1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Avionic Design GmbH
4 */
5
6#include <linux/bcd.h>
7#include <linux/bitfield.h>
8#include <linux/i2c.h>
9#include <linux/module.h>
10#include <linux/regmap.h>
11#include <linux/rtc.h>
12#include <linux/of.h>
13#include <linux/pm_wakeirq.h>
14
15#define PCF8523_REG_CONTROL1 0x00
16#define PCF8523_CONTROL1_CAP_SEL BIT(7)
17#define PCF8523_CONTROL1_STOP    BIT(5)
18#define PCF8523_CONTROL1_AIE    BIT(1)
19
20#define PCF8523_REG_CONTROL2 0x01
21#define PCF8523_CONTROL2_AF BIT(3)
22
23#define PCF8523_REG_CONTROL3 0x02
24#define PCF8523_CONTROL3_PM  GENMASK(7, 5)
25#define PCF8523_PM_STANDBY   0x7
26#define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
27#define PCF8523_CONTROL3_BSF BIT(3)
28
29#define PCF8523_REG_SECONDS  0x03
30#define PCF8523_SECONDS_OS BIT(7)
31
32#define PCF8523_REG_MINUTES  0x04
33#define PCF8523_REG_HOURS    0x05
34#define PCF8523_REG_DAYS     0x06
35#define PCF8523_REG_WEEKDAYS 0x07
36#define PCF8523_REG_MONTHS   0x08
37#define PCF8523_REG_YEARS    0x09
38
39#define PCF8523_REG_MINUTE_ALARM	0x0a
40#define PCF8523_REG_HOUR_ALARM		0x0b
41#define PCF8523_REG_DAY_ALARM		0x0c
42#define PCF8523_REG_WEEKDAY_ALARM	0x0d
43#define ALARM_DIS BIT(7)
44
45#define PCF8523_REG_OFFSET   0x0e
46#define PCF8523_OFFSET_MODE BIT(7)
47
48#define PCF8523_TMR_CLKOUT_CTRL 0x0f
49
50struct pcf8523 {
51	struct rtc_device *rtc;
52	struct regmap *regmap;
53};
54
55static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
56{
57	u32 load, value = 0;
58
59	load = 12500;
60	of_property_read_u32(node, "quartz-load-femtofarads", &load);
61
62	switch (load) {
63	default:
64		dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
65			 load);
66		fallthrough;
67	case 12500:
68		value = PCF8523_CONTROL1_CAP_SEL;
69		break;
70	case 7000:
71		break;
72	}
73
74	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
75				  PCF8523_CONTROL1_CAP_SEL, value);
76}
77
78static irqreturn_t pcf8523_irq(int irq, void *dev_id)
79{
80	struct pcf8523 *pcf8523 = dev_id;
81	u32 value;
82	int err;
83
84	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
85	if (err < 0)
86		return IRQ_HANDLED;
87
88	if (value & PCF8523_CONTROL2_AF) {
89		value &= ~PCF8523_CONTROL2_AF;
90		regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
91		rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
92
93		return IRQ_HANDLED;
94	}
95
96	return IRQ_NONE;
97}
98
99static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
100{
101	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
102	u8 regs[10];
103	int err;
104
105	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
106			       sizeof(regs));
107	if (err < 0)
108		return err;
109
110	if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
111		return -EINVAL;
112
113	tm->tm_sec = bcd2bin(regs[3] & 0x7f);
114	tm->tm_min = bcd2bin(regs[4] & 0x7f);
115	tm->tm_hour = bcd2bin(regs[5] & 0x3f);
116	tm->tm_mday = bcd2bin(regs[6] & 0x3f);
117	tm->tm_wday = regs[7] & 0x7;
118	tm->tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
119	tm->tm_year = bcd2bin(regs[9]) + 100;
120
121	return 0;
122}
123
124static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
125{
126	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
127	u8 regs[7];
128	int err;
129
130	err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
131				 PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
132	if (err < 0)
133		return err;
134
135	/* This will purposely overwrite PCF8523_SECONDS_OS */
136	regs[0] = bin2bcd(tm->tm_sec);
137	regs[1] = bin2bcd(tm->tm_min);
138	regs[2] = bin2bcd(tm->tm_hour);
139	regs[3] = bin2bcd(tm->tm_mday);
140	regs[4] = tm->tm_wday;
141	regs[5] = bin2bcd(tm->tm_mon + 1);
142	regs[6] = bin2bcd(tm->tm_year - 100);
143
144	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
145				sizeof(regs));
146	if (err < 0) {
147		/*
148		 * If the time cannot be set, restart the RTC anyway. Note
149		 * that errors are ignored if the RTC cannot be started so
150		 * that we have a chance to propagate the original error.
