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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 byte.
  12  *
  13  * Copyright (c) 2002-2003, Axis Communications AB
  14  * All rights reserved.
  15  *
  16  * Author: Tobias Anderberg <tobiasa@axis.com>.
  17  *
  18  */
  19
  20 #include <linux/config.h>
  21 #include <linux/version.h>
  22 #include <linux/module.h>
  23 #include <linux/kernel.h>
  24 #include <linux/types.h>
  25 #include <linux/sched.h>
  26 #include <linux/init.h>
  27 #include <linux/fs.h>
  28 #include <linux/ioctl.h>
  29 #include <linux/delay.h>
  30 #include <linux/bcd.h>
  31
  32 #include <asm/uaccess.h>
  33 #include <asm/system.h>
  34 #include <asm/io.h>
  35 #include <asm/rtc.h>
  36
  37 #include "i2c.h"
  38
  39 #define PCF8563_MAJOR   121     /* Local major number. */
  40 #define DEVICE_NAME     "rtc"   /* Name which is registered in /proc/devices. */
  41 #define PCF8563_NAME    "PCF8563"
  42 #define DRIVER_VERSION  "$Revision: 1.1 $"
  43
  44 /* Two simple wrapper macros, saves a few keystrokes. */
  45 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
  46 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
  47
  48 static const unsigned char days_in_month[] =
  49         { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
  50
  51 int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
  52 int pcf8563_open(struct inode *, struct file *);
  53 int pcf8563_release(struct inode *, struct file *);
  54
  55 static struct file_operations pcf8563_fops = {
  56         owner: THIS_MODULE,
  57         ioctl: pcf8563_ioctl,
  58         open: pcf8563_open,
  59         release: pcf8563_release,
  60 };
  61
  62 unsigned char
  63 pcf8563_readreg(int reg)
  64 {
  65         unsigned char res = rtc_read(reg);
  66
  67         /* The PCF8563 does not return 0 for unimplemented bits */
  68         switch (reg) {
  69                 case RTC_SECONDS:
  70                 case RTC_MINUTES:
  71                         res &= 0x7F;
  72                         break;
  73                 case RTC_HOURS:
  74                 case RTC_DAY_OF_MONTH:
  75                         res &= 0x3F;
  76                         break;
  77                 case RTC_WEEKDAY:
  78                         res &= 0x07;
  79                         break;
  80                 case RTC_MONTH:
  81                         res &= 0x1F;
  82                         break;
  83                 case RTC_CONTROL1:
  84                         res &= 0xA8;
  85                         break;
  86                 case RTC_CONTROL2:
  87                         res &= 0x1F;
  88                         break;
  89                 case RTC_CLOCKOUT_FREQ:
  90                 case RTC_TIMER_CONTROL:
  91                         res &= 0x83;
  92                         break;
  93         }
  94         return res;
  95 }
  96
  97 void
  98 pcf8563_writereg(int reg, unsigned char val)
  99 {
 100 #ifdef CONFIG_ETRAX_RTC_READONLY
 101         if (reg == RTC_CONTROL1 || (reg >= RTC_SECONDS && reg <= RTC_YEAR))
 102                 return;
 103 #endif
 104
 105         rtc_write(reg, val);
 106 }
 107
 108 void
 109 get_rtc_time(struct rtc_time *tm)
 110 {
 111         tm->tm_sec  = rtc_read(RTC_SECONDS);
 112         tm->tm_min  = rtc_read(RTC_MINUTES);
 113         tm->tm_hour = rtc_read(RTC_HOURS);
 114         tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
 115         tm->tm_wday = rtc_read(RTC_WEEKDAY);
 116         tm->tm_mon  = rtc_read(RTC_MONTH);
 117         tm->tm_year = rtc_read(RTC_YEAR);
 118
 119         if (tm->tm_sec & 0x80)
 120                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
 121                        "information is no longer guaranteed!\n", PCF8563_NAME);
 122
 123         tm->tm_year  = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
 124         tm->tm_sec  &= 0x7F;
 125         tm->tm_min  &= 0x7F;
 126         tm->tm_hour &= 0x3F;
 127         tm->tm_mday &= 0x3F;
 128         tm->tm_wday &= 0x07; /* Not coded in BCD. */
 129         tm->tm_mon  &= 0x1F;
 130
 131         BCD_TO_BIN(tm->tm_sec);
 132         BCD_TO_BIN(tm->tm_min);
 133         BCD_TO_BIN(tm->tm_hour);
 134         BCD_TO_BIN(tm->tm_mday);
 135         BCD_TO_BIN(tm->tm_mon);
 136         tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 137 }
 138
 139 int __init
 140 pcf8563_init(void)
 141 {
 142         /* Initiate the i2c protocol. */
 143         i2c_init();
 144
 145         /*
 146          * First of all we need to reset the chip. This is done by
 147          * clearing control1, control2 and clk freq and resetting
 148          * all alarms.
