xref: /openbmc/linux/drivers/rtc/rtc-pcf8523.c (revision 31b0cecb)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Avionic Design GmbH
4  */
5 
6 #include <linux/bcd.h>
7 #include <linux/bitfield.h>
8 #include <linux/i2c.h>
9 #include <linux/module.h>
10 #include <linux/regmap.h>
11 #include <linux/rtc.h>
12 #include <linux/of.h>
13 #include <linux/pm_wakeirq.h>
14 
15 #define PCF8523_REG_CONTROL1 0x00
16 #define PCF8523_CONTROL1_CAP_SEL BIT(7)
17 #define PCF8523_CONTROL1_STOP    BIT(5)
18 #define PCF8523_CONTROL1_AIE    BIT(1)
19 
20 #define PCF8523_REG_CONTROL2 0x01
21 #define PCF8523_CONTROL2_AF BIT(3)
22 
23 #define PCF8523_REG_CONTROL3 0x02
24 #define PCF8523_CONTROL3_PM  GENMASK(7, 5)
25 #define PCF8523_PM_STANDBY   0x7
26 #define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */
27 #define PCF8523_CONTROL3_BSF BIT(3)
28 
29 #define PCF8523_REG_SECONDS  0x03
30 #define PCF8523_SECONDS_OS BIT(7)
31 
32 #define PCF8523_REG_MINUTES  0x04
33 #define PCF8523_REG_HOURS    0x05
34 #define PCF8523_REG_DAYS     0x06
35 #define PCF8523_REG_WEEKDAYS 0x07
36 #define PCF8523_REG_MONTHS   0x08
37 #define PCF8523_REG_YEARS    0x09
38 
39 #define PCF8523_REG_MINUTE_ALARM	0x0a
40 #define PCF8523_REG_HOUR_ALARM		0x0b
41 #define PCF8523_REG_DAY_ALARM		0x0c
42 #define PCF8523_REG_WEEKDAY_ALARM	0x0d
43 #define ALARM_DIS BIT(7)
44 
45 #define PCF8523_REG_OFFSET   0x0e
46 #define PCF8523_OFFSET_MODE BIT(7)
47 
48 #define PCF8523_TMR_CLKOUT_CTRL 0x0f
49 
50 struct pcf8523 {
51 	struct rtc_device *rtc;
52 	struct regmap *regmap;
53 };
54 
pcf8523_load_capacitance(struct pcf8523 * pcf8523,struct device_node * node)55 static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node)
56 {
57 	u32 load, value = 0;
58 
59 	load = 12500;
60 	of_property_read_u32(node, "quartz-load-femtofarads", &load);
61 
62 	switch (load) {
63 	default:
64 		dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500",
65 			 load);
66 		fallthrough;
67 	case 12500:
68 		value = PCF8523_CONTROL1_CAP_SEL;
69 		break;
70 	case 7000:
71 		break;
72 	}
73 
74 	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
75 				  PCF8523_CONTROL1_CAP_SEL, value);
76 }
77 
pcf8523_irq(int irq,void * dev_id)78 static irqreturn_t pcf8523_irq(int irq, void *dev_id)
79 {
80 	struct pcf8523 *pcf8523 = dev_id;
81 	u32 value;
82 	int err;
83 
84 	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
85 	if (err < 0)
86 		return IRQ_HANDLED;
87 
88 	if (value & PCF8523_CONTROL2_AF) {
89 		value &= ~PCF8523_CONTROL2_AF;
90 		regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value);
91 		rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF);
92 
93 		return IRQ_HANDLED;
94 	}
95 
96 	return IRQ_NONE;
97 }
98 
pcf8523_rtc_read_time(struct device * dev,struct rtc_time * tm)99 static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
100 {
101 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
102 	u8 regs[10];
103 	int err;
