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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / rtc / rtc-stm32.c
blob781cabb2afca4e441047c473d5f206ceeb31c953
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/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/pm_wakeirq.h>
15 #include <linux/regmap.h>
16 #include <linux/rtc.h>
17
18 #define DRIVER_NAME "stm32_rtc"
19
20 /* STM32_RTC_TR bit fields */
21 #define STM32_RTC_TR_SEC_SHIFT 0
22 #define STM32_RTC_TR_SEC GENMASK(6, 0)
23 #define STM32_RTC_TR_MIN_SHIFT 8
24 #define STM32_RTC_TR_MIN GENMASK(14, 8)
25 #define STM32_RTC_TR_HOUR_SHIFT 16
26 #define STM32_RTC_TR_HOUR GENMASK(21, 16)
27
28 /* STM32_RTC_DR bit fields */
29 #define STM32_RTC_DR_DATE_SHIFT 0
30 #define STM32_RTC_DR_DATE GENMASK(5, 0)
31 #define STM32_RTC_DR_MONTH_SHIFT 8
32 #define STM32_RTC_DR_MONTH GENMASK(12, 8)
33 #define STM32_RTC_DR_WDAY_SHIFT 13
34 #define STM32_RTC_DR_WDAY GENMASK(15, 13)
35 #define STM32_RTC_DR_YEAR_SHIFT 16
36 #define STM32_RTC_DR_YEAR GENMASK(23, 16)
37
38 /* STM32_RTC_CR bit fields */
39 #define STM32_RTC_CR_FMT BIT(6)
40 #define STM32_RTC_CR_ALRAE BIT(8)
41 #define STM32_RTC_CR_ALRAIE BIT(12)
42
43 /* STM32_RTC_ISR/STM32_RTC_ICSR bit fields */
44 #define STM32_RTC_ISR_ALRAWF BIT(0)
45 #define STM32_RTC_ISR_INITS BIT(4)
46 #define STM32_RTC_ISR_RSF BIT(5)
47 #define STM32_RTC_ISR_INITF BIT(6)
48 #define STM32_RTC_ISR_INIT BIT(7)
49 #define STM32_RTC_ISR_ALRAF BIT(8)
50
51 /* STM32_RTC_PRER bit fields */
52 #define STM32_RTC_PRER_PRED_S_SHIFT 0
53 #define STM32_RTC_PRER_PRED_S GENMASK(14, 0)
54 #define STM32_RTC_PRER_PRED_A_SHIFT 16
55 #define STM32_RTC_PRER_PRED_A GENMASK(22, 16)
56
57 /* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */
58 #define STM32_RTC_ALRMXR_SEC_SHIFT 0
59 #define STM32_RTC_ALRMXR_SEC GENMASK(6, 0)
60 #define STM32_RTC_ALRMXR_SEC_MASK BIT(7)
61 #define STM32_RTC_ALRMXR_MIN_SHIFT 8
62 #define STM32_RTC_ALRMXR_MIN GENMASK(14, 8)
63 #define STM32_RTC_ALRMXR_MIN_MASK BIT(15)
64 #define STM32_RTC_ALRMXR_HOUR_SHIFT 16
65 #define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16)
66 #define STM32_RTC_ALRMXR_PM BIT(22)
67 #define STM32_RTC_ALRMXR_HOUR_MASK BIT(23)
68 #define STM32_RTC_ALRMXR_DATE_SHIFT 24
69 #define STM32_RTC_ALRMXR_DATE GENMASK(29, 24)
70 #define STM32_RTC_ALRMXR_WDSEL BIT(30)
71 #define STM32_RTC_ALRMXR_WDAY_SHIFT 24
72 #define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24)
73 #define STM32_RTC_ALRMXR_DATE_MASK BIT(31)
74
75 /* STM32_RTC_SR/_SCR bit fields */
76 #define STM32_RTC_SR_ALRA BIT(0)
77
78 /* STM32_RTC_VERR bit fields */
79 #define STM32_RTC_VERR_MINREV_SHIFT 0
80 #define STM32_RTC_VERR_MINREV GENMASK(3, 0)
81 #define STM32_RTC_VERR_MAJREV_SHIFT 4
82 #define STM32_RTC_VERR_MAJREV GENMASK(7, 4)
83
84 /* STM32_RTC_WPR key constants */
85 #define RTC_WPR_1ST_KEY 0xCA
86 #define RTC_WPR_2ND_KEY 0x53
87 #define RTC_WPR_WRONG_KEY 0xFF
88
89 /* Max STM32 RTC register offset is 0x3FC */
90 #define UNDEF_REG 0xFFFF
91
92 struct stm32_rtc;
93
94 struct stm32_rtc_registers {
95 u16 tr;
96 u16 dr;
97 u16 cr;
98 u16 isr;
99 u16 prer;
100 u16 alrmar;
101 u16 wpr;
102 u16 sr;
103 u16 scr;
104 u16 verr;
105 };
106
107 struct stm32_rtc_events {
108 u32 alra;
109 };
110
111 struct stm32_rtc_data {
112 const struct stm32_rtc_registers regs;
113 const struct stm32_rtc_events events;
114 void (*clear_events)(struct stm32_rtc *rtc, unsigned int flags);
115 bool has_pclk;
116 bool need_dbp;
117 bool has_wakeirq;
