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