104 
105 	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs,
106 			       sizeof(regs));
107 	if (err < 0)
108 		return err;
109 
110 	if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS))
111 		return -EINVAL;
112 
113 	tm->tm_sec = bcd2bin(regs[3] & 0x7f);
114 	tm->tm_min = bcd2bin(regs[4] & 0x7f);
115 	tm->tm_hour = bcd2bin(regs[5] & 0x3f);
116 	tm->tm_mday = bcd2bin(regs[6] & 0x3f);
117 	tm->tm_wday = regs[7] & 0x7;
118 	tm->tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
119 	tm->tm_year = bcd2bin(regs[9]) + 100;
120 
121 	return 0;
122 }
123 
pcf8523_rtc_set_time(struct device * dev,struct rtc_time * tm)124 static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
125 {
126 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
127 	u8 regs[7];
128 	int err;
129 
130 	err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
131 				 PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP);
132 	if (err < 0)
133 		return err;
134 
135 	/* This will purposely overwrite PCF8523_SECONDS_OS */
136 	regs[0] = bin2bcd(tm->tm_sec);
137 	regs[1] = bin2bcd(tm->tm_min);
138 	regs[2] = bin2bcd(tm->tm_hour);
139 	regs[3] = bin2bcd(tm->tm_mday);
140 	regs[4] = tm->tm_wday;
141 	regs[5] = bin2bcd(tm->tm_mon + 1);
142 	regs[6] = bin2bcd(tm->tm_year - 100);
143 
144 	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs,
145 				sizeof(regs));
146 	if (err < 0) {
147 		/*
148 		 * If the time cannot be set, restart the RTC anyway. Note
149 		 * that errors are ignored if the RTC cannot be started so
150 		 * that we have a chance to propagate the original error.
151 		 */
152 		regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
153 				   PCF8523_CONTROL1_STOP, 0);
154 		return err;
155 	}
156 
157 	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
158 				 PCF8523_CONTROL1_STOP, 0);
159 }
160 
pcf8523_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * tm)161 static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
162 {
163 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
164 	u8 regs[4];
165 	u32 value;
166 	int err;
167 
168 	err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
169 			       sizeof(regs));
170 	if (err < 0)
171 		return err;
172 
173 	tm->time.tm_sec = 0;
174 	tm->time.tm_min = bcd2bin(regs[0] & 0x7F);
175 	tm->time.tm_hour = bcd2bin(regs[1] & 0x3F);
176 	tm->time.tm_mday = bcd2bin(regs[2] & 0x3F);
177 	tm->time.tm_wday = bcd2bin(regs[3] & 0x7);
178 
179 	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value);
180 	if (err < 0)
181 		return err;
182 	tm->enabled = !!(value & PCF8523_CONTROL1_AIE);
183 
184 	err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value);
185 	if (err < 0)
186 		return err;
187 	tm->pending = !!(value & PCF8523_CONTROL2_AF);
188 
189 	return 0;
190 }
191 
pcf8523_irq_enable(struct device * dev,unsigned int enabled)192 static int pcf8523_irq_enable(struct device *dev, unsigned int enabled)
