xref: /openbmc/linux/drivers/rtc/rtc-s3c.c (revision 11976fe2)
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 
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 
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 */
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 */
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 */
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 */
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 
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 
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 
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 
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 
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 
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 
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 
388 static void 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 
399 static int s3c_rtc_probe(struct platform_device *pdev)
400 {
401 	struct s3c_rtc *info = NULL;
402 	int ret;
403 
404 	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
405 	if (!info)
406 		return -ENOMEM;
407 
408 	info->dev = &pdev->dev;
409 	info->data = of_device_get_match_data(&pdev->dev);
410 	if (!info->data) {
411 		dev_err(&pdev->dev, "failed getting s3c_rtc_data\n");
412 		return -EINVAL;
413 	}
414 	spin_lock_init(&info->alarm_lock);
415 
416 	platform_set_drvdata(pdev, info);
417 
418 	info->irq_alarm = platform_get_irq(pdev, 0);
419 	if (info->irq_alarm < 0)
420 		return info->irq_alarm;
421 
422 	dev_dbg(&pdev->dev, "s3c2410_rtc: alarm irq %d\n", info->irq_alarm);
423 
424 	/* get the memory region */
425 	info->base = devm_platform_ioremap_resource(pdev, 0);
426 	if (IS_ERR(info->base))
427 		return PTR_ERR(info->base);
428 
429 	info->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
430 	if (IS_ERR(info->rtc_clk))
431 		return dev_err_probe(&pdev->dev, PTR_ERR(info->rtc_clk),
432 				     "failed to find rtc clock\n");
433 	ret = clk_prepare_enable(info->rtc_clk);
434 	if (ret)
435 		return ret;
436 
437 	if (info->data->needs_src_clk) {
438 		info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
439 		if (IS_ERR(info->rtc_src_clk)) {
440 			ret = dev_err_probe(&pdev->dev, PTR_ERR(info->rtc_src_clk),
441 					    "failed to find rtc source clock\n");
442 			goto err_src_clk;
443 		}
444 		ret = clk_prepare_enable(info->rtc_src_clk);
445 		if (ret)
446 			goto err_src_clk;
447 	}
448 
449 	/* disable RTC enable bits potentially set by the bootloader */
450 	if (info->data->disable)
451 		info->data->disable(info);
452 
453 	/* check to see if everything is setup correctly */
454 	if (info->data->enable)
455 		info->data->enable(info);
456 
457 	dev_dbg(&pdev->dev, "s3c2410_rtc: RTCCON=%02x\n",
458 		readw(info->base + S3C2410_RTCCON));
459 
460 	device_init_wakeup(&pdev->dev, 1);
461 
462 	info->rtc = devm_rtc_allocate_device(&pdev->dev);
463 	if (IS_ERR(info->rtc)) {
464 		ret = PTR_ERR(info->rtc);
465 		goto err_nortc;
466 	}
467 
468 	info->rtc->ops = &s3c_rtcops;
469 	info->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
470 	info->rtc->range_max = RTC_TIMESTAMP_END_2099;
471 
472 	ret = devm_rtc_register_device(info->rtc);
473 	if (ret)
474 		goto err_nortc;
475 
476 	ret = devm_request_irq(&pdev->dev, info->irq_alarm, s3c_rtc_alarmirq,
477 			       0, "s3c2410-rtc alarm", info);
478 	if (ret) {
479 		dev_err(&pdev->dev, "IRQ%d error %d\n", info->irq_alarm, ret);
480 		goto err_nortc;
