ds1302ppc.c

linux下ppc对DS1302操作的驱动！对于时序很有帮助！

253                         get_rtc_time(&rtc_tm);                                          
254                         if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
255                                 return -EFAULT; 
256                         return 0;
257                 }
258 
259                 case RTC_SET_TIME:      /* set the RTC */
260                 {
261                         struct rtc_time rtc_tm;
262                         unsigned char mon, day, hrs, min, sec, leap_yr;
263                         unsigned int yrs;
264 
265                         if (!capable(CAP_SYS_TIME))
266                                 return -EPERM;
267 
268                         if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
269                                 return -EFAULT;
270 
271                         yrs = rtc_tm.tm_year + 1900;
272                         mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
273                         day = rtc_tm.tm_mday;
274                         hrs = rtc_tm.tm_hour;
275                         min = rtc_tm.tm_min;
276                         sec = rtc_tm.tm_sec;
277                         
278                         
279                         if ((yrs < 1970) || (yrs > 2069))
280                                 return -EINVAL;
281 
282                         leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
283 
284                         if ((mon > 12) || (day == 0))
285                                 return -EINVAL;
286 
287                         if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
288                                 return -EINVAL;
289                         
290                         if ((hrs >= 24) || (min >= 60) || (sec >= 60))
291                                 return -EINVAL;
292 
293                         if (yrs >= 2000)
294                                 yrs -= 2000;    /* RTC (0, 1, ... 69) */
295                         else
296                                 yrs -= 1900;    /* RTC (70, 71, ... 99) */
297 
298                         BIN_TO_BCD(sec);
299                         BIN_TO_BCD(min);
300                         BIN_TO_BCD(hrs);
301                         BIN_TO_BCD(day);
302                         BIN_TO_BCD(mon);
303                         BIN_TO_BCD(yrs);
304 
305                         local_irq_save(flags);
306                         CMOS_WRITE(yrs, RTC_YEAR);
307                         CMOS_WRITE(mon, RTC_MONTH);
308                         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
309                         CMOS_WRITE(hrs, RTC_HOURS);
310                         CMOS_WRITE(min, RTC_MINUTES);
311                         CMOS_WRITE(sec, RTC_SECONDS);
312                         local_irq_restore(flags);
313 
314                         /* Notice that at this point, the RTC is updated but
315                          * the kernel is still running with the old time.
316                          * You need to set that separately with settimeofday
317                          * or adjtimex.
318                          */
319                         return 0;
320                 }
321 
322                 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
323                 {
324                         int tcs_val;
325 
326                         if (!capable(CAP_SYS_TIME))
327                                 return -EPERM;
328                         
329                         if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
330                                 return -EFAULT;
331 
332                         tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
333                         ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
334                         return 0;
335                 }
336                 case RTC_VL_READ:
337                 {
338                         /* TODO:
339                          * Implement voltage low detection support
340                          */
341                         printk(KERN_WARNING "DS1302: RTC Voltage Low detection"
342                                " is not supported\n");
343                         return 0;
344                 }
345                 case RTC_VL_CLR:
346                 {
347                         /* TODO:
348                          * Nothing to do since Voltage Low detection is not supported
349                          */
350                         return 0;
351                 }
352                 default:
353                         return -ENOIOCTLCMD;
354         }
355 }
356 
357 static void
358 print_rtc_status(void)
359 {
360         struct rtc_time tm;
361 
362         get_rtc_time(&tm);
363 
364         /*
365          * There is no way to tell if the luser has the RTC set for local
366          * time or for Universal Standard Time (GMT). Probably local though.
