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Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
[mirror_ubuntu-artful-kernel.git] / drivers / rtc / rtc-stm32.c
1 /*
2 * Copyright (C) Amelie Delaunay 2016
3 * Author: Amelie Delaunay <amelie.delaunay@st.com>
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
97 struct stm32_rtc_data {
98 bool has_pclk;
99 };
100
101 struct 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
111 static 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
117 static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc)
118 {
119 writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + STM32_RTC_WPR);
120 }
121
122 static 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
145 static 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
153 static 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
170 static 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 */
199 static 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 */
217 static 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
234 static 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
259 static 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);
292 end:
293 stm32_rtc_wpr_lock(rtc);
294
295 return ret;
296 }
297
298 static 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
364 static 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
390 static 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
425 static 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
485 end:
486 stm32_rtc_wpr_lock(rtc);
487
488 return ret;
489 }
490
491 static 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
499 static const struct stm32_rtc_data stm32_rtc_data = {
500 .has_pclk = false,
501 };
502
503 static const struct stm32_rtc_data stm32h7_rtc_data = {
504 .has_pclk = true,
505 };
506
507 static 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 };
512 MODULE_DEVICE_TABLE(of, stm32_rtc_of_match);
513
514 static 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);
569 end:
570 stm32_rtc_wpr_lock(rtc);
571
572 return ret;
573 }
574
575 static 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;
683 err:
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
695 static 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
720 static 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
733 static 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
755 static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops,
756 stm32_rtc_suspend, stm32_rtc_resume);
757
758 static 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
768 module_platform_driver(stm32_rtc_driver);
769
770 MODULE_ALIAS("platform:" DRIVER_NAME);
771 MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>");
772 MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver");
773 MODULE_LICENSE("GPL v2");
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