xref: /linux-6.15/drivers/rtc/rtc-ds1343.c (revision ac08888b) 
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->parent);
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->parent);
111 	int data = 0;
112 	int res;
113 
114 	if (strncmp(buf, "enabled", 7) == 0)
115 		data = DS1343_EGFIL;
116 	else if (strncmp(buf, "disabled", 8))
117 		return -EINVAL;
118 
119 	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
120 				 DS1343_EGFIL, data);
121 	if (res)
122 		return res;
123 
124 	return count;
125 }
126 
127 static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
128 			ds1343_store_glitchfilter);
129 
130 static int ds1343_nvram_write(void *priv, unsigned int off, void *val,
131 			      size_t bytes)
132 {
133 	struct ds1343_priv *ds1343 = priv;
134 
135 	return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
136 }
137 
138 static int ds1343_nvram_read(void *priv, unsigned int off, void *val,
139 			     size_t bytes)
140 {
141 	struct ds1343_priv *ds1343 = priv;
142 
143 	return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
144 }
145 
146 static ssize_t ds1343_show_tricklecharger(struct device *dev,
147 				struct device_attribute *attr, char *buf)
148 {
149 	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
150 	int data;
151 	char *diodes = "disabled", *resistors = " ";
152 
153 	regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
154 
155 	if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
156 		switch (data & 0x0c) {
157 		case DS1343_TRICKLE_DS1:
158 			diodes = "one diode,";
159 			break;
160 
161 		default:
162 			diodes = "no diode,";
163 			break;
164 		}
165 
166 		switch (data & 0x03) {
167 		case DS1343_TRICKLE_1K:
168 			resistors = "1k Ohm";
169 			break;
170 
171 		case DS1343_TRICKLE_2K:
172 			resistors = "2k Ohm";
173 			break;
174 
175 		case DS1343_TRICKLE_4K:
176 			resistors = "4k Ohm";
177 			break;
178 
179 		default:
180 			diodes = "disabled";
181 			break;
182 		}
183 	}
184 
185 	return sprintf(buf, "%s %s\n", diodes, resistors);
186 }
187 
188 static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
189 
190 static struct attribute *ds1343_attrs[] = {
191 	&dev_attr_glitch_filter.attr,
192 	&dev_attr_trickle_charger.attr,
193 	NULL
194 };
195 
196 static const struct attribute_group ds1343_attr_group = {
197 	.attrs  = ds1343_attrs,
198 };
199 
200 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
201 {
202 	struct ds1343_priv *priv = dev_get_drvdata(dev);
203 	unsigned char buf[7];
204 	int res;
205 
206 	res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
207 	if (res)
208 		return res;
209 
210 	dt->tm_sec	= bcd2bin(buf[0]);
211 	dt->tm_min	= bcd2bin(buf[1]);
212 	dt->tm_hour	= bcd2bin(buf[2] & 0x3F);
213 	dt->tm_wday	= bcd2bin(buf[3]) - 1;
214 	dt->tm_mday	= bcd2bin(buf[4]);
215 	dt->tm_mon	= bcd2bin(buf[5] & 0x1F) - 1;
216 	dt->tm_year	= bcd2bin(buf[6]) + 100; /* year offset from 1900 */
217 
218 	return 0;
219 }
220 
221 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
222 {
223 	struct ds1343_priv *priv = dev_get_drvdata(dev);
224 	u8 buf[7];
225 
226 	buf[0] = bin2bcd(dt->tm_sec);
227 	buf[1] = bin2bcd(dt->tm_min);
228 	buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
229 	buf[3] = bin2bcd(dt->tm_wday + 1);
230 	buf[4] = bin2bcd(dt->tm_mday);
231 	buf[5] = bin2bcd(dt->tm_mon + 1);
232 	buf[6] = bin2bcd(dt->tm_year - 100);
233 
234 	return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
235 				 buf, sizeof(buf));
236 }
237 
238 static int ds1343_update_alarm(struct device *dev)
239 {
240 	struct ds1343_priv *priv = dev_get_drvdata(dev);
241 	unsigned int control, stat;
242 	unsigned char buf[4];
243 	int res = 0;
244 
245 	res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
246 	if (res)
247 		return res;
248 
249 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
250 	if (res)
251 		return res;
252 
253 	control &= ~(DS1343_A0IE);
254 	stat &= ~(DS1343_IRQF0);
255 
256 	res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
257 	if (res)
258 		return res;
259 
260 	res = regmap_write(priv->map, DS1343_STATUS_REG, stat);
261 	if (res)
262 		return res;
263 
264 	buf[0] = priv->alarm_sec < 0 || (priv->irqen & RTC_UF) ?
