xref: /linux-6.15/drivers/rtc/rtc-ds1343.c (revision 580daaf4) 
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;
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->parent);
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 struct attribute *ds1343_attrs[] = {
193 	&dev_attr_glitch_filter.attr,
194 	&dev_attr_trickle_charger.attr,
195 	NULL
196 };
197 
198 static const struct attribute_group ds1343_attr_group = {
199 	.attrs  = ds1343_attrs,
200 };
201 
202 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
203 {
204 	struct ds1343_priv *priv = dev_get_drvdata(dev);
205 	unsigned char buf[7];
206 	int res;
207 
208 	res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
209 	if (res)
210 		return res;
211 
212 	dt->tm_sec	= bcd2bin(buf[0]);
213 	dt->tm_min	= bcd2bin(buf[1]);
214 	dt->tm_hour	= bcd2bin(buf[2] & 0x3F);
215 	dt->tm_wday	= bcd2bin(buf[3]) - 1;
216 	dt->tm_mday	= bcd2bin(buf[4]);
217 	dt->tm_mon	= bcd2bin(buf[5] & 0x1F) - 1;
218 	dt->tm_year	= bcd2bin(buf[6]) + 100; /* year offset from 1900 */
219 
220 	return 0;
221 }
222 
223 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
224 {
225 	struct ds1343_priv *priv = dev_get_drvdata(dev);
226 	u8 buf[7];
227 
228 	buf[0] = bin2bcd(dt->tm_sec);
229 	buf[1] = bin2bcd(dt->tm_min);
230 	buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
231 	buf[3] = bin2bcd(dt->tm_wday + 1);
232 	buf[4] = bin2bcd(dt->tm_mday);
233 	buf[5] = bin2bcd(dt->tm_mon + 1);
234 	buf[6] = bin2bcd(dt->tm_year - 100);
235 
236 	return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
237 				 buf, sizeof(buf));
238 }
239 
240 static int ds1343_update_alarm(struct device *dev)
241 {
242 	struct ds1343_priv *priv = dev_get_drvdata(dev);
243 	unsigned int control, stat;
244 	unsigned char buf[4];
245 	int res = 0;
246 
247 	res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
248 	if (res)
249 		return res;
250 
251 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
252 	if (res)
253 		return res;
254 
255 	control &= ~(DS1343_A0IE);
256 	stat &= ~(DS1343_IRQF0);
257 
258 	res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
259 	if (res)
260 		return res;
261 
262 	res = regmap_write(priv->map, DS1343_STATUS_REG, stat);
263 	if (res)
264 		return res;
265 
266 	buf[0] = priv->alarm_sec < 0 || (priv->irqen & RTC_UF) ?
267 		0x80 : bin2bcd(priv->alarm_sec) & 0x7F;
268 	buf[1] = priv->alarm_min < 0 || (priv->irqen & RTC_UF) ?
269 		0x80 : bin2bcd(priv->alarm_min) & 0x7F;
270 	buf[2] = priv->alarm_hour < 0 || (priv->irqen & RTC_UF) ?
271 		0x80 : bin2bcd(priv->alarm_hour) & 0x3F;
272 	buf[3] = priv->alarm_mday < 0 || (priv->irqen & RTC_UF) ?
