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Linux/drivers/rtc/rtc-at91rm9200.c

  1 /*
  2  *      Real Time Clock interface for Linux on Atmel AT91RM9200
  3  *
  4  *      Copyright (C) 2002 Rick Bronson
  5  *
  6  *      Converted to RTC class model by Andrew Victor
  7  *
  8  *      Ported to Linux 2.6 by Steven Scholz
  9  *      Based on s3c2410-rtc.c Simtec Electronics
 10  *
 11  *      Based on sa1100-rtc.c by Nils Faerber
 12  *      Based on rtc.c by Paul Gortmaker
 13  *
 14  *      This program is free software; you can redistribute it and/or
 15  *      modify it under the terms of the GNU General Public License
 16  *      as published by the Free Software Foundation; either version
 17  *      2 of the License, or (at your option) any later version.
 18  *
 19  */
 20 
 21 #include <linux/module.h>
 22 #include <linux/kernel.h>
 23 #include <linux/platform_device.h>
 24 #include <linux/time.h>
 25 #include <linux/rtc.h>
 26 #include <linux/bcd.h>
 27 #include <linux/interrupt.h>
 28 #include <linux/spinlock.h>
 29 #include <linux/ioctl.h>
 30 #include <linux/completion.h>
 31 #include <linux/io.h>
 32 #include <linux/of.h>
 33 #include <linux/of_device.h>
 34 #include <linux/suspend.h>
 35 #include <linux/uaccess.h>
 36 
 37 #include "rtc-at91rm9200.h"
 38 
 39 #define at91_rtc_read(field) \
 40         readl_relaxed(at91_rtc_regs + field)
 41 #define at91_rtc_write(field, val) \
 42         writel_relaxed((val), at91_rtc_regs + field)
 43 
 44 #define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
 45 
 46 struct at91_rtc_config {
 47         bool use_shadow_imr;
 48 };
 49 
 50 static const struct at91_rtc_config *at91_rtc_config;
 51 static DECLARE_COMPLETION(at91_rtc_updated);
 52 static DECLARE_COMPLETION(at91_rtc_upd_rdy);
 53 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
 54 static void __iomem *at91_rtc_regs;
 55 static int irq;
 56 static DEFINE_SPINLOCK(at91_rtc_lock);
 57 static u32 at91_rtc_shadow_imr;
 58 static bool suspended;
 59 static DEFINE_SPINLOCK(suspended_lock);
 60 static unsigned long cached_events;
 61 static u32 at91_rtc_imr;
 62 
 63 static void at91_rtc_write_ier(u32 mask)
 64 {
 65         unsigned long flags;
 66 
 67         spin_lock_irqsave(&at91_rtc_lock, flags);
 68         at91_rtc_shadow_imr |= mask;
 69         at91_rtc_write(AT91_RTC_IER, mask);
 70         spin_unlock_irqrestore(&at91_rtc_lock, flags);
 71 }
 72 
 73 static void at91_rtc_write_idr(u32 mask)
 74 {
 75         unsigned long flags;
 76 
 77         spin_lock_irqsave(&at91_rtc_lock, flags);
 78         at91_rtc_write(AT91_RTC_IDR, mask);
 79         /*
 80          * Register read back (of any RTC-register) needed to make sure
 81          * IDR-register write has reached the peripheral before updating
 82          * shadow mask.
 83          *
 84          * Note that there is still a possibility that the mask is updated
 85          * before interrupts have actually been disabled in hardware. The only
 86          * way to be certain would be to poll the IMR-register, which is is
 87          * the very register we are trying to emulate. The register read back
 88          * is a reasonable heuristic.