265 		0x80 : bin2bcd(priv->alarm_sec) & 0x7F;
266 	buf[1] = priv->alarm_min < 0 || (priv->irqen & RTC_UF) ?
267 		0x80 : bin2bcd(priv->alarm_min) & 0x7F;
268 	buf[2] = priv->alarm_hour < 0 || (priv->irqen & RTC_UF) ?
269 		0x80 : bin2bcd(priv->alarm_hour) & 0x3F;
270 	buf[3] = priv->alarm_mday < 0 || (priv->irqen & RTC_UF) ?
271 		0x80 : bin2bcd(priv->alarm_mday) & 0x7F;
272 
273 	res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
274 	if (res)
275 		return res;
276 
277 	if (priv->irqen) {
278 		control |= DS1343_A0IE;
279 		res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
280 	}
281 
282 	return res;
283 }
284 
285 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
286 {
287 	struct ds1343_priv *priv = dev_get_drvdata(dev);
288 	int res = 0;
289 	unsigned int stat;
290 
291 	if (priv->irq <= 0)
292 		return -EINVAL;
293 
294 	mutex_lock(&priv->mutex);
295 
296 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
297 	if (res)
298 		goto out;
299 
300 	alarm->enabled = !!(priv->irqen & RTC_AF);
301 	alarm->pending = !!(stat & DS1343_IRQF0);
302 
303 	alarm->time.tm_sec = priv->alarm_sec < 0 ? 0 : priv->alarm_sec;
304 	alarm->time.tm_min = priv->alarm_min < 0 ? 0 : priv->alarm_min;
305 	alarm->time.tm_hour = priv->alarm_hour < 0 ? 0 : priv->alarm_hour;
306 	alarm->time.tm_mday = priv->alarm_mday < 0 ? 0 : priv->alarm_mday;
307 
308 out:
309 	mutex_unlock(&priv->mutex);
310 	return res;
311 }
312 
313 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
314 {
315 	struct ds1343_priv *priv = dev_get_drvdata(dev);
316 	int res = 0;
317 
318 	if (priv->irq <= 0)
319 		return -EINVAL;
320 
321 	mutex_lock(&priv->mutex);
322 
323 	priv->alarm_sec = alarm->time.tm_sec;
324 	priv->alarm_min = alarm->time.tm_min;
325 	priv->alarm_hour = alarm->time.tm_hour;
326 	priv->alarm_mday = alarm->time.tm_mday;
327 
328 	if (alarm->enabled)
329 		priv->irqen |= RTC_AF;
330 
331 	res = ds1343_update_alarm(dev);
332 
333 	mutex_unlock(&priv->mutex);
334 
335 	return res;
336 }
337 
338 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
339 {
340 	struct ds1343_priv *priv = dev_get_drvdata(dev);
341 	int res = 0;
342 
343 	if (priv->irq <= 0)
344 		return -EINVAL;
345 
346 	mutex_lock(&priv->mutex);
347 
348 	if (enabled)
349 		priv->irqen |= RTC_AF;
350 	else
351 		priv->irqen &= ~RTC_AF;
352 
353 	res = ds1343_update_alarm(dev);
354 
355 	mutex_unlock(&priv->mutex);
356 
357 	return res;
358 }
359 
360 static irqreturn_t ds1343_thread(int irq, void *dev_id)
361 {
362 	struct ds1343_priv *priv = dev_id;
363 	unsigned int stat, control;
364 	int res = 0;
365 
366 	mutex_lock(&priv->mutex);
367 
368 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
369 	if (res)
370 		goto out;
371 
372 	if (stat & DS1343_IRQF0) {
373 		stat &= ~DS1343_IRQF0;
374 		regmap_write(priv->map, DS1343_STATUS_REG, stat);
375 
376 		res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
377 		if (res)
378 			goto out;
379 
380 		control &= ~DS1343_A0IE;
381 		regmap_write(priv->map, DS1343_CONTROL_REG, control);
382 
383 		rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
384 	}
385 
386 out:
387 	mutex_unlock(&priv->mutex);
388 	return IRQ_HANDLED;
389 }
390 
391 static const struct rtc_class_ops ds1343_rtc_ops = {
392 	.read_time	= ds1343_read_time,
393 	.set_time	= ds1343_set_time,
394 	.read_alarm	= ds1343_read_alarm,
395 	.set_alarm	= ds1343_set_alarm,
396 	.alarm_irq_enable = ds1343_alarm_irq_enable,
397 };
398 
399 static int ds1343_probe(struct spi_device *spi)
400 {
401 	struct ds1343_priv *priv;
402 	struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
403 					.write_flag_mask = 0x80, };
404 	unsigned int data;
405 	int res;
406 	struct nvmem_config nvmem_cfg = {
407 		.name = "ds1343-",
408 		.word_size = 1,
409 		.stride = 1,
