rtc-s3c.c

  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/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 <ben@simtec.co.uk>");
566MODULE_LICENSE("GPL");