arch/cris/arch-v10/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, 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 1.1 2002/12/12 08:27:26 starvik Exp $
  19  */
  20
  21 #include <linux/config.h>
  22 #include <linux/version.h>
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/types.h>
  26 #include <linux/sched.h>
  27 #include <linux/init.h>
  28 #include <linux/fs.h>
  29 #include <linux/ioctl.h>
  30 #include <linux/delay.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: 1.1 $"
  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 const unsigned char days_in_month[] =
  53         { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
  54
  55 int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
  56 int pcf8563_open(struct inode *, struct file *);
  57 int pcf8563_release(struct inode *, struct file *);
  58
  59 static struct file_operations pcf8563_fops = {
  60         .owner = THIS_MODULE,
  61         .ioctl = pcf8563_ioctl,
  62         .open = pcf8563_open,
  63         .release = pcf8563_release,
  64 };
  65
  66 unsigned char
  67 pcf8563_readreg(int reg)
  68 {
  69         unsigned char res = i2c_readreg(RTC_I2C_READ, reg);
  70
  71         /* The PCF8563 does not return 0 for unimplemented bits */
  72         switch(reg)
  73         {
  74                 case RTC_SECONDS:
  75                 case RTC_MINUTES:
  76                      res &= 0x7f;
  77                      break;
  78                 case RTC_HOURS:
  79                 case RTC_DAY_OF_MONTH:
  80                      res &= 0x3f;
  81                      break;
  82                 case RTC_MONTH:
  83                      res = (res & 0x1f) - 1;  /* PCF8563 returns month in range 1-12 */
  84                      break;
  85         }
  86         return res;
  87 }
  88
  89 void
  90 pcf8563_writereg(int reg, unsigned char val)
  91 {
  92         i2c_writereg(RTC_I2C_WRITE,reg,val);
  93 }
  94
  95 void
  96 get_rtc_time(struct rtc_time *tm)
  97 {
  98         tm->tm_sec = rtc_read(RTC_SECONDS);
  99         tm->tm_min = rtc_read(RTC_MINUTES);
 100         tm->tm_hour = rtc_read(RTC_HOURS);
 101         tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
 102         tm->tm_mon = rtc_read(RTC_MONTH);
 103         tm->tm_year = rtc_read(RTC_YEAR);
 104
 105         if (tm->tm_sec & 0x80)
 106                 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
 107
 108         tm->tm_year = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
 109         tm->tm_sec &= 0x7f;
 110         tm->tm_min &= 0x7f;
 111         tm->tm_hour &= 0x3f;
 112         tm->tm_mday &= 0x3f;
 113         tm->tm_mon &= 0x1f;
 114
 115         BCD_TO_BIN(tm->tm_sec);
 116         BCD_TO_BIN(tm->tm_min);
 117         BCD_TO_BIN(tm->tm_hour);
 118         BCD_TO_BIN(tm->tm_mday);
 119         BCD_TO_BIN(tm->tm_mon);
 120         tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
 121 }
 122
 123 int __init
 124 pcf8563_init(void)
 125 {
 126         unsigned char ret;
 127         /*
 128          * First of all we need to reset the chip. This is done by
 129          * clearing control1, control2 and clk freq, clear the
 130          * Voltage Low bit, and resetting all alarms.
 131          */
 132         if (rtc_write(RTC_CONTROL1, 0x00) < 0)
 133                 goto err;
 134
 135         if (rtc_write(RTC_CONTROL2, 0x00) < 0)
 136                 goto err;
 137
 138         if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
 139                 goto err;
 140
 141         /* Clear the VL bit in the seconds register. */
 142         ret = rtc_read(RTC_SECONDS);
 143
 144         if (rtc_write(RTC_SECONDS, (ret & 0x7f)) < 0)
 145                 goto err;
 146
 147         /* Reset the alarms. */
 148         if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
 149                 goto err;
 150
 151         if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
 152                 goto err;
 153
 154         if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
 155                 goto err;
 156
 157         if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 0)
 158                 goto err;
 159
 160         if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
 161                 printk(KERN_INFO "%s: Unable to get major numer %d for RTC device.\n",
 162                        PCF8563_NAME, PCF8563_MAJOR);
 163                 return -1;
 164         }
 165
 166         printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
 167
 168         /* Check for low voltage, and warn about it.. */
 169         if (rtc_read(RTC_SECONDS) & 0x80)
 170                 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
 171
 172         return 0;
 173
 174 err:
 175         printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
 176         return -1;
 177 }
 178
 179 void __exit
 180 pcf8563_exit(void)
 181 {
 182         if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
 183                 printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
 184         }
 185 }
 186
 187 /*
 188  * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 189  * POSIX says so!