118 };
119
120 struct stm32_rtc {
121 struct rtc_device *rtc_dev;
122 void __iomem *base;
123 struct regmap *dbp;
124 unsigned int dbp_reg;
125 unsigned int dbp_mask;
126 struct clk *pclk;
127 struct clk *rtc_ck;
128 const struct stm32_rtc_data *data;
129 int irq_alarm;
130 int wakeirq_alarm;
131 };
132
133 static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc)
134 {
135 const struct stm32_rtc_registers *regs = &rtc->data->regs;
136
137 writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + regs->wpr);
138 writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + regs->wpr);
139 }
140
141 static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc)
142 {
143 const struct stm32_rtc_registers *regs = &rtc->data->regs;
144
145 writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + regs->wpr);
146 }
147
148 static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc)
149 {
150 const struct stm32_rtc_registers *regs = &rtc->data->regs;
151 unsigned int isr = readl_relaxed(rtc->base + regs->isr);
152
153 if (!(isr & STM32_RTC_ISR_INITF)) {
154 isr |= STM32_RTC_ISR_INIT;
155 writel_relaxed(isr, rtc->base + regs->isr);
156
157 /*
158 * It takes around 2 rtc_ck clock cycles to enter in
159 * initialization phase mode (and have INITF flag set). As
160 * slowest rtc_ck frequency may be 32kHz and highest should be
161 * 1MHz, we poll every 10 us with a timeout of 100ms.
162 */
163 return readl_relaxed_poll_timeout_atomic(
164 rtc->base + regs->isr,
165 isr, (isr & STM32_RTC_ISR_INITF),
166 10, 100000);
167 }
168
169 return 0;
170 }
171
172 static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc)
173 {
174 const struct stm32_rtc_registers *regs = &rtc->data->regs;
175 unsigned int isr = readl_relaxed(rtc->base + regs->isr);
176
177 isr &= ~STM32_RTC_ISR_INIT;
178 writel_relaxed(isr, rtc->base + regs->isr);
179 }
180
181 static int stm32_rtc_wait_sync(struct stm32_rtc *rtc)
182 {
183 const struct stm32_rtc_registers *regs = &rtc->data->regs;
184 unsigned int isr = readl_relaxed(rtc->base + regs->isr);
185
186 isr &= ~STM32_RTC_ISR_RSF;
187 writel_relaxed(isr, rtc->base + regs->isr);
188
189 /*
190 * Wait for RSF to be set to ensure the calendar registers are
191 * synchronised, it takes around 2 rtc_ck clock cycles
192 */
193 return readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr,
194 isr,
195 (isr & STM32_RTC_ISR_RSF),
196 10, 100000);
197 }
198
199 static void stm32_rtc_clear_event_flags(struct stm32_rtc *rtc,
200 unsigned int flags)
201 {
202 rtc->data->clear_events(rtc, flags);
203 }
204
205 static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id)
206 {
207 struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id;
208 const struct stm32_rtc_registers *regs = &rtc->data->regs;
209 const struct stm32_rtc_events *evts = &rtc->data->events;
210 unsigned int status, cr;
211
212 mutex_lock(&rtc->rtc_dev->ops_lock);
213
214 status = readl_relaxed(rtc->base + regs->sr);
215 cr = readl_relaxed(rtc->base + regs->cr);
216
217 if ((status & evts->alra) &&
218 (cr & STM32_RTC_CR_ALRAIE)) {
219 /* Alarm A flag - Alarm interrupt */
220 dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n");
221
222 /* Pass event to the kernel */
223 rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
224
225 /* Clear event flags, otherwise new events won't be received */
226 stm32_rtc_clear_event_flags(rtc, evts->alra);
227 }
228
229 mutex_unlock(&rtc->rtc_dev->ops_lock);
230
231 return IRQ_HANDLED;
232 }
233
