1/*!*************************************************************************** 2*! 3*! FILE NAME : ds1302.c 4*! 5*! DESCRIPTION: Implements an interface for the DS1302 RTC 6*! 7*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status 8*! 9*! --------------------------------------------------------------------------- 10*! 11*! (C) Copyright 1999, 2000, 2001 Axis Communications AB, LUND, SWEDEN 12*! 13*!***************************************************************************/ 14 15 16#include <linux/fs.h> 17#include <linux/init.h> 18#include <linux/mm.h> 19#include <linux/module.h> 20#include <linux/miscdevice.h> 21#include <linux/delay.h> 22#include <linux/bcd.h> 23 24#include <asm/uaccess.h> 25#include <asm/system.h> 26#include <asm/io.h> 27#include <asm/rtc.h> 28#if defined(CONFIG_M32R) 29#include <asm/m32r.h> 30#endif 31 32#define RTC_MAJOR_NR 121 /* local major, change later */ 33 34static const char ds1302_name[] = "ds1302"; 35 36/* Send 8 bits. */ 37static void 38out_byte_rtc(unsigned int reg_addr, unsigned char x) 39{ 40 //RST H 41 outw(0x0001,(unsigned long)PLD_RTCRSTODT); 42 //write data 43 outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA); 44 //WE 45 outw(0x0002,(unsigned long)PLD_RTCCR); 46 //wait 47 while(inw((unsigned long)PLD_RTCCR)); 48 49 //RST L 50 outw(0x0000,(unsigned long)PLD_RTCRSTODT); 51 52} 53 54static unsigned char 55in_byte_rtc(unsigned int reg_addr) 56{ 57 unsigned char retval; 58 59 //RST H 60 outw(0x0001,(unsigned long)PLD_RTCRSTODT); 61 //write data 62 outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA); 63 //RE 64 outw(0x0001,(unsigned long)PLD_RTCCR); 65 //wait 66 while(inw((unsigned long)PLD_RTCCR)); 67 68 //read data 69 retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8; 70 71 //RST L 72 outw(0x0000,(unsigned long)PLD_RTCRSTODT); 73 74 return retval; 75} 76 77/* Enable writing. */ 78 79static void 80ds1302_wenable(void) 81{ 82 out_byte_rtc(0x8e,0x00); 83} 84 85/* Disable writing. */ 86 87static void 88ds1302_wdisable(void) 89{ 90 out_byte_rtc(0x8e,0x80); 91} 92 93 94 95/* Read a byte from the selected register in the DS1302. */ 96 97unsigned char 98ds1302_readreg(int reg) 99{ 100 unsigned char x; 101 102 x=in_byte_rtc((0x81 | (reg << 1))); /* read register */ 103 104 return x; 105} 106 107/* Write a byte to the selected register. */ 108 109void 110ds1302_writereg(int reg, unsigned char val) 111{ 112 ds1302_wenable(); 113 out_byte_rtc((0x80 | (reg << 1)),val); 114 ds1302_wdisable(); 115} 116 117void 118get_rtc_time(struct rtc_time *rtc_tm) 119{ 120 unsigned long flags; 121 122 local_irq_save(flags); 123 124 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS); 125 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES); 126 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS); 127 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH); 128 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH); 129 rtc_tm->tm_year = CMOS_READ(RTC_YEAR); 130 131 local_irq_restore(flags); 132 133 BCD_TO_BIN(rtc_tm->tm_sec); 134 BCD_TO_BIN(rtc_tm->tm_min); 135 BCD_TO_BIN(rtc_tm->tm_hour); 136 BCD_TO_BIN(rtc_tm->tm_mday); 137 BCD_TO_BIN(rtc_tm->tm_mon); 138 BCD_TO_BIN(rtc_tm->tm_year); 139 140 /* 141 * Account for differences between how the RTC uses the values 142 * and how they are defined in a struct rtc_time; 143 */ 144 145 if (rtc_tm->tm_year <= 69) 146 rtc_tm->tm_year += 100; 147 148 rtc_tm->tm_mon--; 149} 150 151static unsigned char days_in_mo[] = 152 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; 153 154/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */ 155 156static int 157rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, 158 unsigned long arg) 159{ 160 unsigned long flags; 161 162 switch(cmd) { 163 case RTC_RD_TIME: /* read the time/date from RTC */ 164 { 165 struct rtc_time rtc_tm; 166 167 memset(&rtc_tm, 0, sizeof (struct rtc_time)); 168 get_rtc_time(&rtc_tm); 169 if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time))) 170 return -EFAULT; 171 return 0; 172 } 173 174 case RTC_SET_TIME: /* set the RTC */ 175 { 176 