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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) STMicroelectronics 2017
4 * Author: Amelie Delaunay <amelie.delaunay@st.com>
5 */
6
7#include <linux/bcd.h>
8#include <linux/clk.h>
9#include <linux/errno.h>
10#include <linux/iopoll.h>
11#include <linux/ioport.h>
12#include <linux/mfd/syscon.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/pm_wakeirq.h>
17#include <linux/regmap.h>
18#include <linux/rtc.h>
19
20#define DRIVER_NAME "stm32_rtc"
21
22/* STM32_RTC_TR bit fields */
23#define STM32_RTC_TR_SEC_SHIFT 0
24#define STM32_RTC_TR_SEC GENMASK(6, 0)
25#define STM32_RTC_TR_MIN_SHIFT 8
26#define STM32_RTC_TR_MIN GENMASK(14, 8)
27#define STM32_RTC_TR_HOUR_SHIFT 16
28#define STM32_RTC_TR_HOUR GENMASK(21, 16)
29
30/* STM32_RTC_DR bit fields */
31#define STM32_RTC_DR_DATE_SHIFT 0
32#define STM32_RTC_DR_DATE GENMASK(5, 0)
33#define STM32_RTC_DR_MONTH_SHIFT 8
34#define STM32_RTC_DR_MONTH GENMASK(12, 8)
35#define STM32_RTC_DR_WDAY_SHIFT 13
36#define STM32_RTC_DR_WDAY GENMASK(15, 13)
37#define STM32_RTC_DR_YEAR_SHIFT 16
38#define STM32_RTC_DR_YEAR GENMASK(23, 16)
39
40/* STM32_RTC_CR bit fields */
41#define STM32_RTC_CR_FMT BIT(6)
42#define STM32_RTC_CR_ALRAE BIT(8)
43#define STM32_RTC_CR_ALRAIE BIT(12)
44
45/* STM32_RTC_ISR/STM32_RTC_ICSR bit fields */
46#define STM32_RTC_ISR_ALRAWF BIT(0)
47#define STM32_RTC_ISR_INITS BIT(4)
48#define STM32_RTC_ISR_RSF BIT(5)
49#define STM32_RTC_ISR_INITF BIT(6)
50#define STM32_RTC_ISR_INIT BIT(7)
51#define STM32_RTC_ISR_ALRAF BIT(8)
52
53/* STM32_RTC_PRER bit fields */
54#define STM32_RTC_PRER_PRED_S_SHIFT 0
55#define STM32_RTC_PRER_PRED_S GENMASK(14, 0)
56#define STM32_RTC_PRER_PRED_A_SHIFT 16
57#define STM32_RTC_PRER_PRED_A GENMASK(22, 16)
58
59/* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */
60#define STM32_RTC_ALRMXR_SEC_SHIFT 0
61#define STM32_RTC_ALRMXR_SEC GENMASK(6, 0)
62#define STM32_RTC_ALRMXR_SEC_MASK BIT(7)
63#define STM32_RTC_ALRMXR_MIN_SHIFT 8
64#define STM32_RTC_ALRMXR_MIN GENMASK(14, 8)
65#define STM32_RTC_ALRMXR_MIN_MASK BIT(15)
66#define STM32_RTC_ALRMXR_HOUR_SHIFT 16
67#define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16)
68#define STM32_RTC_ALRMXR_PM BIT(22)
69#define STM32_RTC_ALRMXR_HOUR_MASK BIT(23)
70#define STM32_RTC_ALRMXR_DATE_SHIFT 24
71#define STM32_RTC_ALRMXR_DATE GENMASK(29, 24)
72#define STM32_RTC_ALRMXR_WDSEL BIT(30)
73#define STM32_RTC_ALRMXR_WDAY_SHIFT 24
74#define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24)
75#define STM32_RTC_ALRMXR_DATE_MASK BIT(31)
76
77/* STM32_RTC_SR/_SCR bit fields */
78#define STM32_RTC_SR_ALRA BIT(0)
79
80/* STM32_RTC_VERR bit fields */
81#define STM32_RTC_VERR_MINREV_SHIFT 0
82#define STM32_RTC_VERR_MINREV GENMASK(3, 0)
83#define STM32_RTC_VERR_MAJREV_SHIFT 4
84#define STM32_RTC_VERR_MAJREV GENMASK(7, 4)
85
86/* STM32_RTC_WPR key constants */
87#define RTC_WPR_1ST_KEY 0xCA
88#define RTC_WPR_2ND_KEY 0x53
89#define RTC_WPR_WRONG_KEY 0xFF
90
91/* Max STM32 RTC register offset is 0x3FC */
92#define UNDEF_REG 0xFFFF
93
94/* STM32 RTC driver time helpers */
95#define SEC_PER_DAY (24 * 60 * 60)
96
97struct stm32_rtc;
98
99struct stm32_rtc_registers {
100 u16 tr;
101 u16 dr;
102 u16 cr;
103 u16 isr;
104 u16 prer;
105 u16 alrmar;
106 u16 wpr;
107 u16 sr;
108 u16 scr;
109 u16 verr;
110};
111
112struct stm32_rtc_events {
113 u32 alra;
114};
115
116struct stm32_rtc_data {
117 const struct stm32_rtc_registers regs;
118 const struct stm32_rtc_events events;
119 void (*clear_events)(struct stm32_rtc *rtc, unsigned int flags);
120 bool has_pclk;
121 bool need_dbp;
122 bool need_accuracy;
123};
124
125struct stm32_rtc {
126 struct rtc_device *rtc_dev;
127 void __iomem *base;
128 struct regmap *dbp;
129 unsigned int dbp_reg;
130 unsigned int dbp_mask;
131 struct clk *pclk;
132 struct clk *rtc_ck;
133 const struct stm32_rtc_data *data;
134 int irq_alarm;
135};
136
137static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc)
138{
139 const struct stm32_rtc_registers *regs = &rtc->data->regs;
140
141 writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + regs->wpr);
142 writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + regs->wpr);
143}
144
145static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc)
146{
147 const struct stm32_rtc_registers *regs = &rtc->data->regs;
148
149 writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + regs->wpr);
150}
151
152static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
153{
154 const struct stm32_rtc_registers *regs = &rtc->data->regs;
155 unsigned int isr = readl_relaxed(rtc->base + regs->isr);
156
157 if (!(isr & STM32_RTC_ISR_INITF)) {
158 isr |= STM32_RTC_ISR_INIT;
159 writel_relaxed(isr, rtc->base + regs->isr);
160
161 /*
162 * It takes around 2 rtc_ck clock cycles to enter in
163 * initialization phase mode (and have INITF flag set). As
164 * slowest rtc_ck frequency may be 32kHz and highest should be
165 * 1MHz, we poll every 10 us with a timeout of 100ms.