234 /* Convert rtc_time structure from bin to bcd format */
235 static void tm2bcd(struct rtc_time *tm)
236 {
237 tm->tm_sec = bin2bcd(tm->tm_sec);
238 tm->tm_min = bin2bcd(tm->tm_min);
239 tm->tm_hour = bin2bcd(tm->tm_hour);
240
241 tm->tm_mday = bin2bcd(tm->tm_mday);
242 tm->tm_mon = bin2bcd(tm->tm_mon + 1);
243 tm->tm_year = bin2bcd(tm->tm_year - 100);
244 /*
245 * Number of days since Sunday
246 * - on kernel side, 0=Sunday...6=Saturday
247 * - on rtc side, 0=invalid,1=Monday...7=Sunday
248 */
249 tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday;
250 }
251
252 /* Convert rtc_time structure from bcd to bin format */
253 static void bcd2tm(struct rtc_time *tm)
254 {
255 tm->tm_sec = bcd2bin(tm->tm_sec);
256 tm->tm_min = bcd2bin(tm->tm_min);
257 tm->tm_hour = bcd2bin(tm->tm_hour);
258
259 tm->tm_mday = bcd2bin(tm->tm_mday);
260 tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
261 tm->tm_year = bcd2bin(tm->tm_year) + 100;
262 /*
263 * Number of days since Sunday
264 * - on kernel side, 0=Sunday...6=Saturday
265 * - on rtc side, 0=invalid,1=Monday...7=Sunday
266 */
267 tm->tm_wday %= 7;
268 }
269
270 static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm)
271 {
272 struct stm32_rtc *rtc = dev_get_drvdata(dev);
273 const struct stm32_rtc_registers *regs = &rtc->data->regs;
274 unsigned int tr, dr;
275
276 /* Time and Date in BCD format */
277 tr = readl_relaxed(rtc->base + regs->tr);
278 dr = readl_relaxed(rtc->base + regs->dr);
279
280 tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
281 tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
282 tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
283
284 tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
285 tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
286 tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
287 tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT;
288
289 /* We don't report tm_yday and tm_isdst */
290
291 bcd2tm(tm);
292
293 return 0;
294 }
295
296 static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm)
297 {
298 struct stm32_rtc *rtc = dev_get_drvdata(dev);
299 const struct stm32_rtc_registers *regs = &rtc->data->regs;
300 unsigned int tr, dr;
301 int ret = 0;
302
303 tm2bcd(tm);
304
305 /* Time in BCD format */
306 tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) |
307 ((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) |
308 ((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR);
309
310 /* Date in BCD format */
311 dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) |
312 ((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) |
313 ((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) |
314 ((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY);
315
316 stm32_rtc_wpr_unlock(rtc);
317
318 ret = stm32_rtc_enter_init_mode(rtc);
319 if (ret) {
320 dev_err(dev, "Can't enter in init mode. Set time aborted.\n");
321 goto end;
322 }
323
324 writel_relaxed(tr, rtc->base + regs->tr);
325 writel_relaxed(dr, rtc->base + regs->dr);
326
327 stm32_rtc_exit_init_mode(rtc);
328
329 ret = stm32_rtc_wait_sync(rtc);
330 end:
331 stm32_rtc_wpr_lock(rtc);
332
333 return ret;
334 }
335
336 static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
337 {
338 struct stm32_rtc *rtc = dev_get_drvdata(dev);
339 const struct stm32_rtc_registers *regs = &rtc->data->regs;
340 const struct stm32_rtc_events *evts = &rtc->data->events;
341 struct rtc_time *tm = &alrm->time;
342 unsigned int alrmar, cr, status;
