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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, <[email protected]>
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/uaccess.h>
27#include <linux/io.h>
28
29#include <asm/irq.h>
30#include "rtc-s3c.h"
31
32struct s3c_rtc {
33 struct device *dev;
34 struct rtc_device *rtc;
35
36 void __iomem *base;
37 struct clk *rtc_clk;
38 struct clk *rtc_src_clk;
39 bool alarm_enabled;
40
41 const struct s3c_rtc_data *data;
42
43 int irq_alarm;
44 spinlock_t alarm_lock;
45
46 bool wake_en;
47};
48
49struct s3c_rtc_data {
50 bool needs_src_clk;
51
52 void (*irq_handler) (struct s3c_rtc *info, int mask);
53 void (*enable) (struct s3c_rtc *info);
54 void (*disable) (struct s3c_rtc *info);
55};
56
57static int s3c_rtc_enable_clk(struct s3c_rtc *info)
58{
59 int ret;
60
61 ret = clk_enable(info->rtc_clk);
62 if (ret)
63 return ret;
64
65 if (info->data->needs_src_clk) {
66 ret = clk_enable(info->rtc_src_clk);
67 if (ret) {
68 clk_disable(info->rtc_clk);
69 return ret;
70 }
71 }
72 return 0;
73}
74
75static void s3c_rtc_disable_clk(struct s3c_rtc *info)
76{
77 if (info->data->needs_src_clk)
78 clk_disable(info->rtc_src_clk);
79 clk_disable(info->rtc_clk);
80}
81
82/* IRQ Handler */
83static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
84{
85 struct s3c_rtc *info = (struct s3c_rtc *)id;
86
87 if (info->data->irq_handler)
88 info->data->irq_handler(info, S3C2410_INTP_ALM);
89
90 return IRQ_HANDLED;
91}
92
93/* Update control registers */
94static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
95{
96 struct s3c_rtc *info = dev_get_drvdata(dev);
97 unsigned long flags;
98 unsigned int tmp;
99 int ret;
100
101 dev_dbg(info->dev, "%s: aie=%d\n", __func__, enabled);
102
103 ret = s3c_rtc_enable_clk(info);
104 if (ret)
105 return ret;
106
107 tmp = readb(info->base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
108
109 if (enabled)
110 tmp |= S3C2410_RTCALM_ALMEN;
111
112 writeb(tmp, info->base + S3C2410_RTCALM);
113
114 spin_lock_irqsave(&info->alarm_lock, flags);
115
116 if (info->alarm_enabled && !enabled)
117 s3c_rtc_disable_clk(info);
118 else if (!info->alarm_enabled && enabled)
119 ret = s3c_rtc_enable_clk(info);
120
121 info->alarm_enabled = enabled;
122 spin_unlock_irqrestore(&info->alarm_lock, flags);
123
124 s3c_rtc_disable_clk(info);
125
126 return ret;
127}
128
129/* Read time from RTC and convert it from BCD */
130static int s3c_rtc_read_time(struct s3c_rtc *info, struct rtc_time *tm)
131{
132 unsigned int have_retried = 0;
133 int ret;
134
135 ret = s3c_rtc_enable_clk(info);
136 if (ret)
137 return ret;
138
139retry_get_time:
140 tm->tm_min = readb(info->base + S3C2410_RTCMIN);
141 tm->tm_hour = readb(info->base + S3C2410_RTCHOUR);
142 tm->tm_mday = readb(info->base + S3C2410_RTCDATE);
143 tm->tm_mon = readb(info->base + S3C2410_RTCMON);
144 tm->tm_year = readb(info->base + S3C2410_RTCYEAR);
145 tm->tm_sec = readb(info->base + S3C2410_RTCSEC);
146
147 /*
148 * The only way to work out whether the system was mid-update
149 * when we read it is to check the second counter, and if it
150 * is zero, then we re-try the entire read
151 */
152 if (tm->tm_sec == 0 && !have_retried) {
153 have_retried = 1;
154 goto retry_get_time;
155 }
156
157 s3c_rtc_disable_clk(info);
158
159 tm->tm_sec = bcd2bin(tm->tm_sec);
160 tm->tm_min = bcd2bin(tm->tm_min);
161 tm->tm_hour = bcd2bin(tm->tm_hour);
162 tm->tm_mday = bcd2bin(tm->tm_mday);
163 tm->tm_mon = bcd2bin(tm->tm_mon);
164 tm->tm_year = bcd2bin(tm->tm_year);
165
166 return 0;
167}
168
169/* Convert time to BCD and write it to RTC */
170static int s3c_rtc_write_time(struct s3c_rtc *info, const struct rtc_time *tm)
171{
172 int ret;
173
174 ret = s3c_rtc_enable_clk(info);
175 if (ret)
176 return ret;
177
178 writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_RTCSEC);
179 writeb(bin2bcd(tm->tm_min), info->base + S3C2410_RTCMIN);
180 writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_RTCHOUR);
181 writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_RTCDATE);
182 writeb(bin2bcd(tm->tm_mon), info->base + S3C2410_RTCMON);
183 writeb(bin2bcd(tm->tm_year), info->base + S3C2410_RTCYEAR);
184
185 s3c_rtc_disable_clk(info);
186
187 return 0;
188}
189
190static int s3c_rtc_gettime(struct device *dev, struct rtc_time *tm)
191{
192 struct s3c_rtc *info = dev_get_drvdata(dev);
193 int ret;
194
195 ret = s3c_rtc_read_time(info, tm);
196 if (ret)
197 return ret;
198
199 /* Convert internal representation to actual date/time */
200 tm->tm_year += 100;
201 tm->tm_mon -= 1;
202
203 dev_dbg(dev, "read time %ptR\n", tm);
204 return 0;
205}
206
207static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
208{
209 struct s3c_rtc *info = dev_get_drvdata(dev);
210 struct rtc_time rtc_tm = *tm;
211
212 dev_dbg(dev, "set time %ptR\n", tm);
213
214 /*
215 * Convert actual date/time to internal representation.
