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