343
344 alrmar = readl_relaxed(rtc->base + regs->alrmar);
345 cr = readl_relaxed(rtc->base + regs->cr);
346 status = readl_relaxed(rtc->base + regs->sr);
347
348 if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) {
349 /*
350 * Date/day doesn't matter in Alarm comparison so alarm
351 * triggers every day
352 */
353 tm->tm_mday = -1;
354 tm->tm_wday = -1;
355 } else {
356 if (alrmar & STM32_RTC_ALRMXR_WDSEL) {
357 /* Alarm is set to a day of week */
358 tm->tm_mday = -1;
359 tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >>
360 STM32_RTC_ALRMXR_WDAY_SHIFT;
361 tm->tm_wday %= 7;
362 } else {
363 /* Alarm is set to a day of month */
364 tm->tm_wday = -1;
365 tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >>
366 STM32_RTC_ALRMXR_DATE_SHIFT;
367 }
368 }
369
370 if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) {
371 /* Hours don't matter in Alarm comparison */
372 tm->tm_hour = -1;
373 } else {
374 tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >>
375 STM32_RTC_ALRMXR_HOUR_SHIFT;
376 if (alrmar & STM32_RTC_ALRMXR_PM)
377 tm->tm_hour += 12;
378 }
379
380 if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) {
381 /* Minutes don't matter in Alarm comparison */
382 tm->tm_min = -1;
383 } else {
384 tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >>
385 STM32_RTC_ALRMXR_MIN_SHIFT;
386 }
387
388 if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) {
389 /* Seconds don't matter in Alarm comparison */
390 tm->tm_sec = -1;
391 } else {
392 tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >>
393 STM32_RTC_ALRMXR_SEC_SHIFT;
394 }
395
396 bcd2tm(tm);
397
398 alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0;
399 alrm->pending = (status & evts->alra) ? 1 : 0;
400
401 return 0;
402 }
403
404 static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
405 {
406 struct stm32_rtc *rtc = dev_get_drvdata(dev);
407 const struct stm32_rtc_registers *regs = &rtc->data->regs;
408 const struct stm32_rtc_events *evts = &rtc->data->events;
409 unsigned int cr;
410
411 cr = readl_relaxed(rtc->base + regs->cr);
412
413 stm32_rtc_wpr_unlock(rtc);
414
415 /* We expose Alarm A to the kernel */
416 if (enabled)
417 cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
418 else
419 cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE);
420 writel_relaxed(cr, rtc->base + regs->cr);
421
422 /* Clear event flags, otherwise new events won't be received */
423 stm32_rtc_clear_event_flags(rtc, evts->alra);
424
425 stm32_rtc_wpr_lock(rtc);
426
427 return 0;
428 }
429
430 static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm)
431 {
432 const struct stm32_rtc_registers *regs = &rtc->data->regs;
433 int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec;
434 unsigned int dr = readl_relaxed(rtc->base + regs->dr);
435 unsigned int tr = readl_relaxed(rtc->base + regs->tr);
436
437 cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT;
438 cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT;
439 cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT;
440 cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT;
441 cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT;
442 cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT;
443
444 /*
445 * Assuming current date is M-D-Y H:M:S.
446 * RTC alarm can't be set on a specific month and year.
447 * So the valid alarm range is:
448 * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S
449 * with a specific case for December...