216 * We get around Y2K by simply not supporting it.
217 */
218 rtc_tm.tm_year -= 100;
219 rtc_tm.tm_mon += 1;
220
221 return s3c_rtc_write_time(info, &rtc_tm);
222}
223
224static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
225{
226 struct s3c_rtc *info = dev_get_drvdata(dev);
227 struct rtc_time *alm_tm = &alrm->time;
228 unsigned int alm_en;
229 int ret;
230
231 ret = s3c_rtc_enable_clk(info);
232 if (ret)
233 return ret;
234
235 alm_tm->tm_sec = readb(info->base + S3C2410_ALMSEC);
236 alm_tm->tm_min = readb(info->base + S3C2410_ALMMIN);
237 alm_tm->tm_hour = readb(info->base + S3C2410_ALMHOUR);
238 alm_tm->tm_mon = readb(info->base + S3C2410_ALMMON);
239 alm_tm->tm_mday = readb(info->base + S3C2410_ALMDATE);
240 alm_tm->tm_year = readb(info->base + S3C2410_ALMYEAR);
241
242 alm_en = readb(info->base + S3C2410_RTCALM);
243
244 s3c_rtc_disable_clk(info);
245
246 alrm->enabled = (alm_en & S3C2410_RTCALM_ALMEN) ? 1 : 0;
247
248 dev_dbg(dev, "read alarm %d, %ptR\n", alm_en, alm_tm);
249
250 /* decode the alarm enable field */
251 if (alm_en & S3C2410_RTCALM_SECEN)
252 alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
253
254 if (alm_en & S3C2410_RTCALM_MINEN)
255 alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
256
257 if (alm_en & S3C2410_RTCALM_HOUREN)
258 alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
259
260 if (alm_en & S3C2410_RTCALM_DAYEN)
261 alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
262
263 if (alm_en & S3C2410_RTCALM_MONEN) {
264 alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);
265 alm_tm->tm_mon -= 1;
266 }
267
268 if (alm_en & S3C2410_RTCALM_YEAREN)
269 alm_tm->tm_year = bcd2bin(alm_tm->tm_year);
270
271 return 0;
272}
273
274static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
275{
276 struct s3c_rtc *info = dev_get_drvdata(dev);
277 struct rtc_time *tm = &alrm->time;
278 unsigned int alrm_en;
279 int ret;
280
281 dev_dbg(dev, "s3c_rtc_setalarm: %d, %ptR\n", alrm->enabled, tm);
282
283 ret = s3c_rtc_enable_clk(info);
284 if (ret)
285 return ret;
286
287 alrm_en = readb(info->base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
288 writeb(0x00, info->base + S3C2410_RTCALM);
289
290 if (tm->tm_sec < 60 && tm->tm_sec >= 0) {
291 alrm_en |= S3C2410_RTCALM_SECEN;
292 writeb(bin2bcd(tm->tm_sec), info->base + S3C2410_ALMSEC);
293 }
294
295 if (tm->tm_min < 60 && tm->tm_min >= 0) {
296 alrm_en |= S3C2410_RTCALM_MINEN;
297 writeb(bin2bcd(tm->tm_min), info->base + S3C2410_ALMMIN);
298 }
299
300 if (tm->tm_hour < 24 && tm->tm_hour >= 0) {
301 alrm_en |= S3C2410_RTCALM_HOUREN;
302 writeb(bin2bcd(tm->tm_hour), info->base + S3C2410_ALMHOUR);
303 }
304
305 if (tm->tm_mon < 12 && tm->tm_mon >= 0) {
306 alrm_en |= S3C2410_RTCALM_MONEN;
307 writeb(bin2bcd(tm->tm_mon + 1), info->base + S3C2410_ALMMON);
308 }
309
310 if (tm->tm_mday <= 31 && tm->tm_mday >= 1) {
311 alrm_en |= S3C2410_RTCALM_DAYEN;
312 writeb(bin2bcd(tm->tm_mday), info->base + S3C2410_ALMDATE);
313 }
314
315 dev_dbg(dev, "setting S3C2410_RTCALM to %08x\n", alrm_en);
316
317 writeb(alrm_en, info->base + S3C2410_RTCALM);
318
319 s3c_rtc_setaie(dev, alrm->enabled);
320
321 s3c_rtc_disable_clk(info);
322
323 return 0;
324}
325
