CRIS v32: Update driver for RTC chip pcf8563.

- Moved all calls to register_chrdev to a function called by module_init.
- Added mutex locking.
- Added better error handling at start up.
- Added BIN_TO_BCD of the month value before it is saved to the RTC.
- Corrected the month value returned by pcf8563_readreg.
- Cache the voltage low value at driver init so the battery status
  information does not get 'accidentally' cleared when setting the RTC time.
- Removed obsolete CONFIG_ETRAX_RTC_READONLY
- Voltage low ioctl():s RTC_VLOW_RD -> RTC_VL_READ, RTC_VLOW_SET -> RTC_VL_CLR

1 files changed, 163 insertions, 133 deletions

diff --git a/arch/cris/arch-v32/drivers/pcf8563.c b/arch/cris/arch-v32/drivers/pcf8563.c
index 6dbd700d3d66..53db3870ba04 100644
--- a/arch/cris/arch-v32/drivers/pcf8563.c
+++ b/arch/cris/arch-v32/drivers/pcf8563.c
@@ -10,7 +10,7 @@
  * 400 kbits/s. The built-in word address register is incremented
  * automatically after each written or read byte.
  *
- * Copyright (c) 2002-2003, Axis Communications AB
+ * Copyright (c) 2002-2007, Axis Communications AB
  * All rights reserved.
  *
  * Author: Tobias Anderberg <tobiasa@axis.com>.
@@ -26,6 +26,7 @@
 #include <linux/ioctl.h>
 #include <linux/delay.h>
 #include <linux/bcd.h>
+#include <linux/mutex.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -37,24 +38,27 @@
 #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: 1.1 $"
+#define DRIVER_VERSION  "$Revision: 1.17 $"
 
 /* Two simple wrapper macros, saves a few keystrokes. */
 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
 
+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);
-int pcf8563_open(struct inode *, struct file *);
-int pcf8563_release(struct inode *, struct file *);
+
+/* 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,
-        .open =         pcf8563_open,
-        .release =      pcf8563_release,
+        .ioctl =        pcf8563_ioctl
 };
 
 unsigned char
@@ -62,7 +66,7 @@ pcf8563_readreg(int reg)
 {
         unsigned char res = rtc_read(reg);
 
-        /* The PCF8563 does not return 0 for unimplemented bits */
+        /* The PCF8563 does not return 0 for unimplemented bits. */
         switch (reg) {
                 case RTC_SECONDS:
                 case RTC_MINUTES:
@@ -95,11 +99,6 @@ pcf8563_readreg(int reg)
 void
 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);
 }
 
@@ -114,11 +113,13 @@ get_rtc_time(struct rtc_time *tm)
         tm->tm_mon  = rtc_read(RTC_MONTH);
         tm->tm_year = rtc_read(RTC_YEAR);
 
-        if (tm->tm_sec & 0x80)
-                printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
+        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_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;
@@ -137,8 +138,19 @@ get_rtc_time(struct rtc_time *tm)
 int __init
 pcf8563_init(void)
 {
+        static int res;
+        static int first = 1;
+
+        if (!first)
+                return res;
+        first = 0;
+
         /* Initiate the i2c protocol. */
-        i2c_init();
+        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
@@ -170,24 +182,20 @@ pcf8563_init(void)
         if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
                 goto err;
 
-        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;
+        /* 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);
         }
 
-        printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
-
-        /* Check for low voltage, and warn about it.. */
-        if (rtc_read(RTC_SECONDS) & 0x80)
-                printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
-                       "information is no longer guaranteed!\n", PCF8563_NAME);
-
-        return 0;
+        return res;
 
 err:
         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
-        return -1;
+        res = -1;
+        return res;
 }
 
 void __exit
@@ -200,8 +208,8 @@ 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)
@@ -211,125 +219,147 @@ pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned
                 return -ENOTTY;
 
         switch (cmd) {
-                case RTC_RD_TIME:
-                {
-                        struct rtc_time tm;
-
-                        memset(&tm, 0, sizeof (struct rtc_time));
-                        get_rtc_time(&tm);
-
-                        if (copy_to_user((struct rtc_time *) arg, &tm, sizeof tm)) {
-                                return -EFAULT;
-                        }
-
-                        return 0;
+        case RTC_RD_TIME:
+        {
+                struct rtc_time tm;
+
+                mutex_lock(&rtc_lock);
+                memset(&tm, 0, sizeof tm);
+                get_rtc_time(&tm);
+
+                if (copy_to_user((struct rtc_time *) arg, &tm,
+                                 sizeof tm)) {
+                        spin_unlock(&rtc_lock);
+                        return -EFAULT;
                 }
 
-                case RTC_SET_TIME:
-                {
-#ifdef CONFIG_ETRAX_RTC_READONLY
+                mutex_unlock(&rtc_lock);
+
+                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;
-#else
-                        int leap;
-                        int year;
-                        int century;
-                        struct rtc_time 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_mday);
-                        BIN_TO_BCD(tm.tm_hour);
-                        BIN_TO_BCD(tm.tm_min);
-                        BIN_TO_BCD(tm.tm_sec);
-                        tm.tm_mon |= century;
-
-                        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);
-
-                        return 0;
-#endif /* !CONFIG_ETRAX_RTC_READONLY */
-                }
 
-                case RTC_VLOW_RD:
-                {
-                        int vl_bit = 0;
+                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);
 
-                        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;
+                if (copy_to_user((int *) arg, &voltage_low, sizeof(int)))
+                        return -EFAULT;
+                return 0;
 
-                        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. */
 
-                case RTC_VLOW_SET:
-                {
-                        /* Clear the VL bit in the seconds register */
-                        int ret = rtc_read(RTC_SECONDS);
+                int ret = rtc_read(RTC_SECONDS);
 
-                        rtc_write(RTC_SECONDS, (ret & 0x7F));
+                rtc_write(RTC_SECONDS, (ret & 0x7F));
 
-                        return 0;
-                }
+                /* Clear the cached value. */
+                voltage_low = 0;
 
-                default:
-                        return -ENOTTY;
+                return 0;
+        }
+        default:
+                return -ENOTTY;
         }
 
         return 0;
 }
 
-int
-pcf8563_open(struct inode *inode, struct file *filp)
+static int __init pcf8563_register(void)
 {
-        return 0;
-}
+        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 numer %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);
+
+        /* 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);
+        }
 
-int
-pcf8563_release(struct inode *inode, struct file *filp)
-{
         return 0;
 }
 
-module_init(pcf8563_init);
+module_init(pcf8563_register);
 module_exit(pcf8563_exit);