450 */
451 if ((((tm->tm_year > cur_year) &&
452 (tm->tm_mon == 0x1) && (cur_mon == 0x12)) ||
453 ((tm->tm_year == cur_year) &&
454 (tm->tm_mon <= cur_mon + 1))) &&
455 ((tm->tm_mday > cur_day) ||
456 ((tm->tm_mday == cur_day) &&
457 ((tm->tm_hour > cur_hour) ||
458 ((tm->tm_hour == cur_hour) && (tm->tm_min > cur_min)) ||
459 ((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) &&
460 (tm->tm_sec >= cur_sec))))))
461 return 0;
462
463 return -EINVAL;
464 }
465
466 static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
467 {
468 struct stm32_rtc *rtc = dev_get_drvdata(dev);
469 const struct stm32_rtc_registers *regs = &rtc->data->regs;
470 struct rtc_time *tm = &alrm->time;
471 unsigned int cr, isr, alrmar;
472 int ret = 0;
473
474 tm2bcd(tm);
475
476 /*
477 * RTC alarm can't be set on a specific date, unless this date is
478 * up to the same day of month next month.
479 */
480 if (stm32_rtc_valid_alrm(rtc, tm) < 0) {
481 dev_err(dev, "Alarm can be set only on upcoming month.\n");
482 return -EINVAL;
483 }
484
485 alrmar = 0;
486 /* tm_year and tm_mon are not used because not supported by RTC */
487 alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) &
488 STM32_RTC_ALRMXR_DATE;
489 /* 24-hour format */
490 alrmar &= ~STM32_RTC_ALRMXR_PM;
491 alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) &
492 STM32_RTC_ALRMXR_HOUR;
493 alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) &
494 STM32_RTC_ALRMXR_MIN;
495 alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) &
496 STM32_RTC_ALRMXR_SEC;
497
498 stm32_rtc_wpr_unlock(rtc);
499
500 /* Disable Alarm */
501 cr = readl_relaxed(rtc->base + regs->cr);
502 cr &= ~STM32_RTC_CR_ALRAE;
503 writel_relaxed(cr, rtc->base + regs->cr);
504
505 /*
506 * Poll Alarm write flag to be sure that Alarm update is allowed: it
507 * takes around 2 rtc_ck clock cycles
508 */
509 ret = readl_relaxed_poll_timeout_atomic(rtc->base + regs->isr,
510 isr,
511 (isr & STM32_RTC_ISR_ALRAWF),
512 10, 100000);
513
514 if (ret) {
515 dev_err(dev, "Alarm update not allowed\n");
516 goto end;
517 }
518
519 /* Write to Alarm register */
520 writel_relaxed(alrmar, rtc->base + regs->alrmar);
521
522 stm32_rtc_alarm_irq_enable(dev, alrm->enabled);
523 end:
524 stm32_rtc_wpr_lock(rtc);
525
526 return ret;
527 }
528
529 static const struct rtc_class_ops stm32_rtc_ops = {
530 .read_time = stm32_rtc_read_time,
531 .set_time = stm32_rtc_set_time,
532 .read_alarm = stm32_rtc_read_alarm,
533 .set_alarm = stm32_rtc_set_alarm,
534 .alarm_irq_enable = stm32_rtc_alarm_irq_enable,
535 };
536
537 static void stm32_rtc_clear_events(struct stm32_rtc *rtc,
538 unsigned int flags)
539 {
540 const struct stm32_rtc_registers *regs = &rtc->data->regs;
541
542 /* Flags are cleared by writing 0 in RTC_ISR */
543 writel_relaxed(readl_relaxed(rtc->base + regs->isr) & ~flags,
544 rtc->base + regs->isr);
545 }
546
547 static const struct stm32_rtc_data stm32_rtc_data = {
548 .has_pclk = false,
