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 /* Time read/write */
s3c_rtc_gettime(struct device * dev,struct rtc_time * rtc_tm)131 static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
132 {
133 struct s3c_rtc *info = dev_get_drvdata(dev);
134 unsigned int have_retried = 0;
135 int ret;
136
137 ret = s3c_rtc_enable_clk(info);
138 if (ret)
139 return ret;
140
141 retry_get_time:
142 rtc_tm->tm_min = readb(info->base + S3C2410_RTCMIN);
143 rtc_tm->tm_hour = readb(info->base + S3C2410_RTCHOUR);
144 rtc_tm->tm_mday = readb(info->base + S3C2410_RTCDATE);
145 rtc_tm->tm_mon = readb(info->base + S3C2410_RTCMON);
146 rtc_tm->tm_year = readb(info->base + S3C2410_RTCYEAR);
147 rtc_tm->tm_sec = readb(info->base + S3C2410_RTCSEC);
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
154 if (rtc_tm->tm_sec == 0 && !have_retried) {
155 have_retried = 1;
156 goto retry_get_time;
157 }
158
159 rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
160 rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
161 rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
162 rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
163 rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
164 rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
165
166 s3c_rtc_disable_clk(info);
167
168 rtc_tm->tm_year += 100;
169 rtc_tm->tm_mon -= 1;
170
171 dev_dbg(dev, "read time %ptR\n", rtc_tm);
172 return 0;
173 }
174
s3c_rtc_settime(struct device * dev,struct rtc_time * tm)175 static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
176 {
177 struct s3c_rtc *info = dev_get_drvdata(dev);
178 int year = tm->tm_year - 100;
179 int ret;
180
181 dev_dbg(dev, "set time %ptR\n", tm);
182
183 /* we get around y2k by simply not supporting it */
184
185 if (year < 0 || year >= 100) {
186 dev_err(dev, "rtc only supports 100 years\n");
187 return -EINVAL;
188 }
189
190 ret = s3c_rtc_enable_clk(info);
191 if (ret)
192 return ret;
193
194 writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_RTCSEC);
195 writeb(bin2bcd(tm->tm_min), info->base + S3C2410_RTCMIN);
196 writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_RTCHOUR);
197 writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_RTCDATE);
198 writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_RTCMON);
199 writeb(bin2bcd(year), info->base + S3C2410_RTCYEAR);
200
201 s3c_rtc_disable_clk(info);
202
203 return 0;
204 }
205
s3c_rtc_getalarm(struct device * dev,struct rtc_wkalrm * alrm)206 static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
207 {
208 struct s3c_rtc *info = dev_get_drvdata(dev);
209 struct rtc_time *alm_tm = &alrm->time;
210 unsigned int alm_en;
211 int ret;
212
213 ret = s3c_rtc_enable_clk(info);
214 if (ret)
215 return ret;
216
217 alm_tm->tm_sec = readb(info->base + S3C2410_ALMSEC);
218 alm_tm->tm_min = readb(info->base + S3C2410_ALMMIN);
219 alm_tm->tm_hour = readb(info->base + S3C2410_ALMHOUR);
220 alm_tm->tm_mon = readb(info->base + S3C2410_ALMMON);
221 alm_tm->tm_mday = readb(info->base + S3C2410_ALMDATE);
222 alm_tm->tm_year = readb(info->base + S3C2410_ALMYEAR);
223
224 alm_en = readb(info->base + S3C2410_RTCALM);
225
226 s3c_rtc_disable_clk(info);
227
228 alrm->enabled = (alm_en & S3C2410_RTCALM_ALMEN) ? 1 : 0;
229
230 dev_dbg(dev, "read alarm %d, %ptR\n", alm_en, alm_tm);
231
232 /* decode the alarm enable field */
233 if (alm_en & S3C2410_RTCALM_SECEN)
234 alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
235
