1 // SPDX-License-Identifier: GPL-2.0-only
2 /* drivers/rtc/rtc-s3c.c
3 *
4 * Copyright (c) 2010 Samsung Electronics Co., Ltd.
5 * http://www.samsung.com/
6 *
7 * Copyright (c) 2004,2006 Simtec Electronics
8 * Ben Dooks, <ben@simtec.co.uk>
9 * http://armlinux.simtec.co.uk/
10 *
11 * S3C2410/S3C2440/S3C24XX Internal RTC Driver
12 */
13
14 #include <linux/module.h>
15 #include <linux/fs.h>
16 #include <linux/string.h>
17 #include <linux/init.h>
18 #include <linux/platform_device.h>
19 #include <linux/interrupt.h>
20 #include <linux/rtc.h>
21 #include <linux/bcd.h>
22 #include <linux/clk.h>
23 #include <linux/log2.h>
24 #include <linux/slab.h>
25 #include <linux/of.h>
26 #include <linux/of_device.h>
27 #include <linux/uaccess.h>
28 #include <linux/io.h>
29
30 #include <asm/irq.h>
31 #include "rtc-s3c.h"
32
33 struct s3c_rtc {
34 struct device *dev;
35 struct rtc_device *rtc;
36
37 void __iomem *base;
38 struct clk *rtc_clk;
39 struct clk *rtc_src_clk;
40 bool alarm_enabled;
41
42 const struct s3c_rtc_data *data;
43
44 int irq_alarm;
45 spinlock_t alarm_lock;
46
47 bool wake_en;
48 };
49
50 struct s3c_rtc_data {
51 bool needs_src_clk;
52
53 void (*irq_handler) (struct s3c_rtc *info, int mask);
54 void (*enable) (struct s3c_rtc *info);
55 void (*disable) (struct s3c_rtc *info);
56 };
57
s3c_rtc_enable_clk(struct s3c_rtc * info)58 static int s3c_rtc_enable_clk(struct s3c_rtc *info)
59 {
60 int ret;
61
62 ret = clk_enable(info->rtc_clk);
63 if (ret)
64 return ret;
65
66 if (info->data->needs_src_clk) {
67 ret = clk_enable(info->rtc_src_clk);
68 if (ret) {
69 clk_disable(info->rtc_clk);
70 return ret;
71 }
72 }
73 return 0;
74 }
75
s3c_rtc_disable_clk(struct s3c_rtc * info)76 static void s3c_rtc_disable_clk(struct s3c_rtc *info)
77 {
78 if (info->data->needs_src_clk)
79 clk_disable(info->rtc_src_clk);
80 clk_disable(info->rtc_clk);
81 }
82
83 /* IRQ Handler */
s3c_rtc_alarmirq(int irq,void * id)84 static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
85 {
86 struct s3c_rtc *info = (struct s3c_rtc *)id;
87
88 if (info->data->irq_handler)
89 info->data->irq_handler(info, S3C2410_INTP_ALM);
90
91 return IRQ_HANDLED;
92 }
93
94 /* Update control registers */
s3c_rtc_setaie(struct device * dev,unsigned int enabled)95 static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
96 {
97 struct s3c_rtc *info = dev_get_drvdata(dev);
98 unsigned long flags;
99 unsigned int tmp;
100 int ret;
101
102 dev_dbg(info->dev, "%s: aie=%d\n", __func__, enabled);
103
104 ret = s3c_rtc_enable_clk(info);
105 if (ret)
106 return ret;
107
108 tmp = readb(info->base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
109
110 if (enabled)
111 tmp |= S3C2410_RTCALM_ALMEN;
112
113 writeb(tmp, info->base + S3C2410_RTCALM);
114
115 spin_lock_irqsave(&info->alarm_lock, flags);
116
117 if (info->alarm_enabled && !enabled)
118 s3c_rtc_disable_clk(info);
119 else if (!info->alarm_enabled && enabled)
120 ret = s3c_rtc_enable_clk(info);
121
122 info->alarm_enabled = enabled;
123 spin_unlock_irqrestore(&info->alarm_lock, flags);
124
125 s3c_rtc_disable_clk(info);
126
127 return ret;
128 }
129
130 /* Read time from RTC and convert it from BCD */
s3c_rtc_read_time(struct s3c_rtc * info,struct rtc_time * tm)131 static int s3c_rtc_read_time(struct s3c_rtc *info, struct rtc_time *tm)
132 {
133 unsigned int have_retried = 0;
134 int ret;
135
136 ret = s3c_rtc_enable_clk(info);
137 if (ret)
138 return ret;
139
140 retry_get_time:
141 tm->tm_min = readb(info->base + S3C2410_RTCMIN);
