rtc-pcf8563.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * An I2C driver for the Philips PCF8563 RTC
  4 * Copyright 2005-06 Tower Technologies
  5 *
  6 * Author: Alessandro Zummo <a.zummo@towertech.it>
  7 * Maintainers: http://www.nslu2-linux.org/
  8 *
  9 * based on the other drivers in this same directory.
 10 *
 11 * https://www.nxp.com/docs/en/data-sheet/PCF8563.pdf
 12 */
 13
 14#include <linux/bcd.h>
 15#include <linux/clk-provider.h>
 16#include <linux/err.h>
 17#include <linux/i2c.h>
 18#include <linux/module.h>
 19#include <linux/of.h>
 20#include <linux/regmap.h>
 21#include <linux/rtc.h>
 22#include <linux/slab.h>
 23
 24#define PCF8563_REG_ST1		0x00 /* status */
 25#define PCF8563_REG_ST2		0x01
 26#define PCF8563_BIT_AIE		BIT(1)
 27#define PCF8563_BIT_AF		BIT(3)
 28#define PCF8563_BITS_ST2_N	(7 << 5)
 29
 30#define PCF8563_REG_SC		0x02 /* datetime */
 31#define PCF8563_REG_MN		0x03
 32#define PCF8563_REG_HR		0x04
 33#define PCF8563_REG_DM		0x05
 34#define PCF8563_REG_DW		0x06
 35#define PCF8563_REG_MO		0x07
 36#define PCF8563_REG_YR		0x08
 37
 38#define PCF8563_REG_AMN		0x09 /* alarm */
 39
 40#define PCF8563_REG_CLKO		0x0D /* clock out */
 41#define PCF8563_REG_CLKO_FE		0x80 /* clock out enabled */
 42#define PCF8563_REG_CLKO_F_MASK		0x03 /* frequenc mask */
 43#define PCF8563_REG_CLKO_F_32768HZ	0x00
 44#define PCF8563_REG_CLKO_F_1024HZ	0x01
 45#define PCF8563_REG_CLKO_F_32HZ		0x02
 46#define PCF8563_REG_CLKO_F_1HZ		0x03
 47
 48#define PCF8563_REG_TMRC	0x0E /* timer control */
 49#define PCF8563_TMRC_ENABLE	BIT(7)
 50#define PCF8563_TMRC_4096	0
 51#define PCF8563_TMRC_64		1
 52#define PCF8563_TMRC_1		2
 53#define PCF8563_TMRC_1_60	3
 54#define PCF8563_TMRC_MASK	3
 55
 56#define PCF8563_REG_TMR		0x0F /* timer */
 57
 58#define PCF8563_SC_LV		0x80 /* low voltage */
 59#define PCF8563_MO_C		0x80 /* century */
 60
 61static struct i2c_driver pcf8563_driver;
 62
 63struct pcf8563 {
 64	struct rtc_device *rtc;
 65	/*
 66	 * The meaning of MO_C bit varies by the chip type.
 67	 * From PCF8563 datasheet: this bit is toggled when the years
 68	 * register overflows from 99 to 00
 69	 *   0 indicates the century is 20xx
 70	 *   1 indicates the century is 19xx
 71	 * From RTC8564 datasheet: this bit indicates change of
 72	 * century. When the year digit data overflows from 99 to 00,
 73	 * this bit is set. By presetting it to 0 while still in the
 74	 * 20th century, it will be set in year 2000, ...
 75	 * There seems no reliable way to know how the system use this
 76	 * bit.  So let's do it heuristically, assuming we are live in
 77	 * 1970...2069.