struct rtc_time rtc_tm; 177 unsigned char mon, day, hrs, min, sec, leap_yr; 178 unsigned int yrs; 179 180 if (!capable(CAP_SYS_TIME)) 181 return -EPERM; 182 183 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time))) 184 return -EFAULT; 185 186 yrs = rtc_tm.tm_year + 1900; 187 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ 188 day = rtc_tm.tm_mday; 189 hrs = rtc_tm.tm_hour; 190 min = rtc_tm.tm_min; 191 sec = rtc_tm.tm_sec; 192 193 194 if ((yrs < 1970) || (yrs > 2069)) 195 return -EINVAL; 196 197 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); 198 199 if ((mon > 12) || (day == 0)) 200 return -EINVAL; 201 202 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) 203 return -EINVAL; 204 205 if ((hrs >= 24) || (min >= 60) || (sec >= 60)) 206 return -EINVAL; 207 208 if (yrs >= 2000) 209 yrs -= 2000; /* RTC (0, 1, ... 69) */ 210 else 211 yrs -= 1900; /* RTC (70, 71, ... 99) */ 212 213 BIN_TO_BCD(sec); 214 BIN_TO_BCD(min); 215 BIN_TO_BCD(hrs); 216 BIN_TO_BCD(day); 217 BIN_TO_BCD(mon); 218 BIN_TO_BCD(yrs); 219 220 local_irq_save(flags); 221 CMOS_WRITE(yrs, RTC_YEAR); 222 CMOS_WRITE(mon, RTC_MONTH); 223 CMOS_WRITE(day, RTC_DAY_OF_MONTH); 224 CMOS_WRITE(hrs, RTC_HOURS); 225 CMOS_WRITE(min, RTC_MINUTES); 226 CMOS_WRITE(sec, RTC_SECONDS); 227 local_irq_restore(flags); 228 229 /* Notice that at this point, the RTC is updated but 230 * the kernel is still running with the old time. 231 * You need to set that separately with settimeofday 232 * or adjtimex. 233 */ 234 return 0; 235 } 236 237 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */ 238 { 239 int tcs_val; 240 241 if (!capable(CAP_SYS_TIME)) 242 return -EPERM; 243 244 if(copy_from_user(&tcs_val, (int*)arg, sizeof(int))) 245 return -EFAULT; 246 247 tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F); 248 ds1302_writereg(RTC_TRICKLECHARGER, tcs_val); 249 return 0; 250 } 251 default: 252 return -EINVAL; 253 } 254} 255 256int 257get_rtc_status(char *buf) 258{ 259 char *p; 260 struct rtc_time tm; 261 262 p = buf; 263 264 get_rtc_time(&tm); 265 266 /* 267 * There is no way to tell if the luser has the RTC set for local 268 * time or for Universal Standard Time (GMT). Probably local though. 269 */ 270 271 p += sprintf(p, 272 "rtc_time\t: %02d:%02d:%02d\n" 273 "rtc_date\t: %04d-%02d-%02d\n", 274 tm.tm_hour, tm.tm_min, tm.tm_sec, 275 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); 276 277 return p - buf; 278} 279 280 281/* The various file operations we support. */ 282 283static const struct file_operations rtc_fops = { 284 .owner = THIS_MODULE, 285 .ioctl = rtc_ioctl, 286}; 287 288/* Probe for the chip by writing something to its RAM and try reading it back. */ 289 290#define MAGIC_PATTERN 0x42 291 292static int __init 293ds1302_probe(void) 294{ 295 int retval, res, baur; 296 297 baur=(boot_cpu_data.bus_clock/(2*1000*1000)); 298 299 printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur); 300 301 outw(0x0000,(unsigned long)PLD_RTCCR); 302 outw(0x0000,(unsigned long)PLD_RTCRSTODT); 303 outw(baur,(unsigned long)PLD_RTCBAUR); 304 305 /* Try to talk to timekeeper. */ 306 307 ds1302_wenable(); 308 /* write RAM byte 0 */ 309 /* write something magic */ 310 out_byte_rtc(0xc0,MAGIC_PATTERN); 311 312 /* read RAM byte 0 */ 313 if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) { 314 char buf[100]; 315 ds1302_wdisable(); 316 printk("%s: RTC found.\n", ds1302_name); 317 get_rtc_status(buf); 318 printk(buf); 319 retval = 1; 320 } else { 321 printk("%s: RTC not found.\n", ds1302_name); 322 retval = 0; 323 } 324 325 return retval; 326} 327 328 329/* Just probe for the RTC and register the device to handle the ioctl needed. */ 330 331int __init 332ds1302_init(void) 333{ 334 if (!ds1302_probe()) { 335 return -1; 336 } 337 return 0; 338} 339 340static int __init ds1302_register(void) 341{ 342 ds1302_init(); 343 if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) { 344 printk(KERN_INFO "%s: unable to get major %d for rtc\n", 345 ds1302_name, RTC_MAJOR_NR); 346 return -1; 347 } 348 return 0; 349} 350 351module_init(ds1302_register); 352