 89          */
 90         at91_rtc_read(AT91_RTC_SR);
 91         at91_rtc_shadow_imr &= ~mask;
 92         spin_unlock_irqrestore(&at91_rtc_lock, flags);
 93 }
 94 
 95 static u32 at91_rtc_read_imr(void)
 96 {
 97         unsigned long flags;
 98         u32 mask;
 99 
100         if (at91_rtc_config->use_shadow_imr) {
101                 spin_lock_irqsave(&at91_rtc_lock, flags);
102                 mask = at91_rtc_shadow_imr;
103                 spin_unlock_irqrestore(&at91_rtc_lock, flags);
104         } else {
105                 mask = at91_rtc_read(AT91_RTC_IMR);
106         }
107 
108         return mask;
109 }
110 
111 /*
112  * Decode time/date into rtc_time structure
113  */
114 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
115                                 struct rtc_time *tm)
116 {
117         unsigned int time, date;
118 
119         /* must read twice in case it changes */
120         do {
121                 time = at91_rtc_read(timereg);
122                 date = at91_rtc_read(calreg);
123         } while ((time != at91_rtc_read(timereg)) ||
124                         (date != at91_rtc_read(calreg)));
125 
126         tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
127         tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
128         tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
129 
130         /*
131          * The Calendar Alarm register does not have a field for
132          * the year - so these will return an invalid value.  When an
133          * alarm is set, at91_alarm_year will store the current year.
134          */
135         tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
136         tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
137 
138         tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
139         tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
140         tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
141 }
142 
143 /*
144  * Read current time and date in RTC
145  */
146 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
147 {
148         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
149         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
150         tm->tm_year = tm->tm_year - 1900;
151 
152         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
153                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
154                 tm->tm_hour, tm->tm_min, tm->tm_sec);
155 
156         return 0;
157 }
158 
159 /*
160  * Set current time and date in RTC
161  */
162 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
163 {
164         unsigned long cr;
165 
166         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
167                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
168                 tm->tm_hour, tm->tm_min, tm->tm_sec);
169 
170         wait_for_completion(&at91_rtc_upd_rdy);
171 
172         /* Stop Time/Calendar from counting */
173         cr = at91_rtc_read(AT91_RTC_CR);
174         at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
175 
176         at91_rtc_write_ier(AT91_RTC_ACKUPD);
177         wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
178         at91_rtc_write_idr(AT91_RTC_ACKUPD);
179 
180         at91_rtc_write(AT91_RTC_TIMR,
181                           bin2bcd(tm->tm_sec) << 0
182                         | bin2bcd(tm->tm_min) << 8
183                         | bin2bcd(tm->tm_hour) << 16);
184 
185         at91_rtc_write(AT91_RTC_CALR,
186                           bin2bcd((tm->tm_year + 1900) / 100)   /* century */
187                         | bin2bcd(tm->tm_year % 100) << 8       /* year */
188                         | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
189                         | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
190                         | bin2bcd(tm->tm_mday) << 24);
191 
192         /* Restart Time/Calendar */
193         cr = at91_rtc_read(AT91_RTC_CR);
194         at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV);
195         at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
196         at91_rtc_write_ier(AT91_RTC_SECEV);
197 
198         return 0;
199 }
200 
201 /*
202  * Read alarm time and date in RTC
203  */
204 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
205 {
206         struct rtc_time *tm = &alrm->time;
207 
208         at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
209         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
210         tm->tm_year = at91_alarm_year - 1900;
211 
212         alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
213                         ? 1 : 0;
214 
215         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
216                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
217                 tm->tm_hour, tm->tm_min, tm->tm_sec);
218 
219         return 0;
220 }
221 
222 /*
223  * Set alarm time and date in RTC
224  */
225 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
226 {
227         struct rtc_time tm;
228 
229         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
230 
231         at91_alarm_year = tm.tm_year;
232 
233         tm.tm_mon = alrm->time.tm_mon;
234         tm.tm_mday = alrm->time.tm_mday;
235         tm.tm_hour = alrm->time.tm_hour;
236         tm.tm_min = alrm->time.tm_min;
237         tm.tm_sec = alrm->time.tm_sec;
238 
239         at91_rtc_write_idr(AT91_RTC_ALARM);
240         at91_rtc_write(AT91_RTC_TIMALR,
241                   bin2bcd(tm.tm_sec) << 0
242                 | bin2bcd(tm.tm_min) << 8
243                 | bin2bcd(tm.tm_hour) << 16
244                 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
245         at91_rtc_write(AT91_RTC_CALALR,
246                   bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
247                 | bin2bcd(tm.tm_mday) << 24
248                 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
249 
250         if (alrm->enabled) {
251                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
252                 at91_rtc_write_ier(AT91_RTC_ALARM);
253         }