 78	 */
 79	int c_polarity;	/* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
 80
 81	struct regmap *regmap;
 82#ifdef CONFIG_COMMON_CLK
 83	struct clk_hw		clkout_hw;
 84#endif
 85};
 86
 87static int pcf8563_set_alarm_mode(struct pcf8563 *pcf8563, bool on)
 88{
 89	u32 buf;
 90	int err;
 91
 92	err = regmap_read(pcf8563->regmap, PCF8563_REG_ST2, &buf);
 93	if (err < 0)
 94		return err;
 95
 96	if (on)
 97		buf |= PCF8563_BIT_AIE;
 98	else
 99		buf &= ~PCF8563_BIT_AIE;
100
101	buf &= ~(PCF8563_BIT_AF | PCF8563_BITS_ST2_N);
102
103	return regmap_write(pcf8563->regmap, PCF8563_REG_ST2, buf);
104}
105
106static int pcf8563_get_alarm_mode(struct pcf8563 *pcf8563, unsigned char *en,
107				  unsigned char *pen)
108{
109	u32 buf;
110	int err;
111
112	err = regmap_read(pcf8563->regmap, PCF8563_REG_ST2, &buf);
113	if (err < 0)
114		return err;
115
116	if (en)
117		*en = !!(buf & PCF8563_BIT_AIE);
118	if (pen)
119		*pen = !!(buf & PCF8563_BIT_AF);
120
121	return 0;
122}
123
124static irqreturn_t pcf8563_irq(int irq, void *dev_id)
125{
126	struct pcf8563 *pcf8563 = dev_id;
127	char pending;
128	int err;
129
130	err = pcf8563_get_alarm_mode(pcf8563, NULL, &pending);
131	if (err)
132		return IRQ_NONE;
133
134	if (pending) {
135		rtc_update_irq(pcf8563->rtc, 1, RTC_IRQF | RTC_AF);
136		pcf8563_set_alarm_mode(pcf8563, 1);
137		return IRQ_HANDLED;
138	}
139
140	return IRQ_NONE;
141}
142
143/*
144 * In the routines that deal directly with the pcf8563 hardware, we use
145 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
146 */
147static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
148{
149	struct pcf8563 *pcf8563 = dev_get_drvdata(dev);
150	unsigned char buf[9];
151	int err;
152
153	err = regmap_bulk_read(pcf8563->regmap, PCF8563_REG_ST1, buf,
154			       sizeof(buf));
155	if (err < 0)
156		return err;
157
158	if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
159		dev_err(dev,
160			"low voltage detected, date/time is not reliable.\n");
161		return -EINVAL;
162	}
163
164	dev_dbg(dev,
165		"%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
166		"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
167		__func__,
168		buf[0], buf[1], buf[2], buf[3],
169		buf[4], buf[5], buf[6], buf[7],
170		buf[8]);
171
172	tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
173	tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
174	tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
175	tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
176	tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
177	tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
178	tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]) + 100;
179	/* detect the polarity heuristically. see note above. */
180	pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
181		(tm->tm_year >= 100) : (tm->tm_year < 100);
182
183	dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
184		"mday=%d, mon=%d, year=%d, wday=%d\n",
185		__func__,
186		tm->tm_sec, tm->tm_min, tm->tm_hour,
187		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
188
189	return 0;
190}
191
192static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
193{
194	struct pcf8563 *pcf8563 = dev_get_drvdata(dev);
195	unsigned char buf[9];
196
197	dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "
198		"mday=%d, mon=%d, year=%d, wday=%d\n",
199		__func__,
200		tm->tm_sec, tm->tm_min, tm->tm_hour,
201		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
202
203	/* hours, minutes and seconds */
204	buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