273 		0x80 : bin2bcd(priv->alarm_mday) & 0x7F;
274 
275 	res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
276 	if (res)
277 		return res;
278 
279 	if (priv->irqen) {
280 		control |= DS1343_A0IE;
281 		res = regmap_write(priv->map, DS1343_CONTROL_REG, control);
282 	}
283 
284 	return res;
285 }
286 
287 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
288 {
289 	struct ds1343_priv *priv = dev_get_drvdata(dev);
290 	int res = 0;
291 	unsigned int stat;
292 
293 	if (priv->irq <= 0)
294 		return -EINVAL;
295 
296 	mutex_lock(&priv->mutex);
297 
298 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
299 	if (res)
300 		goto out;
301 
302 	alarm->enabled = !!(priv->irqen & RTC_AF);
303 	alarm->pending = !!(stat & DS1343_IRQF0);
304 
305 	alarm->time.tm_sec = priv->alarm_sec < 0 ? 0 : priv->alarm_sec;
306 	alarm->time.tm_min = priv->alarm_min < 0 ? 0 : priv->alarm_min;
307 	alarm->time.tm_hour = priv->alarm_hour < 0 ? 0 : priv->alarm_hour;
308 	alarm->time.tm_mday = priv->alarm_mday < 0 ? 0 : priv->alarm_mday;
309 
310 out:
311 	mutex_unlock(&priv->mutex);
312 	return res;
313 }
314 
315 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
316 {
317 	struct ds1343_priv *priv = dev_get_drvdata(dev);
318 	int res = 0;
319 
320 	if (priv->irq <= 0)
321 		return -EINVAL;
322 
323 	mutex_lock(&priv->mutex);
324 
325 	priv->alarm_sec = alarm->time.tm_sec;
326 	priv->alarm_min = alarm->time.tm_min;
327 	priv->alarm_hour = alarm->time.tm_hour;
328 	priv->alarm_mday = alarm->time.tm_mday;
329 
330 	if (alarm->enabled)
331 		priv->irqen |= RTC_AF;
332 
333 	res = ds1343_update_alarm(dev);
334 
335 	mutex_unlock(&priv->mutex);
336 
337 	return res;
338 }
339 
340 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
341 {
342 	struct ds1343_priv *priv = dev_get_drvdata(dev);
343 	int res = 0;
344 
345 	if (priv->irq <= 0)
346 		return -EINVAL;
347 
348 	mutex_lock(&priv->mutex);
349 
350 	if (enabled)
351 		priv->irqen |= RTC_AF;
352 	else
353 		priv->irqen &= ~RTC_AF;
354 
355 	res = ds1343_update_alarm(dev);
356 
357 	mutex_unlock(&priv->mutex);
358 
359 	return res;
360 }
361 
362 static irqreturn_t ds1343_thread(int irq, void *dev_id)
363 {
364 	struct ds1343_priv *priv = dev_id;
365 	unsigned int stat, control;
366 	int res = 0;
367 
368 	mutex_lock(&priv->mutex);
369 
370 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
371 	if (res)
372 		goto out;
373 
374 	if (stat & DS1343_IRQF0) {
375 		stat &= ~DS1343_IRQF0;
376 		regmap_write(priv->map, DS1343_STATUS_REG, stat);
377 
378 		res = regmap_read(priv->map, DS1343_CONTROL_REG, &control);
379 		if (res)
380 			goto out;
381 
382 		control &= ~DS1343_A0IE;
383 		regmap_write(priv->map, DS1343_CONTROL_REG, control);
384 
385 		rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
386 	}
387 
388 out:
389 	mutex_unlock(&priv->mutex);
390 	return IRQ_HANDLED;
391 }
392 
393 static const struct rtc_class_ops ds1343_rtc_ops = {
394 	.read_time	= ds1343_read_time,
395 	.set_time	= ds1343_set_time,
396 	.read_alarm	= ds1343_read_alarm,
397 	.set_alarm	= ds1343_set_alarm,
398 	.alarm_irq_enable = ds1343_alarm_irq_enable,
399 };
400 
401 static int ds1343_probe(struct spi_device *spi)
402 {
403 	struct ds1343_priv *priv;
404 	struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
405 					.write_flag_mask = 0x80, };
406 	unsigned int data;
407 	int res;
408 	struct nvmem_config nvmem_cfg = {
409 		.name = "ds1343-",
410 		.word_size = 1,
411 		.stride = 1,
412 		.size = DS1343_NVRAM_LEN,
413 		.reg_read = ds1343_nvram_read,
414 		.reg_write = ds1343_nvram_write,
415 	};
416 
417 	priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