151		 */
152		regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
153				   PCF8523_CONTROL1_STOP, 0);
154		return err;
155	}
156
157	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
158				 PCF8523_CONTROL1_STOP, 0);
159}
160
161static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
162{
163	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
164	u8 regs[4];
165	u32 value;
166	int err;
167
168	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
169			       sizeof(regs));
170	if (err < 0)
171		return err;
172
173	tm->time.tm_sec = 0;
174	tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
175	tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
176	tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
177	tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
178
179	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
180	if (err < 0)
181		return err;
182	tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
183
184	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
185	if (err < 0)
186		return err;
187	tm->pending = !!(value & PCF8523_CONTROL2_AF);
188
189	return 0;
190}
191
192static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
193{
194	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
195
196	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
197				  PCF8523_CONTROL1_AIE, enabled ?
198				  PCF8523_CONTROL1_AIE : 0);
199}
200
201static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
202{
203	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
204	u8 regs[5];
205	int err;
206
207	err = pcf8523_irq_enable(dev, 0);
208	if (err)
209		return err;
210
211	err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
212	if (err < 0)
213		return err;
214
215	regs[0] = bin2bcd(tm->time.tm_min);
216	regs[1] = bin2bcd(tm->time.tm_hour);
217	regs[2] = bin2bcd(tm->time.tm_mday);
218	regs[3] = ALARM_DIS;
219
220	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
221				sizeof(regs));
222	if (err < 0)
223		return err;
224
225	if (tm->enabled)
226		return pcf8523_irq_enable(dev, tm->enabled);
227
228	return 0;
229}
230
231static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
232{
233	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
234	int ret;
235	u32 value;
236
237	switch (param->param) {
238	case RTC_PARAM_BACKUP_SWITCH_MODE:
239		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
240		if (ret < 0)
241			return ret;
242
243		value = FIELD_GET(PCF8523_CONTROL3_PM, value);
244
245		switch (value) {
246		case 0x0:
247		case 0x4:
248			param->uvalue = RTC_BSM_LEVEL;
249			break;
250		case 0x1:
251		case 0x5:
252			param->uvalue = RTC_BSM_DIRECT;
253			break;
254		case PCF8523_PM_STANDBY:
255			param->uvalue = RTC_BSM_STANDBY;
256			break;
257		default:
258			param->uvalue = RTC_BSM_DISABLED;
259		}
260
261		break;
262
263	default:
264		return -EINVAL;
265	}
266
267	return 0;
268}
269
270static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
271{
272	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
273	u8 mode;
274
275	switch (param->param) {
276	case RTC_PARAM_BACKUP_SWITCH_MODE:
277		switch (param->uvalue) {
278		case RTC_BSM_DISABLED:
279			mode = 0x2;
280			break;
281		case RTC_BSM_DIRECT:
282			mode = 0x1;
283			break;
284		case RTC_BSM_LEVEL:
285			mode = 0x0;
286			break;
287		case RTC_BSM_STANDBY:
288			mode = PCF8523_PM_STANDBY;
289			break;
290		default:
291			return -EINVAL;
292		}
293
294		return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
295					  PCF8523_CONTROL3_PM,
296					  FIELD_PREP(PCF8523_CONTROL3_PM, mode));
297
298		break;
299
300	default:
301		return -EINVAL;
302	}
303
304	return 0;
305}
306
307static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
308			     unsigned long arg)
309{
310	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
311	unsigned int flags = 0;
312	u32 value;
313	int ret;
314
315	switch (cmd) {
316	case RTC_VL_READ:
317		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
318		if (ret < 0)
319			return ret;
320
321		if (value & PCF8523_CONTROL3_BLF)
322			flags |= RTC_VL_BACKUP_LOW;
323
324		ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
325		if (ret < 0)
326			return ret;
327
328		if (value & PCF8523_SECONDS_OS)
329			flags |= RTC_VL_DATA_INVALID;
330
331		return put_user(flags, (unsigned int __user *)arg);
332
333	default:
334		return -ENOIOCTLCMD;
335	}
336}
337
338static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
339{
340	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
341	int err;
342	u32 value;
343	s8 val;
344
345	err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
346	if (err < 0)
347		return err;
348
349	/* sign extend the 7-bit offset value */
350	val = value << 1;
351	*offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
