xref: /linux-6.15/drivers/rtc/rtc-ds1343.c (revision f308b682) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* rtc-ds1343.c
3  *
4  * Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
5  * Real Time Clock
6  *
7  * Author : Raghavendra Chandra Ganiga <[email protected]>
8  *	    Ankur Srivastava <[email protected]> : DS1343 Nvram Support
9  */
10 
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include <linux/device.h>
15 #include <linux/spi/spi.h>
16 #include <linux/regmap.h>
17 #include <linux/rtc.h>
18 #include <linux/bcd.h>
19 #include <linux/pm.h>
20 #include <linux/pm_wakeirq.h>
21 #include <linux/slab.h>
22 
23 #define DALLAS_MAXIM_DS1343	0
24 #define DALLAS_MAXIM_DS1344	1
25 
26 /* RTC DS1343 Registers */
27 #define DS1343_SECONDS_REG	0x00
28 #define DS1343_MINUTES_REG	0x01
29 #define DS1343_HOURS_REG	0x02
30 #define DS1343_DAY_REG		0x03
31 #define DS1343_DATE_REG		0x04
32 #define DS1343_MONTH_REG	0x05
33 #define DS1343_YEAR_REG		0x06
34 #define DS1343_ALM0_SEC_REG	0x07
35 #define DS1343_ALM0_MIN_REG	0x08
36 #define DS1343_ALM0_HOUR_REG	0x09
37 #define DS1343_ALM0_DAY_REG	0x0A
38 #define DS1343_ALM1_SEC_REG	0x0B
39 #define DS1343_ALM1_MIN_REG	0x0C
40 #define DS1343_ALM1_HOUR_REG	0x0D
41 #define DS1343_ALM1_DAY_REG	0x0E
42 #define DS1343_CONTROL_REG	0x0F
43 #define DS1343_STATUS_REG	0x10
44 #define DS1343_TRICKLE_REG	0x11
45 #define DS1343_NVRAM		0x20
46 
47 #define DS1343_NVRAM_LEN	96
48 
49 /* DS1343 Control Registers bits */
50 #define DS1343_EOSC		0x80
51 #define DS1343_DOSF		0x20
52 #define DS1343_EGFIL		0x10
53 #define DS1343_SQW		0x08
54 #define DS1343_INTCN		0x04
55 #define DS1343_A1IE		0x02
56 #define DS1343_A0IE		0x01
57 
58 /* DS1343 Status Registers bits */
59 #define DS1343_OSF		0x80
60 #define DS1343_IRQF1		0x02
61 #define DS1343_IRQF0		0x01
62 
63 /* DS1343 Trickle Charger Registers bits */
64 #define DS1343_TRICKLE_MAGIC	0xa0
65 #define DS1343_TRICKLE_DS1	0x08
66 #define DS1343_TRICKLE_1K	0x01
67 #define DS1343_TRICKLE_2K	0x02
68 #define DS1343_TRICKLE_4K	0x03
69 
70 static const struct spi_device_id ds1343_id[] = {
71 	{ "ds1343", DALLAS_MAXIM_DS1343 },
72 	{ "ds1344", DALLAS_MAXIM_DS1344 },
73 	{ }
74 };
75 MODULE_DEVICE_TABLE(spi, ds1343_id);
76 
77 struct ds1343_priv {
78 	struct spi_device *spi;
79 	struct rtc_device *rtc;
80 	struct regmap *map;
81 	struct mutex mutex;
82 	unsigned int irqen;
83 	int irq;
84 	int alarm_sec;
85 	int alarm_min;
86 	int alarm_hour;
87 	int alarm_mday;
88 };
89 
90 static ssize_t ds1343_show_glitchfilter(struct device *dev,
91 				struct device_attribute *attr, char *buf)
92 {
93 	struct ds1343_priv *priv = dev_get_drvdata(dev);
94 	int glitch_filt_status, data;
95 
96 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
97 
98 	glitch_filt_status = !!(data & DS1343_EGFIL);
99 
100 	if (glitch_filt_status)
101 		return sprintf(buf, "enabled\n");
102 	else
103 		return sprintf(buf, "disabled\n");
104 }
105 
106 static ssize_t ds1343_store_glitchfilter(struct device *dev,
107 					struct device_attribute *attr,
108 					const char *buf, size_t count)
109 {
110 	struct ds1343_priv *priv = dev_get_drvdata(dev);
111 	int data;
112 
113 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
114 
115 	if (strncmp(buf, "enabled", 7) == 0)
116 		data |= DS1343_EGFIL;
117 
118 	else if (strncmp(buf, "disabled", 8) == 0)
119 		data &= ~(DS1343_EGFIL);
120 
121 	else
122 		return -EINVAL;
123 
124 	regmap_write(priv->map, DS1343_CONTROL_REG, data);
125 
126 	return count;
127 }
128 
129 static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
130 			ds1343_store_glitchfilter);
131 
132 static int ds1343_nvram_write(void *priv, unsigned int off, void *val,
133 			      size_t bytes)
134 {
135 	struct ds1343_priv *ds1343 = priv;