326static const struct rtc_class_ops s3c_rtcops = {
327 .read_time = s3c_rtc_gettime,
328 .set_time = s3c_rtc_settime,
329 .read_alarm = s3c_rtc_getalarm,
330 .set_alarm = s3c_rtc_setalarm,
331 .alarm_irq_enable = s3c_rtc_setaie,
332};
333
334static void s3c6410_rtc_enable(struct s3c_rtc *info)
335{
336 unsigned int con, tmp;
337
338 con = readw(info->base + S3C2410_RTCCON);
339 /* re-enable the device, and check it is ok */
340 if ((con & S3C2410_RTCCON_RTCEN) == 0) {
341 dev_info(info->dev, "rtc disabled, re-enabling\n");
342
343 tmp = readw(info->base + S3C2410_RTCCON);
344 writew(tmp | S3C2410_RTCCON_RTCEN, info->base + S3C2410_RTCCON);
345 }
346
347 if (con & S3C2410_RTCCON_CNTSEL) {
348 dev_info(info->dev, "removing RTCCON_CNTSEL\n");
349
350 tmp = readw(info->base + S3C2410_RTCCON);
351 writew(tmp & ~S3C2410_RTCCON_CNTSEL,
352 info->base + S3C2410_RTCCON);
353 }
354
355 if (con & S3C2410_RTCCON_CLKRST) {
356 dev_info(info->dev, "removing RTCCON_CLKRST\n");
357
358 tmp = readw(info->base + S3C2410_RTCCON);
359 writew(tmp & ~S3C2410_RTCCON_CLKRST,
360 info->base + S3C2410_RTCCON);
361 }
362}
363
364static void s3c6410_rtc_disable(struct s3c_rtc *info)
365{
366 unsigned int con;
367
368 con = readw(info->base + S3C2410_RTCCON);
369 con &= ~S3C64XX_RTCCON_TICEN;
370 con &= ~S3C2410_RTCCON_RTCEN;
371 writew(con, info->base + S3C2410_RTCCON);
372}
373
374static void s3c_rtc_remove(struct platform_device *pdev)
375{
376 struct s3c_rtc *info = platform_get_drvdata(pdev);
377
378 s3c_rtc_setaie(info->dev, 0);
379
380 if (info->data->needs_src_clk)
381 clk_unprepare(info->rtc_src_clk);
382 clk_unprepare(info->rtc_clk);
383}
384
385static int s3c_rtc_probe(struct platform_device *pdev)
386{
387 struct s3c_rtc *info = NULL;
388 int ret;
389
390 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
391 if (!info)
392 return -ENOMEM;
393
394 info->dev = &pdev->dev;
395 info->data = of_device_get_match_data(&pdev->dev);
396 if (!info->data) {
397 dev_err(&pdev->dev, "failed getting s3c_rtc_data\n");
398 return -EINVAL;
399 }
400 spin_lock_init(&info->alarm_lock);
401
402 platform_set_drvdata(pdev, info);
403
404 info->irq_alarm = platform_get_irq(pdev, 0);
405 if (info->irq_alarm < 0)
406 return info->irq_alarm;
407
408 dev_dbg(&pdev->dev, "s3c2410_rtc: alarm irq %d\n", info->irq_alarm);
409
410 /* get the memory region */
411 info->base = devm_platform_ioremap_resource(pdev, 0);
412 if (IS_ERR(info->base))
413 return PTR_ERR(info->base);
414
415 info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
416 if (IS_ERR(info->rtc_clk))
417 return dev_err_probe(&pdev->dev, PTR_ERR(info->rtc_clk),
418 "failed to find rtc clock\n");
419 ret = clk_prepare_enable(info->rtc_clk);
420 if (ret)
421 return ret;
422
423 if (info->data->needs_src_clk) {
424 info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
425 if (IS_ERR(info->rtc_src_clk)) {
426 ret = dev_err_probe(&pdev->dev, PTR_ERR(info->rtc_src_clk),
427 "failed to find rtc source clock\n");
428 goto err_src_clk;
429 }
430 ret = clk_prepare_enable(info->rtc_src_clk);
431 if (ret)
432 goto err_src_clk;
433 }
434
435 /* disable RTC enable bits potentially set by the bootloader */
436 if (info->data->disable)
437 info->data->disable(info);
