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