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   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, interupt 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 bute.
  12  *
  13  * Copyright (c) 2002, Axis Communications AB
  14  * All rights reserved.
  15  *
  16  * Author: Tobias Anderberg <tobiasa@axis.com>.
  17  *
  18  * $Id: pcf8563.c,v 1.11 2005/03/07 13:13:07 starvik Exp $
  19  */
  20
  21 #include <linux/config.h>
  22 #include <linux/module.h>
  23 #include <linux/kernel.h>
  24 #include <linux/types.h>
  25 #include <linux/sched.h>
  26 #include <linux/init.h>
  27 #include <linux/fs.h>
  28 #include <linux/ioctl.h>
  29 #include <linux/delay.h>
  30 #include <linux/bcd.h>
  31 #include <linux/capability.h>
  32
  33 #include <asm/uaccess.h>
  34 #include <asm/system.h>
  35 #include <asm/io.h>
  36 #include <asm/arch/svinto.h>
  37 #include <asm/rtc.h>
  38 #include "i2c.h"
  39
  40 #define PCF8563_MAJOR 121               /* Local major number. */
  41 #define DEVICE_NAME "rtc"               /* Name which is registered in /proc/devices. */
  42 #define PCF8563_NAME "PCF8563"
  43 #define DRIVER_VERSION "$Revision: 1.11 $"
  44
  45 /* I2C bus slave registers. */
  46 #define RTC_I2C_READ            0xa3
  47 #define RTC_I2C_WRITE           0xa2
  48
  49 /* Two simple wrapper macros, saves a few keystrokes. */
  50 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
  51 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
  52
  53 static DEFINE_SPINLOCK(rtc_lock); /* Protect state etc */
  54
  55 static const unsigned char days_in_month[] =
  56         { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
  57
  58 int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
  59
  60 static struct file_operations pcf8563_fops = {
  61         .owner = THIS_MODULE,
  62         .ioctl = pcf8563_ioctl,
  63 };
  64
  65 unsigned char
  66 pcf8563_readreg(int reg)
  67 {
  68         unsigned char res = i2c_readreg(RTC_I2C_READ, reg);
  69
  70         /* The PCF8563 does not return 0 for unimplemented bits */
  71         switch(reg)
  72         {
  73                 case RTC_SECONDS:
  74                 case RTC_MINUTES:
  75                      res &= 0x7f;
  76                      break;
  77                 case RTC_HOURS:
  78                 case RTC_DAY_OF_MONTH:
  79                      res &= 0x3f;
  80                      break;
  81                 case RTC_MONTH:
  82                      res = (res & 0x1f) - 1;  /* PCF8563 returns month in range 1-12 */
  83                      break;
  84         }
  85         return res;
  86 }
  87
  88 void
  89 pcf8563_writereg(int reg, unsigned char val)
  90 {
  91 #ifdef CONFIG_ETRAX_RTC_READONLY
  92         if (reg == RTC_CONTROL1 || (reg >= RTC_SECONDS && reg <= RTC_YEAR))
  93                 return;
  94 #endif
  95
  96         rtc_write(reg, val);
  97 }
  98
  99 void
 100 get_rtc_time(struct rtc_time *tm)
 101 {
 102         tm->tm_sec = rtc_read(RTC_SECONDS);
 103         tm->tm_min = rtc_read(RTC_MINUTES);
 104         tm->tm_hour = rtc_read(RTC_HOURS);
 105         tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
 106         tm->tm_mon = rtc_read(RTC_MONTH);
 107         tm->tm_year = rtc_read(RTC_YEAR);
 108
 109         if (tm->tm_sec & 0x80)
 110                 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
 111
 112         tm->tm_year = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
 113         tm->tm_sec &= 0x7f;
 114         tm->tm_min &= 0x7f;
 115         tm->tm_hour &= 0x3f;
 116         tm->tm_mday &= 0x3f;
 117         tm->tm_mon &= 0x1f;
 118
 119         BCD_TO_BIN(tm->tm_sec);
 120         BCD_TO_BIN(tm->tm_min);
 121         BCD_TO_BIN(tm->tm_hour);
 122         BCD_TO_BIN(tm->tm_mday);
 123         BCD_TO_BIN(tm->tm_mon);
 124         tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 125 }
 126
 127 int __init
 128 pcf8563_init(void)
 129 {
 130         int ret;
 131
 132         if ((ret = i2c_init())) {
 133                 printk(KERN_CRIT "pcf8563_init: failed to init i2c\n");
 134                 return ret;
 135         }
 136
 137         /*
 138          * First of all we need to reset the chip. This is done by
 139          * clearing control1, control2 and clk freq, clear the
 140          * Voltage Low bit, and resetting all alarms.
