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