549 .need_dbp = true,
550 .has_wakeirq = false,
551 .regs = {
552 .tr = 0x00,
553 .dr = 0x04,
554 .cr = 0x08,
555 .isr = 0x0C,
556 .prer = 0x10,
557 .alrmar = 0x1C,
558 .wpr = 0x24,
559 .sr = 0x0C, /* set to ISR offset to ease alarm management */
560 .scr = UNDEF_REG,
561 .verr = UNDEF_REG,
562 },
563 .events = {
564 .alra = STM32_RTC_ISR_ALRAF,
565 },
566 .clear_events = stm32_rtc_clear_events,
567 };
568
569 static const struct stm32_rtc_data stm32h7_rtc_data = {
570 .has_pclk = true,
571 .need_dbp = true,
572 .has_wakeirq = false,
573 .regs = {
574 .tr = 0x00,
575 .dr = 0x04,
576 .cr = 0x08,
577 .isr = 0x0C,
578 .prer = 0x10,
579 .alrmar = 0x1C,
580 .wpr = 0x24,
581 .sr = 0x0C, /* set to ISR offset to ease alarm management */
582 .scr = UNDEF_REG,
583 .verr = UNDEF_REG,
584 },
585 .events = {
586 .alra = STM32_RTC_ISR_ALRAF,
587 },
588 .clear_events = stm32_rtc_clear_events,
589 };
590
591 static void stm32mp1_rtc_clear_events(struct stm32_rtc *rtc,
592 unsigned int flags)
593 {
594 struct stm32_rtc_registers regs = rtc->data->regs;
595
596 /* Flags are cleared by writing 1 in RTC_SCR */
597 writel_relaxed(flags, rtc->base + regs.scr);
598 }
599
600 static const struct stm32_rtc_data stm32mp1_data = {
601 .has_pclk = true,
602 .need_dbp = false,
603 .has_wakeirq = true,
604 .regs = {
605 .tr = 0x00,
606 .dr = 0x04,
607 .cr = 0x18,
608 .isr = 0x0C, /* named RTC_ICSR on stm32mp1 */
609 .prer = 0x10,
610 .alrmar = 0x40,
611 .wpr = 0x24,
612 .sr = 0x50,
613 .scr = 0x5C,
614 .verr = 0x3F4,
615 },
616 .events = {
617 .alra = STM32_RTC_SR_ALRA,
618 },
619 .clear_events = stm32mp1_rtc_clear_events,
620 };
621
622 static const struct of_device_id stm32_rtc_of_match[] = {
623 { .compatible = "st,stm32-rtc", .data = &stm32_rtc_data },
624 { .compatible = "st,stm32h7-rtc", .data = &stm32h7_rtc_data },
625 { .compatible = "st,stm32mp1-rtc", .data = &stm32mp1_data },
626 {}
627 };
628 MODULE_DEVICE_TABLE(of, stm32_rtc_of_match);
629
630 static int stm32_rtc_init(struct platform_device *pdev,
631 struct stm32_rtc *rtc)
632 {
633 const struct stm32_rtc_registers *regs = &rtc->data->regs;
634 unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr;
635 unsigned int rate;
636 int ret = 0;
637
638 rate = clk_get_rate(rtc->rtc_ck);
639
640 /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */
641 pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT;
642 pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT;
643
644 for (pred_a = pred_a_max; pred_a + 1 > 0; pred_a--) {
645 pred_s = (rate / (pred_a + 1)) - 1;
646
647 if (((pred_s + 1) * (pred_a + 1)) == rate)
648 break;
649 }
650
651 /*
652 * Can't find a 1Hz, so give priority to RTC power consumption
653 * by choosing the higher possible value for prediv_a
654 */
655 if ((pred_s > pred_s_max) || (pred_a > pred_a_max)) {
656 pred_a = pred_a_max;
657 pred_s = (rate / (pred_a + 1)) - 1;
658
659 dev_warn(&pdev->dev, "rtc_ck is %s\n",
660 (rate < ((pred_a + 1) * (pred_s + 1))) ?
