arch/cris/arch-v10/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: 1.24 $"
  42
  43 /* I2C bus slave registers. */
  44 #define RTC_I2C_READ            0xa3
  45 #define RTC_I2C_WRITE           0xa2
  46
  47 /* Two simple wrapper macros, saves a few keystrokes. */
  48 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
  49 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
  50
  51 static DEFINE_MUTEX(pcf8563_mutex);
  52 static DEFINE_MUTEX(rtc_lock); /* Protect state etc */
  53
  54 static const unsigned char days_in_month[] =
  55         { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
  56
  57 static long pcf8563_unlocked_ioctl(struct file *, unsigned int, unsigned long);
  58
  59 /* Cache VL bit value read at driver init since writing the RTC_SECOND
  60  * register clears the VL status.
  61  */
  62 static int voltage_low;
  63
  64 static const struct file_operations pcf8563_fops = {
  65         .owner = THIS_MODULE,
  66         .unlocked_ioctl = pcf8563_unlocked_ioctl,
  67         .llseek         = noop_llseek,
  68 };
  69
  70 unsigned char
  71 pcf8563_readreg(int reg)
  72 {
  73         unsigned char res = rtc_read(reg);
  74
  75         /* The PCF8563 does not return 0 for unimplemented bits. */
  76         switch (reg) {
  77         case RTC_SECONDS:
  78         case RTC_MINUTES:
  79                 res &= 0x7F;
  80                 break;
  81         case RTC_HOURS:
  82         case RTC_DAY_OF_MONTH:
  83                 res &= 0x3F;
  84                 break;
  85         case RTC_WEEKDAY:
  86                 res &= 0x07;
  87                 break;
  88         case RTC_MONTH:
  89                 res &= 0x1F;
  90                 break;
  91         case RTC_CONTROL1:
  92                 res &= 0xA8;
  93                 break;
  94         case RTC_CONTROL2:
  95                 res &= 0x1F;
  96                 break;
  97         case RTC_CLOCKOUT_FREQ:
  98         case RTC_TIMER_CONTROL:
  99                 res &= 0x83;
 100                 break;
 101         }
 102         return res;
 103 }
 104
 105 void
 106 pcf8563_writereg(int reg, unsigned char val)
 107 {
 108         rtc_write(reg, val);
 109 }
 110
 111 void
 112 get_rtc_time(struct rtc_time *tm)
 113 {
 114         tm->tm_sec  = rtc_read(RTC_SECONDS);
 115         tm->tm_min  = rtc_read(RTC_MINUTES);
 116         tm->tm_hour = rtc_read(RTC_HOURS);
 117         tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
 118         tm->tm_wday = rtc_read(RTC_WEEKDAY);
 119         tm->tm_mon  = rtc_read(RTC_MONTH);
 120         tm->tm_year = rtc_read(RTC_YEAR);
 121
 122         if (tm->tm_sec & 0x80) {
 123                 printk(KERN_ERR "%s: RTC Voltage Low - reliable date/time "
 124                        "information is no longer guaranteed!\n", PCF8563_NAME);
 125         }
 126
 127         tm->tm_year  = bcd2bin(tm->tm_year) +
 128                        ((tm->tm_mon & 0x80) ? 100 : 0);
 129         tm->tm_sec  &= 0x7F;
 130         tm->tm_min  &= 0x7F;
 131         tm->tm_hour &= 0x3F;
 132         tm->tm_mday &= 0x3F;
 133         tm->tm_wday &= 0x07; /* Not coded in BCD. */
 134         tm->tm_mon  &= 0x1F;
 135
 136         tm->tm_sec = bcd2bin(tm->tm_sec);
 137         tm->tm_min = bcd2bin(tm->tm_min);
 138         tm->tm_hour = bcd2bin(tm->tm_hour);
 139         tm->tm_mday = bcd2bin(tm->tm_mday);
 140         tm->tm_mon = bcd2bin(tm->tm_mon);
 141         tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 142 }
 143
 144 int __init
 145 pcf8563_init(void)
 146 {
 147         static int res;
 148         static int first = 1;
 149
 150         if (!first)
 151                 return res;
 152         first = 0;
 153
 154         /* Initiate the i2c protocol. */
 155         res = i2c_init();
 156         if (res < 0) {
 157                 printk(KERN_CRIT "pcf8563_init: Failed to init i2c.\n");
 158                 return res;
 159         }
 160
 161         /*
 162          * First of all we need to reset the chip. This is done by
 163          * clearing control1, control2 and clk freq and resetting
 164          * all alarms.
 165          */
 166         if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 167                 goto err;
 168
 169         if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 170                 goto err;
 171
 172         if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 173                 goto err;
 174
 175         if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
 176                 goto err;
 177
 178         /* Reset the alarms. */
 179         if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
 180                 goto err;
 181
 182         if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
 183                 goto err;
 184
 185         if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
 186                 goto err;
 187
 188         if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
 189                 goto err;
 190
 191         /* Check for low voltage, and warn about it. */
 192         if (rtc_read(RTC_SECONDS) & 0x80) {
 193                 voltage_low = 1;
 194                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
 195                        "date/time information is no longer guaranteed!\n",
 196                        PCF8563_NAME);
 197         }
 198
 199         return res;
 200
 201 err:
 202         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 203         res = -1;
 204         return res;
 205 }
 206
 207 void __exit
 208 pcf8563_exit(void)
 209 {
 210         unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME);
 211 }
 212
 213 /*
 214  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 215  * POSIX says so!
