xref: /linux/drivers/rtc/rtc-ds1343.c (revision 4b132aacb0768ac1e652cf517097ea6f237214b9) 
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 <ravi23ganiga@gmail.com>
8  *	    Ankur Srivastava <sankurece@gmail.com> : 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 rtc_device *rtc;
79 	struct regmap *map;
80 	int irq;
81 };
82 
83 static ssize_t ds1343_show_glitchfilter(struct device *dev,
84 				struct device_attribute *attr, char *buf)
85 {
86 	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
87 	int glitch_filt_status, data;
88 	int res;
89 
90 	res = regmap_read(priv->map, DS1343_CONTROL_REG, &data);
91 	if (res)
92 		return res;
93 
94 	glitch_filt_status = !!(data & DS1343_EGFIL);
95 
96 	if (glitch_filt_status)
97 		return sprintf(buf, "enabled\n");
98 	else
99 		return sprintf(buf, "disabled\n");
100 }
101 
102 static ssize_t ds1343_store_glitchfilter(struct device *dev,
103 					struct device_attribute *attr,
104 					const char *buf, size_t count)
105 {
106 	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
107 	int data = 0;
108 	int res;
109 
110 	if (strncmp(buf, "enabled", 7) == 0)
111 		data = DS1343_EGFIL;
112 	else if (strncmp(buf, "disabled", 8))
113 		return -EINVAL;
114 
115 	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
116 				 DS1343_EGFIL, data);
117 	if (res)
118 		return res;
119 
120 	return count;
121 }
122 
123 static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
124 			ds1343_store_glitchfilter);
125 
126 static int ds1343_nvram_write(void *priv, unsigned int off, void *val,
127 			      size_t bytes)
128 {
129 	struct ds1343_priv *ds1343 = priv;
130 
131 	return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
132 }
133 
134 static int ds1343_nvram_read(void *priv, unsigned int off, void *val,
135 			     size_t bytes)
136 {
137 	struct ds1343_priv *ds1343 = priv;
138 
139 	return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
140 }
141 
142 static ssize_t ds1343_show_tricklecharger(struct device *dev,
143 				struct device_attribute *attr, char *buf)
144 {
145 	struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
146 	int res, data;
147 	char *diodes = "disabled", *resistors = " ";
148 
149 	res = regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
150 	if (res)
151 		return res;
152 
153 	if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
154 		switch (data & 0x0c) {
155 		case DS1343_TRICKLE_DS1:
156 			diodes = "one diode,";
157 			break;
158 
159 		default:
160 			diodes = "no diode,";
161 			break;
162 		}
163 
164 		switch (data & 0x03) {
165 		case DS1343_TRICKLE_1K:
166 			resistors = "1k Ohm";
167 			break;
168 
169 		case DS1343_TRICKLE_2K:
170 			resistors = "2k Ohm";
171 			break;
172 
173 		case DS1343_TRICKLE_4K:
174 			resistors = "4k Ohm";
175 			break;
176 
177 		default:
178 			diodes = "disabled";
179 			break;
180 		}
181 	}
182 
183 	return sprintf(buf, "%s %s\n", diodes, resistors);
184 }
185 
186 static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
187 
188 static struct attribute *ds1343_attrs[] = {
189 	&dev_attr_glitch_filter.attr,
190 	&dev_attr_trickle_charger.attr,
191 	NULL
192 };
193 
194 static const struct attribute_group ds1343_attr_group = {
195 	.attrs  = ds1343_attrs,
196 };
197 
198 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
199 {
200 	struct ds1343_priv *priv = dev_get_drvdata(dev);
201 	unsigned char buf[7];
202 	int res;
203 
204 	res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
205 	if (res)
206 		return res;
207 
208 	dt->tm_sec	= bcd2bin(buf[0]);
209 	dt->tm_min	= bcd2bin(buf[1]);
210 	dt->tm_hour	= bcd2bin(buf[2] & 0x3F);
211 	dt->tm_wday	= bcd2bin(buf[3]) - 1;
212 	dt->tm_mday	= bcd2bin(buf[4]);
213 	dt->tm_mon	= bcd2bin(buf[5] & 0x1F) - 1;
214 	dt->tm_year	= bcd2bin(buf[6]) + 100; /* year offset from 1900 */
215 
216 	return 0;
217 }
218 
219 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
220 {
221 	struct ds1343_priv *priv = dev_get_drvdata(dev);
222 	u8 buf[7];
223 
224 	buf[0] = bin2bcd(dt->tm_sec);
