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#include <linux/smp_lock.h> 24#include <linux/uaccess.h> 25#include <linux/io.h> 26 27#include <asm/system.h> 28#include <asm/rtc.h> 29#if defined(CONFIG_M32R) 30#include <asm/m32r.h> 31#endif 32 33#define RTC_MAJOR_NR 121 /* local major, change later */ 34 35static const char ds1302_name[] = "ds1302"; 36 37/* Send 8 bits. */ 38static void 39out_byte_rtc(unsigned int reg_addr, unsigned char x) 40{ 41 //RST H 42 outw(0x0001,(unsigned long)PLD_RTCRSTODT); 43 //write data 44 outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA); 45 //WE 46 outw(0x0002,(unsigned long)PLD_RTCCR); 47 //wait 48 while(inw((unsigned long)PLD_RTCCR)); 49 50 //RST L 51 outw(0x0000,(unsigned long)PLD_RTCRSTODT); 52 53} 54 55static unsigned char 56in_byte_rtc(unsigned int reg_addr) 57{ 58 unsigned char retval; 59 60 //RST H 61 outw(0x0001,(unsigned long)PLD_RTCRSTODT); 62 //write data 63 outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA); 64 //RE 65 outw(0x0001,(unsigned long)PLD_RTCCR); 66 //wait 67 while(inw((unsigned long)PLD_RTCCR)); 68 69 //read data 70 retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8; 71 72 //RST L 73 outw(0x0000,(unsigned long)PLD_RTCRSTODT); 74 75 return retval; 76} 77 78/* Enable writing. */ 79 80static void 81ds1302_wenable(void) 82{ 83 out_byte_rtc(0x8e,0x00); 84} 85 86/* Disable writing. */ 87 88static void 89ds1302_wdisable(void) 90{ 91 out_byte_rtc(0x8e,0x80); 92} 93 94 95 96/* Read a byte from the selected register in the DS1302. */ 97 98unsigned char 99ds1302_readreg(int reg) 100{ 101 unsigned char x; 102 103 x=in_byte_rtc((0x81 | (reg << 1))); /* read register */ 104 105 return x; 106} 107 108/* Write a byte to the selected register. */ 109 110void 111ds1302_writereg(int reg, unsigned char val) 112{ 113 ds1302_wenable(); 114 out_byte_rtc((0x80 | (reg << 1)),val); 115 ds1302_wdisable(); 116} 117 118void 119get_rtc_time(struct rtc_time *rtc_tm) 120{ 121 unsigned long flags; 122 123 local_irq_save(flags); 124 125 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS); 126 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES); 127 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS); 128 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH); 129 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH); 130 rtc_tm->tm_year = CMOS_READ(RTC_YEAR); 131 132 local_irq_restore(flags); 133 134 rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec); 135 rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min); 136 rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour); 137 rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday); 138 rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon); 139 rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year); 140 141 /* 142 * Account for differences between how the RTC uses the values 143 * and how they are defined in a struct rtc_time; 144 */ 145 146 if (rtc_tm->tm_year <= 69) 147 rtc_tm->tm_year += 100; 148 149 rtc_tm->tm_mon--; 150} 151 152static unsigned char days_in_mo[] = 153 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; 154 155/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */ 156 157static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 158{ 159 unsigned long flags; 160 161 switch(cmd) { 162 case RTC_RD_TIME: /* read the time/date from RTC */ 163 { 164 struct rtc_time rtc_tm; 165 166 memset(&rtc_tm, 0, sizeof (struct rtc_time)); 167 lock_kernel(); 168 get_rtc_time(&rtc_tm); 169 unlock_kernel(); 170 if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time))) 171 return -EFAULT; 172 return 0; 173 } 174 175 case RTC_SET_TIME: /* set the RTC */ 176 { 177 struct rtc_time rtc_tm; 178 unsigned char mon, day, hrs, min, sec, leap_yr; 179 unsigned int yrs; 180 181 if (!capable(CAP_SYS_TIME)) 182 return -EPERM; 183 184 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time))) 185 return -EFAULT; 186 187 yrs = rtc_tm.tm_year + 1900; 188 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ 189 day = rtc_tm.tm_mday; 190 hrs = rtc_tm.tm_hour; 191 min = rtc_tm.tm_min; 192 sec = rtc_tm.tm_sec; 193 194 195 if ((yrs < 1970) || (yrs > 2069)) 196 return -EINVAL; 197 198 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); 199 200 if ((mon > 12) || (day == 0)) 201 return -EINVAL; 202 203 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) 204 return -EINVAL; 205 206 if ((hrs >= 24) || (min >= 60) || (sec >= 60)) 207 return -EINVAL; 208 209 if (yrs >= 2000) 210 yrs -= 2000; /* RTC (0, 1, ... 69) */ 211 else 212 yrs -= 1900; /* RTC (70, 71, ... 99) */ 213 214 sec = bin2bcd(sec); 215 min = bin2bcd(min); 216 hrs = bin2bcd(hrs); 217 day = bin2bcd(day); 218 mon = bin2bcd(mon); 219 yrs = bin2bcd(yrs); 220 221 lock_kernel(); 222 local_irq_save(flags); 223 CMOS_WRITE(yrs, RTC_YEAR); 224 CMOS_WRITE(mon, RTC_MONTH); 225 CMOS_WRITE(day, RTC_DAY_OF_MONTH); 226 CMOS_WRITE(hrs, RTC_HOURS); 227 CMOS_WRITE(min, RTC_MINUTES); 228 CMOS_WRITE(sec, RTC_SECONDS); 229 local_irq_restore(flags); 230 unlock_kernel(); 231 232 /* Notice that at this point, the RTC is updated but 233 * the kernel is still running with the old time. 234 * You need to set that separately with settimeofday 235 * or adjtimex. 236 */ 237 return 0; 238 } 239 240 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */ 241 { 242 int tcs_val; 243 244 if (!capable(CAP_SYS_TIME)) 245 return -EPERM; 246 247 if(copy_from_user(&tcs_val, (int*)arg, sizeof(int))) 248 return -EFAULT; 249 250 lock_kernel(); 251 tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F); 252 ds1302_writereg(RTC_TRICKLECHARGER, tcs_val); 253 unlock_kernel(); 254 return 0; 255 } 256 default: 257 return -EINVAL; 258 } 259} 260 261int 262get_rtc_status(char *buf) 263{ 264 char *p; 265 struct rtc_time tm; 266 267 p = buf; 268 269 get_rtc_time(&tm); 270 271 /* 272 * There is no way to tell if the luser has the RTC set for local 273 * time or for Universal Standard Time (GMT). Probably local though. 274 */ 275 276 p += sprintf(p, 277 "rtc_time\t: %02d:%02d:%02d\n" 278 "rtc_date\t: %04d-%02d-%02d\n", 279 tm.tm_hour, tm.tm_min, tm.tm_sec, 280 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); 281 282 return p - buf; 283} 284 285 286/* The various file operations we support. */ 287 288static const struct file_operations rtc_fops = { 289 .owner = THIS_MODULE, 290 .unlocked_ioctl = rtc_ioctl, 291}; 292 293/* Probe for the chip by writing something to its RAM and try reading it back. */ 294 295#define MAGIC_PATTERN 0x42 296 297static int __init 298ds1302_probe(void) 299{ 300 int retval, res, baur; 301 302 baur=(boot_cpu_data.bus_clock/(2*1000*1000)); 303 304 printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur); 305 306 outw(0x0000,(unsigned long)PLD_RTCCR); 307 outw(0x0000,(unsigned long)PLD_RTCRSTODT); 308 outw(baur,(unsigned long)PLD_RTCBAUR); 309 310 /* Try to talk to timekeeper. */ 311 312 ds1302_wenable(); 313 /* write RAM byte 0 */ 314 /* write something magic */ 315 out_byte_rtc(0xc0,MAGIC_PATTERN); 316 317 /* read RAM byte 0 */ 318 if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) { 319 char buf[100]; 320 ds1302_wdisable(); 321 printk("%s: RTC found.\n", ds1302_name); 322 get_rtc_status(buf); 323 printk(buf); 324 retval = 1; 325 } else { 326 printk("%s: RTC not found.\n", ds1302_name); 327 retval = 0; 328 } 329 330 return retval; 331} 332 333 334/* Just probe for the RTC and register the device to handle the ioctl needed. */ 335 336int __init 337ds1302_init(void) 338{ 339 if (!ds1302_probe()) { 340 return -1; 341 } 342 return 0; 343} 344 345static int __init ds1302_register(void) 346{ 347 ds1302_init(); 348 if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) { 349 printk(KERN_INFO "%s: unable to get major %d for rtc\n", 350 ds1302_name, RTC_MAJOR_NR); 351 return -1; 352 } 353 return 0; 354} 355 356module_init(ds1302_register); 357