236 if (alm_en & S3C2410_RTCALM_MINEN)
237 alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
238
239 if (alm_en & S3C2410_RTCALM_HOUREN)
240 alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
241
242 if (alm_en & S3C2410_RTCALM_DAYEN)
243 alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
244
245 if (alm_en & S3C2410_RTCALM_MONEN) {
246 alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);
247 alm_tm->tm_mon -= 1;
248 }
249
250 if (alm_en & S3C2410_RTCALM_YEAREN)
251 alm_tm->tm_year = bcd2bin(alm_tm->tm_year);
252
253 return 0;
254 }
255
s3c_rtc_setalarm(struct device * dev,struct rtc_wkalrm * alrm)256 static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
257 {
258 struct s3c_rtc *info = dev_get_drvdata(dev);
259 struct rtc_time *tm = &alrm->time;
260 unsigned int alrm_en;
261 int ret;
262
263 dev_dbg(dev, "s3c_rtc_setalarm: %d, %ptR\n", alrm->enabled, tm);
264
265 ret = s3c_rtc_enable_clk(info);
266 if (ret)
267 return ret;
268
269 alrm_en = readb(info->base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
270 writeb(0x00, info->base + S3C2410_RTCALM);
271
272 if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
273 alrm_en |= S3C2410_RTCALM_SECEN;
274 writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_ALMSEC);
275 }
276
277 if (tm->tm_min < 60 && tm->tm_min >= 0) {
278 alrm_en |= S3C2410_RTCALM_MINEN;
279 writeb(bin2bcd(tm->tm_min), info->base + S3C2410_ALMMIN);
280 }
281
282 if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
283 alrm_en |= S3C2410_RTCALM_HOUREN;
284 writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_ALMHOUR);
285 }
286
287 if (tm->tm_mon < 12 && tm->tm_mon >= 0) {
288 alrm_en |= S3C2410_RTCALM_MONEN;
289 writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_ALMMON);
290 }
291
292 if (tm->tm_mday <= 31 && tm->tm_mday >= 1) {
293 alrm_en |= S3C2410_RTCALM_DAYEN;
294 writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_ALMDATE);
295 }
296
297 dev_dbg(dev, "setting S3C2410_RTCALM to %08x\n", alrm_en);
298
299 writeb(alrm_en, info->base + S3C2410_RTCALM);
300
301 s3c_rtc_setaie(dev, alrm->enabled);
302
303 s3c_rtc_disable_clk(info);
304
305 return 0;
306 }
307
308 static const struct rtc_class_ops s3c_rtcops = {
309 .read_time = s3c_rtc_gettime,
310 .set_time = s3c_rtc_settime,
311 .read_alarm = s3c_rtc_getalarm,
312 .set_alarm = s3c_rtc_setalarm,
313 .alarm_irq_enable = s3c_rtc_setaie,
314 };
315
s3c24xx_rtc_enable(struct s3c_rtc * info)316 static void s3c24xx_rtc_enable(struct s3c_rtc *info)
317 {
318 unsigned int con, tmp;
319
320 con = readw(info->base + S3C2410_RTCCON);
321 /* re-enable the device, and check it is ok */
322 if ((con & S3C2410_RTCCON_RTCEN) == 0) {
323 dev_info(info->dev, "rtc disabled, re-enabling\n");
324
325 tmp = readw(info->base + S3C2410_RTCCON);
326 writew(tmp | S3C2410_RTCCON_RTCEN, info->base + S3C2410_RTCCON);
327 }
328
329 if (con & S3C2410_RTCCON_CNTSEL) {
330 dev_info(info->dev, "removing RTCCON_CNTSEL\n");
331
332 tmp = readw(info->base + S3C2410_RTCCON);
333 writew(tmp & ~S3C2410_RTCCON_CNTSEL,
334 info->base + S3C2410_RTCCON);
335 }
336
337 if (con & S3C2410_RTCCON_CLKRST) {
338 dev_info(info->dev, "removing RTCCON_CLKRST\n");
339
340 tmp = readw(info->base + S3C2410_RTCCON);
341 writew(tmp & ~S3C2410_RTCCON_CLKRST,
342 info->base + S3C2410_RTCCON);
343 }
344 }
345
s3c24xx_rtc_disable(struct s3c_rtc * info)346 static void s3c24xx_rtc_disable(struct s3c_rtc *info)
347 {
348 unsigned int con;