142 tm->tm_hour = readb(info->base + S3C2410_RTCHOUR);
143 tm->tm_mday = readb(info->base + S3C2410_RTCDATE);
144 tm->tm_mon = readb(info->base + S3C2410_RTCMON);
145 tm->tm_year = readb(info->base + S3C2410_RTCYEAR);
146 tm->tm_sec = readb(info->base + S3C2410_RTCSEC);
147
148 /*
149 * The only way to work out whether the system was mid-update
150 * when we read it is to check the second counter, and if it
151 * is zero, then we re-try the entire read
152 */
153 if (tm->tm_sec == 0 && !have_retried) {
154 have_retried = 1;
155 goto retry_get_time;
156 }
157
158 s3c_rtc_disable_clk(info);
159
160 tm->tm_sec = bcd2bin(tm->tm_sec);
161 tm->tm_min = bcd2bin(tm->tm_min);
162 tm->tm_hour = bcd2bin(tm->tm_hour);
163 tm->tm_mday = bcd2bin(tm->tm_mday);
164 tm->tm_mon = bcd2bin(tm->tm_mon);
165 tm->tm_year = bcd2bin(tm->tm_year);
166
167 return 0;
168 }
169
170 /* Convert time to BCD and write it to RTC */
s3c_rtc_write_time(struct s3c_rtc * info,const struct rtc_time * tm)171 static int s3c_rtc_write_time(struct s3c_rtc *info, const struct rtc_time *tm)
172 {
173 int ret;
174
175 ret = s3c_rtc_enable_clk(info);
176 if (ret)
177 return ret;
178
179 writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_RTCSEC);
180 writeb(bin2bcd(tm->tm_min), info->base + S3C2410_RTCMIN);
181 writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_RTCHOUR);
182 writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_RTCDATE);
183 writeb(bin2bcd(tm->tm_mon), info->base + S3C2410_RTCMON);
184 writeb(bin2bcd(tm->tm_year), info->base + S3C2410_RTCYEAR);
185
186 s3c_rtc_disable_clk(info);
187
188 return 0;
189 }
190
s3c_rtc_gettime(struct device * dev,struct rtc_time * tm)191 static int s3c_rtc_gettime(struct device *dev, struct rtc_time *tm)
192 {
193 struct s3c_rtc *info = dev_get_drvdata(dev);
194 int ret;
195
196 ret = s3c_rtc_read_time(info, tm);
197 if (ret)
198 return ret;
199
200 /* Convert internal representation to actual date/time */
201 tm->tm_year += 100;
202 tm->tm_mon -= 1;
203
204 dev_dbg(dev, "read time %ptR\n", tm);
205 return 0;
206 }
207
s3c_rtc_settime(struct device * dev,struct rtc_time * tm)208 static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
209 {
210 struct s3c_rtc *info = dev_get_drvdata(dev);
211 struct rtc_time rtc_tm = *tm;
212
213 dev_dbg(dev, "set time %ptR\n", tm);
214
215 /*
216 * Convert actual date/time to internal representation.
217 * We get around Y2K by simply not supporting it.
218 */
219 rtc_tm.tm_year -= 100;
220 rtc_tm.tm_mon += 1;
221
222 return s3c_rtc_write_time(info, &rtc_tm);
223 }
224
s3c_rtc_getalarm(struct device * dev,struct rtc_wkalrm * alrm)225 static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
226 {
227 struct s3c_rtc *info = dev_get_drvdata(dev);
228 struct rtc_time *alm_tm = &alrm->time;
229 unsigned int alm_en;
230 int ret;
231
232 ret = s3c_rtc_enable_clk(info);
233 if (ret)
234 return ret;
235
236 alm_tm->tm_sec = readb(info->base + S3C2410_ALMSEC);
237 alm_tm->tm_min = readb(info->base + S3C2410_ALMMIN);
238 alm_tm->tm_hour = readb(info->base + S3C2410_ALMHOUR);
239 alm_tm->tm_mon = readb(info->base + S3C2410_ALMMON);
240 alm_tm->tm_mday = readb(info->base + S3C2410_ALMDATE);
241 alm_tm->tm_year = readb(info->base + S3C2410_ALMYEAR);
242
243 alm_en = readb(info->base + S3C2410_RTCALM);
244
245 s3c_rtc_disable_clk(info);
246
247 alrm->enabled = (alm_en & S3C2410_RTCALM_ALMEN) ? 1 : 0;
248
249 dev_dbg(dev, "read alarm %d, %ptR\n", alm_en, alm_tm);
250
251 /* decode the alarm enable field */
252 if (alm_en & S3C2410_RTCALM_SECEN)
