAP_SYS_TIME))
+			return -EPERM;
+
+		if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof tm))
+			return -EFAULT;
+
+		/* Convert from struct tm to struct rtc_time. */
+		tm.tm_year += 1900;
+		tm.tm_mon += 1;
+
+		/*
+		 * Check if tm.tm_year is a leap year. A year is a leap
+		 * year if it is divisible by 4 but not 100, except
+		 * that years divisible by 400 _are_ leap years.
+		 */
+		year = tm.tm_year;
+		leap = (tm.tm_mon == 2) &&
+			((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
+
+		/* Perform some sanity checks. */
+		if ((tm.tm_year < 1970) ||
+		    (tm.tm_mon > 12) ||
+		    (tm.tm_mday == 0) ||
+		    (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
+		    (tm.tm_wday >= 7) ||
+		    (tm.tm_hour >= 24) ||
+		    (tm.tm_min >= 60) ||
+		    (tm.tm_sec >= 60))
+			return -EINVAL;
+
+		century = (tm.tm_year >= 2000) ? 0x80 : 0;
+		tm.tm_year = tm.tm_year % 100;
+
+		BIN_TO_BCD(tm.tm_year);
+		BIN_TO_BCD(tm.tm_mon);
+		BIN_TO_BCD(tm.tm_mday);
+		BIN_TO_BCD(tm.tm_hour);
+		BIN_TO_BCD(tm.tm_min);
+		BIN_TO_BCD(tm.tm_sec);
+		tm.tm_mon |= century;
+
+		mutex_lock(&rtc_lock);
+
+		rtc_write(RTC_YEAR, tm.tm_year);
+		rtc_write(RTC_MONTH, tm.tm_mon);
+		rtc_write(RTC_WEEKDAY, tm.tm_wday); /* Not coded in BCD. */
+		rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
+		rtc_write(RTC_HOURS, tm.tm_hour);
+		rtc_write(RTC_MINUTES, tm.tm_min);
+		rtc_write(RTC_SECONDS, tm.tm_sec);
+
+		mutex_unlock(&rtc_lock);
+
+		return 0;
+	}
+	case RTC_VL_READ:
+		if (voltage_low) {
+			printk(KERN_ERR "%s: RTC Voltage Low - "
+			       "reliable date/time information is no "
+			       "longer guaranteed!\n", PCF8563_NAME);
 		}
 
-		default:
-				return -ENOTTY;
+		if (copy_to_user((int *) arg, &voltage_low, sizeof(int)))
+			return -EFAULT;
+		return 0;
+
+	case RTC_VL_CLR:
+	{
+		/* Clear the VL bit in the seconds register in case
+		 * the time has not been set already (which would
+		 * have cleared it). This does not really matter
+		 * because of the cached voltage_low value but do it
+		 * anyway for consistency. */
+
+		int ret = rtc_read(RTC_SECONDS);
+
+		rtc_write(RTC_SECONDS, (ret & 0x7F));
+
+		/* Clear the cached value. */
+		voltage_low = 0;
+
+		return 0;
+	}
+	default:
+		return -ENOTTY;
 	}
 
 	return 0;
 }
 
-static int __init
-pcf8563_register(void)
+static int __init pcf8563_register(void)
 {
-	pcf8563_init();
+	if (pcf8563_init() < 0) {
+		printk(KERN_INFO "%s: Unable to initialize Real-Time Clock "
+		       "Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
+		return -1;
+	}
+
 	if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 		printk(KERN_INFO "%s: Unable to get major number %d for RTC device.\n",
 		       PCF8563_NAME, PCF8563_MAJOR);
 		return -1;
 	}
 
-	printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
-        return 0;
+	printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME,
+	       DRIVER_VERSION);
+
+	/* Check for low voltage, and warn about it. */
+	if (voltage_low) {
+		printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
+		       "information is no longer guaranteed!\n", PCF8563_NAME);
+	}
+
+	return 0;
 }
 
 module_init(pcf8563_register);