166 */
167 return readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr, isr,
168 (isr & STM32_RTC_ISR_INITF),
169 10, 100000);
170 }
171
172 return 0;
173}
174
175static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc)
176{
177 const struct stm32_rtc_registers *regs = &rtc->data->regs;
178 unsigned int isr = readl_relaxed(rtc->base + regs->isr);
179
180 isr &= ~STM32_RTC_ISR_INIT;
181 writel_relaxed(isr, rtc->base + regs->isr);
182}
183
184static int stm32_rtc_wait_sync(struct stm32_rtc *rtc)
185{
186 const struct stm32_rtc_registers *regs = &rtc->data->regs;
187 unsigned int isr = readl_relaxed(rtc->base + regs->isr);
188
189 isr &= ~STM32_RTC_ISR_RSF;
190 writel_relaxed(isr, rtc->base + regs->isr);
191
192 /*
193 * Wait for RSF to be set to ensure the calendar registers are
194 * synchronised, it takes around 2 rtc_ck clock cycles
195 */
196 return readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr,
197 isr,
198 (isr & STM32_RTC_ISR_RSF),
199 10, 100000);
200}
201
202static void stm32_rtc_clear_event_flags(struct stm32_rtc *rtc,
203 unsigned int flags)
204{
205 rtc->data->clear_events(rtc, flags);
206}
207
208static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id)
209{
210 struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id;
211 const struct stm32_rtc_registers *regs = &rtc->data->regs;
212 const struct stm32_rtc_events *evts = &rtc->data->events;
213 unsigned int status, cr;
214
215 rtc_lock(rtc->rtc_dev);
216
217 status = readl_relaxed(rtc->base + regs->sr);
218 cr = readl_relaxed(rtc->base + regs->cr);
219
220 if ((status & evts->alra) &&
221 (cr & STM32_RTC_CR_ALRAIE)) {
222 /* Alarm A flag - Alarm interrupt */
223 dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n");
224
225 /* Pass event to the kernel */
226 rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
227
228 /* Clear event flags, otherwise new events won't be received */
229 stm32_rtc_clear_event_flags(rtc, evts->alra);
230 }
231
232 rtc_unlock(rtc->rtc_dev);
233
234 return IRQ_HANDLED;
235}
236
237/* Convert rtc_time structure from bin to bcd format */
238static void tm2bcd(struct rtc_time *tm)
239{
240 tm->tm_sec = bin2bcd(tm->tm_sec);
241 tm->tm_min = bin2bcd(tm->tm_min);
242 tm->tm_hour = bin2bcd(tm->tm_hour);
243
244 tm->tm_mday = bin2bcd(tm->tm_mday);
245 tm->tm_mon = bin2bcd(tm->tm_mon + 1);
246 tm->tm_year = bin2bcd(tm->tm_year - 100);
247 /*
248 * Number of days since Sunday
249 * - on kernel side, 0=Sunday...6=Saturday
250 * - on rtc side, 0=invalid,1=Monday...7=Sunday
251 */
252 tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday;
253}
254
255/* Convert rtc_time structure from bcd to bin format */
256static void bcd2tm(struct rtc_time *tm)
257{
258 tm->tm_sec = bcd2bin(tm->tm_sec);
259 tm->tm_min = bcd2bin(tm->tm_min);
260 tm->tm_hour = bcd2bin(tm->tm_hour);
261
262 tm->tm_mday = bcd2bin(tm->tm_mday);
263 tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
264 tm->tm_year = bcd2bin(tm->tm_year) + 100;
265 /*
266 * Number of days since Sunday
267 * - on kernel side, 0=Sunday...6=Saturday
268 * - on rtc side, 0=invalid,1=Monday...7=Sunday
269 */
270 tm->tm_wday %= 7;
271}
272
273static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm)
274{
275 struct stm32_rtc *rtc = dev_get_drvdata(dev);
276 const struct stm32_rtc_registers *regs = &rtc->data->regs;
277 unsigned int tr, dr;
278
279 /* Time and Date in BCD format */
280 tr = readl_relaxed(rtc->base + regs->tr);
281 dr = readl_relaxed(rtc->base + regs->dr);
282
283 tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
284 tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
285 tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
286
287 tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
288 tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
289 tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
290 tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT;
291
292 /* We don't report tm_yday and tm_isdst */
293
294 bcd2tm(tm);
295
296 return 0;
297}
298
299static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm)
300{
301 struct stm32_rtc *rtc = dev_get_drvdata(dev);
302 const struct stm32_rtc_registers *regs = &rtc->data->regs;
303 unsigned int tr, dr;
304 int ret = 0;
305
306 tm2bcd(tm);
307
308 /* Time in BCD format */
309 tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) |
310 ((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) |
311 ((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR);
312
313 /* Date in BCD format */
314 dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) |
315 ((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) |
316 ((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) |
317 ((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY);
318
319 stm32_rtc_wpr_unlock(rtc);
320
321 ret = stm32_rtc_enter_init_mode(rtc);
322 if (ret) {
323 dev_err(dev, "Can't enter in init mode. Set time aborted.\n");
324 goto end;
325 }
326
327 writel_relaxed(tr, rtc->base + regs->tr);
328 writel_relaxed(dr, rtc->base + regs->dr);
329
330 stm32_rtc_exit_init_mode(rtc);
331
332 ret = stm32_rtc_wait_sync(rtc);
333end:
334 stm32_rtc_wpr_lock(rtc);
335
336 return ret;
337}
338
339static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
340{
341 struct stm32_rtc *rtc = dev_get_drvdata(dev);
342 const struct stm32_rtc_registers *regs = &rtc->data->regs;
343 const struct stm32_rtc_events *evts = &rtc->data->events;
344 struct rtc_time *tm = &alrm->time;
345 unsigned int alrmar, cr, status;
346
347 alrmar = readl_relaxed(rtc->base + regs->alrmar);
348 cr = readl_relaxed(rtc->base + regs->cr);
349 status = readl_relaxed(rtc->base + regs->sr);
350
351 if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) {
352 /*
353 * Date/day doesn't matter in Alarm comparison so alarm
354 * triggers every day
355 */
356 tm->tm_mday = -1;
357 tm->tm_wday = -1;
358 } else {
359 if (alrmar & STM32_RTC_ALRMXR_WDSEL) {
360 /* Alarm is set to a day of week */
361 tm->tm_mday = -1;
362 tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >>
363 STM32_RTC_ALRMXR_WDAY_SHIFT;
364 tm->tm_wday %= 7;
365 } else {
366 /* Alarm is set to a day of month */
367 tm->tm_wday = -1;
368 tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >>
369 STM32_RTC_ALRMXR_DATE_SHIFT;
370 }
371 }
372
373 if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) {
374 /* Hours don't matter in Alarm comparison */
375 tm->tm_hour = -1;
376 } else {
377 tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >>
378 STM32_RTC_ALRMXR_HOUR_SHIFT;
379 if (alrmar & STM32_RTC_ALRMXR_PM)
380 tm->tm_hour += 12;
381 }
382
383 if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) {
384 /* Minutes don't matter in Alarm comparison */
385 tm->tm_min = -1;
386 } else {
387 tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >>
388 STM32_RTC_ALRMXR_MIN_SHIFT;
389 }
390
391 if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) {
392 /* Seconds don't matter in Alarm comparison */
393 tm->tm_sec = -1;
394 } else {
395 tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >>
396 STM32_RTC_ALRMXR_SEC_SHIFT;
397 }
398
399 bcd2tm(tm);
400
401 alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0;
402 alrm->pending = (status & evts->alra) ? 1 : 0;
403
404 return 0;
405}
406
407static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
408{
409 struct stm32_rtc *rtc = dev_get_drvdata(dev);
410 const struct stm32_rtc_registers *regs = &rtc->data->regs;
411 const struct stm32_rtc_events *evts = &rtc->data->events;
412 unsigned int cr;
413
414 cr = readl_relaxed(rtc->base + regs->cr);
415
416 stm32_rtc_wpr_unlock(rtc);
417
418 /* We expose Alarm A to the kernel */
419 if (enabled)
420 cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
421 else
422 cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
423 writel_relaxed(cr, rtc->base + regs->cr);
424
425 /* Clear event flags, otherwise new events won't be received */
426 stm32_rtc_clear_event_flags(rtc, evts->alra);
427
428 stm32_rtc_wpr_lock(rtc);
429
430 return 0;
431}
432
433static int stm32_rtc_valid_alrm(struct device *dev, struct rtc_time *tm)
434{
435 static struct rtc_time now;
436 time64_t max_alarm_time64;
437 int max_day_forward;
438 int next_month;
439 int next_year;
440
441 /*
442 * Assuming current date is M-D-Y H:M:S.