349
350 con = readw(info->base + S3C2410_RTCCON);
351 con &= ~S3C2410_RTCCON_RTCEN;
352 writew(con, info->base + S3C2410_RTCCON);
353
354 con = readb(info->base + S3C2410_TICNT);
355 con &= ~S3C2410_TICNT_ENABLE;
356 writeb(con, info->base + S3C2410_TICNT);
357 }
358
s3c6410_rtc_disable(struct s3c_rtc * info)359 static void s3c6410_rtc_disable(struct s3c_rtc *info)
360 {
361 unsigned int con;
362
363 con = readw(info->base + S3C2410_RTCCON);
364 con &= ~S3C64XX_RTCCON_TICEN;
365 con &= ~S3C2410_RTCCON_RTCEN;
366 writew(con, info->base + S3C2410_RTCCON);
367 }
368
s3c_rtc_remove(struct platform_device * pdev)369 static int s3c_rtc_remove(struct platform_device *pdev)
370 {
371 struct s3c_rtc *info = platform_get_drvdata(pdev);
372
373 s3c_rtc_setaie(info->dev, 0);
374
375 if (info->data->needs_src_clk)
376 clk_unprepare(info->rtc_src_clk);
377 clk_unprepare(info->rtc_clk);
378
379 return 0;
380 }
381
s3c_rtc_probe(struct platform_device * pdev)382 static int s3c_rtc_probe(struct platform_device *pdev)
383 {
384 struct s3c_rtc *info = NULL;
385 int ret;
386
387 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
388 if (!info)
389 return -ENOMEM;
390
391 info->dev = &pdev->dev;
392 info->data = of_device_get_match_data(&pdev->dev);
393 if (!info->data) {
394 dev_err(&pdev->dev, "failed getting s3c_rtc_data\n");
395 return -EINVAL;
396 }
397 spin_lock_init(&info->alarm_lock);
398
399 platform_set_drvdata(pdev, info);
400
401 info->irq_alarm = platform_get_irq(pdev, 0);
402 if (info->irq_alarm < 0)
403 return info->irq_alarm;
404
405 dev_dbg(&pdev->dev, "s3c2410_rtc: alarm irq %d\n", info->irq_alarm);
406
407 /* get the memory region */
408 info->base = devm_platform_ioremap_resource(pdev, 0);
409 if (IS_ERR(info->base))
410 return PTR_ERR(info->base);
411
412 info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
413 if (IS_ERR(info->rtc_clk)) {
414 ret = PTR_ERR(info->rtc_clk);
415 if (ret != -EPROBE_DEFER)
416 dev_err(&pdev->dev, "failed to find rtc clock\n");
417 else
418 dev_dbg(&pdev->dev, "probe deferred due to missing rtc clk\n");
419 return ret;
420 }
421 ret = clk_prepare_enable(info->rtc_clk);
422 if (ret)
423 return ret;
424
425 if (info->data->needs_src_clk) {
426 info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
427 if (IS_ERR(info->rtc_src_clk)) {
428 ret = dev_err_probe(&pdev->dev, PTR_ERR(info->rtc_src_clk),
429 "failed to find rtc source clock\n");
430 goto err_src_clk;
431 }
432 ret = clk_prepare_enable(info->rtc_src_clk);
433 if (ret)
434 goto err_src_clk;
435 }
436
437 /* disable RTC enable bits potentially set by the bootloader */
438 if (info->data->disable)
439 info->data->disable(info);
440
441 /* check to see if everything is setup correctly */
442 if (info->data->enable)
443 info->data->enable(info);
444
445 dev_dbg(&pdev->dev, "s3c2410_rtc: RTCCON=%02x\n",
446 readw(info->base + S3C2410_RTCCON));
447
448 device_init_wakeup(&pdev->dev, 1);
449
450 /* register RTC and exit */
451 info->rtc = devm_rtc_device_register(&pdev->dev, "s3c", &s3c_rtcops,
452 THIS_MODULE);
453 if (IS_ERR(info->rtc)) {
454 dev_err(&pdev->dev, "cannot attach rtc\n");
455 ret = PTR_ERR(info->rtc);
456 goto err_nortc;
457 }
458
459 ret = devm_request_irq(&pdev->dev, info->irq_alarm, s3c_rtc_alarmirq,
460 0, "s3c2410-rtc alarm", info);
461 if (ret) {
462 dev_err(&pdev->dev, "IRQ%d error %d\n", info->irq_alarm, ret);
463 goto err_nortc;
464 }
465
466 s3c_rtc_disable_clk(info);
467