225 	buf[1] = bin2bcd(dt->tm_min);
226 	buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
227 	buf[3] = bin2bcd(dt->tm_wday + 1);
228 	buf[4] = bin2bcd(dt->tm_mday);
229 	buf[5] = bin2bcd(dt->tm_mon + 1);
230 	buf[6] = bin2bcd(dt->tm_year - 100);
231 
232 	return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
233 				 buf, sizeof(buf));
234 }
235 
236 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
237 {
238 	struct ds1343_priv *priv = dev_get_drvdata(dev);
239 	unsigned char buf[4];
240 	unsigned int val;
241 	int res;
242 
243 	if (priv->irq <= 0)
244 		return -EINVAL;
245 
246 	res = regmap_read(priv->map, DS1343_STATUS_REG, &val);
247 	if (res)
248 		return res;
249 
250 	alarm->pending = !!(val & DS1343_IRQF0);
251 
252 	res = regmap_read(priv->map, DS1343_CONTROL_REG, &val);
253 	if (res)
254 		return res;
255 	alarm->enabled = !!(val & DS1343_A0IE);
256 
257 	res = regmap_bulk_read(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
258 	if (res)
259 		return res;
260 
261 	alarm->time.tm_sec = bcd2bin(buf[0]) & 0x7f;
262 	alarm->time.tm_min = bcd2bin(buf[1]) & 0x7f;
263 	alarm->time.tm_hour = bcd2bin(buf[2]) & 0x3f;
264 	alarm->time.tm_mday = bcd2bin(buf[3]) & 0x3f;
265 
266 	return 0;
267 }
268 
269 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
270 {
271 	struct ds1343_priv *priv = dev_get_drvdata(dev);
272 	unsigned char buf[4];
273 	int res = 0;
274 
275 	if (priv->irq <= 0)
276 		return -EINVAL;
277 
278 	res = regmap_update_bits(priv->map, DS1343_CONTROL_REG, DS1343_A0IE, 0);
279 	if (res)
280 		return res;
281 
282 	buf[0] = bin2bcd(alarm->time.tm_sec);
283 	buf[1] = bin2bcd(alarm->time.tm_min);
284 	buf[2] = bin2bcd(alarm->time.tm_hour);
285 	buf[3] = bin2bcd(alarm->time.tm_mday);
286 
287 	res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
288 	if (res)
289 		return res;
290 
291 	if (alarm->enabled)
292 		res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
293 					 DS1343_A0IE, DS1343_A0IE);
294 
295 	return res;
296 }
297 
298 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
299 {
300 	struct ds1343_priv *priv = dev_get_drvdata(dev);
301 
302 	if (priv->irq <= 0)
303 		return -EINVAL;
304 
305 	return regmap_update_bits(priv->map, DS1343_CONTROL_REG,
306 				  DS1343_A0IE, enabled ? DS1343_A0IE : 0);
307 }
308 
309 static irqreturn_t ds1343_thread(int irq, void *dev_id)
310 {
311 	struct ds1343_priv *priv = dev_id;
312 	unsigned int stat;
313 	int res = 0;
314 
315 	rtc_lock(priv->rtc);
316 
317 	res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
318 	if (res)
319 		goto out;
320 
321 	if (stat & DS1343_IRQF0) {
322 		stat &= ~DS1343_IRQF0;
323 		regmap_write(priv->map, DS1343_STATUS_REG, stat);
324 
325 		rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
326 
327 		regmap_update_bits(priv->map, DS1343_CONTROL_REG,
328 				   DS1343_A0IE, 0);
329 	}
330 
331 out:
332 	rtc_unlock(priv->rtc);
333 	return IRQ_HANDLED;
334 }
335 
336 static const struct rtc_class_ops ds1343_rtc_ops = {
337 	.read_time	= ds1343_read_time,
338 	.set_time	= ds1343_set_time,
339 	.read_alarm	= ds1343_read_alarm,
340 	.set_alarm	= ds1343_set_alarm,
341 	.alarm_irq_enable = ds1343_alarm_irq_enable,
342 };
343 
344 static int ds1343_probe(struct spi_device *spi)
345 {
346 	struct ds1343_priv *priv;
347 	struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
348 					.write_flag_mask = 0x80, };
349 	unsigned int data;
350 	int res;
351 	struct nvmem_config nvmem_cfg = {
352 		.name = "ds1343-",
353 		.word_size = 1,
354 		.stride = 1,
355 		.size = DS1343_NVRAM_LEN,
356 		.reg_read = ds1343_nvram_read,
357 		.reg_write = ds1343_nvram_write,
358 	};
359 
360 	priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
361 	if (!priv)
362 		return -ENOMEM;
363 
364 	/* RTC DS1347 works in spi mode 3 and
365 	 * its chip select is active high. Active high should be defined as
366 	 * "inverse polarity" as GPIO-based chip selects can be logically
367 	 * active high but inverted by the GPIO library.