661 "fast" : "slow");
662 }
663
664 stm32_rtc_wpr_unlock(rtc);
665
666 ret = stm32_rtc_enter_init_mode(rtc);
667 if (ret) {
668 dev_err(&pdev->dev,
669 "Can't enter in init mode. Prescaler config failed.\n");
670 goto end;
671 }
672
673 prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S;
674 writel_relaxed(prer, rtc->base + regs->prer);
675 prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A;
676 writel_relaxed(prer, rtc->base + regs->prer);
677
678 /* Force 24h time format */
679 cr = readl_relaxed(rtc->base + regs->cr);
680 cr &= ~STM32_RTC_CR_FMT;
681 writel_relaxed(cr, rtc->base + regs->cr);
682
683 stm32_rtc_exit_init_mode(rtc);
684
685 ret = stm32_rtc_wait_sync(rtc);
686 end:
687 stm32_rtc_wpr_lock(rtc);
688
689 return ret;
690 }
691
692 static int stm32_rtc_probe(struct platform_device *pdev)
693 {
694 struct stm32_rtc *rtc;
695 const struct stm32_rtc_registers *regs;
696 int ret;
697
698 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
699 if (!rtc)
700 return -ENOMEM;
701
702 rtc->base = devm_platform_ioremap_resource(pdev, 0);
703 if (IS_ERR(rtc->base))
704 return PTR_ERR(rtc->base);
705
706 rtc->data = (struct stm32_rtc_data *)
707 of_device_get_match_data(&pdev->dev);
708 regs = &rtc->data->regs;
709
710 if (rtc->data->need_dbp) {
711 rtc->dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
712 "st,syscfg");
713 if (IS_ERR(rtc->dbp)) {
714 dev_err(&pdev->dev, "no st,syscfg\n");
715 return PTR_ERR(rtc->dbp);
716 }
717
718 ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg",
719 1, &rtc->dbp_reg);
720 if (ret) {
721 dev_err(&pdev->dev, "can't read DBP register offset\n");
722 return ret;
723 }
724
725 ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg",
726 2, &rtc->dbp_mask);
727 if (ret) {
728 dev_err(&pdev->dev, "can't read DBP register mask\n");
729 return ret;
730 }
731 }
732
733 if (!rtc->data->has_pclk) {
734 rtc->pclk = NULL;
735 rtc->rtc_ck = devm_clk_get(&pdev->dev, NULL);
736 } else {
737 rtc->pclk = devm_clk_get(&pdev->dev, "pclk");
738 if (IS_ERR(rtc->pclk)) {
739 dev_err(&pdev->dev, "no pclk clock");
740 return PTR_ERR(rtc->pclk);
741 }
742 rtc->rtc_ck = devm_clk_get(&pdev->dev, "rtc_ck");
743 }
744 if (IS_ERR(rtc->rtc_ck)) {
745 dev_err(&pdev->dev, "no rtc_ck clock");
746 return PTR_ERR(rtc->rtc_ck);
747 }
748
749 if (rtc->data->has_pclk) {
750 ret = clk_prepare_enable(rtc->pclk);
751 if (ret)
752 return ret;
753 }
754
755 ret = clk_prepare_enable(rtc->rtc_ck);
756 if (ret)
757 goto err;
758
759 if (rtc->data->need_dbp)
760 regmap_update_bits(rtc->dbp, rtc->dbp_reg,
761 rtc->dbp_mask, rtc->dbp_mask);
762
763 /*
764 * After a system reset, RTC_ISR.INITS flag can be read to check if
765 * the calendar has been initialized or not. INITS flag is reset by a
766 * power-on reset (no vbat, no power-supply). It is not reset if
767 * rtc_ck parent clock has changed (so RTC prescalers need to be
768 * changed). That's why we cannot rely on this flag to know if RTC
769 * init has to be done.
770 */
771 ret = stm32_rtc_init(pdev, rtc);
772 if (ret)
773 goto err;
774
775 rtc->irq_alarm = platform_get_irq(pdev, 0);
776 if (rtc->irq_alarm <= 0) {
777 ret = rtc->irq_alarm;
778 goto err;
779 }
780
781 ret = device_init_wakeup(&pdev->dev, true);
782 if (rtc->data->has_wakeirq) {
783 rtc->wakeirq_alarm = platform_get_irq(pdev, 1);
784 if (rtc->wakeirq_alarm > 0) {
785 ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
786 rtc->wakeirq_alarm);
787 } else {
788 ret = rtc->wakeirq_alarm;
789 if (rtc->wakeirq_alarm == -EPROBE_DEFER)
790 goto err;
791 }
792 }
793 if (ret)
794 dev_warn(&pdev->dev, "alarm can't wake up the system: %d", ret);