481 	}
482 
483 	s3c_rtc_disable_clk(info);
484 
485 	return 0;
486 
487 err_nortc:
488 	if (info->data->disable)
489 		info->data->disable(info);
490 
491 	if (info->data->needs_src_clk)
492 		clk_disable_unprepare(info->rtc_src_clk);
493 err_src_clk:
494 	clk_disable_unprepare(info->rtc_clk);
495 
496 	return ret;
497 }
498 
499 #ifdef CONFIG_PM_SLEEP
500 
501 static int s3c_rtc_suspend(struct device *dev)
502 {
503 	struct s3c_rtc *info = dev_get_drvdata(dev);
504 	int ret;
505 
506 	ret = s3c_rtc_enable_clk(info);
507 	if (ret)
508 		return ret;
509 
510 	if (info->data->disable)
511 		info->data->disable(info);
512 
513 	if (device_may_wakeup(dev) && !info->wake_en) {
514 		if (enable_irq_wake(info->irq_alarm) == 0)
515 			info->wake_en = true;
516 		else
517 			dev_err(dev, "enable_irq_wake failed\n");
518 	}
519 
520 	return 0;
521 }
522 
523 static int s3c_rtc_resume(struct device *dev)
524 {
525 	struct s3c_rtc *info = dev_get_drvdata(dev);
526 
527 	if (info->data->enable)
528 		info->data->enable(info);
529 
530 	s3c_rtc_disable_clk(info);
531 
532 	if (device_may_wakeup(dev) && info->wake_en) {
533 		disable_irq_wake(info->irq_alarm);
534 		info->wake_en = false;
535 	}
536 
537 	return 0;
538 }
539 #endif
540 static SIMPLE_DEV_PM_OPS(s3c_rtc_pm_ops, s3c_rtc_suspend, s3c_rtc_resume);
541 
542 static void s3c24xx_rtc_irq(struct s3c_rtc *info, int mask)
543 {
544 	rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
545 }
546 
547 static void s3c6410_rtc_irq(struct s3c_rtc *info, int mask)
548 {
549 	rtc_update_irq(info->rtc, 1, RTC_AF | RTC_IRQF);
550 	writeb(mask, info->base + S3C2410_INTP);
551 }
552 
553 static struct s3c_rtc_data const s3c2410_rtc_data = {
554 	.irq_handler		= s3c24xx_rtc_irq,
555 	.enable			= s3c24xx_rtc_enable,
556 	.disable		= s3c24xx_rtc_disable,
557 };
558 
559 static struct s3c_rtc_data const s3c2416_rtc_data = {
560 	.irq_handler		= s3c24xx_rtc_irq,
561 	.enable			= s3c24xx_rtc_enable,
562 	.disable		= s3c24xx_rtc_disable,
563 };
564 
565 static struct s3c_rtc_data const s3c2443_rtc_data = {
566 	.irq_handler		= s3c24xx_rtc_irq,
567 	.enable			= s3c24xx_rtc_enable,
568 	.disable		= s3c24xx_rtc_disable,
569 };
570 
571 static struct s3c_rtc_data const s3c6410_rtc_data = {
572 	.needs_src_clk		= true,
573 	.irq_handler		= s3c6410_rtc_irq,
574 	.enable			= s3c24xx_rtc_enable,
575 	.disable		= s3c6410_rtc_disable,
576 };
577 
578 static const __maybe_unused struct of_device_id s3c_rtc_dt_match[] = {
579 	{
580 		.compatible = "samsung,s3c2410-rtc",
581 		.data = &s3c2410_rtc_data,
582 	}, {
583 		.compatible = "samsung,s3c2416-rtc",
584 		.data = &s3c2416_rtc_data,
585 	}, {
586 		.compatible = "samsung,s3c2443-rtc",
587 		.data = &s3c2443_rtc_data,
588 	}, {
589 		.compatible = "samsung,s3c6410-rtc",
590 		.data = &s3c6410_rtc_data,
591 	}, {
592 		.compatible = "samsung,exynos3250-rtc",
593 		.data = &s3c6410_rtc_data,
594 	},
595 	{ /* sentinel */ },
596 };
597 MODULE_DEVICE_TABLE(of, s3c_rtc_dt_match);
598 
599 static struct platform_driver s3c_rtc_driver = {
600 	.probe		= s3c_rtc_probe,
601 	.remove_new	= s3c_rtc_remove,
602 	.driver		= {
603 		.name	= "s3c-rtc",
604 		.pm	= &s3c_rtc_pm_ops,
605 		.of_match_table	= of_match_ptr(s3c_rtc_dt_match),
606 	},
607 };
608 module_platform_driver(s3c_rtc_driver);
609 
610 MODULE_DESCRIPTION("Samsung S3C RTC Driver");
611 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
612 MODULE_LICENSE("GPL");
613 MODULE_ALIAS("platform:s3c2410-rtc");
614