443 * RTC alarm can't be set on a specific month and year.
444 * So the valid alarm range is:
445 * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S
446 */
447 stm32_rtc_read_time(dev, &now);
448
449 /*
450 * Find the next month and the year of the next month.
451 * Note: tm_mon and next_month are from 0 to 11
452 */
453 next_month = now.tm_mon + 1;
454 if (next_month == 12) {
455 next_month = 0;
456 next_year = now.tm_year + 1;
457 } else {
458 next_year = now.tm_year;
459 }
460
461 /* Find the maximum limit of alarm in days. */
462 max_day_forward = rtc_month_days(now.tm_mon, now.tm_year)
463 - now.tm_mday
464 + min(rtc_month_days(next_month, next_year), now.tm_mday);
465
466 /* Convert to timestamp and compare the alarm time and its upper limit */
467 max_alarm_time64 = rtc_tm_to_time64(&now) + max_day_forward * SEC_PER_DAY;
468 return rtc_tm_to_time64(tm) <= max_alarm_time64 ? 0 : -EINVAL;
469}
470
471static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
472{
473 struct stm32_rtc *rtc = dev_get_drvdata(dev);
474 const struct stm32_rtc_registers *regs = &rtc->data->regs;
475 struct rtc_time *tm = &alrm->time;
476 unsigned int cr, isr, alrmar;
477 int ret = 0;
478
479 /*
480 * RTC alarm can't be set on a specific date, unless this date is
481 * up to the same day of month next month.
482 */
483 if (stm32_rtc_valid_alrm(dev, tm) < 0) {
484 dev_err(dev, "Alarm can be set only on upcoming month.\n");
485 return -EINVAL;
486 }
487
488 tm2bcd(tm);
489
490 alrmar = 0;
491 /* tm_year and tm_mon are not used because not supported by RTC */
492 alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) &
493 STM32_RTC_ALRMXR_DATE;
494 /* 24-hour format */
495 alrmar &= ~STM32_RTC_ALRMXR_PM;
496 alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) &
497 STM32_RTC_ALRMXR_HOUR;
498 alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) &
499 STM32_RTC_ALRMXR_MIN;
500 alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) &
501 STM32_RTC_ALRMXR_SEC;
502
503 stm32_rtc_wpr_unlock(rtc);
504
505 /* Disable Alarm */
506 cr = readl_relaxed(rtc->base + regs->cr);
507 cr &= ~STM32_RTC_CR_ALRAE;
508 writel_relaxed(cr, rtc->base + regs->cr);
509
510 /*
511 * Poll Alarm write flag to be sure that Alarm update is allowed: it
512 * takes around 2 rtc_ck clock cycles
513 */
514 ret = readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr,
515 isr,
516 (isr & STM32_RTC_ISR_ALRAWF),
517 10, 100000);
518
519 if (ret) {
520 dev_err(dev, "Alarm update not allowed\n");
521 goto end;
522 }
523
524 /* Write to Alarm register */
525 writel_relaxed(alrmar, rtc->base + regs->alrmar);
526
527 stm32_rtc_alarm_irq_enable(dev, alrm->enabled);
528end:
529 stm32_rtc_wpr_lock(rtc);
530
531 return ret;
532}
533
534static const struct rtc_class_ops stm32_rtc_ops = {
535 .read_time = stm32_rtc_read_time,
536 .set_time = stm32_rtc_set_time,
537 .read_alarm = stm32_rtc_read_alarm,
538 .set_alarm = stm32_rtc_set_alarm,
539 .alarm_irq_enable = stm32_rtc_alarm_irq_enable,
540};
541
542static void stm32_rtc_clear_events(struct stm32_rtc *rtc,
543 unsigned int flags)
544{
545 const struct stm32_rtc_registers *regs = &rtc->data->regs;
546
547 /* Flags are cleared by writing 0 in RTC_ISR */
548 writel_relaxed(readl_relaxed(rtc->base + regs->isr) & ~flags,
549 rtc->base + regs->isr);
550}
551
552static const struct stm32_rtc_data stm32_rtc_data = {
553 .has_pclk = false,
554 .need_dbp = true,
555 .need_accuracy = false,
556 .regs = {
557 .tr = 0x00,
558 .dr = 0x04,
559 .cr = 0x08,
560 .isr = 0x0C,
561 .prer = 0x10,
562 .alrmar = 0x1C,
563 .wpr = 0x24,
564 .sr = 0x0C, /* set to ISR offset to ease alarm management */
565 .scr = UNDEF_REG,
566 .verr = UNDEF_REG,
567 },
568 .events = {
569 .alra = STM32_RTC_ISR_ALRAF,
570 },
571 .clear_events = stm32_rtc_clear_events,
572};
573
574static const struct stm32_rtc_data stm32h7_rtc_data = {
575 .has_pclk = true,
576 .need_dbp = true,
577 .need_accuracy = false,
578 .regs = {
579 .tr = 0x00,
580 .dr = 0x04,
581 .cr = 0x08,
582 .isr = 0x0C,
583 .prer = 0x10,
584 .alrmar = 0x1C,
585 .wpr = 0x24,
586 .sr = 0x0C, /* set to ISR offset to ease alarm management */
587 .scr = UNDEF_REG,
588 .verr = UNDEF_REG,
589 },
590 .events = {
591 .alra = STM32_RTC_ISR_ALRAF,
592 },
593 .clear_events = stm32_rtc_clear_events,
594};
595
596static void stm32mp1_rtc_clear_events(struct stm32_rtc *rtc,
597 unsigned int flags)
598{
599 struct stm32_rtc_registers regs = rtc->data->regs;
600
601 /* Flags are cleared by writing 1 in RTC_SCR */
602 writel_relaxed(flags, rtc->base + regs.scr);
603}
604
605static const struct stm32_rtc_data stm32mp1_data = {
606 .has_pclk = true,
607 .need_dbp = false,
608 .need_accuracy = true,
609 .regs = {
610 .tr = 0x00,
611 .dr = 0x04,
612 .cr = 0x18,
613 .isr = 0x0C, /* named RTC_ICSR on stm32mp1 */
614 .prer = 0x10,
615 .alrmar = 0x40,
616 .wpr = 0x24,
617 .sr = 0x50,
618 .scr = 0x5C,
619 .verr = 0x3F4,
620 },
621 .events = {
622 .alra = STM32_RTC_SR_ALRA,
623 },
624 .clear_events = stm32mp1_rtc_clear_events,
625};
626
627static const struct of_device_id stm32_rtc_of_match[] = {
628 { .compatible = "st,stm32-rtc", .data = &stm32_rtc_data },
629 { .compatible = "st,stm32h7-rtc", .data = &stm32h7_rtc_data },
630 { .compatible = "st,stm32mp1-rtc", .data = &stm32mp1_data },
631 {}
632};
633MODULE_DEVICE_TABLE(of, stm32_rtc_of_match);
634
635static int stm32_rtc_init(struct platform_device *pdev,
636 struct stm32_rtc *rtc)
637{
638 const struct stm32_rtc_registers *regs = &rtc->data->regs;
639 unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr;
640 unsigned int rate;
641 int ret;
642
643 rate = clk_get_rate(rtc->rtc_ck);
644
645 /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */
646 pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT;
647 pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT;
648
649 if (rate > (pred_a_max + 1) * (pred_s_max + 1)) {
650 dev_err(&pdev->dev, "rtc_ck rate is too high: %dHz\n", rate);
651 return -EINVAL;
652 }
653
654 if (rtc->data->need_accuracy) {
655 for (pred_a = 0; pred_a <= pred_a_max; pred_a++) {
656 pred_s = (rate / (pred_a + 1)) - 1;
657
658 if (pred_s <= pred_s_max && ((pred_s + 1) * (pred_a + 1)) == rate)
659 break;
660 }
661 } else {
662 for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) {
663 pred_s = (rate / (pred_a + 1)) - 1;
664
665 if (((pred_s + 1) * (pred_a + 1)) == rate)
666 break;
667 }
668 }
669
670 /*
671 * Can't find a 1Hz, so give priority to RTC power consumption
672 * by choosing the higher possible value for prediv_a
673 */
674 if (pred_s > pred_s_max || pred_a > pred_a_max) {
675 pred_a = pred_a_max;
676 pred_s = (rate / (pred_a + 1)) - 1;
677
678 dev_warn(&pdev->dev, "rtc_ck is %s\n",
679 (rate < ((pred_a + 1) * (pred_s + 1))) ?