795
796 platform_set_drvdata(pdev, rtc);
797
798 rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
799 &stm32_rtc_ops, THIS_MODULE);
800 if (IS_ERR(rtc->rtc_dev)) {
801 ret = PTR_ERR(rtc->rtc_dev);
802 dev_err(&pdev->dev, "rtc device registration failed, err=%d\n",
803 ret);
804 goto err;
805 }
806
807 /* Handle RTC alarm interrupts */
808 ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL,
809 stm32_rtc_alarm_irq, IRQF_ONESHOT,
810 pdev->name, rtc);
811 if (ret) {
812 dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n",
813 rtc->irq_alarm);
814 goto err;
815 }
816
817 /*
818 * If INITS flag is reset (calendar year field set to 0x00), calendar
819 * must be initialized
820 */
821 if (!(readl_relaxed(rtc->base + regs->isr) & STM32_RTC_ISR_INITS))
822 dev_warn(&pdev->dev, "Date/Time must be initialized\n");
823
824 if (regs->verr != UNDEF_REG) {
825 u32 ver = readl_relaxed(rtc->base + regs->verr);
826
827 dev_info(&pdev->dev, "registered rev:%d.%d\n",
828 (ver >> STM32_RTC_VERR_MAJREV_SHIFT) & 0xF,
829 (ver >> STM32_RTC_VERR_MINREV_SHIFT) & 0xF);
830 }
831
832 return 0;
833 err:
834 if (rtc->data->has_pclk)
835 clk_disable_unprepare(rtc->pclk);
836 clk_disable_unprepare(rtc->rtc_ck);
837
838 if (rtc->data->need_dbp)
839 regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0);
840
841 dev_pm_clear_wake_irq(&pdev->dev);
842 device_init_wakeup(&pdev->dev, false);
843
844 return ret;
845 }
846
847 static int stm32_rtc_remove(struct platform_device *pdev)
848 {
849 struct stm32_rtc *rtc = platform_get_drvdata(pdev);
850 const struct stm32_rtc_registers *regs = &rtc->data->regs;
851 unsigned int cr;
852
853 /* Disable interrupts */
854 stm32_rtc_wpr_unlock(rtc);
855 cr = readl_relaxed(rtc->base + regs->cr);
856 cr &= ~STM32_RTC_CR_ALRAIE;
857 writel_relaxed(cr, rtc->base + regs->cr);
858 stm32_rtc_wpr_lock(rtc);
859
860 clk_disable_unprepare(rtc->rtc_ck);
861 if (rtc->data->has_pclk)
862 clk_disable_unprepare(rtc->pclk);
863
864 /* Enable backup domain write protection if needed */
865 if (rtc->data->need_dbp)
866 regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0);
867
868 dev_pm_clear_wake_irq(&pdev->dev);
869 device_init_wakeup(&pdev->dev, false);
870
871 return 0;
872 }
873
874 #ifdef CONFIG_PM_SLEEP
875 static int stm32_rtc_suspend(struct device *dev)
876 {
877 struct stm32_rtc *rtc = dev_get_drvdata(dev);
878
879 if (rtc->data->has_pclk)
880 clk_disable_unprepare(rtc->pclk);
881
882 if (device_may_wakeup(dev))
883 return enable_irq_wake(rtc->irq_alarm);
884
885 return 0;
886 }
887
888 static int stm32_rtc_resume(struct device *dev)
889 {
890 struct stm32_rtc *rtc = dev_get_drvdata(dev);
891 int ret = 0;
892
893 if (rtc->data->has_pclk) {
894 ret = clk_prepare_enable(rtc->pclk);
895 if (ret)
896 return ret;
897 }
898
899 ret = stm32_rtc_wait_sync(rtc);
900 if (ret < 0)
901 return ret;
902
903 if (device_may_wakeup(dev))
904 return disable_irq_wake(rtc->irq_alarm);
905
906 return ret;
907 }
908 #endif
909
910 static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops,
911 stm32_rtc_suspend, stm32_rtc_resume);
912
913 static struct platform_driver stm32_rtc_driver = {
914 .probe = stm32_rtc_probe,
915 .remove = stm32_rtc_remove,
916 .driver = {
917 .name = DRIVER_NAME,
918 .pm = &stm32_rtc_pm_ops,
919 .of_match_table = stm32_rtc_of_match,
920 },
921 };
922
923 module_platform_driver(stm32_rtc_driver);
924
925 MODULE_ALIAS("platform:" DRIVER_NAME);
926 MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
927 MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver");
928 MODULE_LICENSE("GPL v2");
Linux with added FPC-III support