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   1 /*
   2  * PCF8563 RTC
   3  *
   4  * From Phillips' datasheet:
   5  *
   6  * The PCF8563 is a CMOS real-time clock/calendar optimized for low power
   7  * consumption. A programmable clock output, interupt output and voltage
   8  * low detector are also provided. All address and data are transferred
   9  * serially via two-line bidirectional I2C-bus. Maximum bus speed is
  10  * 400 kbits/s. The built-in word address register is incremented
  11  * automatically after each written or read bute.
  12  *
  13  * Copyright (c) 2002, Axis Communications AB
  14  * All rights reserved.
  15  *
  16  * Author: Tobias Anderberg <tobiasa@axis.com>.
  17  *
  18  * $Id: pcf8563.c,v 1.8 2004/08/24 06:42:51 starvik Exp $
  19  */
  20
  21 #include <linux/config.h>
  22 #include <linux/version.h>
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/types.h>
  26 #include <linux/sched.h>
  27 #include <linux/init.h>
  28 #include <linux/fs.h>
  29 #include <linux/ioctl.h>
  30 #include <linux/delay.h>
  31 #include <linux/bcd.h>
  32
  33 #include <asm/uaccess.h>
  34 #include <asm/system.h>
  35 #include <asm/io.h>
  36 #include <asm/arch/svinto.h>
  37 #include <asm/rtc.h>
  38 #include "i2c.h"
  39
  40 #define PCF8563_MAJOR 121               /* Local major number. */
  41 #define DEVICE_NAME "rtc"               /* Name which is registered in /proc/devices. */
  42 #define PCF8563_NAME "PCF8563"
  43 #define DRIVER_VERSION "$Revision: 1.8 $"
  44
  45 /* I2C bus slave registers. */
  46 #define RTC_I2C_READ            0xa3
  47 #define RTC_I2C_WRITE           0xa2
  48
  49 /* Two simple wrapper macros, saves a few keystrokes. */
  50 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
  51 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
  52
  53 static const unsigned char days_in_month[] =
  54         { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
  55
  56 int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
  57
  58 static struct file_operations pcf8563_fops = {
  59         .owner = THIS_MODULE,
  60         .ioctl = pcf8563_ioctl,
  61 };
  62
  63 unsigned char
  64 pcf8563_readreg(int reg)
  65 {
  66         unsigned char res = i2c_readreg(RTC_I2C_READ, reg);
  67
  68         /* The PCF8563 does not return 0 for unimplemented bits */
  69         switch(reg)
  70         {
  71                 case RTC_SECONDS:
  72                 case RTC_MINUTES:
  73                      res &= 0x7f;
  74                      break;
  75                 case RTC_HOURS:
  76                 case RTC_DAY_OF_MONTH:
  77                      res &= 0x3f;
  78                      break;
  79                 case RTC_MONTH:
  80                      res = (res & 0x1f) - 1;  /* PCF8563 returns month in range 1-12 */
  81                      break;
  82         }
  83         return res;
  84 }
  85
  86 void
  87 pcf8563_writereg(int reg, unsigned char val)
  88 {
  89 #ifdef CONFIG_ETRAX_RTC_READONLY
  90         if (reg == RTC_CONTROL1 || (reg >= RTC_SECONDS && reg <= RTC_YEAR))
  91                 return;
  92 #endif
  93
  94         rtc_write(reg, val);
  95 }
  96
  97 void
  98 get_rtc_time(struct rtc_time *tm)
  99 {
 100         tm->tm_sec = rtc_read(RTC_SECONDS);
 101         tm->tm_min = rtc_read(RTC_MINUTES);
 102         tm->tm_hour = rtc_read(RTC_HOURS);
 103         tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
 104         tm->tm_mon = rtc_read(RTC_MONTH);
 105         tm->tm_year = rtc_read(RTC_YEAR);
 106
 107         if (tm->tm_sec & 0x80)
 108                 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
 109
 110         tm->tm_year = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
 111         tm->tm_sec &= 0x7f;
 112         tm->tm_min &= 0x7f;
 113         tm->tm_hour &= 0x3f;
 114         tm->tm_mday &= 0x3f;
 115         tm->tm_mon &= 0x1f;
 116
 117         BCD_TO_BIN(tm->tm_sec);
 118         BCD_TO_BIN(tm->tm_min);
 119         BCD_TO_BIN(tm->tm_hour);
 120         BCD_TO_BIN(tm->tm_mday);
 121         BCD_TO_BIN(tm->tm_mon);
 122         tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 123 }
 124
 125 int __init
 126 pcf8563_init(void)
 127 {
 128         unsigned char ret;
 129
 130         i2c_init();
 131
 132         /*
 133          * First of all we need to reset the chip. This is done by
 134          * clearing control1, control2 and clk freq, clear the
 135          * Voltage Low bit, and resetting all alarms.
