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
ds1343_show_glitchfilter(struct device * dev,struct device_attribute * attr,char * buf)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
ds1343_store_glitchfilter(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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
ds1343_nvram_write(void * priv,unsigned int off,void * val,size_t bytes)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
ds1343_nvram_read(void * priv,unsigned int off,void * val,size_t bytes)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
ds1343_show_tricklecharger(struct device * dev,struct device_attribute * attr,char * buf)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
ds1343_read_time(struct device * dev,struct rtc_time * dt)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
ds1343_set_time(struct device * dev,struct rtc_time * dt)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
ds1343_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)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
ds1343_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)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
ds1343_alarm_irq_enable(struct device * dev,unsigned int enabled)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
ds1343_thread(int irq,void * dev_id)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
ds1343_probe(struct spi_device * spi)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
ds1343_remove(struct spi_device * spi)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
ds1343_suspend(struct device * dev)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
ds1343_resume(struct device * dev)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