205	buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
206	buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
207
208	buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
209
210	/* month, 1 - 12 */
211	buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
212
213	/* year and century */
214	buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year - 100);
215	if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
216		buf[PCF8563_REG_MO] |= PCF8563_MO_C;
217
218	buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
219
220	return regmap_bulk_write(pcf8563->regmap, PCF8563_REG_SC,
221				buf + PCF8563_REG_SC,
222				sizeof(buf) - PCF8563_REG_SC);
223}
224
225static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
226{
227	struct pcf8563 *pcf8563 = dev_get_drvdata(dev);
228	int ret;
229
230	switch (cmd) {
231	case RTC_VL_READ:
232		ret = regmap_test_bits(pcf8563->regmap, PCF8563_REG_SC,
233				       PCF8563_SC_LV);
234		if (ret < 0)
235			return ret;
236
237		return put_user(ret ? RTC_VL_DATA_INVALID : 0,
238				(unsigned int __user *)arg);
239	default:
240		return -ENOIOCTLCMD;
241	}
242}
243
244static int pcf8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
245{
246	struct pcf8563 *pcf8563 = dev_get_drvdata(dev);
247	unsigned char buf[4];
248	int err;
249
250	err = regmap_bulk_read(pcf8563->regmap, PCF8563_REG_AMN, buf,
251			       sizeof(buf));
252	if (err < 0)
253		return err;
254
255	dev_dbg(dev,
256		"%s: raw data is min=%02x, hr=%02x, mday=%02x, wday=%02x\n",
257		__func__, buf[0], buf[1], buf[2], buf[3]);
258
259	tm->time.tm_sec = 0;
260	tm->time.tm_min = bcd2bin(buf[0] & 0x7F);
261	tm->time.tm_hour = bcd2bin(buf[1] & 0x3F);
262	tm->time.tm_mday = bcd2bin(buf[2] & 0x3F);
263	tm->time.tm_wday = bcd2bin(buf[3] & 0x7);
264
265	err = pcf8563_get_alarm_mode(pcf8563, &tm->enabled, &tm->pending);
266	if (err < 0)
267		return err;
268
269	dev_dbg(dev, "%s: tm is mins=%d, hours=%d, mday=%d, wday=%d,"
270		" enabled=%d, pending=%d\n", __func__, tm->time.tm_min,
271		tm->time.tm_hour, tm->time.tm_mday, tm->time.tm_wday,
272		tm->enabled, tm->pending);
273
274	return 0;
275}
276
277static int pcf8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
278{
279	struct pcf8563 *pcf8563 = dev_get_drvdata(dev);
280	unsigned char buf[4];
281	int err;
282
283	buf[0] = bin2bcd(tm->time.tm_min);
284	buf[1] = bin2bcd(tm->time.tm_hour);
285	buf[2] = bin2bcd(tm->time.tm_mday);
286	buf[3] = tm->time.tm_wday & 0x07;
287
288	err = regmap_bulk_write(pcf8563->regmap, PCF8563_REG_AMN, buf,
289				sizeof(buf));
290	if (err)
291		return err;
292
293	return pcf8563_set_alarm_mode(pcf8563, !!tm->enabled);
294}
295
296static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
297{
298	struct pcf8563 *pcf8563 = dev_get_drvdata(dev);
299
300	dev_dbg(dev, "%s: en=%d\n", __func__, enabled);
301	return pcf8563_set_alarm_mode(pcf8563, !!enabled);
302}
303
304#ifdef CONFIG_COMMON_CLK
305/*
306 * Handling of the clkout
307 */
308
309#define clkout_hw_to_pcf8563(_hw) container_of(_hw, struct pcf8563, clkout_hw)
310
311static const int clkout_rates[] = {
312	32768,
313	1024,
314	32,
315	1,
316};
317
318static unsigned long pcf8563_clkout_recalc_rate(struct clk_hw *hw,
319						unsigned long parent_rate)
320{
321	struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
322	u32 buf;
323	int ret;
324
325	ret = regmap_read(pcf8563->regmap, PCF8563_REG_CLKO, &buf);
326	if (ret < 0)
327		return 0;
328
329	buf &= PCF8563_REG_CLKO_F_MASK;
330	return clkout_rates[buf];
331}
332
333static int pcf8563_clkout_determine_rate(struct clk_hw *hw,
