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1/*
2 * drivers/rtc/rtc-pcf85363.c
3 *
4 * Driver for NXP PCF85363 real-time clock.
5 *
6 * Copyright (C) 2017 Eric Nelson
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 *
12 * Based loosely on rtc-8583 by Russell King, Wolfram Sang and Juergen Beisert
13 */
14#include <linux/module.h>
15#include <linux/i2c.h>
16#include <linux/slab.h>
17#include <linux/rtc.h>
18#include <linux/init.h>
19#include <linux/err.h>
20#include <linux/errno.h>
21#include <linux/bcd.h>
22#include <linux/of.h>
23#include <linux/of_device.h>
24#include <linux/regmap.h>
25
26/*
27 * Date/Time registers
28 */
29#define DT_100THS 0x00
30#define DT_SECS 0x01
31#define DT_MINUTES 0x02
32#define DT_HOURS 0x03
33#define DT_DAYS 0x04
34#define DT_WEEKDAYS 0x05
35#define DT_MONTHS 0x06
36#define DT_YEARS 0x07
37
38/*
39 * Alarm registers
40 */
41#define DT_SECOND_ALM1 0x08
42#define DT_MINUTE_ALM1 0x09
43#define DT_HOUR_ALM1 0x0a
44#define DT_DAY_ALM1 0x0b
45#define DT_MONTH_ALM1 0x0c
46#define DT_MINUTE_ALM2 0x0d
47#define DT_HOUR_ALM2 0x0e
48#define DT_WEEKDAY_ALM2 0x0f
49#define DT_ALARM_EN 0x10
50
51/*
52 * Time stamp registers
53 */
54#define DT_TIMESTAMP1 0x11
55#define DT_TIMESTAMP2 0x17
56#define DT_TIMESTAMP3 0x1d
57#define DT_TS_MODE 0x23
58
59/*
60 * control registers
61 */
62#define CTRL_OFFSET 0x24
63#define CTRL_OSCILLATOR 0x25
64#define CTRL_BATTERY 0x26
65#define CTRL_PIN_IO 0x27
66#define CTRL_FUNCTION 0x28
67#define CTRL_INTA_EN 0x29
68#define CTRL_INTB_EN 0x2a
69#define CTRL_FLAGS 0x2b
70#define CTRL_RAMBYTE 0x2c
71#define CTRL_WDOG 0x2d
72#define CTRL_STOP_EN 0x2e
73#define CTRL_RESETS 0x2f
74#define CTRL_RAM 0x40
75
76#define ALRM_SEC_A1E BIT(0)
77#define ALRM_MIN_A1E BIT(1)
78#define ALRM_HR_A1E BIT(2)
79#define ALRM_DAY_A1E BIT(3)
80#define ALRM_MON_A1E BIT(4)
81#define ALRM_MIN_A2E BIT(5)
82#define ALRM_HR_A2E BIT(6)
83#define ALRM_DAY_A2E BIT(7)
84
85#define INT_WDIE BIT(0)
86#define INT_BSIE BIT(1)
87#define INT_TSRIE BIT(2)
88#define INT_A2IE BIT(3)
89#define INT_A1IE BIT(4)
90#define INT_OIE BIT(5)
91#define INT_PIE BIT(6)
92#define INT_ILP BIT(7)
93
94#define FLAGS_TSR1F BIT(0)
95#define FLAGS_TSR2F BIT(1)
96#define FLAGS_TSR3F BIT(2)
97#define FLAGS_BSF BIT(3)
98#define FLAGS_WDF BIT(4)
99#define FLAGS_A1F BIT(5)
100#define FLAGS_A2F BIT(6)
101#define FLAGS_PIF BIT(7)
102
103#define PIN_IO_INTAPM GENMASK(1, 0)
104#define PIN_IO_INTA_CLK 0
105#define PIN_IO_INTA_BAT 1
106#define PIN_IO_INTA_OUT 2
107#define PIN_IO_INTA_HIZ 3
108
109#define STOP_EN_STOP BIT(0)
110
111#define RESET_CPR 0xa4
112
113#define NVRAM_SIZE 0x40
114
115static struct i2c_driver pcf85363_driver;
116
117struct pcf85363 {
118 struct device *dev;
119 struct rtc_device *rtc;
120 struct regmap *regmap;
121};
122
123static int pcf85363_rtc_read_time(struct device *dev, struct rtc_time *tm)
124{
125 struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
126 unsigned char buf[DT_YEARS + 1];
127 int ret, len = sizeof(buf);
128
129 /* read the RTC date and time registers all at once */
130 ret = regmap_bulk_read(pcf85363->regmap, DT_100THS, buf, len);
131 if (ret) {
132 dev_err(dev, "%s: error %d\n", __func__, ret);
133 return ret;
134 }
135
136 tm->tm_year = bcd2bin(buf[DT_YEARS]);
137 /* adjust for 1900 base of rtc_time */
138 tm->tm_year += 100;
139
140 tm->tm_wday = buf[DT_WEEKDAYS] & 7;
141 buf[DT_SECS] &= 0x7F;
142 tm->tm_sec = bcd2bin(buf[DT_SECS]);
143 buf[DT_MINUTES] &= 0x7F;
144 tm->tm_min = bcd2bin(buf[DT_MINUTES]);