368 	 */
369 	spi->mode |= SPI_MODE_3;
370 	spi->mode ^= SPI_CS_HIGH;
371 	spi->bits_per_word = 8;
372 	res = spi_setup(spi);
373 	if (res)
374 		return res;
375 
376 	spi_set_drvdata(spi, priv);
377 
378 	priv->map = devm_regmap_init_spi(spi, &config);
379 
380 	if (IS_ERR(priv->map)) {
381 		dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
382 		return PTR_ERR(priv->map);
383 	}
384 
385 	res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
386 	if (res)
387 		return res;
388 
389 	regmap_read(priv->map, DS1343_CONTROL_REG, &data);
390 	data |= DS1343_INTCN;
391 	data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
392 	regmap_write(priv->map, DS1343_CONTROL_REG, data);
393 
394 	regmap_read(priv->map, DS1343_STATUS_REG, &data);
395 	data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
396 	regmap_write(priv->map, DS1343_STATUS_REG, data);
397 
398 	priv->rtc = devm_rtc_allocate_device(&spi->dev);
399 	if (IS_ERR(priv->rtc))
400 		return PTR_ERR(priv->rtc);
401 
402 	priv->rtc->ops = &ds1343_rtc_ops;
403 	priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
404 	priv->rtc->range_max = RTC_TIMESTAMP_END_2099;
405 
406 	res = rtc_add_group(priv->rtc, &ds1343_attr_group);
407 	if (res)
408 		dev_err(&spi->dev,
409 			"unable to create sysfs entries for rtc ds1343\n");
410 
411 	res = devm_rtc_register_device(priv->rtc);
412 	if (res)
413 		return res;
414 
415 	nvmem_cfg.priv = priv;
416 	devm_rtc_nvmem_register(priv->rtc, &nvmem_cfg);
417 
418 	priv->irq = spi->irq;
419 
420 	if (priv->irq >= 0) {
421 		res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
422 						ds1343_thread, IRQF_ONESHOT,
423 						"ds1343", priv);
424 		if (res) {
425 			priv->irq = -1;
426 			dev_err(&spi->dev,
427 				"unable to request irq for rtc ds1343\n");
428 		} else {
429 			device_init_wakeup(&spi->dev, true);
430 			dev_pm_set_wake_irq(&spi->dev, spi->irq);
431 		}
432 	}
433 
434 	return 0;
435 }
436 
437 static void ds1343_remove(struct spi_device *spi)
438 {
439 	dev_pm_clear_wake_irq(&spi->dev);
440 }
441 
442 #ifdef CONFIG_PM_SLEEP
443 
444 static int ds1343_suspend(struct device *dev)
445 {
446 	struct spi_device *spi = to_spi_device(dev);
447 
448 	if (spi->irq >= 0 && device_may_wakeup(dev))
449 		enable_irq_wake(spi->irq);
450 
451 	return 0;
452 }
453 
454 static int ds1343_resume(struct device *dev)
455 {
456 	struct spi_device *spi = to_spi_device(dev);
457 
458 	if (spi->irq >= 0 && device_may_wakeup(dev))
459 		disable_irq_wake(spi->irq);
460 
461 	return 0;
462 }
463 
464 #endif
465 
466 static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
467 
468 static struct spi_driver ds1343_driver = {
469 	.driver = {
470 		.name = "ds1343",
471 		.pm = &ds1343_pm,
472 	},
473 	.probe = ds1343_probe,
474 	.remove = ds1343_remove,
475 	.id_table = ds1343_id,
476 };
477 
478 module_spi_driver(ds1343_driver);
479 
480 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
481 MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
482 		"Ankur Srivastava <sankurece@gmail.com>");
483 MODULE_LICENSE("GPL v2");
484