Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-2.6-microblaze.git] / drivers / rtc / rtc-stm32.c
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         struct resource *res;
697         int ret;
698
699         rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
700         if (!rtc)
701                 return -ENOMEM;
702
703         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
704         rtc->base = devm_ioremap_resource(&pdev->dev, res);
705         if (IS_ERR(rtc->base))
706                 return PTR_ERR(rtc->base);
707
708         rtc->data = (struct stm32_rtc_data *)
709                     of_device_get_match_data(&pdev->dev);
710         regs = &rtc->data->regs;
711
712         if (rtc->data->need_dbp) {
713                 rtc->dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
714                                                            "st,syscfg");
715                 if (IS_ERR(rtc->dbp)) {
716                         dev_err(&pdev->dev, "no st,syscfg\n");
717                         return PTR_ERR(rtc->dbp);
718                 }
719
720                 ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg",
721                                                  1, &rtc->dbp_reg);
722                 if (ret) {
723                         dev_err(&pdev->dev, "can't read DBP register offset\n");
724                         return ret;
725                 }
726
727                 ret = of_property_read_u32_index(pdev->dev.of_node, "st,syscfg",
728                                                  2, &rtc->dbp_mask);
729                 if (ret) {
730                         dev_err(&pdev->dev, "can't read DBP register mask\n");
731                         return ret;
732                 }
733         }
734
735         if (!rtc->data->has_pclk) {
736                 rtc->pclk = NULL;
737                 rtc->rtc_ck = devm_clk_get(&pdev->dev, NULL);
738         } else {
739                 rtc->pclk = devm_clk_get(&pdev->dev, "pclk");
740                 if (IS_ERR(rtc->pclk)) {
741                         dev_err(&pdev->dev, "no pclk clock");
742                         return PTR_ERR(rtc->pclk);
743                 }
744                 rtc->rtc_ck = devm_clk_get(&pdev->dev, "rtc_ck");
745         }
746         if (IS_ERR(rtc->rtc_ck)) {
747                 dev_err(&pdev->dev, "no rtc_ck clock");
748                 return PTR_ERR(rtc->rtc_ck);
749         }
750
751         if (rtc->data->has_pclk) {
752                 ret = clk_prepare_enable(rtc->pclk);
753                 if (ret)
754                         return ret;
755         }
756
757         ret = clk_prepare_enable(rtc->rtc_ck);
758         if (ret)
759                 goto err;
760
761         if (rtc->data->need_dbp)
762                 regmap_update_bits(rtc->dbp, rtc->dbp_reg,
763                                    rtc->dbp_mask, rtc->dbp_mask);
764
765         /*
766          * After a system reset, RTC_ISR.INITS flag can be read to check if
767          * the calendar has been initialized or not. INITS flag is reset by a
768          * power-on reset (no vbat, no power-supply). It is not reset if
769          * rtc_ck parent clock has changed (so RTC prescalers need to be
770          * changed). That's why we cannot rely on this flag to know if RTC
771          * init has to be done.
772          */
773         ret = stm32_rtc_init(pdev, rtc);
774         if (ret)
775                 goto err;
776
777         rtc->irq_alarm = platform_get_irq(pdev, 0);
778         if (rtc->irq_alarm <= 0) {
779                 dev_err(&pdev->dev, "no alarm irq\n");
780                 ret = rtc->irq_alarm;
781                 goto err;
782         }
783
784         ret = device_init_wakeup(&pdev->dev, true);
785         if (rtc->data->has_wakeirq) {
786                 rtc->wakeirq_alarm = platform_get_irq(pdev, 1);
787                 if (rtc->wakeirq_alarm > 0) {
788                         ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
789                                                             rtc->wakeirq_alarm);
790                 } else {
791                         ret = rtc->wakeirq_alarm;
792                         if (rtc->wakeirq_alarm == -EPROBE_DEFER)
793                                 goto err;
794                 }
795         }
796         if (ret)
797                 dev_warn(&pdev->dev, "alarm can't wake up the system: %d", ret);
798
799         platform_set_drvdata(pdev, rtc);
800
801         rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