145 tm->tm_hour = bcd2bin(buf[DT_HOURS]);
146 tm->tm_mday = bcd2bin(buf[DT_DAYS]);
147 tm->tm_mon = bcd2bin(buf[DT_MONTHS]) - 1;
148
149 return 0;
150}
151
152static int pcf85363_rtc_set_time(struct device *dev, struct rtc_time *tm)
153{
154 struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
155 unsigned char tmp[11];
156 unsigned char *buf = &tmp[2];
157 int ret;
158
159 tmp[0] = STOP_EN_STOP;
160 tmp[1] = RESET_CPR;
161
162 buf[DT_100THS] = 0;
163 buf[DT_SECS] = bin2bcd(tm->tm_sec);
164 buf[DT_MINUTES] = bin2bcd(tm->tm_min);
165 buf[DT_HOURS] = bin2bcd(tm->tm_hour);
166 buf[DT_DAYS] = bin2bcd(tm->tm_mday);
167 buf[DT_WEEKDAYS] = tm->tm_wday;
168 buf[DT_MONTHS] = bin2bcd(tm->tm_mon + 1);
169 buf[DT_YEARS] = bin2bcd(tm->tm_year % 100);
170
171 ret = regmap_bulk_write(pcf85363->regmap, CTRL_STOP_EN,
172 tmp, sizeof(tmp));
173 if (ret)
174 return ret;
175
176 return regmap_write(pcf85363->regmap, CTRL_STOP_EN, 0);
177}
178
179static int pcf85363_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
180{
181 struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
182 unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
183 unsigned int val;
184 int ret;
185
186 ret = regmap_bulk_read(pcf85363->regmap, DT_SECOND_ALM1, buf,
187 sizeof(buf));
188 if (ret)
189 return ret;
190
191 alrm->time.tm_sec = bcd2bin(buf[0]);
192 alrm->time.tm_min = bcd2bin(buf[1]);
193 alrm->time.tm_hour = bcd2bin(buf[2]);
194 alrm->time.tm_mday = bcd2bin(buf[3]);
195 alrm->time.tm_mon = bcd2bin(buf[4]) - 1;
196
197 ret = regmap_read(pcf85363->regmap, CTRL_INTA_EN, &val);
198 if (ret)
199 return ret;
200
201 alrm->enabled = !!(val & INT_A1IE);
202
203 return 0;
204}
205
206static int _pcf85363_rtc_alarm_irq_enable(struct pcf85363 *pcf85363, unsigned
207 int enabled)
208{
209 unsigned int alarm_flags = ALRM_SEC_A1E | ALRM_MIN_A1E | ALRM_HR_A1E |
210 ALRM_DAY_A1E | ALRM_MON_A1E;
211 int ret;
212
213 ret = regmap_update_bits(pcf85363->regmap, DT_ALARM_EN, alarm_flags,
214 enabled ? alarm_flags : 0);
215 if (ret)
216 return ret;
217
218 ret = regmap_update_bits(pcf85363->regmap, CTRL_INTA_EN,
219 INT_A1IE, enabled ? INT_A1IE : 0);
220
221 if (ret || enabled)
222 return ret;
223
224 /* clear current flags */
225 return regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
226}
227
228static int pcf85363_rtc_alarm_irq_enable(struct device *dev,
229 unsigned int enabled)
230{
231 struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
232
233 return _pcf85363_rtc_alarm_irq_enable(pcf85363, enabled);
234}
235
236static int pcf85363_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
237{
238 struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
239 unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
240 int ret;
241
242 buf[0] = bin2bcd(alrm->time.tm_sec);
243 buf[1] = bin2bcd(alrm->time.tm_min);
244 buf[2] = bin2bcd(alrm->time.tm_hour);
245 buf[3] = bin2bcd(alrm->time.tm_mday);
246 buf[4] = bin2bcd(alrm->time.tm_mon + 1);
247
248 /*
249 * Disable the alarm interrupt before changing the value to avoid
250 * spurious interrupts
251 */
252 ret = _pcf85363_rtc_alarm_irq_enable(pcf85363, 0);
253 if (ret)
254 return ret;
255
256 ret = regmap_bulk_write(pcf85363->regmap, DT_SECOND_ALM1, buf,
257 sizeof(buf));
258 if (ret)
259 return ret;
260
261 return _pcf85363_rtc_alarm_irq_enable(pcf85363, alrm->enabled);
262}
263
264static irqreturn_t pcf85363_rtc_handle_irq(int irq, void *dev_id)
265{
266 struct pcf85363 *pcf85363 = i2c_get_clientdata(dev_id);