 136          */
 137         if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 138                 goto err;
 139
 140         if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 141                 goto err;
 142
 143         if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 144                 goto err;
 145
 146         /* Clear the VL bit in the seconds register. */
 147         ret = rtc_read(RTC_SECONDS);
 148
 149         if (rtc_write(RTC_SECONDS, (ret & 0x7f)) < 0)
 150                 goto err;
 151
 152         /* Reset the alarms. */
 153         if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
 154                 goto err;
 155
 156         if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
 157                 goto err;
 158
 159         if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
 160                 goto err;
 161
 162         if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 0)
 163                 goto err;
 164
 165         /* Check for low voltage, and warn about it.. */
 166         if (rtc_read(RTC_SECONDS) & 0x80)
 167                 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
 168
 169         return 0;
 170
 171 err:
 172         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 173         return -1;
 174 }
 175
 176 void __exit
 177 pcf8563_exit(void)
 178 {
 179         if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
 180                 printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
 181         }
 182 }
 183
 184 /*
 185  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 186  * POSIX says so!
 187  */
 188 int
 189 pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
 190 {
 191         /* Some sanity checks. */
 192         if (_IOC_TYPE(cmd) != RTC_MAGIC)
 193                 return -ENOTTY;
 194
 195         if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
 196                 return -ENOTTY;
 197
 198         switch (cmd) {
 199                 case RTC_RD_TIME:
 200                         {
 201                                 struct rtc_time tm;
 202
 203                                 get_rtc_time(&tm);
 204
 205                                 if (copy_to_user((struct rtc_time *) arg, &tm, sizeof(struct rtc_time))) {
 206                                         return -EFAULT;
 207                                 }
 208
 209                                 return 0;
 210                         }
 211                         break;
 212                 case RTC_SET_TIME:
 213                         {
 214 #ifdef CONFIG_ETRAX_RTC_READONLY
 215                                 return -EPERM;
 216 #else
 217                                 int leap;
 218                                 int century;
 219                                 struct rtc_time tm;
 220
 221                                 memset(&tm, 0, sizeof (struct rtc_time));
 222                                 if (!capable(CAP_SYS_TIME))
 223                                         return -EPERM;
 224
 225                                 if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
 226                                         return -EFAULT;
 227
 228                                 /* Convert from struct tm to struct rtc_time. */
 229                                 tm.tm_year += 1900;
 230                                 tm.tm_mon += 1;
 231
 232                                 leap = ((tm.tm_mon == 2) && ((tm.tm_year % 4) == 0)) ? 1 : 0;
 233
 234                                 /* Perform some sanity checks. */
 235                                 if ((tm.tm_year < 1970) ||
 236                                     (tm.tm_mon > 12) ||
 237                                     (tm.tm_mday == 0) ||
 238                                     (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
 239                                     (tm.tm_hour >= 24) ||
 240                                     (tm.tm_min >= 60) ||
 241                                     (tm.tm_sec >= 60))
 242                                         return -EINVAL;
 243
 244                                 century = (tm.tm_year >= 2000) ? 0x80 : 0;
 245                                 tm.tm_year = tm.tm_year % 100;
 246
 247                                 BIN_TO_BCD(tm.tm_year);
 248                                 BIN_TO_BCD(tm.tm_mday);
 249                                 BIN_TO_BCD(tm.tm_hour);
 250                                 BIN_TO_BCD(tm.tm_min);
 251                                 BIN_TO_BCD(tm.tm_sec);
 252                                 tm.tm_mon |= century;
 253
 254                                 rtc_write(RTC_YEAR, tm.tm_year);
 255                                 rtc_write(RTC_MONTH, tm.tm_mon);
 256                                 rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
 257                                 rtc_write(RTC_HOURS, tm.tm_hour);
 258                                 rtc_write(RTC_MINUTES, tm.tm_min);
 259                                 rtc_write(RTC_SECONDS, tm.tm_sec);
 260
 261                                 return 0;
 262 #endif /* !CONFIG_ETRAX_RTC_READONLY */
 263                         }
 264
 265                 case RTC_VLOW_RD:
 266                 {
 267                         int vl_bit = 0;
 268
 269                         if (rtc_read(RTC_SECONDS) & 0x80) {
 270                                 vl_bit = 1;
 271                                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
 272                                        "date/time information is no longer guaranteed!\n",
 273                                        PCF8563_NAME);
 274                         }
 275                         if (copy_to_user((int *) arg, &vl_bit, sizeof(int)))
 276                                 return -EFAULT;
 277
 278                         return 0;
 279                 }
 280
 281                 case RTC_VLOW_SET:
 282                 {
 283                         /* Clear the VL bit in the seconds register */
 284                         int ret = rtc_read(RTC_SECONDS);
 285
 286                         rtc_write(RTC_SECONDS, (ret & 0x7F));
 287
 288                         return 0;
 289                 }
 290
 291                 default:
 292                                 return -ENOTTY;
 293         }
 294
 295         return 0;
 296 }
 297
 298 static int __init
 299 pcf8563_register(void)
 300 {
 301         pcf8563_init();
 302         if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 303                 printk(KERN_INFO "%s: Unable to get major numer %d for RTC device.\n",
 304                        PCF8563_NAME, PCF8563_MAJOR);
 305                 return -1;
 306         }
 307
 308         printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 309         return 0;
 310 }
 311
 312 module_init(pcf8563_register);
 313 module_exit(pcf8563_exit);