680 "fast" : "slow");
681 }
682
683 cr = readl_relaxed(rtc->base + regs->cr);
684
685 prer = readl_relaxed(rtc->base + regs->prer);
686 prer &= STM32_RTC_PRER_PRED_S | STM32_RTC_PRER_PRED_A;
687
688 pred_s = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) &
689 STM32_RTC_PRER_PRED_S;
690 pred_a = (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) &
691 STM32_RTC_PRER_PRED_A;
692
693 /* quit if there is nothing to initialize */
694 if ((cr & STM32_RTC_CR_FMT) == 0 && prer == (pred_s | pred_a))
695 return 0;
696
697 stm32_rtc_wpr_unlock(rtc);
698
699 ret = stm32_rtc_enter_init_mode(rtc);
700 if (ret) {
701 dev_err(&pdev->dev,
702 "Can't enter in init mode. Prescaler config failed.\n");
703 goto end;
704 }
705
706 writel_relaxed(pred_s, rtc->base + regs->prer);
707 writel_relaxed(pred_a | pred_s, rtc->base + regs->prer);
708
709 /* Force 24h time format */
710 cr &= ~STM32_RTC_CR_FMT;
711 writel_relaxed(cr, rtc->base + regs->cr);
712
713 stm32_rtc_exit_init_mode(rtc);
714
715 ret = stm32_rtc_wait_sync(rtc);
716end:
717 stm32_rtc_wpr_lock(rtc);
718
719 return ret;
720}
721
722static int stm32_rtc_probe(struct platform_device *pdev)
723{
724 struct stm32_rtc *rtc;
725 const struct stm32_rtc_registers *regs;
726 int ret;
727
728 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
729 if (!rtc)
730 return -ENOMEM;
731
732 rtc->base = devm_platform_ioremap_resource(pdev, 0);
733 if (IS_ERR(rtc->base))
734 return PTR_ERR(rtc->base);
735
736 rtc->data = (struct stm32_rtc_data *)
737 of_device_get_match_data(&pdev->dev);
738 regs = &rtc->data->regs;
739
740 if (rtc->data->need_dbp) {
741 rtc->dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
742 "st,syscfg");
743 if (IS_ERR(rtc->dbp)) {
744 dev_err(&pdev->dev, "no st,syscfg\n");
745 return PTR_ERR(rtc->dbp);
746 }
747
748 ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg",
749 1, &rtc->dbp_reg);
750 if (ret) {
751 dev_err(&pdev->dev, "can't read DBP register offset\n");
752 return ret;
753 }
754
755 ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg",
756 2, &rtc->dbp_mask);
757 if (ret) {
758 dev_err(&pdev->dev, "can't read DBP register mask\n");
759 return ret;
760 }
761 }
762
763 if (!rtc->data->has_pclk) {
764 rtc->pclk = NULL;
765 rtc->rtc_ck = devm_clk_get(&pdev->dev, NULL);
766 } else {
767 rtc->pclk = devm_clk_get(&pdev->dev, "pclk");
768 if (IS_ERR(rtc->pclk))
769 return dev_err_probe(&pdev->dev, PTR_ERR(rtc->pclk), "no pclk clock");
770
771 rtc->rtc_ck = devm_clk_get(&pdev->dev, "rtc_ck");
772 }
773 if (IS_ERR(rtc->rtc_ck))
774 return dev_err_probe(&pdev->dev, PTR_ERR(rtc->rtc_ck), "no rtc_ck clock");
775
776 if (rtc->data->has_pclk) {
777 ret = clk_prepare_enable(rtc->pclk);
778 if (ret)
779 return ret;
780 }
781
782 ret = clk_prepare_enable(rtc->rtc_ck);
783 if (ret)
784 goto err_no_rtc_ck;
785
786 if (rtc->data->need_dbp)
787 regmap_update_bits(rtc->dbp, rtc->dbp_reg,
788 rtc->dbp_mask, rtc->dbp_mask);
789
790 /*
791 * After a system reset, RTC_ISR.INITS flag can be read to check if
792 * the calendar has been initialized or not. INITS flag is reset by a
793 * power-on reset (no vbat, no power-supply). It is not reset if
794 * rtc_ck parent clock has changed (so RTC prescalers need to be
795 * changed). That's why we cannot rely on this flag to know if RTC
796 * init has to be done.