418 	if (!priv)
419 		return -ENOMEM;
420 
421 	priv->spi = spi;
422 	mutex_init(&priv->mutex);
423 
424 	/* RTC DS1347 works in spi mode 3 and
425 	 * its chip select is active high
426 	 */
427 	spi->mode = SPI_MODE_3 | SPI_CS_HIGH;
428 	spi->bits_per_word = 8;
429 	res = spi_setup(spi);
430 	if (res)
431 		return res;
432 
433 	spi_set_drvdata(spi, priv);
434 
435 	priv->map = devm_regmap_init_spi(spi, &config);
436 
437 	if (IS_ERR(priv->map)) {
438 		dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
439 		return PTR_ERR(priv->map);
440 	}
441 
442 	res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
443 	if (res)
444 		return res;
445 
446 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
447 	data |= DS1343_INTCN;
448 	data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
449 	regmap_write(priv->map, DS1343_CONTROL_REG, data);
450 
451 	regmap_read(priv->map, DS1343_STATUS_REG, &data);
452 	data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
453 	regmap_write(priv->map, DS1343_STATUS_REG, data);
454 
455 	priv->rtc = devm_rtc_allocate_device(&spi->dev);
456 	if (IS_ERR(priv->rtc))
457 		return PTR_ERR(priv->rtc);
458 
459 	priv->rtc->nvram_old_abi = true;
460 	priv->rtc->ops = &ds1343_rtc_ops;
461 	priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
462 	priv->rtc->range_max = RTC_TIMESTAMP_END_2099;
463 
464 	res = rtc_add_group(priv->rtc, &ds1343_attr_group);
465 	if (res)
466 		dev_err(&spi->dev,
467 			"unable to create sysfs entries for rtc ds1343\n");
468 
469 	res = rtc_register_device(priv->rtc);
470 	if (res)
471 		return res;
472 
473 	nvmem_cfg.priv = priv;
474 	rtc_nvmem_register(priv->rtc, &nvmem_cfg);
475 
476 	priv->irq = spi->irq;
477 
478 	if (priv->irq >= 0) {
479 		res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
480 						ds1343_thread, IRQF_ONESHOT,
481 						"ds1343", priv);
482 		if (res) {
483 			priv->irq = -1;
484 			dev_err(&spi->dev,
485 				"unable to request irq for rtc ds1343\n");
486 		} else {
487 			device_init_wakeup(&spi->dev, true);
488 			dev_pm_set_wake_irq(&spi->dev, spi->irq);
489 		}
490 	}
491 
492 	return 0;
493 }
494 
495 static int ds1343_remove(struct spi_device *spi)
496 {
497 	struct ds1343_priv *priv = spi_get_drvdata(spi);
498 
499 	if (spi->irq) {
500 		mutex_lock(&priv->mutex);
501 		priv->irqen &= ~RTC_AF;
502 		mutex_unlock(&priv->mutex);
503 
504 		dev_pm_clear_wake_irq(&spi->dev);
505 		device_init_wakeup(&spi->dev, false);
506 		devm_free_irq(&spi->dev, spi->irq, priv);
507 	}
508 
509 	spi_set_drvdata(spi, NULL);
510 
511 	return 0;
512 }
513 
514 #ifdef CONFIG_PM_SLEEP
515 
516 static int ds1343_suspend(struct device *dev)
517 {
518 	struct spi_device *spi = to_spi_device(dev);
519 
520 	if (spi->irq >= 0 && device_may_wakeup(dev))
521 		enable_irq_wake(spi->irq);
522 
523 	return 0;
524 }
525 
526 static int ds1343_resume(struct device *dev)
527 {
528 	struct spi_device *spi = to_spi_device(dev);
529 
530 	if (spi->irq >= 0 && device_may_wakeup(dev))
531 		disable_irq_wake(spi->irq);
532 
533 	return 0;
534 }
535 
536 #endif
537 
538 static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
539 
540 static struct spi_driver ds1343_driver = {
541 	.driver = {
542 		.name = "ds1343",
543 		.pm = &ds1343_pm,
544 	},
545 	.probe = ds1343_probe,
546 	.remove = ds1343_remove,
547 	.id_table = ds1343_id,
548 };
549 
550 module_spi_driver(ds1343_driver);
551 
552 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
553 MODULE_AUTHOR("Raghavendra Chandra Ganiga <[email protected]>,"
554 		"Ankur Srivastava <[email protected]>");
555 MODULE_LICENSE("GPL v2");
556