254 
255         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
256                 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
257                 tm.tm_min, tm.tm_sec);
258 
259         return 0;
260 }
261 
262 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
263 {
264         dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
265 
266         if (enabled) {
267                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
268                 at91_rtc_write_ier(AT91_RTC_ALARM);
269         } else
270                 at91_rtc_write_idr(AT91_RTC_ALARM);
271 
272         return 0;
273 }
274 /*
275  * Provide additional RTC information in /proc/driver/rtc
276  */
277 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
278 {
279         unsigned long imr = at91_rtc_read_imr();
280 
281         seq_printf(seq, "update_IRQ\t: %s\n",
282                         (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
283         seq_printf(seq, "periodic_IRQ\t: %s\n",
284                         (imr & AT91_RTC_SECEV) ? "yes" : "no");
285 
286         return 0;
287 }
288 
289 /*
290  * IRQ handler for the RTC
291  */
292 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
293 {
294         struct platform_device *pdev = dev_id;
295         struct rtc_device *rtc = platform_get_drvdata(pdev);
296         unsigned int rtsr;
297         unsigned long events = 0;
298         int ret = IRQ_NONE;
299 
300         spin_lock(&suspended_lock);
301         rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
302         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
303                 if (rtsr & AT91_RTC_ALARM)
304                         events |= (RTC_AF | RTC_IRQF);
305                 if (rtsr & AT91_RTC_SECEV) {
306                         complete(&at91_rtc_upd_rdy);
307                         at91_rtc_write_idr(AT91_RTC_SECEV);
308                 }
309                 if (rtsr & AT91_RTC_ACKUPD)
310                         complete(&at91_rtc_updated);
311 
312                 at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
313 
314                 if (!suspended) {
315                         rtc_update_irq(rtc, 1, events);
316 
317                         dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n",
318                                 __func__, events >> 8, events & 0x000000FF);
319                 } else {
320                         cached_events |= events;
321                         at91_rtc_write_idr(at91_rtc_imr);
322                         pm_system_wakeup();
323                 }
324 
325                 ret = IRQ_HANDLED;
326         }
327         spin_unlock(&suspended_lock);
328 
329         return ret;
330 }
331 
332 static const struct at91_rtc_config at91rm9200_config = {
333 };
334 
335 static const struct at91_rtc_config at91sam9x5_config = {
336         .use_shadow_imr = true,
337 };
338 
339 #ifdef CONFIG_OF
340 static const struct of_device_id at91_rtc_dt_ids[] = {
341         {
342                 .compatible = "atmel,at91rm9200-rtc",
343                 .data = &at91rm9200_config,
344         }, {
345                 .compatible = "atmel,at91sam9x5-rtc",
346                 .data = &at91sam9x5_config,
347         }, {
348                 /* sentinel */
349         }
350 };
351 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
352 #endif
353 
354 static const struct at91_rtc_config *
355 at91_rtc_get_config(struct platform_device *pdev)
356 {
357         const struct of_device_id *match;
358 
359         if (pdev->dev.of_node) {
360                 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
361                 if (!match)
362                         return NULL;
363                 return (const struct at91_rtc_config *)match->data;
364         }
365 
366         return &at91rm9200_config;
367 }
368 
369 static const struct rtc_class_ops at91_rtc_ops = {
370         .read_time      = at91_rtc_readtime,
371         .set_time       = at91_rtc_settime,
372         .read_alarm     = at91_rtc_readalarm,
373         .set_alarm      = at91_rtc_setalarm,
374         .proc           = at91_rtc_proc,
375         .alarm_irq_enable = at91_rtc_alarm_irq_enable,
376 };
377 
378 /*
379  * Initialize and install RTC driver
380  */
381 static int __init at91_rtc_probe(struct platform_device *pdev)
382 {
383         struct rtc_device *rtc;
384         struct resource *regs;
385         int ret = 0;
386 
387         at91_rtc_config = at91_rtc_get_config(pdev);
388         if (!at91_rtc_config)
389                 return -ENODEV;
390 
391         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
392         if (!regs) {
393                 dev_err(&pdev->dev, "no mmio resource defined\n");
394                 return -ENXIO;
395         }
396 
397         irq = platform_get_irq(pdev, 0);
398         if (irq < 0) {
399                 dev_err(&pdev->dev, "no irq resource defined\n");
400                 return -ENXIO;
401         }
402 
403         at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start,
404                                      resource_size(regs));
405         if (!at91_rtc_regs) {
406                 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
407                 return -ENOMEM;
408         }
409 
410         at91_rtc_write(AT91_RTC_CR, 0);
411         at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
412 
413         /* Disable all interrupts */
414         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
415                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
416                                         AT91_RTC_CALEV);
417 
418         ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt,
419                                IRQF_SHARED | IRQF_COND_SUSPEND,
420                                "at91_rtc", pdev);
421         if (ret) {
422                 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
423                 return ret;
424         }
425 
426         /* cpu init code should really have flagged this device as
427          * being wake-capable; if it didn't, do that here.