136 
137 	return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
138 }
139 
140 static int ds1343_nvram_read(void *priv, unsigned int off, void *val,
141 			     size_t bytes)
142 {
143 	struct ds1343_priv *ds1343 = priv;
144 
145 	return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
146 }
147 
148 static ssize_t ds1343_show_tricklecharger(struct device *dev,
149 				struct device_attribute *attr, char *buf)
150 {
151 	struct ds1343_priv *priv = dev_get_drvdata(dev);
152 	int data;
153 	char *diodes = "disabled", *resistors = " ";
154 
155 	regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
156 
157 	if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
158 		switch (data & 0x0c) {
159 		case DS1343_TRICKLE_DS1:
160 			diodes = "one diode,";
161 			break;
162 
163 		default:
164 			diodes = "no diode,";
165 			break;
166 		}
167 
168 		switch (data & 0x03) {
169 		case DS1343_TRICKLE_1K:
170 			resistors = "1k Ohm";
171 			break;
172 
173 		case DS1343_TRICKLE_2K:
174 			resistors = "2k Ohm";
175 			break;
176 
177 		case DS1343_TRICKLE_4K:
178 			resistors = "4k Ohm";
179 			break;
180 
181 		default:
182 			diodes = "disabled";
183 			break;
184 		}
185 	}
186 
187 	return sprintf(buf, "%s %s\n", diodes, resistors);
188 }
189 
190 static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
191 
192 static int ds1343_sysfs_register(struct device *dev)
193 {
194 	int err;
195 
196 	err = device_create_file(dev, &dev_attr_glitch_filter);
197 	if (err)
198 		return err;
199 
200 	err = device_create_file(dev, &dev_attr_trickle_charger);
201 	if (!err)
202 		return 0;
203 
204 	device_remove_file(dev, &dev_attr_glitch_filter);
205 
206 	return err;
207 }
208 
209 static void ds1343_sysfs_unregister(struct device *dev)
210 {
211 	device_remove_file(dev, &dev_attr_glitch_filter);
212 	device_remove_file(dev, &dev_attr_trickle_charger);
213 }
214 
215 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
216 {
217 	struct ds1343_priv *priv = dev_get_drvdata(dev);
218 	unsigned char buf[7];
219 	int res;
220 
221 	res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
222 	if (res)
223 		return res;
224 
225 	dt->tm_sec	= bcd2bin(buf[0]);
226 	dt->tm_min	= bcd2bin(buf[1]);
227 	dt->tm_hour	= bcd2bin(buf[2] & 0x3F);
228 	dt->tm_wday	= bcd2bin(buf[3]) - 1;
229 	dt->tm_mday	= bcd2bin(buf[4]);
230 	dt->tm_mon	= bcd2bin(buf[5] & 0x1F) - 1;
231 	dt->tm_year	= bcd2bin(buf[6]) + 100; /* year offset from 1900 */
232 
233 	return 0;
234 }
235 
236 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
237 {
238 	struct ds1343_priv *priv = dev_get_drvdata(dev);
239 	u8 buf[7];
240 
241 	buf[0] = bin2bcd(dt->tm_sec);
242 	buf[1] = bin2bcd(dt->tm_min);
243 	buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
244 	buf[3] = bin2bcd(dt->tm_wday + 1);
245 	buf[4] = bin2bcd(dt->tm_mday);
246 	buf[5] = bin2bcd(dt->tm_mon + 1);
247 	buf[6] = bin2bcd(dt->tm_year - 100);
248 
249 	return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
250 				 buf, sizeof(buf));
251 }
252 
253 static int ds1343_update_alarm(struct device *dev)
254 {
255 	struct ds1343_priv *priv = dev_get_drvdata(dev);
256 	unsigned int control, stat;
257 	unsigned char buf[4];
258 	int res = 0;
259 
260 	res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
261 	if (res)
262 		return res;
263 
264 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
265 	if (res)
266 		return res;
267 
268 	control &= ~(DS1343_A0IE);
269 	stat &= ~(DS1343_IRQF0);
270 
271 	res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
272 	if (res)
273 		return res;
274 
275 	res = regmap_write(priv->map, DS1343_STATUS_REG, stat);
276 	if (res)
277 		return res;
278 
279 	buf[0] = priv->alarm_sec < 0 || (priv->irqen & RTC_UF) ?