 190  */
 191 int
 192 pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
 193 {
 194         /* Some sanity checks. */
 195         if (_IOC_TYPE(cmd) != RTC_MAGIC)
 196                 return -ENOTTY;
 197
 198         if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
 199                 return -ENOTTY;
 200
 201         switch (cmd) {
 202                 case RTC_RD_TIME:
 203                         {
 204                                 struct rtc_time tm;
 205
 206                                 get_rtc_time(&tm);
 207
 208                                 if (copy_to_user((struct rtc_time *) arg, &tm, sizeof(struct rtc_time))) {
 209                                         return -EFAULT;
 210                                 }
 211
 212                                 return 0;
 213                         }
 214                         break;
 215                 case RTC_SET_TIME:
 216                         {
 217                                 int leap;
 218                                 int century;
 219                                 unsigned long flags;
 220                                 struct rtc_time tm;
 221
 222                                 memset(&tm, 0, sizeof (struct rtc_time));
 223                                 if (!capable(CAP_SYS_TIME))
 224                                         return -EPERM;
 225
 226                                 if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
 227                                         return -EFAULT;
 228
 229                                 /* Convert from struct tm to struct rtc_time. */
 230                                 tm.tm_year += 1900;
 231                                 tm.tm_mon += 1;
 232
 233                                 leap = ((tm.tm_mon == 2) && ((tm.tm_year % 4) == 0)) ? 1 : 0;
 234
 235                                 /* Perform some sanity checks. */
 236                                 if ((tm.tm_year < 1970) ||
 237                                     (tm.tm_mon > 12) ||
 238                                     (tm.tm_mday == 0) ||
 239                                     (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
 240                                     (tm.tm_hour >= 24) ||
 241                                     (tm.tm_min >= 60) ||
 242                                     (tm.tm_sec >= 60))
 243                                         return -EINVAL;
 244
 245                                 century = (tm.tm_year >= 2000) ? 0x80 : 0;
 246                                 tm.tm_year = tm.tm_year % 100;
 247
 248                                 BIN_TO_BCD(tm.tm_year);
 249                                 BIN_TO_BCD(tm.tm_mday);
 250                                 BIN_TO_BCD(tm.tm_hour);
 251                                 BIN_TO_BCD(tm.tm_min);
 252                                 BIN_TO_BCD(tm.tm_sec);
 253                                 tm.tm_mon |= century;
 254
 255                                 rtc_write(RTC_YEAR, tm.tm_year);
 256                                 rtc_write(RTC_MONTH, tm.tm_mon);
 257                                 rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
 258                                 rtc_write(RTC_HOURS, tm.tm_hour);
 259                                 rtc_write(RTC_MINUTES, tm.tm_min);
 260                                 rtc_write(RTC_SECONDS, tm.tm_sec);
 261
 262                                 return 0;
 263                         }
 264                         break;
 265                 default:
 266                                 return -ENOTTY;
 267         }
 268
 269         return 0;
 270 }
 271
 272 int
 273 pcf8563_open(struct inode *inode, struct file *filp)
 274 {
 275         MOD_INC_USE_COUNT;
 276         return 0;
 277 }
 278
 279 int
 280 pcf8563_release(struct inode *inode, struct file *filp)
 281 {
 282         MOD_DEC_USE_COUNT;
 283         return 0;
 284 }
 285
 286 module_init(pcf8563_init);
 287 module_exit(pcf8563_exit);