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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
50struct pcf8523 {
51 struct rtc_device *rtc;
52 struct regmap *regmap;
53};
54
55static 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
78static 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
99static 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
124static 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
161static 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
192static 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
201static 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
231static 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
239 case RTC_PARAM_BACKUP_SWITCH_MODE:
240 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
241 if (ret < 0)
242 return ret;
243
244 value = FIELD_GET(PCF8523_CONTROL3_PM, value);
245
246 switch(value) {
247 case 0x0:
248 case 0x4:
249 param->uvalue = RTC_BSM_LEVEL;
250 break;
251 case 0x1:
252 case 0x5:
253 param->uvalue = RTC_BSM_DIRECT;
254 break;
255 case PCF8523_PM_STANDBY:
256 param->uvalue = RTC_BSM_STANDBY;
257 break;
258 default:
259 param->uvalue = RTC_BSM_DISABLED;
260 }
261
262 break;
263
264 default:
265 return -EINVAL;
266 }
267
268 return 0;
269}
270
271static int pcf8523_param_set(struct device *dev, struct rtc_param *param)
272{
273 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
274 u8 mode;
275
276 switch(param->param) {
277 case RTC_PARAM_BACKUP_SWITCH_MODE:
278 switch (param->uvalue) {
279 case RTC_BSM_DISABLED:
280 mode = 0x2;
281 break;
282 case RTC_BSM_DIRECT:
283 mode = 0x1;
284 break;
285 case RTC_BSM_LEVEL:
286 mode = 0x0;
287 break;
288 case RTC_BSM_STANDBY:
289 mode = PCF8523_PM_STANDBY;
290 break;
291 default:
292 return -EINVAL;
293 }
294
295 return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3,
296 PCF8523_CONTROL3_PM,
297 FIELD_PREP(PCF8523_CONTROL3_PM, mode));
298
299 break;
300
301 default:
302 return -EINVAL;
303 }
304
305 return 0;
306}
307
308static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
309 unsigned long arg)
310{
311 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
312 unsigned int flags = 0;
313 u32 value;
314 int ret;
315
316 switch (cmd) {
317 case RTC_VL_READ:
318 ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
319 if (ret < 0)
320 return ret;
321
322 if (value & PCF8523_CONTROL3_BLF)
323 flags |= RTC_VL_BACKUP_LOW;
324
325 ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
326 if (ret < 0)
327 return ret;
328
329 if (value & PCF8523_SECONDS_OS)
330 flags |= RTC_VL_DATA_INVALID;
331
332 return put_user(flags, (unsigned int __user *)arg);
333
334 default:
335 return -ENOIOCTLCMD;
336 }
337}
338
339static int pcf8523_rtc_read_offset(struct device *dev, long *offset)
340{
341 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
342 int err;
343 u32 value;
344 s8 val;
345
346 err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value);
347 if (err < 0)
348 return err;
349
350 /* sign extend the 7-bit offset value */
351 val = value << 1;
352 *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1);
353
354 return 0;
355}
356
357static int pcf8523_rtc_set_offset(struct device *dev, long offset)
358{
359 struct pcf8523 *pcf8523 = dev_get_drvdata(dev);
360 long reg_m0, reg_m1;
361 u32 value;
362
363 reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L);
364 reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L);
365
366 if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset))
367 value = reg_m0 & 0x7f;
368 else
369 value = (reg_m1 & 0x7f) | PCF8523_OFFSET_MODE;
370
371 return regmap_write(pcf8523->regmap, PCF8523_REG_OFFSET, value);
372}
373
374static const struct rtc_class_ops pcf8523_rtc_ops = {
375 .read_time = pcf8523_rtc_read_time,
376 .set_time = pcf8523_rtc_set_time,
377 .read_alarm = pcf8523_rtc_read_alarm,
378 .set_alarm = pcf8523_rtc_set_alarm,
379 .alarm_irq_enable = pcf8523_irq_enable,
380 .ioctl = pcf8523_rtc_ioctl,
381 .read_offset = pcf8523_rtc_read_offset,
382 .set_offset = pcf8523_rtc_set_offset,
383 .param_get = pcf8523_param_get,
384 .param_set = pcf8523_param_set,
385};
386
387static const struct regmap_config regmap_config = {
388 .reg_bits = 8,
389 .val_bits = 8,
390 .max_register = 0x13,
391};
392
393static int pcf8523_probe(struct i2c_client *client)
394{
395 struct pcf8523 *pcf8523;
396 struct rtc_device *rtc;
397 bool wakeup_source = false;
398 u32 value;
399 int err;
400
401 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
402 return -ENODEV;
403
404 pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL);
405 if (!pcf8523)
406 return -ENOMEM;
407
408 pcf8523->regmap = devm_regmap_init_i2c(client, ®map_config);
409 if (IS_ERR(pcf8523->regmap))
410 return PTR_ERR(pcf8523->regmap);
411
412 i2c_set_clientdata(client, pcf8523);
413
414 rtc = devm_rtc_allocate_device(&client->dev);
415 if (IS_ERR(rtc))
416 return PTR_ERR(rtc);
417 pcf8523->rtc = rtc;
418
419 err = pcf8523_load_capacitance(pcf8523, client->dev.of_node);
420 if (err < 0)
421 dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
422 err);
423
424 err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value);
425 if (err < 0)
426 return err;
427
428 if (value & PCF8523_SECONDS_OS) {
429 err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value);
430 if (err < 0)
431 return err;
432
433 if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) {
434 err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3,
435 value & ~PCF8523_CONTROL3_PM);
436 if (err < 0)
437 return err;
438 }
439 }
440
441 rtc->ops = &pcf8523_rtc_ops;
442 rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
443 rtc->range_max = RTC_TIMESTAMP_END_2099;
444 set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features);
445 clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
446
447 if (client->irq > 0) {
448 err = regmap_write(pcf8523->regmap, PCF8523_TMR_CLKOUT_CTRL, 0x38);
449 if (err < 0)
450 return err;
451
452 err = devm_request_threaded_irq(&client->dev, client->irq,
453 NULL, pcf8523_irq,
454 IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_LOW,
455 dev_name(&rtc->dev), pcf8523);
456 if (err)
457 return err;
458
459 dev_pm_set_wake_irq(&client->dev, client->irq);
460 }
461
462 wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source");
463 if (client->irq > 0 || wakeup_source)
464 device_init_wakeup(&client->dev, true);
465
466 return devm_rtc_register_device(rtc);
467}
468
469static const struct i2c_device_id pcf8523_id[] = {
470 { "pcf8523", 0 },
471 { }
472};
473MODULE_DEVICE_TABLE(i2c, pcf8523_id);
474
475static const struct of_device_id pcf8523_of_match[] = {
476 { .compatible = "nxp,pcf8523" },
477 { .compatible = "microcrystal,rv8523" },
478 { }
479};
480MODULE_DEVICE_TABLE(of, pcf8523_of_match);
481
482static struct i2c_driver pcf8523_driver = {
483 .driver = {
484 .name = "rtc-pcf8523",
485 .of_match_table = pcf8523_of_match,
486 },
487 .probe_new = pcf8523_probe,
488 .id_table = pcf8523_id,
489};
490module_i2c_driver(pcf8523_driver);
491
492MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
493MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
494MODULE_LICENSE("GPL v2");