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
35 #include <asm/uaccess.h>
36
37 #include "rtc-at91rm9200.h"
38
39 #define at91_rtc_read(field) \
40 __raw_readl(at91_rtc_regs + field)
41 #define at91_rtc_write(field, val) \
42 __raw_writel((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 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
at91_rtc_write_ier(u32 mask)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
at91_rtc_write_idr(u32 mask)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
at91_rtc_read_imr(void)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 */
at91_rtc_decodetime(unsigned int timereg,unsigned int calreg,struct rtc_time * tm)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 */
at91_rtc_readtime(struct device * dev,struct rtc_time * tm)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 */
at91_rtc_settime(struct device * dev,struct rtc_time * tm)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 /* Stop Time/Calendar from counting */
166 cr = at91_rtc_read(AT91_RTC_CR);
167 at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
168
169 at91_rtc_write_ier(AT91_RTC_ACKUPD);
170 wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
171 at91_rtc_write_idr(AT91_RTC_ACKUPD);
172
173 at91_rtc_write(AT91_RTC_TIMR,
174 bin2bcd(tm->tm_sec) << 0
175 | bin2bcd(tm->tm_min) << 8
176 | bin2bcd(tm->tm_hour) << 16);
177
178 at91_rtc_write(AT91_RTC_CALR,
179 bin2bcd((tm->tm_year + 1900) / 100) /* century */
180 | bin2bcd(tm->tm_year % 100) << 8 /* year */
181 | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
182 | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
183 | bin2bcd(tm->tm_mday) << 24);
184
185 /* Restart Time/Calendar */
186 cr = at91_rtc_read(AT91_RTC_CR);
187 at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
188
189 return 0;
190 }
191
192 /*
193 * Read alarm time and date in RTC
194 */
at91_rtc_readalarm(struct device * dev,struct rtc_wkalrm * alrm)195 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
196 {
197 struct rtc_time *tm = &alrm->time;
198
199 at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
200 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
201 tm->tm_year = at91_alarm_year - 1900;
202
203 alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
204 ? 1 : 0;
205
206 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
207 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
208 tm->tm_hour, tm->tm_min, tm->tm_sec);
209
210 return 0;
211 }
212
213 /*
214 * Set alarm time and date in RTC
215 */
at91_rtc_setalarm(struct device * dev,struct rtc_wkalrm * alrm)216 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
217 {
218 struct rtc_time tm;
219
220 at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
221
222 at91_alarm_year = tm.tm_year;
223
224 tm.tm_hour = alrm->time.tm_hour;
225 tm.tm_min = alrm->time.tm_min;
226 tm.tm_sec = alrm->time.tm_sec;
227
228 at91_rtc_write_idr(AT91_RTC_ALARM);
229 at91_rtc_write(AT91_RTC_TIMALR,
230 bin2bcd(tm.tm_sec) << 0
231 | bin2bcd(tm.tm_min) << 8
232 | bin2bcd(tm.tm_hour) << 16
233 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
234 at91_rtc_write(AT91_RTC_CALALR,
235 bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
236 | bin2bcd(tm.tm_mday) << 24
237 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
238
239 if (alrm->enabled) {
240 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
241 at91_rtc_write_ier(AT91_RTC_ALARM);
242 }
243
244 dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
245 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
246 tm.tm_min, tm.tm_sec);
247
248 return 0;
249 }
250
at91_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)251 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
252 {
253 dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
254
255 if (enabled) {
256 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
257 at91_rtc_write_ier(AT91_RTC_ALARM);
258 } else
259 at91_rtc_write_idr(AT91_RTC_ALARM);
260
261 return 0;
262 }
263 /*
264 * Provide additional RTC information in /proc/driver/rtc
265 */
at91_rtc_proc(struct device * dev,struct seq_file * seq)266 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
267 {
268 unsigned long imr = at91_rtc_read_imr();
269
270 seq_printf(seq, "update_IRQ\t: %s\n",
271 (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
272 seq_printf(seq, "periodic_IRQ\t: %s\n",
273 (imr & AT91_RTC_SECEV) ? "yes" : "no");
274
275 return 0;
276 }
277
278 /*
279 * IRQ handler for the RTC
280 */
at91_rtc_interrupt(int irq,void * dev_id)281 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
282 {
283 struct platform_device *pdev = dev_id;
284 struct rtc_device *rtc = platform_get_drvdata(pdev);
285 unsigned int rtsr;
286 unsigned long events = 0;
287
288 rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
289 if (rtsr) { /* this interrupt is shared! Is it ours? */
290 if (rtsr & AT91_RTC_ALARM)
291 events |= (RTC_AF | RTC_IRQF);
292 if (rtsr & AT91_RTC_SECEV)
293 events |= (RTC_UF | RTC_IRQF);
294 if (rtsr & AT91_RTC_ACKUPD)
295 complete(&at91_rtc_updated);
296
297 at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
298
299 rtc_update_irq(rtc, 1, events);
300