280 		0x80 : bin2bcd(priv->alarm_sec) & 0x7F;
281 	buf[1] = priv->alarm_min < 0 || (priv->irqen & RTC_UF) ?
282 		0x80 : bin2bcd(priv->alarm_min) & 0x7F;
283 	buf[2] = priv->alarm_hour < 0 || (priv->irqen & RTC_UF) ?
284 		0x80 : bin2bcd(priv->alarm_hour) & 0x3F;
285 	buf[3] = priv->alarm_mday < 0 || (priv->irqen & RTC_UF) ?
286 		0x80 : bin2bcd(priv->alarm_mday) & 0x7F;
287 
288 	res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
289 	if (res)
290 		return res;
291 
292 	if (priv->irqen) {
293 		control |= DS1343_A0IE;
294 		res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
295 	}
296 
297 	return res;
298 }
299 
300 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
301 {
302 	struct ds1343_priv *priv = dev_get_drvdata(dev);
303 	int res = 0;
304 	unsigned int stat;
305 
306 	if (priv->irq <= 0)
307 		return -EINVAL;
308 
309 	mutex_lock(&priv->mutex);
310 
311 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
312 	if (res)
313 		goto out;
314 
315 	alarm->enabled = !!(priv->irqen & RTC_AF);
316 	alarm->pending = !!(stat & DS1343_IRQF0);
317 
318 	alarm->time.tm_sec = priv->alarm_sec < 0 ? 0 : priv->alarm_sec;
319 	alarm->time.tm_min = priv->alarm_min < 0 ? 0 : priv->alarm_min;
320 	alarm->time.tm_hour = priv->alarm_hour < 0 ? 0 : priv->alarm_hour;
321 	alarm->time.tm_mday = priv->alarm_mday < 0 ? 0 : priv->alarm_mday;
322 
323 out:
324 	mutex_unlock(&priv->mutex);
325 	return res;
326 }
327 
328 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
329 {
330 	struct ds1343_priv *priv = dev_get_drvdata(dev);
331 	int res = 0;
332 
333 	if (priv->irq <= 0)
334 		return -EINVAL;
335 
336 	mutex_lock(&priv->mutex);
337 
338 	priv->alarm_sec = alarm->time.tm_sec;
339 	priv->alarm_min = alarm->time.tm_min;
340 	priv->alarm_hour = alarm->time.tm_hour;
341 	priv->alarm_mday = alarm->time.tm_mday;
342 
343 	if (alarm->enabled)
344 		priv->irqen |= RTC_AF;
345 
346 	res = ds1343_update_alarm(dev);
347 
348 	mutex_unlock(&priv->mutex);
349 
350 	return res;
351 }
352 
353 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
354 {
355 	struct ds1343_priv *priv = dev_get_drvdata(dev);
356 	int res = 0;
357 
358 	if (priv->irq <= 0)
359 		return -EINVAL;
360 
361 	mutex_lock(&priv->mutex);
362 
363 	if (enabled)
364 		priv->irqen |= RTC_AF;
365 	else
366 		priv->irqen &= ~RTC_AF;
367 
368 	res = ds1343_update_alarm(dev);
369 
370 	mutex_unlock(&priv->mutex);
371 
372 	return res;
373 }
374 
375 static irqreturn_t ds1343_thread(int irq, void *dev_id)
376 {
377 	struct ds1343_priv *priv = dev_id;
378 	unsigned int stat, control;
379 	int res = 0;
380 
381 	mutex_lock(&priv->mutex);
382 
383 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
384 	if (res)
385 		goto out;
386 
387 	if (stat & DS1343_IRQF0) {
388 		stat &= ~DS1343_IRQF0;
389 		regmap_write(priv->map, DS1343_STATUS_REG, stat);
390 
391 		res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
392 		if (res)
393 			goto out;
394 
395 		control &= ~DS1343_A0IE;
396 		regmap_write(priv->map, DS1343_CONTROL_REG, control);
397 
398 		rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
399 	}
400 
401 out:
402 	mutex_unlock(&priv->mutex);
403 	return IRQ_HANDLED;
404 }
405 
406 static const struct rtc_class_ops ds1343_rtc_ops = {
407 	.read_time	= ds1343_read_time,
408 	.set_time	= ds1343_set_time,
409 	.read_alarm	= ds1343_read_alarm,
410 	.set_alarm	= ds1343_set_alarm,
411 	.alarm_irq_enable = ds1343_alarm_irq_enable,
412 };
413 
414 static int ds1343_probe(struct spi_device *spi)
415 {
416 	struct ds1343_priv *priv;
417 	struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
418 					.write_flag_mask = 0x80, };
419 	unsigned int data;
420 	int res;
421 	struct nvmem_config nvmem_cfg = {
422 		.name = "ds1343-",
423 		.word_size = 1,
424 		.stride = 1,
425 		.size = DS1343_NVRAM_LEN,
