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

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