193 {
194 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
195 
196 	return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1,
197 				  PCF8523_CONTROL1_AIE, enabled ?
198 				  PCF8523_CONTROL1_AIE : 0);
199 }
200 
pcf8523_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * tm)201 static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
202 {
203 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
204 	u8 regs[5];
205 	int err;
206 
207 	err = pcf8523_irq_enable(dev, 0);
208 	if (err)
209 		return err;
210 
211 	err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0);
212 	if (err < 0)
213 		return err;
214 
215 	regs[0] = bin2bcd(tm->time.tm_min);
216 	regs[1] = bin2bcd(tm->time.tm_hour);
217 	regs[2] = bin2bcd(tm->time.tm_mday);
218 	regs[3] = ALARM_DIS;
219 
220 	err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs,
221 				sizeof(regs));
222 	if (err < 0)
223 		return err;
224 
225 	if (tm->enabled)
226 		return pcf8523_irq_enable(dev, tm->enabled);
227 
228 	return 0;
229 }
230 
pcf8523_param_get(struct device * dev,struct rtc_param * param)231 static int pcf8523_param_get(struct device *dev, struct rtc_param *param)
232 {
233 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
234 	int ret;
235 	u32 value;
236 
237 	switch (param->param) {
238 	case RTC_PARAM_BACKUP_SWITCH_MODE:
239 		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
240 		if (ret < 0)
241 			return ret;
242 
243 		value = FIELD_GET(PCF8523_CONTROL3_PM, value);
244 
245 		switch (value) {
246 		case 0x0:
247 		case 0x4:
248 			param->uvalue = RTC_BSM_LEVEL;
249 			break;
250 		case 0x1:
251 		case 0x5:
252 			param->uvalue = RTC_BSM_DIRECT;
253 			break;
254 		case PCF8523_PM_STANDBY:
255 			param->uvalue = RTC_BSM_STANDBY;
256 			break;
257 		default:
258 			param->uvalue = RTC_BSM_DISABLED;
259 		}
260 
261 		break;
262 
263 	default:
264 		return -EINVAL;
265 	}
266 
267 	return 0;
268 }
269 
pcf8523_param_set(struct device * dev,struct rtc_param * param)270 static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
271 {
272 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
273 	u8 mode;
274 
275 	switch (param->param) {
276 	case RTC_PARAM_BACKUP_SWITCH_MODE:
277 		switch (param->uvalue) {
278 		case RTC_BSM_DISABLED:
279 			mode = 0x2;
280 			break;
281 		case RTC_BSM_DIRECT:
282 			mode = 0x1;
283 			break;
284 		case RTC_BSM_LEVEL:
285 			mode = 0x0;
286 			break;
287 		case RTC_BSM_STANDBY:
288 			mode = PCF8523_PM_STANDBY;
289 			break;
290 		default:
291 			return -EINVAL;
292 		}
293 
294 		return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
295 					  PCF8523_CONTROL3_PM,
296 					  FIELD_PREP(PCF8523_CONTROL3_PM, mode));
297 
298 		break;
299 
300 	default:
301 		return -EINVAL;
302 	}
303 
304 	return 0;
305 }
306 
pcf8523_rtc_ioctl(struct device * dev,unsigned int cmd,unsigned long arg)307 static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
308 			     unsigned long arg)
309 {
310 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
311 	unsigned int flags = 0;
312 	u32 value;
313 	int ret;
314 
315 	switch (cmd) {
316 	case RTC_VL_READ:
317 		ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
318 		if (ret < 0)
319 			return ret;
320 
321 		if (value & PCF8523_CONTROL3_BLF)
322 			flags |= RTC_VL_BACKUP_LOW;
323 
324 		ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
325 		if (ret < 0)
326 			return ret;
327 
328 		if (value & PCF8523_SECONDS_OS)
329 			flags |= RTC_VL_DATA_INVALID;
330 
331 		return put_user(flags, (unsigned int __user *)arg);
332 
333 	default:
334 		return -ENOIOCTLCMD;
335 	}
336 }
337 
pcf8523_rtc_read_offset(struct device * dev,long * offset)338 static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
339 {
340 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
341 	int err;
342 	u32 value;
343 	s8 val;
344 
345 	err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
346 	if (err < 0)
347 		return err;
348 
349 	/* sign extend the 7-bit offset value */
350 	val = value << 1;
351 	*offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
352 
353 	return 0;
354 }
355 
pcf8523_rtc_set_offset(struct device * dev,long offset)356 static int pcf8523_rtc_set_offset(struct device *dev, long offset)
