LXR linux/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
  47static DEFINE_MUTEX(rtc_lock); /* Protect state etc */
  48
  49static const unsigned char days_in_month[] =
  50        { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
  51
  52int 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 */
  57static int voltage_low;
  58
  59static const struct file_operations pcf8563_fops = {
  60        .owner =        THIS_MODULE,
  61        .ioctl =        pcf8563_ioctl
  62};
  63
  64unsigned char
  65pcf8563_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
  99void
 100pcf8563_writereg(int reg, unsigned char val)
 101{
 102        rtc_write(reg, val);
 103}
 104
 105void
 106get_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
 138int __init
 139pcf8563_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
 195err:
 196        printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 197        res = -1;
 198        return res;
 199}
 200
 201void __exit
 202pcf8563_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 */
 211int 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
 338static 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
 364module_init(pcf8563_register);
 365module_exit(pcf8563_exit);
 366