797 */
798 ret = stm32_rtc_init(pdev, rtc);
799 if (ret)
800 goto err;
801
802 rtc->irq_alarm = platform_get_irq(pdev, 0);
803 if (rtc->irq_alarm <= 0) {
804 ret = rtc->irq_alarm;
805 goto err;
806 }
807
808 ret = device_init_wakeup(&pdev->dev, true);
809 if (ret)
810 goto err;
811
812 ret = dev_pm_set_wake_irq(&pdev->dev, rtc->irq_alarm);
813 if (ret)
814 goto err;
815
816 platform_set_drvdata(pdev, rtc);
817
818 rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
819 &stm32_rtc_ops, THIS_MODULE);
820 if (IS_ERR(rtc->rtc_dev)) {
821 ret = PTR_ERR(rtc->rtc_dev);
822 dev_err(&pdev->dev, "rtc device registration failed, err=%d\n",
823 ret);
824 goto err;
825 }
826
827 /* Handle RTC alarm interrupts */
828 ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL,
829 stm32_rtc_alarm_irq, IRQF_ONESHOT,
830 pdev->name, rtc);
831 if (ret) {
832 dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n",
833 rtc->irq_alarm);
834 goto err;
835 }
836
837 /*
838 * If INITS flag is reset (calendar year field set to 0x00), calendar
839 * must be initialized
840 */
841 if (!(readl_relaxed(rtc->base + regs->isr) & STM32_RTC_ISR_INITS))
842 dev_warn(&pdev->dev, "Date/Time must be initialized\n");
843
844 if (regs->verr != UNDEF_REG) {
845 u32 ver = readl_relaxed(rtc->base + regs->verr);
846
847 dev_info(&pdev->dev, "registered rev:%d.%d\n",
848 (ver >> STM32_RTC_VERR_MAJREV_SHIFT) & 0xF,
849 (ver >> STM32_RTC_VERR_MINREV_SHIFT) & 0xF);
850 }
851
852 return 0;
853
854err:
855 clk_disable_unprepare(rtc->rtc_ck);
856err_no_rtc_ck:
857 if (rtc->data->has_pclk)
858 clk_disable_unprepare(rtc->pclk);
859
860 if (rtc->data->need_dbp)
861 regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0);
862
863 dev_pm_clear_wake_irq(&pdev->dev);
864 device_init_wakeup(&pdev->dev, false);
865
866 return ret;
867}
868
869static void stm32_rtc_remove(struct platform_device *pdev)
870{
871 struct stm32_rtc *rtc = platform_get_drvdata(pdev);
872 const struct stm32_rtc_registers *regs = &rtc->data->regs;
873 unsigned int cr;
874
875 /* Disable interrupts */
876 stm32_rtc_wpr_unlock(rtc);
877 cr = readl_relaxed(rtc->base + regs->cr);
878 cr &= ~STM32_RTC_CR_ALRAIE;
879 writel_relaxed(cr, rtc->base + regs->cr);
880 stm32_rtc_wpr_lock(rtc);
881
882 clk_disable_unprepare(rtc->rtc_ck);
883 if (rtc->data->has_pclk)
884 clk_disable_unprepare(rtc->pclk);
885
886 /* Enable backup domain write protection if needed */
887 if (rtc->data->need_dbp)
888 regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0);
889
890 dev_pm_clear_wake_irq(&pdev->dev);
891 device_init_wakeup(&pdev->dev, false);
892}
893
894static int stm32_rtc_suspend(struct device *dev)
895{
896 struct stm32_rtc *rtc = dev_get_drvdata(dev);
897
898 if (rtc->data->has_pclk)
899 clk_disable_unprepare(rtc->pclk);
900
901 return 0;
902}
903
904static int stm32_rtc_resume(struct device *dev)
905{
906 struct stm32_rtc *rtc = dev_get_drvdata(dev);
907 int ret = 0;
908
909 if (rtc->data->has_pclk) {
910 ret = clk_prepare_enable(rtc->pclk);
911 if (ret)
912 return ret;
913 }
914
915 ret = stm32_rtc_wait_sync(rtc);
916 if (ret < 0) {
917 if (rtc->data->has_pclk)
918 clk_disable_unprepare(rtc->pclk);
919 return ret;
920 }
921
922 return ret;
923}
924
925static const struct dev_pm_ops stm32_rtc_pm_ops = {
926 NOIRQ_SYSTEM_SLEEP_PM_OPS(stm32_rtc_suspend, stm32_rtc_resume)
927};
928
929static struct platform_driver stm32_rtc_driver = {
930 .probe = stm32_rtc_probe,
931 .remove_new = stm32_rtc_remove,
932 .driver = {
933 .name = DRIVER_NAME,
934 .pm = &stm32_rtc_pm_ops,
935 .of_match_table = stm32_rtc_of_match,
936 },
937};
938
939module_platform_driver(stm32_rtc_driver);
940
941MODULE_ALIAS("platform:" DRIVER_NAME);
942MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
943MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver");
944MODULE_LICENSE("GPL v2");
1/*
2 * Copyright (C) STMicroelectronics SA 2017
3 * Author: Amelie Delaunay <amelie.delaunay@st.com> for STMicroelectronics.
4 * License terms: GNU General Public License (GPL), version 2
5 */
6
7#include <linux/bcd.h>
8#include <linux/clk.h>
9#include <linux/iopoll.h>
10#include <linux/ioport.h>
11#include <linux/mfd/syscon.h>
12#include <linux/module.h>
13#include <linux/of_device.h>
14#include <linux/regmap.h>
15#include <linux/rtc.h>
16
17#define DRIVER_NAME "stm32_rtc"
18
19/* STM32 RTC registers */
20#define STM32_RTC_TR 0x00
21#define STM32_RTC_DR 0x04
22#define STM32_RTC_CR 0x08
23#define STM32_RTC_ISR 0x0C
24#define STM32_RTC_PRER 0x10
25#define STM32_RTC_ALRMAR 0x1C
26#define STM32_RTC_WPR 0x24
27
28/* STM32_RTC_TR bit fields */
29#define STM32_RTC_TR_SEC_SHIFT 0
30#define STM32_RTC_TR_SEC GENMASK(6, 0)
31#define STM32_RTC_TR_MIN_SHIFT 8
32#define STM32_RTC_TR_MIN GENMASK(14, 8)
33#define STM32_RTC_TR_HOUR_SHIFT 16
34#define STM32_RTC_TR_HOUR GENMASK(21, 16)
35
36/* STM32_RTC_DR bit fields */
37#define STM32_RTC_DR_DATE_SHIFT 0
38#define STM32_RTC_DR_DATE GENMASK(5, 0)
39#define STM32_RTC_DR_MONTH_SHIFT 8
40#define STM32_RTC_DR_MONTH GENMASK(12, 8)
41#define STM32_RTC_DR_WDAY_SHIFT 13
42#define STM32_RTC_DR_WDAY GENMASK(15, 13)
43#define STM32_RTC_DR_YEAR_SHIFT 16
44#define STM32_RTC_DR_YEAR GENMASK(23, 16)
45
46/* STM32_RTC_CR bit fields */
47#define STM32_RTC_CR_FMT BIT(6)
48#define STM32_RTC_CR_ALRAE BIT(8)
49#define STM32_RTC_CR_ALRAIE BIT(12)
50
51/* STM32_RTC_ISR bit fields */
52#define STM32_RTC_ISR_ALRAWF BIT(0)
53#define STM32_RTC_ISR_INITS BIT(4)
54#define STM32_RTC_ISR_RSF BIT(5)
55#define STM32_RTC_ISR_INITF BIT(6)
56#define STM32_RTC_ISR_INIT BIT(7)
57#define STM32_RTC_ISR_ALRAF BIT(8)
58
59/* STM32_RTC_PRER bit fields */
60#define STM32_RTC_PRER_PRED_S_SHIFT 0
61#define STM32_RTC_PRER_PRED_S GENMASK(14, 0)
62#define STM32_RTC_PRER_PRED_A_SHIFT 16
63#define STM32_RTC_PRER_PRED_A GENMASK(22, 16)
64
65/* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */
66#define STM32_RTC_ALRMXR_SEC_SHIFT 0
67#define STM32_RTC_ALRMXR_SEC GENMASK(6, 0)
68#define STM32_RTC_ALRMXR_SEC_MASK BIT(7)
69#define STM32_RTC_ALRMXR_MIN_SHIFT 8
70#define STM32_RTC_ALRMXR_MIN GENMASK(14, 8)
71#define STM32_RTC_ALRMXR_MIN_MASK BIT(15)
72#define STM32_RTC_ALRMXR_HOUR_SHIFT 16
73#define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16)
74#define STM32_RTC_ALRMXR_PM BIT(22)
75#define STM32_RTC_ALRMXR_HOUR_MASK BIT(23)
76#define STM32_RTC_ALRMXR_DATE_SHIFT 24
77#define STM32_RTC_ALRMXR_DATE GENMASK(29, 24)
78#define STM32_RTC_ALRMXR_WDSEL BIT(30)
79#define STM32_RTC_ALRMXR_WDAY_SHIFT 24
80#define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24)
81#define STM32_RTC_ALRMXR_DATE_MASK BIT(31)
82
83/* STM32_RTC_WPR key constants */
84#define RTC_WPR_1ST_KEY 0xCA
85#define RTC_WPR_2ND_KEY 0x53
86#define RTC_WPR_WRONG_KEY 0xFF
87
88/*
89 * RTC registers are protected against parasitic write access.