 141          */
 142         if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 143                 goto err;
 144
 145         if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 146                 goto err;
 147
 148         if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 149                 goto err;
 150
 151         /* Clear the VL bit in the seconds register. */
 152         ret = rtc_read(RTC_SECONDS);
 153
 154         if (rtc_write(RTC_SECONDS, (ret & 0x7f)) < 0)
 155                 goto err;
 156
 157         /* Reset the alarms. */
 158         if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
 159                 goto err;
 160
 161         if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
 162                 goto err;
 163
 164         if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
 165                 goto err;
 166
 167         if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 0)
 168                 goto err;
 169
 170         /* Check for low voltage, and warn about it.. */
 171         if (rtc_read(RTC_SECONDS) & 0x80)
 172                 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
 173
 174         return 0;
 175
 176 err:
 177         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 178         return -1;
 179 }
 180
 181 void __exit
 182 pcf8563_exit(void)
 183 {
 184         if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
 185                 printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
 186         }
 187 }
 188
 189 /*
 190  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 191  * POSIX says so!
 192  */
 193 int
 194 pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
 195 {
 196         /* Some sanity checks. */
 197         if (_IOC_TYPE(cmd) != RTC_MAGIC)
 198                 return -ENOTTY;
 199
 200         if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
 201                 return -ENOTTY;
 202
 203         switch (cmd) {
 204                 case RTC_RD_TIME:
 205                         {
 206                                 struct rtc_time tm;
 207
 208                                 spin_lock(&rtc_lock);
 209                                 get_rtc_time(&tm);
 210
 211                                 if (copy_to_user((struct rtc_time *) arg, &tm, sizeof(struct rtc_time))) {
 212                                         spin_unlock(&rtc_lock);
 213                                         return -EFAULT;
 214                                 }
 215
 216                                 spin_unlock(&rtc_lock);
 217                                 return 0;
 218                         }
 219                         break;
 220                 case RTC_SET_TIME:
 221                         {
 222 #ifdef CONFIG_ETRAX_RTC_READONLY
 223                                 return -EPERM;
 224 #else
 225                                 int leap;
 226                                 int century;
 227                                 struct rtc_time tm;
 228
 229                                 memset(&tm, 0, sizeof (struct rtc_time));
 230                                 if (!capable(CAP_SYS_TIME))
 231                                         return -EPERM;
 232
 233                                 if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
 234                                         return -EFAULT;
 235
 236                                 /* Convert from struct tm to struct rtc_time. */
 237                                 tm.tm_year += 1900;
 238                                 tm.tm_mon += 1;
 239
 240                                 leap = ((tm.tm_mon == 2) && ((tm.tm_year % 4) == 0)) ? 1 : 0;
 241
 242                                 /* Perform some sanity checks. */
 243                                 if ((tm.tm_year < 1970) ||
 244                                     (tm.tm_mon > 12) ||
 245                                     (tm.tm_mday == 0) ||
 246                                     (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
 247                                     (tm.tm_hour >= 24) ||
 248                                     (tm.tm_min >= 60) ||
 249                                     (tm.tm_sec >= 60))
 250                                         return -EINVAL;
 251
 252                                 century = (tm.tm_year >= 2000) ? 0x80 : 0;
 253                                 tm.tm_year = tm.tm_year % 100;
 254
 255                                 BIN_TO_BCD(tm.tm_year);
 256                                 BIN_TO_BCD(tm.tm_mday);
 257                                 BIN_TO_BCD(tm.tm_hour);
 258                                 BIN_TO_BCD(tm.tm_min);
 259                                 BIN_TO_BCD(tm.tm_sec);
 260                                 tm.tm_mon |= century;
 261
 262                                 spin_lock(&rtc_lock);
 263
 264                                 rtc_write(RTC_YEAR, tm.tm_year);
 265                                 rtc_write(RTC_MONTH, tm.tm_mon);
 266                                 rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
 267                                 rtc_write(RTC_HOURS, tm.tm_hour);
 268                                 rtc_write(RTC_MINUTES, tm.tm_min);
 269                                 rtc_write(RTC_SECONDS, tm.tm_sec);
 270
 271                                 spin_unlock(&rtc_lock);
 272
 273                                 return 0;
 274 #endif /* !CONFIG_ETRAX_RTC_READONLY */
 275                         }
 276
 277                 case RTC_VLOW_RD:
 278                 {
 279                         int vl_bit = 0;
 280
 281                         if (rtc_read(RTC_SECONDS) & 0x80) {
 282                                 vl_bit = 1;
 283                                 printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
 284                                        "date/time information is no longer guaranteed!\n",
 285                                        PCF8563_NAME);
 286                         }
 287                         if (copy_to_user((int *) arg, &vl_bit, sizeof(int)))
 288                                 return -EFAULT;
 289
 290                         return 0;
 291                 }
 292
 293                 case RTC_VLOW_SET:
 294                 {
 295                         /* Clear the VL bit in the seconds register */
 296                         int ret = rtc_read(RTC_SECONDS);
 297
 298                         rtc_write(RTC_SECONDS, (ret & 0x7F));
 299
 300                         return 0;
 301                 }
 302
 303                 default:
 304                                 return -ENOTTY;
 305         }
 306
 307         return 0;
 308 }
 309
 310 static int __init
 311 pcf8563_register(void)
 312 {
 313         pcf8563_init();
 314         if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 315                 printk(KERN_INFO "%s: Unable to get major numer %d for RTC device.\n",
 316                        PCF8563_NAME, PCF8563_MAJOR);
 317                 return -1;
 318         }
 319
 320         printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 321         return 0;
 322 }
 323
 324 module_init(pcf8563_register);
 325 module_exit(pcf8563_exit);