301 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
302 events >> 8, events & 0x000000FF);
303
304 return IRQ_HANDLED;
305 }
306 return IRQ_NONE; /* not handled */
307 }
308
309 static const struct at91_rtc_config at91rm9200_config = {
310 };
311
312 static const struct at91_rtc_config at91sam9x5_config = {
313 .use_shadow_imr = true,
314 };
315
316 #ifdef CONFIG_OF
317 static const struct of_device_id at91_rtc_dt_ids[] = {
318 {
319 .compatible = "atmel,at91rm9200-rtc",
320 .data = &at91rm9200_config,
321 }, {
322 .compatible = "atmel,at91sam9x5-rtc",
323 .data = &at91sam9x5_config,
324 }, {
325 /* sentinel */
326 }
327 };
328 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
329 #endif
330
331 static const struct at91_rtc_config *
at91_rtc_get_config(struct platform_device * pdev)332 at91_rtc_get_config(struct platform_device *pdev)
333 {
334 const struct of_device_id *match;
335
336 if (pdev->dev.of_node) {
337 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
338 if (!match)
339 return NULL;
340 return (const struct at91_rtc_config *)match->data;
341 }
342
343 return &at91rm9200_config;
344 }
345
346 static const struct rtc_class_ops at91_rtc_ops = {
347 .read_time = at91_rtc_readtime,
348 .set_time = at91_rtc_settime,
349 .read_alarm = at91_rtc_readalarm,
350 .set_alarm = at91_rtc_setalarm,
351 .proc = at91_rtc_proc,
352 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
353 };
354
355 /*
356 * Initialize and install RTC driver
357 */
at91_rtc_probe(struct platform_device * pdev)358 static int __init at91_rtc_probe(struct platform_device *pdev)
359 {
360 struct rtc_device *rtc;
361 struct resource *regs;
362 int ret = 0;
363
364 at91_rtc_config = at91_rtc_get_config(pdev);
365 if (!at91_rtc_config)
366 return -ENODEV;
367
368 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
369 if (!regs) {
370 dev_err(&pdev->dev, "no mmio resource defined\n");
371 return -ENXIO;
372 }
373
374 irq = platform_get_irq(pdev, 0);
375 if (irq < 0) {
376 dev_err(&pdev->dev, "no irq resource defined\n");
377 return -ENXIO;
378 }
379
380 at91_rtc_regs = ioremap(regs->start, resource_size(regs));
381 if (!at91_rtc_regs) {
382 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
383 return -ENOMEM;
384 }
385
386 at91_rtc_write(AT91_RTC_CR, 0);
387 at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
388
389 /* Disable all interrupts */
390 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
391 AT91_RTC_SECEV | AT91_RTC_TIMEV |
392 AT91_RTC_CALEV);
393
394 ret = request_irq(irq, at91_rtc_interrupt,
395 IRQF_SHARED,
396 "at91_rtc", pdev);
397 if (ret) {
398 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
399 goto err_unmap;
400 }
401
402 /* cpu init code should really have flagged this device as
403 * being wake-capable; if it didn't, do that here.
404 */
405 if (!device_can_wakeup(&pdev->dev))
406 device_init_wakeup(&pdev->dev, 1);
407
408 rtc = rtc_device_register(pdev->name, &pdev->dev,
409 &at91_rtc_ops, THIS_MODULE);
410 if (IS_ERR(rtc)) {
411 ret = PTR_ERR(rtc);
412 goto err_free_irq;
413 }
414 platform_set_drvdata(pdev, rtc);
415
416 dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
417 return 0;
418
419 err_free_irq:
420 free_irq(irq, pdev);
421 err_unmap:
422 iounmap(at91_rtc_regs);
423
424 return ret;
425 }
426
427 /*
428 * Disable and remove the RTC driver
429 */
at91_rtc_remove(struct platform_device * pdev)430 static int __exit at91_rtc_remove(struct platform_device *pdev)
431 {
432 struct rtc_device *rtc = platform_get_drvdata(pdev);
433
434 /* Disable all interrupts */
435 at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
436 AT91_RTC_SECEV | AT91_RTC_TIMEV |
437 AT91_RTC_CALEV);
438 free_irq(irq, pdev);
439
440 rtc_device_unregister(rtc);
441 iounmap(at91_rtc_regs);
442 platform_set_drvdata(pdev, NULL);
443
444 return 0;
445 }
446
447 #ifdef CONFIG_PM_SLEEP
448
449 /* AT91RM9200 RTC Power management control */
450
451 static u32 at91_rtc_imr;
452
at91_rtc_suspend(struct device * dev)453 static int at91_rtc_suspend(struct device *dev)
454 {
455 /* this IRQ is shared with DBGU and other hardware which isn't
456 * necessarily doing PM like we are...
457 */
458 at91_rtc_imr = at91_rtc_read_imr()
459 & (AT91_RTC_ALARM|AT91_RTC_SECEV);
460 if (at91_rtc_imr) {
461 if (device_may_wakeup(dev))
462 enable_irq_wake(irq);
463 else
464 at91_rtc_write_idr(at91_rtc_imr);
465 }
466 return 0;
467 }
468
at91_rtc_resume(struct device * dev)469 static int at91_rtc_resume(struct device *dev)
470 {
471 if (at91_rtc_imr) {
472 if (device_may_wakeup(dev))
473 disable_irq_wake(irq);
474 else
475 at91_rtc_write_ier(at91_rtc_imr);
476 }
477 return 0;
478 }
479 #endif
480
481 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
482
483 static struct platform_driver at91_rtc_driver = {
484 .remove = __exit_p(at91_rtc_remove),
485 .driver = {
486 .name = "at91_rtc",
487 .owner = THIS_MODULE,
488 .pm = &at91_rtc_pm_ops,
489 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
490 },
491 };
492
493 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
494
495 MODULE_AUTHOR("Rick Bronson");
496 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
497 MODULE_LICENSE("GPL");
498 MODULE_ALIAS("platform:at91_rtc");
499