90 * PWR_CR_DBP bit must be set to enable write access to RTC registers.
91 */
92/* STM32_PWR_CR */
93#define PWR_CR 0x00
94/* STM32_PWR_CR bit field */
95#define PWR_CR_DBP BIT(8)
96
97struct stm32_rtc_data {
98 bool has_pclk;
99};
100
101struct stm32_rtc {
102 struct rtc_device *rtc_dev;
103 void __iomem *base;
104 struct regmap *dbp;
105 struct stm32_rtc_data *data;
106 struct clk *pclk;
107 struct clk *rtc_ck;
108 int irq_alarm;
109};
110
111static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc)
112{
113 writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + STM32_RTC_WPR);
114 writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + STM32_RTC_WPR);
115}
116
117static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc)
118{
119 writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + STM32_RTC_WPR);
120}
121
122static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
123{
124 unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
125
126 if (!(isr & STM32_RTC_ISR_INITF)) {
127 isr |= STM32_RTC_ISR_INIT;
128 writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
129
130 /*
131 * It takes around 2 rtc_ck clock cycles to enter in
132 * initialization phase mode (and have INITF flag set). As
133 * slowest rtc_ck frequency may be 32kHz and highest should be
134 * 1MHz, we poll every 10 us with a timeout of 100ms.
135 */
136 return readl_relaxed_poll_timeout_atomic(
137 rtc->base + STM32_RTC_ISR,
138 isr, (isr & STM32_RTC_ISR_INITF),
139 10, 100000);
140 }
141
142 return 0;
143}
144
145static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc)
146{
147 unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
148
149 isr &= ~STM32_RTC_ISR_INIT;
150 writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
151}
152
153static int stm32_rtc_wait_sync(struct stm32_rtc *rtc)
154{
155 unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
156
157 isr &= ~STM32_RTC_ISR_RSF;
158 writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
159
160 /*
161 * Wait for RSF to be set to ensure the calendar registers are
162 * synchronised, it takes around 2 rtc_ck clock cycles
163 */
164 return readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
165 isr,
166 (isr & STM32_RTC_ISR_RSF),
167 10, 100000);
168}
169
170static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id)
171{
172 struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id;
173 unsigned int isr, cr;
174
175 mutex_lock(&rtc->rtc_dev->ops_lock);
176
177 isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
178 cr = readl_relaxed(rtc->base + STM32_RTC_CR);
179
180 if ((isr & STM32_RTC_ISR_ALRAF) &&
181 (cr & STM32_RTC_CR_ALRAIE)) {
182 /* Alarm A flag - Alarm interrupt */
183 dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n");
184
185 /* Pass event to the kernel */
186 rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
187
188 /* Clear event flag, otherwise new events won't be received */
189 writel_relaxed(isr & ~STM32_RTC_ISR_ALRAF,
190 rtc->base + STM32_RTC_ISR);
191 }
192
193 mutex_unlock(&rtc->rtc_dev->ops_lock);
194
195 return IRQ_HANDLED;
196}
197
198/* Convert rtc_time structure from bin to bcd format */
199static void tm2bcd(struct rtc_time *tm)
200{
201 tm->tm_sec = bin2bcd(tm->tm_sec);
202 tm->tm_min = bin2bcd(tm->tm_min);
203 tm->tm_hour = bin2bcd(tm->tm_hour);
204
205 tm->tm_mday = bin2bcd(tm->tm_mday);
206 tm->tm_mon = bin2bcd(tm->tm_mon + 1);
207 tm->tm_year = bin2bcd(tm->tm_year - 100);
208 /*
209 * Number of days since Sunday
210 * - on kernel side, 0=Sunday...6=Saturday
211 * - on rtc side, 0=invalid,1=Monday...7=Sunday
212 */
213 tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday;
214}
215
216/* Convert rtc_time structure from bcd to bin format */
217static void bcd2tm(struct rtc_time *tm)
218{
219 tm->tm_sec = bcd2bin(tm->tm_sec);
220 tm->tm_min = bcd2bin(tm->tm_min);
221 tm->tm_hour = bcd2bin(tm->tm_hour);
222
223 tm->tm_mday = bcd2bin(tm->tm_mday);
224 tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
225 tm->tm_year = bcd2bin(tm->tm_year) + 100;
226 /*
227 * Number of days since Sunday
228 * - on kernel side, 0=Sunday...6=Saturday
229 * - on rtc side, 0=invalid,1=Monday...7=Sunday
230 */
231 tm->tm_wday %= 7;
232}
233
234static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm)
235{
236 struct stm32_rtc *rtc = dev_get_drvdata(dev);
237 unsigned int tr, dr;
238
239 /* Time and Date in BCD format */
240 tr = readl_relaxed(rtc->base + STM32_RTC_TR);
241 dr = readl_relaxed(rtc->base + STM32_RTC_DR);
242
243 tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
244 tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
245 tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
246
247 tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
248 tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
249 tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
250 tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT;
251
252 /* We don't report tm_yday and tm_isdst */
253
254 bcd2tm(tm);
255
256 return 0;
257}
258
259static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm)
260{
261 struct stm32_rtc *rtc = dev_get_drvdata(dev);
262 unsigned int tr, dr;
263 int ret = 0;
264
265 tm2bcd(tm);
266
267 /* Time in BCD format */
268 tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) |
269 ((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) |
270 ((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR);
271
272 /* Date in BCD format */
273 dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) |
274 ((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) |
275 ((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) |
276 ((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY);
277
278 stm32_rtc_wpr_unlock(rtc);
279
280 ret = stm32_rtc_enter_init_mode(rtc);
281 if (ret) {
282 dev_err(dev, "Can't enter in init mode. Set time aborted.\n");
283 goto end;
284 }
285
286 writel_relaxed(tr, rtc->base + STM32_RTC_TR);
287 writel_relaxed(dr, rtc->base + STM32_RTC_DR);
288
289 stm32_rtc_exit_init_mode(rtc);
290
291 ret = stm32_rtc_wait_sync(rtc);
292end:
293 stm32_rtc_wpr_lock(rtc);
294
295 return ret;
296}
297
298static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
299{
300 struct stm32_rtc *rtc = dev_get_drvdata(dev);
301 struct rtc_time *tm = &alrm->time;
302 unsigned int alrmar, cr, isr;
303
304 alrmar = readl_relaxed(rtc->base + STM32_RTC_ALRMAR);
305 cr = readl_relaxed(rtc->base + STM32_RTC_CR);
306 isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
307
308 if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) {
309 /*
310 * Date/day doesn't matter in Alarm comparison so alarm
311 * triggers every day
312 */
313 tm->tm_mday = -1;
314 tm->tm_wday = -1;
315 } else {
316 if (alrmar & STM32_RTC_ALRMXR_WDSEL) {
317 /* Alarm is set to a day of week */
318 tm->tm_mday = -1;