267 unsigned int flags;
268 int err;
269
270 err = regmap_read(pcf85363->regmap, CTRL_FLAGS, &flags);
271 if (err)
272 return IRQ_NONE;
273
274 if (flags & FLAGS_A1F) {
275 rtc_update_irq(pcf85363->rtc, 1, RTC_IRQF | RTC_AF);
276 regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
277 return IRQ_HANDLED;
278 }
279
280 return IRQ_NONE;
281}
282
283static const struct rtc_class_ops rtc_ops = {
284 .read_time = pcf85363_rtc_read_time,
285 .set_time = pcf85363_rtc_set_time,
286};
287
288static const struct rtc_class_ops rtc_ops_alarm = {
289 .read_time = pcf85363_rtc_read_time,
290 .set_time = pcf85363_rtc_set_time,
291 .read_alarm = pcf85363_rtc_read_alarm,
292 .set_alarm = pcf85363_rtc_set_alarm,
293 .alarm_irq_enable = pcf85363_rtc_alarm_irq_enable,
294};
295
296static int pcf85363_nvram_read(void *priv, unsigned int offset, void *val,
297 size_t bytes)
298{
299 struct pcf85363 *pcf85363 = priv;
300
301 return regmap_bulk_read(pcf85363->regmap, CTRL_RAM + offset,
302 val, bytes);
303}
304
305static int pcf85363_nvram_write(void *priv, unsigned int offset, void *val,
306 size_t bytes)
307{
308 struct pcf85363 *pcf85363 = priv;
309
310 return regmap_bulk_write(pcf85363->regmap, CTRL_RAM + offset,
311 val, bytes);
312}
313
314static const struct regmap_config regmap_config = {
315 .reg_bits = 8,
316 .val_bits = 8,
317 .max_register = 0x7f,
318};
319
320static int pcf85363_probe(struct i2c_client *client,
321 const struct i2c_device_id *id)
322{
323 struct pcf85363 *pcf85363;
324 struct nvmem_config nvmem_cfg = {
325 .name = "pcf85363-",
326 .word_size = 1,
327 .stride = 1,
328 .size = NVRAM_SIZE,
329 .reg_read = pcf85363_nvram_read,
330 .reg_write = pcf85363_nvram_write,
331 };
332 int ret;
333
334 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
335 return -ENODEV;
336
337 pcf85363 = devm_kzalloc(&client->dev, sizeof(struct pcf85363),
338 GFP_KERNEL);
339 if (!pcf85363)
340 return -ENOMEM;
341
342 pcf85363->regmap = devm_regmap_init_i2c(client, ®map_config);
343 if (IS_ERR(pcf85363->regmap)) {
344 dev_err(&client->dev, "regmap allocation failed\n");
345 return PTR_ERR(pcf85363->regmap);
346 }
347
348 pcf85363->dev = &client->dev;
349 i2c_set_clientdata(client, pcf85363);
350
351 pcf85363->rtc = devm_rtc_allocate_device(pcf85363->dev);
352 if (IS_ERR(pcf85363->rtc))
353 return PTR_ERR(pcf85363->rtc);
354
355 pcf85363->rtc->ops = &rtc_ops;
356
357 if (client->irq > 0) {
358 regmap_write(pcf85363->regmap, CTRL_FLAGS, 0);
359 regmap_update_bits(pcf85363->regmap, CTRL_PIN_IO,
360 PIN_IO_INTA_OUT, PIN_IO_INTAPM);
361 ret = devm_request_threaded_irq(pcf85363->dev, client->irq,
362 NULL, pcf85363_rtc_handle_irq,
363 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
364 "pcf85363", client);
365 if (ret)
366 dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
367 else
368 pcf85363->rtc->ops = &rtc_ops_alarm;
369 }
370
371 ret = rtc_register_device(pcf85363->rtc);
372
373 nvmem_cfg.priv = pcf85363;
374 rtc_nvmem_register(pcf85363->rtc, &nvmem_cfg);
375
376 return ret;
377}
378
379static const struct of_device_id dev_ids[] = {
380 { .compatible = "nxp,pcf85363" },
381 {}
382};
383MODULE_DEVICE_TABLE(of, dev_ids);
384
385static struct i2c_driver pcf85363_driver = {
386 .driver = {
387 .name = "pcf85363",
388 .of_match_table = of_match_ptr(dev_ids),
389 },
390 .probe = pcf85363_probe,
391};
392
393module_i2c_driver(pcf85363_driver);
394
395MODULE_AUTHOR("Eric Nelson");
396MODULE_DESCRIPTION("pcf85363 I2C RTC driver");
397MODULE_LICENSE("GPL");