410 		.size = DS1343_NVRAM_LEN,
411 		.reg_read = ds1343_nvram_read,
412 		.reg_write = ds1343_nvram_write,
413 	};
414 
415 	priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
416 	if (!priv)
417 		return -ENOMEM;
418 
419 	priv->spi = spi;
420 	mutex_init(&priv->mutex);
421 
422 	/* RTC DS1347 works in spi mode 3 and
423 	 * its chip select is active high
424 	 */
425 	spi->mode = SPI_MODE_3 | SPI_CS_HIGH;
426 	spi->bits_per_word = 8;
427 	res = spi_setup(spi);
428 	if (res)
429 		return res;
430 
431 	spi_set_drvdata(spi, priv);
432 
433 	priv->map = devm_regmap_init_spi(spi, &config);
434 
435 	if (IS_ERR(priv->map)) {
436 		dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
437 		return PTR_ERR(priv->map);
438 	}
439 
440 	res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
441 	if (res)
442 		return res;
443 
444 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
445 	data |= DS1343_INTCN;
446 	data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
447 	regmap_write(priv->map, DS1343_CONTROL_REG, data);
448 
449 	regmap_read(priv->map, DS1343_STATUS_REG, &data);
450 	data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
451 	regmap_write(priv->map, DS1343_STATUS_REG, data);
452 
453 	priv->rtc = devm_rtc_allocate_device(&spi->dev);
454 	if (IS_ERR(priv->rtc))
455 		return PTR_ERR(priv->rtc);
456 
457 	priv->rtc->nvram_old_abi = true;
458 	priv->rtc->ops = &ds1343_rtc_ops;
459 	priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
460 	priv->rtc->range_max = RTC_TIMESTAMP_END_2099;
461 
462 	res = rtc_add_group(priv->rtc, &ds1343_attr_group);
463 	if (res)
464 		dev_err(&spi->dev,
465 			"unable to create sysfs entries for rtc ds1343\n");
466 
467 	res = rtc_register_device(priv->rtc);
468 	if (res)
469 		return res;
470 
471 	nvmem_cfg.priv = priv;
472 	rtc_nvmem_register(priv->rtc, &nvmem_cfg);
473 
474 	priv->irq = spi->irq;
475 
476 	if (priv->irq >= 0) {
477 		res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
478 						ds1343_thread, IRQF_ONESHOT,
479 						"ds1343", priv);
480 		if (res) {
481 			priv->irq = -1;
482 			dev_err(&spi->dev,
483 				"unable to request irq for rtc ds1343\n");
484 		} else {
485 			device_init_wakeup(&spi->dev, true);
486 			dev_pm_set_wake_irq(&spi->dev, spi->irq);
487 		}
488 	}
489 
490 	return 0;
491 }
492 
493 static int ds1343_remove(struct spi_device *spi)
494 {
495 	struct ds1343_priv *priv = spi_get_drvdata(spi);
496 
497 	if (spi->irq) {
498 		mutex_lock(&priv->mutex);
499 		priv->irqen &= ~RTC_AF;
500 		mutex_unlock(&priv->mutex);
501 
502 		dev_pm_clear_wake_irq(&spi->dev);
503 		device_init_wakeup(&spi->dev, false);
504 		devm_free_irq(&spi->dev, spi->irq, priv);
505 	}
506 
507 	spi_set_drvdata(spi, NULL);
508 
509 	return 0;
510 }
511 
512 #ifdef CONFIG_PM_SLEEP
513 
514 static int ds1343_suspend(struct device *dev)
515 {
516 	struct spi_device *spi = to_spi_device(dev);
517 
518 	if (spi->irq >= 0 && device_may_wakeup(dev))
519 		enable_irq_wake(spi->irq);
520 
521 	return 0;
522 }
523 
524 static int ds1343_resume(struct device *dev)
525 {
526 	struct spi_device *spi = to_spi_device(dev);
527 
528 	if (spi->irq >= 0 && device_may_wakeup(dev))
529 		disable_irq_wake(spi->irq);
530 
531 	return 0;
532 }
533 
534 #endif
535 
536 static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
537 
538 static struct spi_driver ds1343_driver = {
539 	.driver = {
540 		.name = "ds1343",
541 		.pm = &ds1343_pm,
542 	},
543 	.probe = ds1343_probe,
544 	.remove = ds1343_remove,
545 	.id_table = ds1343_id,
546 };
547 
548 module_spi_driver(ds1343_driver);
549 
550 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
551 MODULE_AUTHOR("Raghavendra Chandra Ganiga <[email protected]>,"
552 		"Ankur Srivastava <[email protected]>");
553 MODULE_LICENSE("GPL v2");
554