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