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

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