334					 struct clk_rate_request *req)
335{
336	int i;
337
338	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
339		if (clkout_rates[i] <= req->rate) {
340			req->rate = clkout_rates[i];
341
342			return 0;
343		}
344
345	req->rate = clkout_rates[0];
346
347	return 0;
348}
349
350static int pcf8563_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
351				   unsigned long parent_rate)
352{
353	struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
354	int i, ret;
355	u32 buf;
356
357	ret = regmap_read(pcf8563->regmap, PCF8563_REG_CLKO, &buf);
358	if (ret < 0)
359		return ret;
360
361	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
362		if (clkout_rates[i] == rate) {
363			buf &= ~PCF8563_REG_CLKO_F_MASK;
364			buf |= i;
365			return regmap_update_bits(pcf8563->regmap,
366					    PCF8563_REG_CLKO,
367					    PCF8563_REG_CLKO_F_MASK,
368					    buf);
369		}
370
371	return -EINVAL;
372}
373
374static int pcf8563_clkout_control(struct clk_hw *hw, bool enable)
375{
376	struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
377	u32 buf;
378	int ret;
379
380	ret = regmap_read(pcf8563->regmap, PCF8563_REG_CLKO, &buf);
381	if (ret < 0)
382		return ret;
383
384	if (enable)
385		buf |= PCF8563_REG_CLKO_FE;
386	else
387		buf &= ~PCF8563_REG_CLKO_FE;
388
389	return regmap_update_bits(pcf8563->regmap, PCF8563_REG_CLKO,
390				  PCF8563_REG_CLKO_FE, buf);
391}
392
393static int pcf8563_clkout_prepare(struct clk_hw *hw)
394{
395	return pcf8563_clkout_control(hw, 1);
396}
397
398static void pcf8563_clkout_unprepare(struct clk_hw *hw)
399{
400	pcf8563_clkout_control(hw, 0);
401}
402
403static int pcf8563_clkout_is_prepared(struct clk_hw *hw)
404{
405	struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
406	u32 buf;
407	int ret;
408
409	ret = regmap_read(pcf8563->regmap, PCF8563_REG_CLKO, &buf);
410	if (ret < 0)
411		return ret;
412
413	return !!(buf & PCF8563_REG_CLKO_FE);
414}
415
416static const struct clk_ops pcf8563_clkout_ops = {
417	.prepare = pcf8563_clkout_prepare,
418	.unprepare = pcf8563_clkout_unprepare,
419	.is_prepared = pcf8563_clkout_is_prepared,
420	.recalc_rate = pcf8563_clkout_recalc_rate,
421	.determine_rate = pcf8563_clkout_determine_rate,
422	.set_rate = pcf8563_clkout_set_rate,
423};
424
425static struct clk *pcf8563_clkout_register_clk(struct pcf8563 *pcf8563)
426{
427	struct device_node *node = pcf8563->rtc->dev.parent->of_node;
428	struct clk_init_data init;
429	struct clk *clk;
430	int ret;
431
432	/* disable the clkout output */
433	ret = regmap_clear_bits(pcf8563->regmap, PCF8563_REG_CLKO,
434				PCF8563_REG_CLKO_FE);
435	if (ret < 0)
436		return ERR_PTR(ret);
437
438	init.name = "pcf8563-clkout";
439	init.ops = &pcf8563_clkout_ops;
440	init.flags = 0;
441	init.parent_names = NULL;
442	init.num_parents = 0;
443	pcf8563->clkout_hw.init = &init;
444
445	/* optional override of the clockname */
446	of_property_read_string(node, "clock-output-names", &init.name);
447
448	/* register the clock */
449	clk = devm_clk_register(&pcf8563->rtc->dev, &pcf8563->clkout_hw);
450
451	if (!IS_ERR(clk))
452		of_clk_add_provider(node, of_clk_src_simple_get, clk);
453
454	return clk;
455}
456#endif
457
458static const struct rtc_class_ops pcf8563_rtc_ops = {
459	.ioctl		= pcf8563_rtc_ioctl,
460	.read_time	= pcf8563_rtc_read_time,
461	.set_time	= pcf8563_rtc_set_time,
462	.read_alarm	= pcf8563_rtc_read_alarm,
463	.set_alarm	= pcf8563_rtc_set_alarm,
464	.alarm_irq_enable = pcf8563_irq_enable,
465};
466
467static const struct regmap_config regmap_config = {
468	.reg_bits = 8,