253 alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
254
255 if (alm_en & S3C2410_RTCALM_MINEN)
256 alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
257
258 if (alm_en & S3C2410_RTCALM_HOUREN)
259 alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
260
261 if (alm_en & S3C2410_RTCALM_DAYEN)
262 alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
263
264 if (alm_en & S3C2410_RTCALM_MONEN) {
265 alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);
266 alm_tm->tm_mon -= 1;
267 }
268
269 if (alm_en & S3C2410_RTCALM_YEAREN)
270 alm_tm->tm_year = bcd2bin(alm_tm->tm_year);
271
272 return 0;
273 }
274
s3c_rtc_setalarm(struct device * dev,struct rtc_wkalrm * alrm)275 static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
276 {
277 struct s3c_rtc *info = dev_get_drvdata(dev);
278 struct rtc_time *tm = &alrm->time;
279 unsigned int alrm_en;
280 int ret;
281
282 dev_dbg(dev, "s3c_rtc_setalarm: %d, %ptR\n", alrm->enabled, tm);
283
284 ret = s3c_rtc_enable_clk(info);
285 if (ret)
286 return ret;
287
288 alrm_en = readb(info->base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
289 writeb(0x00, info->base + S3C2410_RTCALM);
290
291 if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
292 alrm_en |= S3C2410_RTCALM_SECEN;
293 writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_ALMSEC);
294 }
295
296 if (tm->tm_min < 60 && tm->tm_min >= 0) {
297 alrm_en |= S3C2410_RTCALM_MINEN;
298 writeb(bin2bcd(tm->tm_min), info->base + S3C2410_ALMMIN);
299 }
300
301 if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
302 alrm_en |= S3C2410_RTCALM_HOUREN;
303 writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_ALMHOUR);
304 }
305
306 if (tm->tm_mon < 12 && tm->tm_mon >= 0) {
307 alrm_en |= S3C2410_RTCALM_MONEN;
308 writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_ALMMON);
309 }
310
311 if (tm->tm_mday <= 31 && tm->tm_mday >= 1) {
312 alrm_en |= S3C2410_RTCALM_DAYEN;
313 writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_ALMDATE);
314 }
315
316 dev_dbg(dev, "setting S3C2410_RTCALM to %08x\n", alrm_en);
317
318 writeb(alrm_en, info->base + S3C2410_RTCALM);
319
320 s3c_rtc_setaie(dev, alrm->enabled);
321
322 s3c_rtc_disable_clk(info);
323
324 return 0;
325 }
326
327 static const struct rtc_class_ops s3c_rtcops = {
328 .read_time = s3c_rtc_gettime,
329 .set_time = s3c_rtc_settime,
330 .read_alarm = s3c_rtc_getalarm,
331 .set_alarm = s3c_rtc_setalarm,
332 .alarm_irq_enable = s3c_rtc_setaie,
333 };
334
s3c24xx_rtc_enable(struct s3c_rtc * info)335 static void s3c24xx_rtc_enable(struct s3c_rtc *info)
336 {
337 unsigned int con, tmp;
338
339 con = readw(info->base + S3C2410_RTCCON);
340 /* re-enable the device, and check it is ok */
341 if ((con & S3C2410_RTCCON_RTCEN) == 0) {
342 dev_info(info->dev, "rtc disabled, re-enabling\n");
343
344 tmp = readw(info->base + S3C2410_RTCCON);
345 writew(tmp | S3C2410_RTCCON_RTCEN, info->base + S3C2410_RTCCON);
346 }
347
348 if (con & S3C2410_RTCCON_CNTSEL) {
349 dev_info(info->dev, "removing RTCCON_CNTSEL\n");
350
351 tmp = readw(info->base + S3C2410_RTCCON);
352 writew(tmp & ~S3C2410_RTCCON_CNTSEL,
353 info->base + S3C2410_RTCCON);
354 }
355
356 if (con & S3C2410_RTCCON_CLKRST) {
357 dev_info(info->dev, "removing RTCCON_CLKRST\n");
358
359 tmp = readw(info->base + S3C2410_RTCCON);
360 writew(tmp & ~S3C2410_RTCCON_CLKRST,
361 info->base + S3C2410_RTCCON);
362 }
363 }
364
s3c24xx_rtc_disable(struct s3c_rtc * info)365 static void s3c24xx_rtc_disable(struct s3c_rtc *info)
366 {