 149          */
 150         if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 151                 goto err;
 152
 153         if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 154                 goto err;
 155
 156         if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 157                 goto err;
 158
 159         if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
 160                 goto err;
 161
 162         /* Reset the alarms. */
 163         if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
 164                 goto err;
 165
 166         if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
 167                 goto err;
 168
 169         if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
 170                 goto err;
 171
 172         if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
 173                 goto err;
 174
 175         if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 176                 printk(KERN_INFO "%s: Unable to get major numer %d for RTC device.\n",
 177                        PCF8563_NAME, PCF8563_MAJOR);
 178                 return -1;
 179         }
 180
 181         printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 182
 183         /* Check for low voltage, and warn about it.. */
 184         if (rtc_read(RTC_SECONDS) & 0x80)
 185                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
 186                        "information is no longer guaranteed!\n", PCF8563_NAME);
 187
 188         return 0;
 189
 190 err:
 191         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 192         return -1;
 193 }
 194
 195 void __exit
 196 pcf8563_exit(void)
 197 {
 198         if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
 199                 printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
 200         }
 201 }
 202
 203 /*
 204  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 205  * POSIX says so!
 206  */
 207 int
 208 pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
 209 {
 210         /* Some sanity checks. */
 211         if (_IOC_TYPE(cmd) != RTC_MAGIC)
 212                 return -ENOTTY;
 213
 214         if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
 215                 return -ENOTTY;
 216
 217         switch (cmd) {
 218                 case RTC_RD_TIME:
 219                 {
 220                         struct rtc_time tm;
 221
 222                         memset(&tm, 0, sizeof (struct rtc_time));
 223                         get_rtc_time(&tm);
 224
 225                         if (copy_to_user((struct rtc_time *) arg, &tm, sizeof tm)) {
 226                                 return -EFAULT;
 227                         }
 228
 229                         return 0;
 230                 }
 231
 232                 case RTC_SET_TIME:
 233                 {
 234 #ifdef CONFIG_ETRAX_RTC_READONLY
 235                         return -EPERM;
 236 #else
 237                         int leap;
 238                         int year;
 239                         int century;
 240                         struct rtc_time tm;
 241
 242                         if (!capable(CAP_SYS_TIME))
 243                                 return -EPERM;
 244
 245                         if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof tm))
 246                                 return -EFAULT;
 247
 248                         /* Convert from struct tm to struct rtc_time. */
 249                         tm.tm_year += 1900;
 250                         tm.tm_mon += 1;
 251
 252                         /*
 253                          * Check if tm.tm_year is a leap year. A year is a leap
 254                          * year if it is divisible by 4 but not 100, except
 255                          * that years divisible by 400 _are_ leap years.
 256                          */
 257                         year = tm.tm_year;
 258                         leap = (tm.tm_mon == 2) && ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
 259
 260                         /* Perform some sanity checks. */
 261                         if ((tm.tm_year < 1970) ||
 262                             (tm.tm_mon > 12) ||
 263                             (tm.tm_mday == 0) ||
 264                             (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
 265                             (tm.tm_wday >= 7) ||
 266                             (tm.tm_hour >= 24) ||
 267                             (tm.tm_min >= 60) ||
 268                             (tm.tm_sec >= 60))
 269                                 return -EINVAL;
 270
 271                         century = (tm.tm_year >= 2000) ? 0x80 : 0;
 272                         tm.tm_year = tm.tm_year % 100;
 273
 274                         BIN_TO_BCD(tm.tm_year);
 275                         BIN_TO_BCD(tm.tm_mday);
 276                         BIN_TO_BCD(tm.tm_hour);
 277                         BIN_TO_BCD(tm.tm_min);
 278                         BIN_TO_BCD(tm.tm_sec);
 279                         tm.tm_mon |= century;
 280
 281                         rtc_write(RTC_YEAR, tm.tm_year);
 282                         rtc_write(RTC_MONTH, tm.tm_mon);
 283                         rtc_write(RTC_WEEKDAY, tm.tm_wday); /* Not coded in BCD. */
 284                         rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
 285                         rtc_write(RTC_HOURS, tm.tm_hour);
 286                         rtc_write(RTC_MINUTES, tm.tm_min);
 287                         rtc_write(RTC_SECONDS, tm.tm_sec);
 288
 289                         return 0;
 290 #endif /* !CONFIG_ETRAX_RTC_READONLY */
 291                 }
 292
 293                 case RTC_VLOW_RD:
 294                 {
 295                         int vl_bit = 0;
 296
 297                         if (rtc_read(RTC_SECONDS) & 0x80) {
 298                                 vl_bit = 1;
 299                                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
 300                                        "date/time information is no longer guaranteed!\n",
 301                                        PCF8563_NAME);
 302                         }
 303                         if (copy_to_user((int *) arg, &vl_bit, sizeof(int)))
 304                                 return -EFAULT;
 305
 306                         return 0;
 307                 }
 308
 309                 case RTC_VLOW_SET:
 310                 {
 311                         /* Clear the VL bit in the seconds register */
 312                         int ret = rtc_read(RTC_SECONDS);
 313
 314                         rtc_write(RTC_SECONDS, (ret & 0x7F));
 315
 316                         return 0;
 317                 }
 318
 319                 default:
 320                         return -ENOTTY;
 321         }
 322
 323         return 0;
 324 }
 325
 326 int
 327 pcf8563_open(struct inode *inode, struct file *filp)
 328 {
 329         MOD_INC_USE_COUNT;
 330         return 0;
 331 }
 332
 333 int
 334 pcf8563_release(struct inode *inode, struct file *filp)
 335 {
 336         MOD_DEC_USE_COUNT;
 337         return 0;
 338 }
 339
 340 module_init(pcf8563_init);
 341 module_exit(pcf8563_exit);