release/src-rt-6.x.4708/linux/linux-2.6.36/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/smp_lock.h>
  28 #include <linux/delay.h>
  29 #include <linux/bcd.h>
  30 #include <linux/mutex.h>
  31
  32 #include <asm/uaccess.h>
  33 #include <asm/system.h>
  34 #include <asm/io.h>
  35 #include <asm/rtc.h>
  36
  37 #include "i2c.h"
  38
  39 #define PCF8563_MAJOR   121     /* Local major number. */
  40 #define DEVICE_NAME     "rtc"   /* Name which is registered in /proc/devices. */
  41 #define PCF8563_NAME    "PCF8563"
  42 #define DRIVER_VERSION  "$Revision: 1.17 $"
  43
  44 /* Two simple wrapper macros, saves a few keystrokes. */
  45 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
  46 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
  47
  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 };
  64
  65 unsigned char
  66 pcf8563_readreg(int reg)
  67 {
  68         unsigned char res = rtc_read(reg);
  69
  70         /* The PCF8563 does not return 0 for unimplemented bits. */
  71         switch (reg) {
  72                 case RTC_SECONDS:
  73                 case RTC_MINUTES:
  74                         res &= 0x7F;
  75                         break;
  76                 case RTC_HOURS:
  77                 case RTC_DAY_OF_MONTH:
  78                         res &= 0x3F;
  79                         break;
  80                 case RTC_WEEKDAY:
  81                         res &= 0x07;
  82                         break;
  83                 case RTC_MONTH:
  84                         res &= 0x1F;
  85                         break;
  86                 case RTC_CONTROL1:
  87                         res &= 0xA8;
  88                         break;
  89                 case RTC_CONTROL2:
  90                         res &= 0x1F;
  91                         break;
  92                 case RTC_CLOCKOUT_FREQ:
  93                 case RTC_TIMER_CONTROL:
  94                         res &= 0x83;
  95                         break;
  96         }
  97         return res;
  98 }
  99
 100 void
 101 pcf8563_writereg(int reg, unsigned char val)
 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_ERR "%s: RTC Voltage Low - reliable date/time "
 119                        "information is no longer guaranteed!\n", PCF8563_NAME);
 120         }
 121
 122         tm->tm_year  = bcd2bin(tm->tm_year) +
 123                        ((tm->tm_mon & 0x80) ? 100 : 0);
 124         tm->tm_sec  &= 0x7F;
 125         tm->tm_min  &= 0x7F;
 126         tm->tm_hour &= 0x3F;
 127         tm->tm_mday &= 0x3F;
 128         tm->tm_wday &= 0x07; /* Not coded in BCD. */
 129         tm->tm_mon  &= 0x1F;
 130
 131         tm->tm_sec = bcd2bin(tm->tm_sec);
 132         tm->tm_min = bcd2bin(tm->tm_min);
 133         tm->tm_hour = bcd2bin(tm->tm_hour);
 134         tm->tm_mday = bcd2bin(tm->tm_mday);
 135         tm->tm_mon = bcd2bin(tm->tm_mon);
 136         tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 137 }
 138
 139 int __init
 140 pcf8563_init(void)
 141 {
 142         static int res;
 143         static int first = 1;
 144
 145         if (!first)
 146                 return res;
 147         first = 0;
 148
 149         /* Initiate the i2c protocol. */
 150         res = i2c_init();
 151         if (res < 0) {
 152                 printk(KERN_CRIT "pcf8563_init: Failed to init i2c.\n");
 153                 return res;
 154         }
 155
 156         /*
 157          * First of all we need to reset the chip. This is done by
 158          * clearing control1, control2 and clk freq and resetting
 159          * all alarms.
 160          */
 161         if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 162                 goto err;
 163
 164         if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 165                 goto err;
 166
 167         if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 168                 goto err;
 169
 170         if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
 171                 goto err;
 172
 173         /* Reset the alarms. */
 174         if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
 175                 goto err;
 176
 177         if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
 178                 goto err;
 179
 180         if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
 181                 goto err;
 182
 183         if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
 184                 goto err;
 185
 186         /* Check for low voltage, and warn about it. */
 187         if (rtc_read(RTC_SECONDS) & 0x80) {
 188                 voltage_low = 1;
 189                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
 190                        "date/time information is no longer guaranteed!\n",
 191                        PCF8563_NAME);
 192         }
 193
 194         return res;
 195
 196 err:
 197         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 198         res = -1;
 199         return res;
 200 }
 201
 202 void __exit
 203 pcf8563_exit(void)
 204 {
 205         unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME);
 206 }
 207
 208 /*
 209  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 210  * POSIX says so!
 211  */
 212 static int pcf8563_ioctl(struct file *filp, unsigned int cmd, 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 long pcf8563_unlocked_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 339 {
 340         int ret;
 341
 342         lock_kernel();
 343         return pcf8563_ioctl(filp, cmd, arg);
 344         unlock_kernel();
 345
 346         return ret;
 347 }
 348
 349 static int __init pcf8563_register(void)
 350 {
 351         if (pcf8563_init() < 0) {
 352                 printk(KERN_INFO "%s: Unable to initialize Real-Time Clock "
 353                        "Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 354                 return -1;
 355         }
 356
 357         if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 358                 printk(KERN_INFO "%s: Unable to get major numer %d for RTC "
 359                        "device.\n", PCF8563_NAME, PCF8563_MAJOR);
 360                 return -1;
 361         }
 362
 363         printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME,
 364                DRIVER_VERSION);
 365
 366         /* Check for low voltage, and warn about it. */
 367         if (voltage_low) {
 368                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
 369                        "information is no longer guaranteed!\n", PCF8563_NAME);
 370         }
 371
 372         return 0;
 373 }
 374
 375 module_init(pcf8563_register);
 376 module_exit(pcf8563_exit);