352
353	return 0;
354}
355
356static int pcf8523_rtc_set_offset(struct device *dev, long offset)
357{
358	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
359	long reg_m0, reg_m1;
360	u32 value;
361
362	reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
363	reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
364
365	if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
366		value = reg_m0 & 0x7f;
367	else
368		value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
369
370	return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
371}
372
373#ifdef CONFIG_PM_SLEEP
374static int pcf8523_suspend(struct device *dev)
375{
376	struct i2c_client *client = to_i2c_client(dev);
377
378	if (client->irq > 0 && device_may_wakeup(dev))
379		enable_irq_wake(client->irq);
380
381	return 0;
382}
383
384static int pcf8523_resume(struct device *dev)
385{
386	struct i2c_client *client = to_i2c_client(dev);
387
388	if (client->irq > 0 && device_may_wakeup(dev))
389		disable_irq_wake(client->irq);
390
391	return 0;
392}
393#endif
394
395static SIMPLE_DEV_PM_OPS(pcf8523_pm, pcf8523_suspend, pcf8523_resume);
396
397static const struct rtc_class_ops pcf8523_rtc_ops = {
398	.read_time = pcf8523_rtc_read_time,
399	.set_time = pcf8523_rtc_set_time,
400	.read_alarm = pcf8523_rtc_read_alarm,
401	.set_alarm = pcf8523_rtc_set_alarm,
402	.alarm_irq_enable = pcf8523_irq_enable,
403	.ioctl = pcf8523_rtc_ioctl,
404	.read_offset = pcf8523_rtc_read_offset,
405	.set_offset = pcf8523_rtc_set_offset,
406	.param_get = pcf8523_param_get,
407	.param_set = pcf8523_param_set,
408};
409
410static const struct regmap_config regmap_config = {
411	.reg_bits = 8,
412	.val_bits = 8,
413	.max_register = 0x13,
414};
415
416static int pcf8523_probe(struct i2c_client *client)
417{
418	struct pcf8523 *pcf8523;
419	struct rtc_device *rtc;
420	bool wakeup_source = false;
421	u32 value;
422	int err;
423
424	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
425		return -ENODEV;
426
427	pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
428	if (!pcf8523)
429		return -ENOMEM;
430
431	pcf8523->regmap = devm_regmap_init_i2c(client, &regmap_config);
432	if (IS_ERR(pcf8523->regmap))
433		return PTR_ERR(pcf8523->regmap);
434
435	i2c_set_clientdata(client, pcf8523);
436
437	rtc = devm_rtc_allocate_device(&client->dev);
438	if (IS_ERR(rtc))
439		return PTR_ERR(rtc);
440	pcf8523->rtc = rtc;
441
442	err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
443	if (err < 0)
444		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
445			 err);
446
447	err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
448	if (err < 0)
449		return err;
450
451	if (value & PCF8523_SECONDS_OS) {
452		err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
453		if (err < 0)
454			return err;
455
456		if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
457			err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
458					   value & ~PCF8523_CONTROL3_PM);
459			if (err < 0)
460				return err;
461		}
462	}
463
464	rtc->ops = &pcf8523_rtc_ops;
465	rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
466	rtc->range_max = RTC_TIMESTAMP_END_2099;
467	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
468	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
469
470	if (client->irq > 0) {
471		unsigned long irqflags = IRQF_TRIGGER_LOW;
472
473		if (dev_fwnode(&client->dev))
474			irqflags = 0;
475
476		err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
477		if (err < 0)
478			return err;
479
480		err = devm_request_threaded_irq(&client->dev, client->irq,
481						NULL, pcf8523_irq,
482						IRQF_SHARED | IRQF_ONESHOT | irqflags,
483						dev_name(&rtc->dev), pcf8523);
484		if (err)
485			return err;
486
487		dev_pm_set_wake_irq(&client->dev, client->irq);
488	}
489
490	wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
491	if (client->irq > 0 || wakeup_source)
492		device_init_wakeup(&client->dev, true);
493
494	return devm_rtc_register_device(rtc);
495}
496
497static const struct i2c_device_id pcf8523_id[] = {
498	{ "pcf8523", 0 },
499	{ }
500};
501MODULE_DEVICE_TABLE(i2c, pcf8523_id);
502
503static const struct of_device_id pcf8523_of_match[] = {
504	{ .compatible = "nxp,pcf8523" },
505	{ .compatible = "microcrystal,rv8523" },
506	{ }
507};
508MODULE_DEVICE_TABLE(of, pcf8523_of_match);
509
510static struct i2c_driver pcf8523_driver = {
511	.driver = {
512		.name = "rtc-pcf8523",
513		.of_match_table = pcf8523_of_match,
514		.pm = &pcf8523_pm,
515	},
516	.probe = pcf8523_probe,
517	.id_table = pcf8523_id,
518};
519module_i2c_driver(pcf8523_driver);
520
521MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
522MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
523MODULE_LICENSE("GPL v2");
524