438
439 /* check to see if everything is setup correctly */
440 if (info->data->enable)
441 info->data->enable(info);
442
443 dev_dbg(&pdev->dev, "s3c2410_rtc: RTCCON=%02x\n",
444 readw(info->base + S3C2410_RTCCON));
445
446 device_init_wakeup(&pdev->dev, true);
447
448 info->rtc = devm_rtc_allocate_device(&pdev->dev);
449 if (IS_ERR(info->rtc)) {
450 ret = PTR_ERR(info->rtc);
451 goto err_nortc;
452 }
453
454 info->rtc->ops = &s3c_rtcops;
455 info->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
456 info->rtc->range_max = RTC_TIMESTAMP_END_2099;
457
458 ret = devm_rtc_register_device(info->rtc);
459 if (ret)
460 goto err_nortc;
461
462 ret = devm_request_irq(&pdev->dev, info->irq_alarm, s3c_rtc_alarmirq,
463 0, "s3c2410-rtc alarm", info);
464 if (ret) {
465 dev_err(&pdev->dev, "IRQ%d error %d\n", info->irq_alarm, ret);
466 goto err_nortc;
467 }
468
469 s3c_rtc_disable_clk(info);
470
471 return 0;
472
473err_nortc:
474 if (info->data->disable)
475 info->data->disable(info);
476
477 if (info->data->needs_src_clk)
478 clk_disable_unprepare(info->rtc_src_clk);
479err_src_clk:
480 clk_disable_unprepare(info->rtc_clk);
481
482 return ret;
483}
484
485#ifdef CONFIG_PM_SLEEP
486
487static int s3c_rtc_suspend(struct device *dev)
488{
489 struct s3c_rtc *info = dev_get_drvdata(dev);
490 int ret;
491
492 ret = s3c_rtc_enable_clk(info);
493 if (ret)
494 return ret;
495
496 if (info->data->disable)
497 info->data->disable(info);
498
499 if (device_may_wakeup(dev) && !info->wake_en) {
500 if (enable_irq_wake(info->irq_alarm) == 0)
501 info->wake_en = true;
502 else
503 dev_err(dev, "enable_irq_wake failed\n");
504 }
505
506 return 0;
507}
508
509static int s3c_rtc_resume(struct device *dev)
510{
511 struct s3c_rtc *info = dev_get_drvdata(dev);
512
513 if (info->data->enable)
514 info->data->enable(info);
515
516 s3c_rtc_disable_clk(info);
517
518 if (device_may_wakeup(dev) && info->wake_en) {
519 disable_irq_wake(info->irq_alarm);
520 info->wake_en = false;
521 }
522
523 return 0;
524}
525#endif
526static SIMPLE_DEV_PM_OPS(s3c_rtc_pm_ops, s3c_rtc_suspend, s3c_rtc_resume);
527
528static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
529{
530 rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
531 writeb(mask, info->base + S3C2410_INTP);
532}
533
534static const struct s3c_rtc_data s3c6410_rtc_data = {
535 .needs_src_clk = true,
536 .irq_handler = s3c6410_rtc_irq,
537 .enable = s3c6410_rtc_enable,
538 .disable = s3c6410_rtc_disable,
539};
540
541static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
542 {
543 .compatible = "samsung,s3c6410-rtc",
544 .data = &s3c6410_rtc_data,
545 }, {
546 .compatible = "samsung,exynos3250-rtc",
547 .data = &s3c6410_rtc_data,
548 },
549 { /* sentinel */ },
550};
551MODULE_DEVICE_TABLE(of, s3c_rtc_dt_match);
552
553static struct platform_driver s3c_rtc_driver = {
554 .probe = s3c_rtc_probe,
555 .remove = s3c_rtc_remove,
556 .driver = {
557 .name = "s3c-rtc",
558 .pm = &s3c_rtc_pm_ops,
559 .of_match_table = of_match_ptr(s3c_rtc_dt_match),
560 },
561};
562module_platform_driver(s3c_rtc_driver);
563
564MODULE_DESCRIPTION("Samsung S3C RTC Driver");
565MODULE_AUTHOR("Ben Dooks <[email protected]>");
566MODULE_LICENSE("GPL");