428          */
429         if (!device_can_wakeup(&pdev->dev))
430                 device_init_wakeup(&pdev->dev, 1);
431 
432         rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
433                                 &at91_rtc_ops, THIS_MODULE);
434         if (IS_ERR(rtc))
435                 return PTR_ERR(rtc);
436         platform_set_drvdata(pdev, rtc);
437 
438         /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
439          * completion.
440          */
441         at91_rtc_write_ier(AT91_RTC_SECEV);
442 
443         dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
444         return 0;
445 }
446 
447 /*
448  * Disable and remove the RTC driver
449  */
450 static int __exit at91_rtc_remove(struct platform_device *pdev)
451 {
452         /* Disable all interrupts */
453         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
454                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
455                                         AT91_RTC_CALEV);
456 
457         return 0;
458 }
459 
460 static void at91_rtc_shutdown(struct platform_device *pdev)
461 {
462         /* Disable all interrupts */
463         at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
464                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
465                                         AT91_RTC_CALEV);
466 }
467 
468 #ifdef CONFIG_PM_SLEEP
469 
470 /* AT91RM9200 RTC Power management control */
471 
472 static int at91_rtc_suspend(struct device *dev)
473 {
474         /* this IRQ is shared with DBGU and other hardware which isn't
475          * necessarily doing PM like we are...
476          */
477         at91_rtc_imr = at91_rtc_read_imr()
478                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
479         if (at91_rtc_imr) {
480                 if (device_may_wakeup(dev)) {
481                         unsigned long flags;
482 
483                         enable_irq_wake(irq);
484 
485                         spin_lock_irqsave(&suspended_lock, flags);
486                         suspended = true;
487                         spin_unlock_irqrestore(&suspended_lock, flags);
488                 } else {
489                         at91_rtc_write_idr(at91_rtc_imr);
490                 }
491         }
492         return 0;
493 }
494 
495 static int at91_rtc_resume(struct device *dev)
496 {
497         struct rtc_device *rtc = dev_get_drvdata(dev);
498 
499         if (at91_rtc_imr) {
500                 if (device_may_wakeup(dev)) {
501                         unsigned long flags;
502 
503                         spin_lock_irqsave(&suspended_lock, flags);
504 
505                         if (cached_events) {
506                                 rtc_update_irq(rtc, 1, cached_events);
507                                 cached_events = 0;
508                         }
509 
510                         suspended = false;
511                         spin_unlock_irqrestore(&suspended_lock, flags);
512 
513                         disable_irq_wake(irq);
514                 }
515                 at91_rtc_write_ier(at91_rtc_imr);
516         }
517         return 0;
518 }
519 #endif
520 
521 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
522 
523 static struct platform_driver at91_rtc_driver = {
524         .remove         = __exit_p(at91_rtc_remove),
525         .shutdown       = at91_rtc_shutdown,
526         .driver         = {
527                 .name   = "at91_rtc",
528                 .pm     = &at91_rtc_pm_ops,
529                 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
530         },
531 };
532 
533 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
534 
535 MODULE_AUTHOR("Rick Bronson");
536 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
537 MODULE_LICENSE("GPL");
538 MODULE_ALIAS("platform:at91_rtc");
539 

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