319 tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >>
320 STM32_RTC_ALRMXR_WDAY_SHIFT;
321 tm->tm_wday %= 7;
322 } else {
323 /* Alarm is set to a day of month */
324 tm->tm_wday = -1;
325 tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >>
326 STM32_RTC_ALRMXR_DATE_SHIFT;
327 }
328 }
329
330 if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) {
331 /* Hours don't matter in Alarm comparison */
332 tm->tm_hour = -1;
333 } else {
334 tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >>
335 STM32_RTC_ALRMXR_HOUR_SHIFT;
336 if (alrmar & STM32_RTC_ALRMXR_PM)
337 tm->tm_hour += 12;
338 }
339
340 if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) {
341 /* Minutes don't matter in Alarm comparison */
342 tm->tm_min = -1;
343 } else {
344 tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >>
345 STM32_RTC_ALRMXR_MIN_SHIFT;
346 }
347
348 if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) {
349 /* Seconds don't matter in Alarm comparison */
350 tm->tm_sec = -1;
351 } else {
352 tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >>
353 STM32_RTC_ALRMXR_SEC_SHIFT;
354 }
355
356 bcd2tm(tm);
357
358 alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0;
359 alrm->pending = (isr & STM32_RTC_ISR_ALRAF) ? 1 : 0;
360
361 return 0;
362}
363
364static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
365{
366 struct stm32_rtc *rtc = dev_get_drvdata(dev);
367 unsigned int isr, cr;
368
369 cr = readl_relaxed(rtc->base + STM32_RTC_CR);
370
371 stm32_rtc_wpr_unlock(rtc);
372
373 /* We expose Alarm A to the kernel */
374 if (enabled)
375 cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
376 else
377 cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
378 writel_relaxed(cr, rtc->base + STM32_RTC_CR);
379
380 /* Clear event flag, otherwise new events won't be received */
381 isr = readl_relaxed(rtc->base + STM32_RTC_ISR);
382 isr &= ~STM32_RTC_ISR_ALRAF;
383 writel_relaxed(isr, rtc->base + STM32_RTC_ISR);
384
385 stm32_rtc_wpr_lock(rtc);
386
387 return 0;
388}
389
390static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm)
391{
392 int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec;
393 unsigned int dr = readl_relaxed(rtc->base + STM32_RTC_DR);
394 unsigned int tr = readl_relaxed(rtc->base + STM32_RTC_TR);
395
396 cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
397 cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
398 cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
399 cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
400 cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
401 cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
402
403 /*
404 * Assuming current date is M-D-Y H:M:S.
405 * RTC alarm can't be set on a specific month and year.
406 * So the valid alarm range is:
407 * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S
408 * with a specific case for December...
409 */
410 if ((((tm->tm_year > cur_year) &&
411 (tm->tm_mon == 0x1) && (cur_mon == 0x12)) ||
412 ((tm->tm_year == cur_year) &&
413 (tm->tm_mon <= cur_mon + 1))) &&
414 ((tm->tm_mday > cur_day) ||
415 ((tm->tm_mday == cur_day) &&
416 ((tm->tm_hour > cur_hour) ||
417 ((tm->tm_hour == cur_hour) && (tm->tm_min > cur_min)) ||
418 ((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) &&
419 (tm->tm_sec >= cur_sec))))))
420 return 0;
421
422 return -EINVAL;
423}
424
425static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
426{
427 struct stm32_rtc *rtc = dev_get_drvdata(dev);
428 struct rtc_time *tm = &alrm->time;
429 unsigned int cr, isr, alrmar;
430 int ret = 0;
431
432 tm2bcd(tm);
433
434 /*
435 * RTC alarm can't be set on a specific date, unless this date is
436 * up to the same day of month next month.
437 */
438 if (stm32_rtc_valid_alrm(rtc, tm) < 0) {
439 dev_err(dev, "Alarm can be set only on upcoming month.\n");
440 return -EINVAL;
441 }
442
443 alrmar = 0;
444 /* tm_year and tm_mon are not used because not supported by RTC */
445 alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) &
446 STM32_RTC_ALRMXR_DATE;
447 /* 24-hour format */
448 alrmar &= ~STM32_RTC_ALRMXR_PM;
449 alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) &
450 STM32_RTC_ALRMXR_HOUR;
451 alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) &
452 STM32_RTC_ALRMXR_MIN;
453 alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) &
454 STM32_RTC_ALRMXR_SEC;
455
456 stm32_rtc_wpr_unlock(rtc);
457
458 /* Disable Alarm */
459 cr = readl_relaxed(rtc->base + STM32_RTC_CR);
460 cr &= ~STM32_RTC_CR_ALRAE;
461 writel_relaxed(cr, rtc->base + STM32_RTC_CR);
462
463 /*
464 * Poll Alarm write flag to be sure that Alarm update is allowed: it
465 * takes around 2 rtc_ck clock cycles
466 */
467 ret = readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR,
468 isr,
469 (isr & STM32_RTC_ISR_ALRAWF),
470 10, 100000);
471
472 if (ret) {
473 dev_err(dev, "Alarm update not allowed\n");
474 goto end;
475 }
476
477 /* Write to Alarm register */
478 writel_relaxed(alrmar, rtc->base + STM32_RTC_ALRMAR);
479
480 if (alrm->enabled)
481 stm32_rtc_alarm_irq_enable(dev, 1);
482 else
483 stm32_rtc_alarm_irq_enable(dev, 0);
484
485end:
486 stm32_rtc_wpr_lock(rtc);
487
488 return ret;
489}
490
491static const struct rtc_class_ops stm32_rtc_ops = {
492 .read_time = stm32_rtc_read_time,
493 .set_time = stm32_rtc_set_time,
494 .read_alarm = stm32_rtc_read_alarm,
495 .set_alarm = stm32_rtc_set_alarm,
496 .alarm_irq_enable = stm32_rtc_alarm_irq_enable,
497};
498
499static const struct stm32_rtc_data stm32_rtc_data = {
500 .has_pclk = false,
501};
502
503static const struct stm32_rtc_data stm32h7_rtc_data = {
504 .has_pclk = true,
505};
506
507static const struct of_device_id stm32_rtc_of_match[] = {
508 { .compatible = "st,stm32-rtc", .data = &stm32_rtc_data },
509 { .compatible = "st,stm32h7-rtc", .data = &stm32h7_rtc_data },
510 {}
511};
512MODULE_DEVICE_TABLE(of, stm32_rtc_of_match);
513
514static int stm32_rtc_init(struct platform_device *pdev,
515 struct stm32_rtc *rtc)
516{
517 unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr;
518 unsigned int rate;
519 int ret = 0;
520
521 rate = clk_get_rate(rtc->rtc_ck);
522
523 /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */
524 pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT;
525 pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT;
526
527 for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) {
528 pred_s = (rate / (pred_a + 1)) - 1;
529
530 if (((pred_s + 1) * (pred_a + 1)) == rate)
531 break;
532 }
533
534 /*
535 * Can't find a 1Hz, so give priority to RTC power consumption
536 * by choosing the higher possible value for prediv_a
537 */
538 if ((pred_s > pred_s_max) || (pred_a > pred_a_max)) {
539 pred_a = pred_a_max;
540 pred_s = (rate / (pred_a + 1)) - 1;
541
542 dev_warn(&pdev->dev, "rtc_ck is %s\n",
543 (rate < ((pred_a + 1) * (pred_s + 1))) ?
