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 1.1.1.1 2007/08/03 18:51:41 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: 1.1.1.1 $" 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 52static DEFINE_SPINLOCK(rtc_lock); /* Protect state etc */ 53 54static const unsigned char days_in_month[] = 55 { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; 56 57int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long); 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 = 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 87void 88pcf8563_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 98void 99get_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 126int __init 127pcf8563_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 175err: 176 printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME); 177 return -1; 178} 179 180void __exit 181pcf8563_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 */ 192int 193pcf8563_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 309static int __init 310pcf8563_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 number %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 323module_init(pcf8563_register); 324module_exit(pcf8563_exit); 325