802                                                 &stm32_rtc_ops, THIS_MODULE);
803         if (IS_ERR(rtc->rtc_dev)) {
804                 ret = PTR_ERR(rtc->rtc_dev);
805                 dev_err(&pdev->dev, "rtc device registration failed, err=%d\n",
806                         ret);
807                 goto err;
808         }
809
810         /* Handle RTC alarm interrupts */
811         ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL,
812                                         stm32_rtc_alarm_irq, IRQF_ONESHOT,
813                                         pdev->name, rtc);
814         if (ret) {
815                 dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n",
816                         rtc->irq_alarm);
817                 goto err;
818         }
819
820         /*
821          * If INITS flag is reset (calendar year field set to 0x00), calendar
822          * must be initialized
823          */
824         if (!(readl_relaxed(rtc->base + regs->isr) & STM32_RTC_ISR_INITS))
825                 dev_warn(&pdev->dev, "Date/Time must be initialized\n");
826
827         if (regs->verr != UNDEF_REG) {
828                 u32 ver = readl_relaxed(rtc->base + regs->verr);
829
830                 dev_info(&pdev->dev, "registered rev:%d.%d\n",
831                          (ver >> STM32_RTC_VERR_MAJREV_SHIFT) & 0xF,
832                          (ver >> STM32_RTC_VERR_MINREV_SHIFT) & 0xF);
833         }
834
835         return 0;
836 err:
837         if (rtc->data->has_pclk)
838                 clk_disable_unprepare(rtc->pclk);
839         clk_disable_unprepare(rtc->rtc_ck);
840
841         if (rtc->data->need_dbp)
842                 regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0);
843
844         dev_pm_clear_wake_irq(&pdev->dev);
845         device_init_wakeup(&pdev->dev, false);
846
847         return ret;
848 }
849
850 static int stm32_rtc_remove(struct platform_device *pdev)
851 {
852         struct stm32_rtc *rtc = platform_get_drvdata(pdev);
853         const struct stm32_rtc_registers *regs = &rtc->data->regs;
854         unsigned int cr;
855
856         /* Disable interrupts */
857         stm32_rtc_wpr_unlock(rtc);
858         cr = readl_relaxed(rtc->base + regs->cr);
859         cr &= ~STM32_RTC_CR_ALRAIE;
860         writel_relaxed(cr, rtc->base + regs->cr);
861         stm32_rtc_wpr_lock(rtc);
862
863         clk_disable_unprepare(rtc->rtc_ck);
864         if (rtc->data->has_pclk)
865                 clk_disable_unprepare(rtc->pclk);
866
867         /* Enable backup domain write protection if needed */
868         if (rtc->data->need_dbp)
869                 regmap_update_bits(rtc->dbp, rtc->dbp_reg, rtc->dbp_mask, 0);
870
871         dev_pm_clear_wake_irq(&pdev->dev);
872         device_init_wakeup(&pdev->dev, false);
873
874         return 0;
875 }
876
877 #ifdef CONFIG_PM_SLEEP
878 static int stm32_rtc_suspend(struct device *dev)
879 {
880         struct stm32_rtc *rtc = dev_get_drvdata(dev);
881
882         if (rtc->data->has_pclk)
883                 clk_disable_unprepare(rtc->pclk);
884
885         if (device_may_wakeup(dev))
886                 return enable_irq_wake(rtc->irq_alarm);
887
888         return 0;
889 }
890
891 static int stm32_rtc_resume(struct device *dev)
892 {
893         struct stm32_rtc *rtc = dev_get_drvdata(dev);
894         int ret = 0;
895
896         if (rtc->data->has_pclk) {
897                 ret = clk_prepare_enable(rtc->pclk);
898                 if (ret)
899                         return ret;
900         }
901
902         ret = stm32_rtc_wait_sync(rtc);
903         if (ret < 0)
904                 return ret;
905
906         if (device_may_wakeup(dev))
907                 return disable_irq_wake(rtc->irq_alarm);
908
909         return ret;
910 }
911 #endif
912
913 static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops,
914                          stm32_rtc_suspend, stm32_rtc_resume);
915
916 static struct platform_driver stm32_rtc_driver = {
917         .probe          = stm32_rtc_probe,
918         .remove         = stm32_rtc_remove,
919         .driver         = {
920                 .name   = DRIVER_NAME,
921                 .pm     = &stm32_rtc_pm_ops,
922                 .of_match_table = stm32_rtc_of_match,
923         },
924 };
925
926 module_platform_driver(stm32_rtc_driver);
927
928 MODULE_ALIAS("platform:" DRIVER_NAME);
929 MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
930 MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver");
931 MODULE_LICENSE("GPL v2");