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