367 unsigned int con;
368
369 con = readw(info->base + S3C2410_RTCCON);
370 con &= ~S3C2410_RTCCON_RTCEN;
371 writew(con, info->base + S3C2410_RTCCON);
372
373 con = readb(info->base + S3C2410_TICNT);
374 con &= ~S3C2410_TICNT_ENABLE;
375 writeb(con, info->base + S3C2410_TICNT);
376 }
377
s3c6410_rtc_disable(struct s3c_rtc * info)378 static void s3c6410_rtc_disable(struct s3c_rtc *info)
379 {
380 unsigned int con;
381
382 con = readw(info->base + S3C2410_RTCCON);
383 con &= ~S3C64XX_RTCCON_TICEN;
384 con &= ~S3C2410_RTCCON_RTCEN;
385 writew(con, info->base + S3C2410_RTCCON);
386 }
387
s3c_rtc_remove(struct platform_device * pdev)388 static int s3c_rtc_remove(struct platform_device *pdev)
389 {
390 struct s3c_rtc *info = platform_get_drvdata(pdev);
391
392 s3c_rtc_setaie(info->dev, 0);
393
394 if (info->data->needs_src_clk)
395 clk_unprepare(info->rtc_src_clk);
396 clk_unprepare(info->rtc_clk);
397
398 return 0;
399 }
400
s3c_rtc_probe(struct platform_device * pdev)401 static int s3c_rtc_probe(struct platform_device *pdev)
402 {
403 struct s3c_rtc *info = NULL;
404 int ret;
405
406 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
407 if (!info)
408 return -ENOMEM;
409
410 info->dev = &pdev->dev;
411 info->data = of_device_get_match_data(&pdev->dev);
412 if (!info->data) {
413 dev_err(&pdev->dev, "failed getting s3c_rtc_data\n");
414 return -EINVAL;
415 }
416 spin_lock_init(&info->alarm_lock);
417
418 platform_set_drvdata(pdev, info);
419
420 info->irq_alarm = platform_get_irq(pdev, 0);
421 if (info->irq_alarm < 0)
422 return info->irq_alarm;
423
424 dev_dbg(&pdev->dev, "s3c2410_rtc: alarm irq %d\n", info->irq_alarm);
425
426 /* get the memory region */
427 info->base = devm_platform_ioremap_resource(pdev, 0);
428 if (IS_ERR(info->base))
429 return PTR_ERR(info->base);
430
431 info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
432 if (IS_ERR(info->rtc_clk)) {
433 ret = PTR_ERR(info->rtc_clk);
434 if (ret != -EPROBE_DEFER)
435 dev_err(&pdev->dev, "failed to find rtc clock\n");
436 else
437 dev_dbg(&pdev->dev, "probe deferred due to missing rtc clk\n");
438 return ret;
439 }
440 ret = clk_prepare_enable(info->rtc_clk);
441 if (ret)
442 return ret;
443
444 if (info->data->needs_src_clk) {
445 info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
446 if (IS_ERR(info->rtc_src_clk)) {
447 ret = dev_err_probe(&pdev->dev, PTR_ERR(info->rtc_src_clk),
448 "failed to find rtc source clock\n");
449 goto err_src_clk;
450 }
451 ret = clk_prepare_enable(info->rtc_src_clk);
452 if (ret)
453 goto err_src_clk;
454 }
455
456 /* disable RTC enable bits potentially set by the bootloader */
457 if (info->data->disable)
458 info->data->disable(info);
459
460 /* check to see if everything is setup correctly */
461 if (info->data->enable)
462 info->data->enable(info);
463
464 dev_dbg(&pdev->dev, "s3c2410_rtc: RTCCON=%02x\n",
465 readw(info->base + S3C2410_RTCCON));
466
467 device_init_wakeup(&pdev->dev, 1);
468
469 info->rtc = devm_rtc_allocate_device(&pdev->dev);
470 if (IS_ERR(info->rtc)) {
471 ret = PTR_ERR(info->rtc);
472 goto err_nortc;
473 }
474
475 info->rtc->ops = &s3c_rtcops;
476 info->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
477 info->rtc->range_max = RTC_TIMESTAMP_END_2099;
478
479 ret = devm_rtc_register_device(info->rtc);
480 if (ret)
481 goto err_nortc;
482
483 ret = devm_request_irq(&pdev->dev, info->irq_alarm, s3c_rtc_alarmirq,
484 0, "s3c2410-rtc alarm", info);
485 if (ret) {
486 dev_err(&pdev->dev, "IRQ%d error %d\n", info->irq_alarm, ret);