426 		.reg_read = ds1343_nvram_read,
427 		.reg_write = ds1343_nvram_write,
428 	};
429 
430 	priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
431 	if (!priv)
432 		return -ENOMEM;
433 
434 	priv->spi = spi;
435 	mutex_init(&priv->mutex);
436 
437 	/* RTC DS1347 works in spi mode 3 and
438 	 * its chip select is active high
439 	 */
440 	spi->mode = SPI_MODE_3 | SPI_CS_HIGH;
441 	spi->bits_per_word = 8;
442 	res = spi_setup(spi);
443 	if (res)
444 		return res;
445 
446 	spi_set_drvdata(spi, priv);
447 
448 	priv->map = devm_regmap_init_spi(spi, &config);
449 
450 	if (IS_ERR(priv->map)) {
451 		dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
452 		return PTR_ERR(priv->map);
453 	}
454 
455 	res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
456 	if (res)
457 		return res;
458 
459 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
460 	data |= DS1343_INTCN;
461 	data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
462 	regmap_write(priv->map, DS1343_CONTROL_REG, data);
463 
464 	regmap_read(priv->map, DS1343_STATUS_REG, &data);
465 	data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
466 	regmap_write(priv->map, DS1343_STATUS_REG, data);
467 
468 	priv->rtc = devm_rtc_allocate_device(&spi->dev);
469 	if (IS_ERR(priv->rtc))
470 		return PTR_ERR(priv->rtc);
471 
472 	priv->rtc->nvram_old_abi = true;
473 	priv->rtc->ops = &ds1343_rtc_ops;
474 	priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
475 	priv->rtc->range_max = RTC_TIMESTAMP_END_2099;
476 
477 	res = rtc_register_device(priv->rtc);
478 	if (res)
479 		return res;
480 
481 	nvmem_cfg.priv = priv;
482 	rtc_nvmem_register(priv->rtc, &nvmem_cfg);
483 
484 	priv->irq = spi->irq;
485 
486 	if (priv->irq >= 0) {
487 		res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
488 						ds1343_thread, IRQF_ONESHOT,
489 						"ds1343", priv);
490 		if (res) {
491 			priv->irq = -1;
492 			dev_err(&spi->dev,
493 				"unable to request irq for rtc ds1343\n");
494 		} else {
495 			device_init_wakeup(&spi->dev, true);
496 			dev_pm_set_wake_irq(&spi->dev, spi->irq);
497 		}
498 	}
499 
500 	res = ds1343_sysfs_register(&spi->dev);
501 	if (res)
502 		dev_err(&spi->dev,
503 			"unable to create sysfs entries for rtc ds1343\n");
504 
505 	return 0;
506 }
507 
508 static int ds1343_remove(struct spi_device *spi)
509 {
510 	struct ds1343_priv *priv = spi_get_drvdata(spi);
511 
512 	if (spi->irq) {
513 		mutex_lock(&priv->mutex);
514 		priv->irqen &= ~RTC_AF;
515 		mutex_unlock(&priv->mutex);
516 
517 		dev_pm_clear_wake_irq(&spi->dev);
518 		device_init_wakeup(&spi->dev, false);
519 		devm_free_irq(&spi->dev, spi->irq, priv);
520 	}
521 
522 	spi_set_drvdata(spi, NULL);
523 
524 	ds1343_sysfs_unregister(&spi->dev);
525 
526 	return 0;
527 }
528 
529 #ifdef CONFIG_PM_SLEEP
530 
531 static int ds1343_suspend(struct device *dev)
532 {
533 	struct spi_device *spi = to_spi_device(dev);
534 
535 	if (spi->irq >= 0 && device_may_wakeup(dev))
536 		enable_irq_wake(spi->irq);
537 
538 	return 0;
539 }
540 
541 static int ds1343_resume(struct device *dev)
542 {
543 	struct spi_device *spi = to_spi_device(dev);
544 
545 	if (spi->irq >= 0 && device_may_wakeup(dev))
546 		disable_irq_wake(spi->irq);
547 
548 	return 0;
549 }
550 
551 #endif
552 
553 static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
554 
555 static struct spi_driver ds1343_driver = {
556 	.driver = {
557 		.name = "ds1343",
558 		.pm = &ds1343_pm,
559 	},
560 	.probe = ds1343_probe,
561 	.remove = ds1343_remove,
562 	.id_table = ds1343_id,
563 };
564 
565 module_spi_driver(ds1343_driver);
566 
567 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
568 MODULE_AUTHOR("Raghavendra Chandra Ganiga <[email protected]>,"
569 		"Ankur Srivastava <[email protected]>");
570 MODULE_LICENSE("GPL v2");
571