 216  */
 217 static int pcf8563_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 218 {
 219         /* Some sanity checks. */
 220         if (_IOC_TYPE(cmd) != RTC_MAGIC)
 221                 return -ENOTTY;
 222
 223         if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
 224                 return -ENOTTY;
 225
 226         switch (cmd) {
 227         case RTC_RD_TIME:
 228         {
 229                 struct rtc_time tm;
 230
 231                 mutex_lock(&rtc_lock);
 232                 memset(&tm, 0, sizeof tm);
 233                 get_rtc_time(&tm);
 234
 235                 if (copy_to_user((struct rtc_time *) arg, &tm,
 236                                  sizeof tm)) {
 237                         mutex_unlock(&rtc_lock);
 238                         return -EFAULT;
 239                 }
 240
 241                 mutex_unlock(&rtc_lock);
 242
 243                 return 0;
 244         }
 245         case RTC_SET_TIME:
 246         {
 247                 int leap;
 248                 int year;
 249                 int century;
 250                 struct rtc_time tm;
 251
 252                 memset(&tm, 0, sizeof tm);
 253                 if (!capable(CAP_SYS_TIME))
 254                         return -EPERM;
 255
 256                 if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof tm))
 257                         return -EFAULT;
 258
 259                 /* Convert from struct tm to struct rtc_time. */
 260                 tm.tm_year += 1900;
 261                 tm.tm_mon += 1;
 262
 263                 /*
 264                  * Check if tm.tm_year is a leap year. A year is a leap
 265                  * year if it is divisible by 4 but not 100, except
 266                  * that years divisible by 400 _are_ leap years.
 267                  */
 268                 year = tm.tm_year;
 269                 leap = (tm.tm_mon == 2) &&
 270                         ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
 271
 272                 /* Perform some sanity checks. */
 273                 if ((tm.tm_year < 1970) ||
 274                     (tm.tm_mon > 12) ||
 275                     (tm.tm_mday == 0) ||
 276                     (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
 277                     (tm.tm_wday >= 7) ||
 278                     (tm.tm_hour >= 24) ||
 279                     (tm.tm_min >= 60) ||
 280                     (tm.tm_sec >= 60))
 281                         return -EINVAL;
 282
 283                 century = (tm.tm_year >= 2000) ? 0x80 : 0;
 284                 tm.tm_year = tm.tm_year % 100;
 285
 286                 tm.tm_year = bin2bcd(tm.tm_year);
 287                 tm.tm_mon = bin2bcd(tm.tm_mon);
 288                 tm.tm_mday = bin2bcd(tm.tm_mday);
 289                 tm.tm_hour = bin2bcd(tm.tm_hour);
 290                 tm.tm_min = bin2bcd(tm.tm_min);
 291                 tm.tm_sec = bin2bcd(tm.tm_sec);
 292                 tm.tm_mon |= century;
 293
 294                 mutex_lock(&rtc_lock);
 295
 296                 rtc_write(RTC_YEAR, tm.tm_year);
 297                 rtc_write(RTC_MONTH, tm.tm_mon);
 298                 rtc_write(RTC_WEEKDAY, tm.tm_wday); /* Not coded in BCD. */
 299                 rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
 300                 rtc_write(RTC_HOURS, tm.tm_hour);
 301                 rtc_write(RTC_MINUTES, tm.tm_min);
 302                 rtc_write(RTC_SECONDS, tm.tm_sec);
 303
 304                 mutex_unlock(&rtc_lock);
 305
 306                 return 0;
 307         }
 308         case RTC_VL_READ:
 309                 if (voltage_low) {
 310                         printk(KERN_ERR "%s: RTC Voltage Low - "
 311                                "reliable date/time information is no "
 312                                "longer guaranteed!\n", PCF8563_NAME);
 313                 }
 314
 315                 if (copy_to_user((int *) arg, &voltage_low, sizeof(int)))
 316                         return -EFAULT;
 317                 return 0;
 318
 319         case RTC_VL_CLR:
 320         {
 321                 /* Clear the VL bit in the seconds register in case
 322                  * the time has not been set already (which would
 323                  * have cleared it). This does not really matter
 324                  * because of the cached voltage_low value but do it
 325                  * anyway for consistency. */
 326
 327                 int ret = rtc_read(RTC_SECONDS);
 328
 329                 rtc_write(RTC_SECONDS, (ret & 0x7F));
 330
 331                 /* Clear the cached value. */
 332                 voltage_low = 0;
 333
 334                 return 0;
 335         }
 336         default:
 337                 return -ENOTTY;
 338         }
 339
 340         return 0;
 341 }
 342
 343 static long pcf8563_unlocked_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 344 {
 345         int ret;
 346
 347         mutex_lock(&pcf8563_mutex);
 348         ret = pcf8563_ioctl(filp, cmd, arg);
 349         mutex_unlock(&pcf8563_mutex);
 350
 351         return ret;
 352 }
 353
 354 static int __init pcf8563_register(void)
 355 {
 356         if (pcf8563_init() < 0) {
 357                 printk(KERN_INFO "%s: Unable to initialize Real-Time Clock "
 358                        "Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 359                 return -1;
 360         }
 361
 362         if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 363                 printk(KERN_INFO "%s: Unable to get major number %d for RTC device.\n",
 364                        PCF8563_NAME, PCF8563_MAJOR);
 365                 return -1;
 366         }
 367
 368         printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME,
 369                DRIVER_VERSION);
 370
 371         /* Check for low voltage, and warn about it. */
 372         if (voltage_low) {
 373                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
 374                        "information is no longer guaranteed!\n", PCF8563_NAME);
 375         }
 376
 377         return 0;
 378 }
 379
 380 module_init(pcf8563_register);
 381 module_exit(pcf8563_exit);