544 "fast" : "slow");
545 }
546
547 stm32_rtc_wpr_unlock(rtc);
548
549 ret = stm32_rtc_enter_init_mode(rtc);
550 if (ret) {
551 dev_err(&pdev->dev,
552 "Can't enter in init mode. Prescaler config failed.\n");
553 goto end;
554 }
555
556 prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S;
557 writel_relaxed(prer, rtc->base + STM32_RTC_PRER);
558 prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A;
559 writel_relaxed(prer, rtc->base + STM32_RTC_PRER);
560
561 /* Force 24h time format */
562 cr = readl_relaxed(rtc->base + STM32_RTC_CR);
563 cr &= ~STM32_RTC_CR_FMT;
564 writel_relaxed(cr, rtc->base + STM32_RTC_CR);
565
566 stm32_rtc_exit_init_mode(rtc);
567
568 ret = stm32_rtc_wait_sync(rtc);
569end:
570 stm32_rtc_wpr_lock(rtc);
571
572 return ret;
573}
574
575static int stm32_rtc_probe(struct platform_device *pdev)
576{
577 struct stm32_rtc *rtc;
578 struct resource *res;
579 const struct of_device_id *match;
580 int ret;
581
582 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
583 if (!rtc)
584 return -ENOMEM;
585
586 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
587 rtc->base = devm_ioremap_resource(&pdev->dev, res);
588 if (IS_ERR(rtc->base))
589 return PTR_ERR(rtc->base);
590
591 rtc->dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
592 "st,syscfg");
593 if (IS_ERR(rtc->dbp)) {
594 dev_err(&pdev->dev, "no st,syscfg\n");
595 return PTR_ERR(rtc->dbp);
596 }
597
598 match = of_match_device(stm32_rtc_of_match, &pdev->dev);
599 rtc->data = (struct stm32_rtc_data *)match->data;
600
601 if (!rtc->data->has_pclk) {
602 rtc->pclk = NULL;
603 rtc->rtc_ck = devm_clk_get(&pdev->dev, NULL);
604 } else {
605 rtc->pclk = devm_clk_get(&pdev->dev, "pclk");
606 if (IS_ERR(rtc->pclk)) {
607 dev_err(&pdev->dev, "no pclk clock");
608 return PTR_ERR(rtc->pclk);
609 }
610 rtc->rtc_ck = devm_clk_get(&pdev->dev, "rtc_ck");
611 }
612 if (IS_ERR(rtc->rtc_ck)) {
613 dev_err(&pdev->dev, "no rtc_ck clock");
614 return PTR_ERR(rtc->rtc_ck);
615 }
616
617 if (rtc->data->has_pclk) {
618 ret = clk_prepare_enable(rtc->pclk);
619 if (ret)
620 return ret;
621 }
622
623 ret = clk_prepare_enable(rtc->rtc_ck);
624 if (ret)
625 goto err;
626
627 regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, PWR_CR_DBP);
628
629 /*
630 * After a system reset, RTC_ISR.INITS flag can be read to check if
631 * the calendar has been initalized or not. INITS flag is reset by a
632 * power-on reset (no vbat, no power-supply). It is not reset if
633 * rtc_ck parent clock has changed (so RTC prescalers need to be
634 * changed). That's why we cannot rely on this flag to know if RTC
635 * init has to be done.
636 */
637 ret = stm32_rtc_init(pdev, rtc);
638 if (ret)
639 goto err;
640
641 rtc->irq_alarm = platform_get_irq(pdev, 0);
642 if (rtc->irq_alarm <= 0) {
643 dev_err(&pdev->dev, "no alarm irq\n");
644 ret = rtc->irq_alarm;
645 goto err;
646 }
647
648 platform_set_drvdata(pdev, rtc);
649
650 ret = device_init_wakeup(&pdev->dev, true);
651 if (ret)
652 dev_warn(&pdev->dev,
653 "alarm won't be able to wake up the system");
654
655 rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
656 &stm32_rtc_ops, THIS_MODULE);
657 if (IS_ERR(rtc->rtc_dev)) {
658 ret = PTR_ERR(rtc->rtc_dev);
659 dev_err(&pdev->dev, "rtc device registration failed, err=%d\n",
660 ret);
661 goto err;
662 }
663
664 /* Handle RTC alarm interrupts */
665 ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL,
666 stm32_rtc_alarm_irq,
667 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
668 pdev->name, rtc);
669 if (ret) {
670 dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n",
671 rtc->irq_alarm);
672 goto err;
673 }
674
675 /*
676 * If INITS flag is reset (calendar year field set to 0x00), calendar
677 * must be initialized
678 */
679 if (!(readl_relaxed(rtc->base + STM32_RTC_ISR) & STM32_RTC_ISR_INITS))
680 dev_warn(&pdev->dev, "Date/Time must be initialized\n");
681
682 return 0;
683err:
684 if (rtc->data->has_pclk)
685 clk_disable_unprepare(rtc->pclk);
686 clk_disable_unprepare(rtc->rtc_ck);
687
688 regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, 0);
689
690 device_init_wakeup(&pdev->dev, false);
691
692 return ret;
693}
694
695static int stm32_rtc_remove(struct platform_device *pdev)
696{
697 struct stm32_rtc *rtc = platform_get_drvdata(pdev);
698 unsigned int cr;
699
700 /* Disable interrupts */
701 stm32_rtc_wpr_unlock(rtc);
702 cr = readl_relaxed(rtc->base + STM32_RTC_CR);
703 cr &= ~STM32_RTC_CR_ALRAIE;
704 writel_relaxed(cr, rtc->base + STM32_RTC_CR);
705 stm32_rtc_wpr_lock(rtc);
706
707 clk_disable_unprepare(rtc->rtc_ck);
708 if (rtc->data->has_pclk)
709 clk_disable_unprepare(rtc->pclk);
710
711 /* Enable backup domain write protection */
712 regmap_update_bits(rtc->dbp, PWR_CR, PWR_CR_DBP, 0);
713
714 device_init_wakeup(&pdev->dev, false);
715
716 return 0;
717}
718
719#ifdef CONFIG_PM_SLEEP
720static int stm32_rtc_suspend(struct device *dev)
721{
722 struct stm32_rtc *rtc = dev_get_drvdata(dev);
723
724 if (rtc->data->has_pclk)
725 clk_disable_unprepare(rtc->pclk);
726
727 if (device_may_wakeup(dev))
728 return enable_irq_wake(rtc->irq_alarm);
729
730 return 0;
731}
732
733static int stm32_rtc_resume(struct device *dev)
734{
735 struct stm32_rtc *rtc = dev_get_drvdata(dev);
736 int ret = 0;
737
738 if (rtc->data->has_pclk) {
739 ret = clk_prepare_enable(rtc->pclk);
740 if (ret)
741 return ret;
742 }
743
744 ret = stm32_rtc_wait_sync(rtc);
745 if (ret < 0)
746 return ret;
747
748 if (device_may_wakeup(dev))
749 return disable_irq_wake(rtc->irq_alarm);
750
751 return ret;
752}
753#endif
754
755static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops,
756 stm32_rtc_suspend, stm32_rtc_resume);
757
758static struct platform_driver stm32_rtc_driver = {
759 .probe = stm32_rtc_probe,
760 .remove = stm32_rtc_remove,
761 .driver = {
762 .name = DRIVER_NAME,
763 .pm = &stm32_rtc_pm_ops,
764 .of_match_table = stm32_rtc_of_match,
765 },
766};
767
768module_platform_driver(stm32_rtc_driver);
769
770MODULE_ALIAS("platform:" DRIVER_NAME);
771MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
772MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver");
773MODULE_LICENSE("GPL v2");