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Sourcecode: linux-2.6 version File versions

pcf8563.c

/*
 * PCF8563 RTC
 *
 * From Phillips' datasheet:
 *
 * The PCF8563 is a CMOS real-time clock/calendar optimized for low power
 * consumption. A programmable clock output, interupt output and voltage
 * 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.
 *
 * Copyright (c) 2002, 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>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/delay.h>
#include <linux/bcd.h>
#include <linux/capability.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_NAME "PCF8563"
#define DRIVER_VERSION "$Revision: 1.11 $"

/* I2C bus slave registers. */
#define RTC_I2C_READ          0xa3
#define RTC_I2C_WRITE         0xa2

/* 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_SPINLOCK(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);

static struct file_operations pcf8563_fops = {
      .owner = THIS_MODULE,
      .ioctl = pcf8563_ioctl,
};

unsigned char
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;
      }
      return res;
}

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);
}

void
get_rtc_time(struct rtc_time *tm)
{
      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_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);

      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;

      BCD_TO_BIN(tm->tm_sec);
      BCD_TO_BIN(tm->tm_min);
      BCD_TO_BIN(tm->tm_hour);
      BCD_TO_BIN(tm->tm_mday);
      BCD_TO_BIN(tm->tm_mon);
      tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
}

int __init
pcf8563_init(void)
{
      int ret;

      if ((ret = i2c_init())) {
            printk(KERN_CRIT "pcf8563_init: failed to init i2c\n");
            return ret;
      }

      /*
       * 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.
       */
      if (rtc_write(RTC_CONTROL1, 0x00) < 0)
            goto err;

      if (rtc_write(RTC_CONTROL2, 0x00) < 0)
            goto err;

      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)
            goto err;
            
      /* Reset the alarms. */
      if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
            goto err;
      
      if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
            goto err;
      
      if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
            goto err;
      
      if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 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;

err:
      printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
      return -1;
}

void __exit
pcf8563_exit(void)
{
      if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
            printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
      }
}

/*
 * 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)
{
      /* Some sanity checks. */
      if (_IOC_TYPE(cmd) != RTC_MAGIC)
            return -ENOTTY;

      if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
            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_VLOW_SET:
            {
                  /* Clear the VL bit in the seconds register */
                  int ret = rtc_read(RTC_SECONDS);

                  rtc_write(RTC_SECONDS, (ret & 0x7F));

                  return 0;
            }

            default:
                        return -ENOTTY;
      }

      return 0;
}

static int __init
pcf8563_register(void)
{
      pcf8563_init();
      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);
        return 0;
}

module_init(pcf8563_register);
module_exit(pcf8563_exit);

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