367          */
368 
369         printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
370                tm.tm_hour, tm.tm_min, tm.tm_sec);
371         printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
372                tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
373 }
374 
375 /* The various file operations we support. */
376 
377 static const struct file_operations rtc_fops = {
378         .owner =        THIS_MODULE,
379         .ioctl =        rtc_ioctl,
380 }; 
381 
382 /* Probe for the chip by writing something to its RAM and try reading it back. */
383 
384 #define MAGIC_PATTERN 0x42
385 
386 static int __init
387 ds1302_probe(void) 
388 {
389         int retval, res; 
390 
391         TK_RST_DIR(1);
392         TK_SCL_DIR(1);
393         TK_SDA_DIR(0);
394         
395         /* Try to talk to timekeeper. */
396 
397         ds1302_wenable();  
398         start();
399         out_byte(0xc0); /* write RAM byte 0 */  
400         out_byte(MAGIC_PATTERN); /* write something magic */
401         start();
402         out_byte(0xc1); /* read RAM byte 0 */
403 
404         if((res = in_byte()) == MAGIC_PATTERN) {
405                 stop();
406                 ds1302_wdisable();
407                 printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
408                 printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
409                        ds1302_name,
410                        CONFIG_ETRAX_DS1302_SDABIT,
411                        CONFIG_ETRAX_DS1302_SCLBIT,
412 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
413                        "GENIO",
414 #else
415                        "PB",
416 #endif
417                        CONFIG_ETRAX_DS1302_RSTBIT);
418                        print_rtc_status();
419                 retval = 1;
420         } else {
421                 stop();
422                 retval = 0;
423         }
424 
425         return retval;
426 }
427 
428 
429 /* Just probe for the RTC and register the device to handle the ioctl needed. */
430 
431 int __init
432 ds1302_init(void) 
433 {
434 #ifdef CONFIG_ETRAX_I2C
435         i2c_init();
436 #endif
437 
438         if (!ds1302_probe()) {
439 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
440 #if CONFIG_ETRAX_DS1302_RSTBIT == 27
441                 /*
442                  * The only way to set g27 to output is to enable ATA.
443                  *
444                  * Make sure that R_GEN_CONFIG is setup correct.
445                  */
446                 /* Allocating the ATA interface will grab almost all
447                  * pins in I/O groups a, b, c and d.  A consequence of
448                  * allocating the ATA interface is that the fixed
449                  * interfaces shared RAM, parallel port 0, parallel
450                  * port 1, parallel port W, SCSI-8 port 0, SCSI-8 port
451                  * 1, SCSI-W, serial port 2, serial port 3,
452                  * synchronous serial port 3 and USB port 2 and almost
453                  * all GPIO pins on port g cannot be used.
454                  */
455                 if (cris_request_io_interface(if_ata, "ds1302/ATA")) {
456                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
457                         return -1;
458                 }
459 
460 #elif CONFIG_ETRAX_DS1302_RSTBIT == 0
461                 if (cris_io_interface_allocate_pins(if_gpio_grp_a,
462                                                     'g',
463                                                     CONFIG_ETRAX_DS1302_RSTBIT,
464                                                     CONFIG_ETRAX_DS1302_RSTBIT)) {
465                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
466                         return -1;
467                 }
468 
469                 /* Set the direction of this bit to out. */
470                 genconfig_shadow = ((genconfig_shadow &
471                                      ~IO_MASK(R_GEN_CONFIG, g0dir)) |
472                                    (IO_STATE(R_GEN_CONFIG, g0dir, out)));
473                 *R_GEN_CONFIG = genconfig_shadow;
474 #endif
475                 if (!ds1302_probe()) {
476                         printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
477                         return -1;
478                 }
479 #else
480                 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
481                 return -1;
482 #endif
483         }
484         /* Initialise trickle charger */
485         ds1302_writereg(RTC_TRICKLECHARGER,
486                         RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
487         /* Start clock by resetting CLOCK_HALT */
488         ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
489         return 0;
490 }
491 
492 static int __init ds1302_register(void)
493 {
494         ds1302_init();
495         if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
496                 printk(KERN_INFO "%s: unable to get major %d for rtc\n", 
497                        ds1302_name, RTC_MAJOR_NR);
498                 return -1;
499         }
500         return 0;
501 
502 }