arch/cris/arch-v32/drivers/pcf8563.c

   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, interrupt 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) 2002-2007, 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 #include <linux/mutex.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: 1.17 $"
  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 DEFINE_MUTEX(pcf8563_mutex);
  48 static DEFINE_MUTEX(rtc_lock); /* Protect state etc */
  49
  50 static const unsigned char days_in_month[] =
  51         { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
  52
  53 static long pcf8563_unlocked_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
  54
  55 /* Cache VL bit value read at driver init since writing the RTC_SECOND
  56  * register clears the VL status.
  57  */
  58 static int voltage_low;
  59
  60 static const struct file_operations pcf8563_fops = {
  61         .owner          = THIS_MODULE,
  62         .unlocked_ioctl = pcf8563_unlocked_ioctl,
  63         .llseek         = noop_llseek,
  64 };
  65
  66 unsigned char
  67 pcf8563_readreg(int reg)
  68 {
  69         unsigned char res = rtc_read(reg);
  70
  71         /* The PCF8563 does not return 0 for unimplemented bits. */
  72         switch (reg) {
  73                 case RTC_SECONDS:
  74                 case RTC_MINUTES:
  75                         res &= 0x7F;
  76                         break;
  77                 case RTC_HOURS:
  78                 case RTC_DAY_OF_MONTH:
  79                         res &= 0x3F;
  80                         break;
  81                 case RTC_WEEKDAY:
  82                         res &= 0x07;
  83                         break;
  84                 case RTC_MONTH:
  85                         res &= 0x1F;
  86                         break;
  87                 case RTC_CONTROL1:
  88                         res &= 0xA8;
  89                         break;
  90                 case RTC_CONTROL2:
  91                         res &= 0x1F;
  92                         break;
  93                 case RTC_CLOCKOUT_FREQ:
  94                 case RTC_TIMER_CONTROL:
  95                         res &= 0x83;
  96                         break;
  97         }
  98         return res;
  99 }
 100
 101 void
 102 pcf8563_writereg(int reg, unsigned char val)
 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_ERR "%s: RTC Voltage Low - reliable date/time "
 120                        "information is no longer guaranteed!\n", PCF8563_NAME);
 121         }
 122
 123         tm->tm_year  = bcd2bin(tm->tm_year) +
 124                        ((tm->tm_mon & 0x80) ? 100 : 0);
 125         tm->tm_sec  &= 0x7F;
 126         tm->tm_min  &= 0x7F;
 127         tm->tm_hour &= 0x3F;
 128         tm->tm_mday &= 0x3F;
 129         tm->tm_wday &= 0x07; /* Not coded in BCD. */
 130         tm->tm_mon  &= 0x1F;
 131
 132         tm->tm_sec = bcd2bin(tm->tm_sec);
 133         tm->tm_min = bcd2bin(tm->tm_min);
 134         tm->tm_hour = bcd2bin(tm->tm_hour);
 135         tm->tm_mday = bcd2bin(tm->tm_mday);
 136         tm->tm_mon = bcd2bin(tm->tm_mon);
 137         tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 138 }
 139
 140 int __init
 141 pcf8563_init(void)
 142 {
 143         static int res;
 144         static int first = 1;
 145
 146         if (!first)
 147                 return res;
 148         first = 0;
 149
 150         /* Initiate the i2c protocol. */
 151         res = i2c_init();
 152         if (res < 0) {
 153                 printk(KERN_CRIT "pcf8563_init: Failed to init i2c.\n");
 154                 return res;
 155         }
 156
 157         /*
 158          * First of all we need to reset the chip. This is done by
 159          * clearing control1, control2 and clk freq and resetting
 160          * all alarms.
 161          */
 162         if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 163                 goto err;
 164
 165         if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 166                 goto err;
 167
 168         if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 169                 goto err;
 170
 171         if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
 172                 goto err;
 173
 174         /* Reset the alarms. */
 175         if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
 176                 goto err;
 177
 178         if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
 179                 goto err;
 180
 181         if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
 182                 goto err;
 183
 184         if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
 185                 goto err;
 186
 187         /* Check for low voltage, and warn about it. */
 188         if (rtc_read(RTC_SECONDS) & 0x80) {
 189                 voltage_low = 1;
 190                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
 191                        "date/time information is no longer guaranteed!\n",
 192                        PCF8563_NAME);
 193         }
 194
 195         return res;
 196
 197 err:
 198         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 199         res = -1;
 200         return res;
 201 }
 202
 203 void __exit
 204 pcf8563_exit(void)
 205 {
 206         unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME);
 207 }
 208
 209 /*
 210  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 211  * POSIX says so!