468 return 0;
469
470 err_nortc:
471 if (info->data->disable)
472 info->data->disable(info);
473
474 if (info->data->needs_src_clk)
475 clk_disable_unprepare(info->rtc_src_clk);
476 err_src_clk:
477 clk_disable_unprepare(info->rtc_clk);
478
479 return ret;
480 }
481
482 #ifdef CONFIG_PM_SLEEP
483
s3c_rtc_suspend(struct device * dev)484 static int s3c_rtc_suspend(struct device *dev)
485 {
486 struct s3c_rtc *info = dev_get_drvdata(dev);
487 int ret;
488
489 ret = s3c_rtc_enable_clk(info);
490 if (ret)
491 return ret;
492
493 if (info->data->disable)
494 info->data->disable(info);
495
496 if (device_may_wakeup(dev) && !info->wake_en) {
497 if (enable_irq_wake(info->irq_alarm) == 0)
498 info->wake_en = true;
499 else
500 dev_err(dev, "enable_irq_wake failed\n");
501 }
502
503 return 0;
504 }
505
s3c_rtc_resume(struct device * dev)506 static int s3c_rtc_resume(struct device *dev)
507 {
508 struct s3c_rtc *info = dev_get_drvdata(dev);
509
510 if (info->data->enable)
511 info->data->enable(info);
512
513 s3c_rtc_disable_clk(info);
514
515 if (device_may_wakeup(dev) && info->wake_en) {
516 disable_irq_wake(info->irq_alarm);
517 info->wake_en = false;
518 }
519
520 return 0;
521 }
522 #endif
523 static SIMPLE_DEV_PM_OPS(s3c_rtc_pm_ops, s3c_rtc_suspend, s3c_rtc_resume);
524
s3c24xx_rtc_irq(struct s3c_rtc * info,int mask)525 static void s3c24xx_rtc_irq(struct s3c_rtc *info, int mask)
526 {
527 rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
528 }
529
s3c6410_rtc_irq(struct s3c_rtc * info,int mask)530 static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
531 {
532 rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
533 writeb(mask, info->base + S3C2410_INTP);
534 }
535
536 static struct s3c_rtc_data const s3c2410_rtc_data = {
537 .irq_handler = s3c24xx_rtc_irq,
538 .enable = s3c24xx_rtc_enable,
539 .disable = s3c24xx_rtc_disable,
540 };
541
542 static struct s3c_rtc_data const s3c2416_rtc_data = {
543 .irq_handler = s3c24xx_rtc_irq,
544 .enable = s3c24xx_rtc_enable,
545 .disable = s3c24xx_rtc_disable,
546 };
547
548 static struct s3c_rtc_data const s3c2443_rtc_data = {
549 .irq_handler = s3c24xx_rtc_irq,
550 .enable = s3c24xx_rtc_enable,
551 .disable = s3c24xx_rtc_disable,
552 };
553
554 static struct s3c_rtc_data const s3c6410_rtc_data = {
555 .needs_src_clk = true,
556 .irq_handler = s3c6410_rtc_irq,
557 .enable = s3c24xx_rtc_enable,
558 .disable = s3c6410_rtc_disable,
559 };
560
561 static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
562 {
563 .compatible = "samsung,s3c2410-rtc",
564 .data = &s3c2410_rtc_data,
565 }, {
566 .compatible = "samsung,s3c2416-rtc",
567 .data = &s3c2416_rtc_data,
568 }, {
569 .compatible = "samsung,s3c2443-rtc",
570 .data = &s3c2443_rtc_data,
571 }, {
572 .compatible = "samsung,s3c6410-rtc",
573 .data = &s3c6410_rtc_data,
574 }, {
575 .compatible = "samsung,exynos3250-rtc",
576 .data = &s3c6410_rtc_data,
577 },
578 { /* sentinel */ },
579 };
580 MODULE_DEVICE_TABLE(of, s3c_rtc_dt_match);
581
582 static struct platform_driver s3c_rtc_driver = {
583 .probe = s3c_rtc_probe,
584 .remove = s3c_rtc_remove,
585 .driver = {
586 .name = "s3c-rtc",
587 .pm = &s3c_rtc_pm_ops,
588 .of_match_table = of_match_ptr(s3c_rtc_dt_match),
589 },
590 };
591 module_platform_driver(s3c_rtc_driver);
592
593 MODULE_DESCRIPTION("Samsung S3C RTC Driver");
594 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
595 MODULE_LICENSE("GPL");
596 MODULE_ALIAS("platform:s3c2410-rtc");
597