487 goto err_nortc;
488 }
489
490 s3c_rtc_disable_clk(info);
491
492 return 0;
493
494 err_nortc:
495 if (info->data->disable)
496 info->data->disable(info);
497
498 if (info->data->needs_src_clk)
499 clk_disable_unprepare(info->rtc_src_clk);
500 err_src_clk:
501 clk_disable_unprepare(info->rtc_clk);
502
503 return ret;
504 }
505
506 #ifdef CONFIG_PM_SLEEP
507
s3c_rtc_suspend(struct device * dev)508 static int s3c_rtc_suspend(struct device *dev)
509 {
510 struct s3c_rtc *info = dev_get_drvdata(dev);
511 int ret;
512
513 ret = s3c_rtc_enable_clk(info);
514 if (ret)
515 return ret;
516
517 if (info->data->disable)
518 info->data->disable(info);
519
520 if (device_may_wakeup(dev) && !info->wake_en) {
521 if (enable_irq_wake(info->irq_alarm) == 0)
522 info->wake_en = true;
523 else
524 dev_err(dev, "enable_irq_wake failed\n");
525 }
526
527 return 0;
528 }
529
s3c_rtc_resume(struct device * dev)530 static int s3c_rtc_resume(struct device *dev)
531 {
532 struct s3c_rtc *info = dev_get_drvdata(dev);
533
534 if (info->data->enable)
535 info->data->enable(info);
536
537 s3c_rtc_disable_clk(info);
538
539 if (device_may_wakeup(dev) && info->wake_en) {
540 disable_irq_wake(info->irq_alarm);
541 info->wake_en = false;
542 }
543
544 return 0;
545 }
546 #endif
547 static SIMPLE_DEV_PM_OPS(s3c_rtc_pm_ops, s3c_rtc_suspend, s3c_rtc_resume);
548
s3c24xx_rtc_irq(struct s3c_rtc * info,int mask)549 static void s3c24xx_rtc_irq(struct s3c_rtc *info, int mask)
550 {
551 rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
552 }
553
s3c6410_rtc_irq(struct s3c_rtc * info,int mask)554 static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
555 {
556 rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
557 writeb(mask, info->base + S3C2410_INTP);
558 }
559
560 static struct s3c_rtc_data const s3c2410_rtc_data = {
561 .irq_handler = s3c24xx_rtc_irq,
562 .enable = s3c24xx_rtc_enable,
563 .disable = s3c24xx_rtc_disable,
564 };
565
566 static struct s3c_rtc_data const s3c2416_rtc_data = {
567 .irq_handler = s3c24xx_rtc_irq,
568 .enable = s3c24xx_rtc_enable,
569 .disable = s3c24xx_rtc_disable,
570 };
571
572 static struct s3c_rtc_data const s3c2443_rtc_data = {
573 .irq_handler = s3c24xx_rtc_irq,
574 .enable = s3c24xx_rtc_enable,
575 .disable = s3c24xx_rtc_disable,
576 };
577
578 static struct s3c_rtc_data const s3c6410_rtc_data = {
579 .needs_src_clk = true,
580 .irq_handler = s3c6410_rtc_irq,
581 .enable = s3c24xx_rtc_enable,
582 .disable = s3c6410_rtc_disable,
583 };
584
585 static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
586 {
587 .compatible = "samsung,s3c2410-rtc",
588 .data = &s3c2410_rtc_data,
589 }, {
590 .compatible = "samsung,s3c2416-rtc",
591 .data = &s3c2416_rtc_data,
592 }, {
593 .compatible = "samsung,s3c2443-rtc",
594 .data = &s3c2443_rtc_data,
595 }, {
596 .compatible = "samsung,s3c6410-rtc",
597 .data = &s3c6410_rtc_data,
598 }, {
599 .compatible = "samsung,exynos3250-rtc",
600 .data = &s3c6410_rtc_data,
601 },
602 { /* sentinel */ },
603 };
604 MODULE_DEVICE_TABLE(of, s3c_rtc_dt_match);
605
606 static struct platform_driver s3c_rtc_driver = {
607 .probe = s3c_rtc_probe,
608 .remove = s3c_rtc_remove,
609 .driver = {
610 .name = "s3c-rtc",
611 .pm = &s3c_rtc_pm_ops,
612 .of_match_table = of_match_ptr(s3c_rtc_dt_match),
613 },
614 };
615 module_platform_driver(s3c_rtc_driver);
616
617 MODULE_DESCRIPTION("Samsung S3C RTC Driver");
618 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
619 MODULE_LICENSE("GPL");
620 MODULE_ALIAS("platform:s3c2410-rtc");
621