 212  */
 213 static int pcf8563_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 214 {
 215         /* Some sanity checks. */
 216         if (_IOC_TYPE(cmd) != RTC_MAGIC)
 217                 return -ENOTTY;
 218
 219         if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
 220                 return -ENOTTY;
 221
 222         switch (cmd) {
 223         case RTC_RD_TIME:
 224         {
 225                 struct rtc_time tm;
 226
 227                 mutex_lock(&rtc_lock);
 228                 memset(&tm, 0, sizeof tm);
 229                 get_rtc_time(&tm);
 230
 231                 if (copy_to_user((struct rtc_time *) arg, &tm,
 232                                  sizeof tm)) {
 233                         mutex_unlock(&rtc_lock);
 234                         return -EFAULT;
 235                 }
 236
 237                 mutex_unlock(&rtc_lock);
 238
 239                 return 0;
 240         }
 241         case RTC_SET_TIME:
 242         {
 243                 int leap;
 244                 int year;
 245                 int century;
 246                 struct rtc_time tm;
 247
 248                 memset(&tm, 0, sizeof tm);
 249                 if (!capable(CAP_SYS_TIME))
 250                         return -EPERM;
 251
 252                 if (copy_from_user(&tm, (struct rtc_time *) arg,
 253                                    sizeof tm))
 254                         return -EFAULT;
 255
 256                 /* Convert from struct tm to struct rtc_time. */
 257                 tm.tm_year += 1900;
 258                 tm.tm_mon += 1;
 259
 260                 /*
 261                  * Check if tm.tm_year is a leap year. A year is a leap
 262                  * year if it is divisible by 4 but not 100, except
 263                  * that years divisible by 400 _are_ leap years.
 264                  */
 265                 year = tm.tm_year;
 266                 leap = (tm.tm_mon == 2) &&
 267                         ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
 268
 269                 /* Perform some sanity checks. */
 270                 if ((tm.tm_year < 1970) ||
 271                     (tm.tm_mon > 12) ||
 272                     (tm.tm_mday == 0) ||
 273                     (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
 274                     (tm.tm_wday >= 7) ||
 275                     (tm.tm_hour >= 24) ||
 276                     (tm.tm_min >= 60) ||
 277                     (tm.tm_sec >= 60))
 278                         return -EINVAL;
 279
 280                 century = (tm.tm_year >= 2000) ? 0x80 : 0;
 281                 tm.tm_year = tm.tm_year % 100;
 282
 283                 tm.tm_year = bin2bcd(tm.tm_year);
 284                 tm.tm_mon = bin2bcd(tm.tm_mon);
 285                 tm.tm_mday = bin2bcd(tm.tm_mday);
 286                 tm.tm_hour = bin2bcd(tm.tm_hour);
 287                 tm.tm_min = bin2bcd(tm.tm_min);
 288                 tm.tm_sec = bin2bcd(tm.tm_sec);
 289                 tm.tm_mon |= century;
 290
 291                 mutex_lock(&rtc_lock);
 292
 293                 rtc_write(RTC_YEAR, tm.tm_year);
 294                 rtc_write(RTC_MONTH, tm.tm_mon);
 295                 rtc_write(RTC_WEEKDAY, tm.tm_wday); /* Not coded in BCD. */
 296                 rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
 297                 rtc_write(RTC_HOURS, tm.tm_hour);
 298                 rtc_write(RTC_MINUTES, tm.tm_min);
 299                 rtc_write(RTC_SECONDS, tm.tm_sec);
 300
 301                 mutex_unlock(&rtc_lock);
 302
 303                 return 0;
 304         }
 305         case RTC_VL_READ:
 306                 if (voltage_low)
 307                         printk(KERN_ERR "%s: RTC Voltage Low - "
 308                                "reliable date/time information is no "
 309                                "longer guaranteed!\n", PCF8563_NAME);
 310
 311                 if (copy_to_user((int *) arg, &voltage_low, sizeof(int)))
 312                         return -EFAULT;
 313                 return 0;
 314
 315         case RTC_VL_CLR:
 316         {
 317                 /* Clear the VL bit in the seconds register in case
 318                  * the time has not been set already (which would
 319                  * have cleared it). This does not really matter
 320                  * because of the cached voltage_low value but do it
 321                  * anyway for consistency. */
 322
 323                 int ret = rtc_read(RTC_SECONDS);
 324
 325                 rtc_write(RTC_SECONDS, (ret & 0x7F));
 326
 327                 /* Clear the cached value. */
 328                 voltage_low = 0;
 329
 330                 return 0;
 331         }
 332         default:
 333                 return -ENOTTY;
 334         }
 335
 336         return 0;
 337 }
 338
 339 static long pcf8563_unlocked_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 340 {
 341         int ret;
 342
 343         mutex_lock(&pcf8563_mutex);
 344         return pcf8563_ioctl(filp, cmd, arg);
 345         mutex_unlock(&pcf8563_mutex);
 346
 347         return ret;
 348 }
 349
 350 static int __init pcf8563_register(void)
 351 {
 352         if (pcf8563_init() < 0) {
 353                 printk(KERN_INFO "%s: Unable to initialize Real-Time Clock "
 354                        "Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 355                 return -1;
 356         }
 357
 358         if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 359                 printk(KERN_INFO "%s: Unable to get major numer %d for RTC "
 360                        "device.\n", PCF8563_NAME, PCF8563_MAJOR);
 361                 return -1;
 362         }
 363
 364         printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME,
 365                DRIVER_VERSION);
 366
 367         /* Check for low voltage, and warn about it. */
 368         if (voltage_low) {
 369                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
 370                        "information is no longer guaranteed!\n", PCF8563_NAME);
 371         }
 372
 373         return 0;
 374 }
 375
 376 module_init(pcf8563_register);
 377 module_exit(pcf8563_exit);