357 {
358 	struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
359 	long reg_m0, reg_m1;
360 	u32 value;
361 
362 	reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
363 	reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
364 
365 	if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
366 		value = reg_m0 & 0x7f;
367 	else
368 		value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
369 
370 	return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
371 }
372 
373 static const struct rtc_class_ops pcf8523_rtc_ops = {
374 	.read_time = pcf8523_rtc_read_time,
375 	.set_time = pcf8523_rtc_set_time,
376 	.read_alarm = pcf8523_rtc_read_alarm,
377 	.set_alarm = pcf8523_rtc_set_alarm,
378 	.alarm_irq_enable = pcf8523_irq_enable,
379 	.ioctl = pcf8523_rtc_ioctl,
380 	.read_offset = pcf8523_rtc_read_offset,
381 	.set_offset = pcf8523_rtc_set_offset,
382 	.param_get = pcf8523_param_get,
383 	.param_set = pcf8523_param_set,
384 };
385 
386 static const struct regmap_config regmap_config = {
387 	.reg_bits = 8,
388 	.val_bits = 8,
389 	.max_register = 0x13,
390 };
391 
pcf8523_probe(struct i2c_client * client)392 static int pcf8523_probe(struct i2c_client *client)
393 {
394 	struct pcf8523 *pcf8523;
395 	struct rtc_device *rtc;
396 	bool wakeup_source = false;
397 	u32 value;
398 	int err;
399 
400 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
401 		return -ENODEV;
402 
403 	pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
404 	if (!pcf8523)
405 		return -ENOMEM;
406 
407 	pcf8523->regmap = devm_regmap_init_i2c(client, &regmap_config);
408 	if (IS_ERR(pcf8523->regmap))
409 		return PTR_ERR(pcf8523->regmap);
410 
411 	i2c_set_clientdata(client, pcf8523);
412 
413 	rtc = devm_rtc_allocate_device(&client->dev);
414 	if (IS_ERR(rtc))
415 		return PTR_ERR(rtc);
416 	pcf8523->rtc = rtc;
417 
418 	err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
419 	if (err < 0)
420 		dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
421 			 err);
422 
423 	err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
424 	if (err < 0)
425 		return err;
426 
427 	if (value & PCF8523_SECONDS_OS) {
428 		err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
429 		if (err < 0)
430 			return err;
431 
432 		if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
433 			err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
434 					   value & ~PCF8523_CONTROL3_PM);
435 			if (err < 0)
436 				return err;
437 		}
438 	}
439 
440 	rtc->ops = &pcf8523_rtc_ops;
441 	rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
442 	rtc->range_max = RTC_TIMESTAMP_END_2099;
443 	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
444 	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
445 
446 	if (client->irq > 0) {
447 		unsigned long irqflags = IRQF_TRIGGER_LOW;
448 
449 		if (dev_fwnode(&client->dev))
450 			irqflags = 0;
451 
452 		err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
453 		if (err < 0)
454 			return err;
455 
456 		err = devm_request_threaded_irq(&client->dev, client->irq,
457 						NULL, pcf8523_irq,
458 						IRQF_SHARED | IRQF_ONESHOT | irqflags,
459 						dev_name(&rtc->dev), pcf8523);
460 		if (err)
461 			return err;
462 
463 		dev_pm_set_wake_irq(&client->dev, client->irq);
464 	}
465 
466 	wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
467 	if (client->irq > 0 || wakeup_source)
468 		device_init_wakeup(&client->dev, true);
469 
470 	return devm_rtc_register_device(rtc);
471 }
472 
473 static const struct i2c_device_id pcf8523_id[] = {
474 	{ "pcf8523", 0 },
475 	{ }
476 };
477 MODULE_DEVICE_TABLE(i2c, pcf8523_id);
478 
479 static const struct of_device_id pcf8523_of_match[] = {
480 	{ .compatible = "nxp,pcf8523" },
481 	{ .compatible = "microcrystal,rv8523" },
482 	{ }
483 };
484 MODULE_DEVICE_TABLE(of, pcf8523_of_match);
485 
486 static struct i2c_driver pcf8523_driver = {
487 	.driver = {
488 		.name = "rtc-pcf8523",
489 		.of_match_table = pcf8523_of_match,
490 	},
491 	.probe = pcf8523_probe,
492 	.id_table = pcf8523_id,
493 };
494 module_i2c_driver(pcf8523_driver);
495 
496 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
497 MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
498 MODULE_LICENSE("GPL v2");
499