469	.val_bits = 8,
470	.max_register = 0xF,
471};
472
473static int pcf8563_probe(struct i2c_client *client)
474{
475	struct pcf8563 *pcf8563;
476	int err;
477
478	dev_dbg(&client->dev, "%s\n", __func__);
479
480	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
481		return -ENODEV;
482
483	pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),
484				GFP_KERNEL);
485	if (!pcf8563)
486		return -ENOMEM;
487
488	pcf8563->regmap = devm_regmap_init_i2c(client, &regmap_config);
489	if (IS_ERR(pcf8563->regmap))
490		return PTR_ERR(pcf8563->regmap);
491
492	i2c_set_clientdata(client, pcf8563);
493	device_set_wakeup_capable(&client->dev, 1);
494
495	/* Set timer to lowest frequency to save power (ref Haoyu datasheet) */
496	err = regmap_set_bits(pcf8563->regmap, PCF8563_REG_TMRC,
497			      PCF8563_TMRC_1_60);
498	if (err < 0) {
499		dev_err(&client->dev, "%s: write error\n", __func__);
500		return err;
501	}
502
503	/* Clear flags and disable interrupts */
504	err = regmap_write(pcf8563->regmap, PCF8563_REG_ST2, 0);
505	if (err < 0) {
506		dev_err(&client->dev, "%s: write error\n", __func__);
507		return err;
508	}
509
510	pcf8563->rtc = devm_rtc_allocate_device(&client->dev);
511	if (IS_ERR(pcf8563->rtc))
512		return PTR_ERR(pcf8563->rtc);
513
514	pcf8563->rtc->ops = &pcf8563_rtc_ops;
515	/* the pcf8563 alarm only supports a minute accuracy */
516	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, pcf8563->rtc->features);
517	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, pcf8563->rtc->features);
518	clear_bit(RTC_FEATURE_ALARM, pcf8563->rtc->features);
519	pcf8563->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
520	pcf8563->rtc->range_max = RTC_TIMESTAMP_END_2099;
521	pcf8563->rtc->set_start_time = true;
522
523	if (client->irq > 0) {
524		unsigned long irqflags = IRQF_TRIGGER_LOW;
525
526		if (dev_fwnode(&client->dev))
527			irqflags = 0;
528
529		err = devm_request_threaded_irq(&client->dev, client->irq,
530				NULL, pcf8563_irq,
531				IRQF_SHARED | IRQF_ONESHOT | irqflags,
532				pcf8563_driver.driver.name, client);
533		if (err) {
534			dev_err(&client->dev, "unable to request IRQ %d\n",
535								client->irq);
536			return err;
537		}
538	} else {
539		client->irq = 0;
540	}
541
542	if (client->irq > 0 || device_property_read_bool(&client->dev, "wakeup-source")) {
543		device_init_wakeup(&client->dev, true);
544		set_bit(RTC_FEATURE_ALARM, pcf8563->rtc->features);
545	}
546
547	err = devm_rtc_register_device(pcf8563->rtc);
548	if (err)
549		return err;
550
551#ifdef CONFIG_COMMON_CLK
552	/* register clk in common clk framework */
553	pcf8563_clkout_register_clk(pcf8563);
554#endif
555
556	return 0;
557}
558
559static const struct i2c_device_id pcf8563_id[] = {
560	{ "pcf8563" },
561	{ "rtc8564" },
562	{ "pca8565" },
563	{ }
564};
565MODULE_DEVICE_TABLE(i2c, pcf8563_id);
566
567#ifdef CONFIG_OF
568static const struct of_device_id pcf8563_of_match[] = {
569	{ .compatible = "nxp,pcf8563" },
570	{ .compatible = "epson,rtc8564" },
571	{ .compatible = "microcrystal,rv8564" },
572	{ .compatible = "nxp,pca8565" },
573	{}
574};
575MODULE_DEVICE_TABLE(of, pcf8563_of_match);
576#endif
577
578static struct i2c_driver pcf8563_driver = {
579	.driver		= {
580		.name	= "rtc-pcf8563",
581		.of_match_table = of_match_ptr(pcf8563_of_match),
582	},
583	.probe		= pcf8563_probe,
584	.id_table	= pcf8563_id,
585};
586
587module_i2c_driver(pcf8563_driver);
588
589MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
590MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
591MODULE_LICENSE("GPL");