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Merge tag 'io_uring-5.11-2021-01-16' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / drivers / rtc / rtc-ab-b5ze-s3.c
blob6e3e320dc727dbe04dd0d5480a23f7fc1322f77c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * rtc-ab-b5ze-s3 - Driver for Abracon AB-RTCMC-32.768Khz-B5ZE-S3
4 * I2C RTC / Alarm chip
5 *
6 * Copyright (C) 2014, Arnaud EBALARD <arno@natisbad.org>
7 *
8 * Detailed datasheet of the chip is available here:
9 *
10 * https://www.abracon.com/realtimeclock/AB-RTCMC-32.768kHz-B5ZE-S3-Application-Manual.pdf
11 *
12 * This work is based on ISL12057 driver (drivers/rtc/rtc-isl12057.c).
13 *
14 */
15
16 #include <linux/module.h>
17 #include <linux/rtc.h>
18 #include <linux/i2c.h>
19 #include <linux/bcd.h>
20 #include <linux/of.h>
21 #include <linux/regmap.h>
22 #include <linux/interrupt.h>
23
24 #define DRV_NAME "rtc-ab-b5ze-s3"
25
26 /* Control section */
27 #define ABB5ZES3_REG_CTRL1 0x00 /* Control 1 register */
28 #define ABB5ZES3_REG_CTRL1_CIE BIT(0) /* Pulse interrupt enable */
29 #define ABB5ZES3_REG_CTRL1_AIE BIT(1) /* Alarm interrupt enable */
30 #define ABB5ZES3_REG_CTRL1_SIE BIT(2) /* Second interrupt enable */
31 #define ABB5ZES3_REG_CTRL1_PM BIT(3) /* 24h/12h mode */
32 #define ABB5ZES3_REG_CTRL1_SR BIT(4) /* Software reset */
33 #define ABB5ZES3_REG_CTRL1_STOP BIT(5) /* RTC circuit enable */
34 #define ABB5ZES3_REG_CTRL1_CAP BIT(7)
35
36 #define ABB5ZES3_REG_CTRL2 0x01 /* Control 2 register */
37 #define ABB5ZES3_REG_CTRL2_CTBIE BIT(0) /* Countdown timer B int. enable */
38 #define ABB5ZES3_REG_CTRL2_CTAIE BIT(1) /* Countdown timer A int. enable */
39 #define ABB5ZES3_REG_CTRL2_WTAIE BIT(2) /* Watchdog timer A int. enable */
40 #define ABB5ZES3_REG_CTRL2_AF BIT(3) /* Alarm interrupt status */
41 #define ABB5ZES3_REG_CTRL2_SF BIT(4) /* Second interrupt status */
42 #define ABB5ZES3_REG_CTRL2_CTBF BIT(5) /* Countdown timer B int. status */
43 #define ABB5ZES3_REG_CTRL2_CTAF BIT(6) /* Countdown timer A int. status */
44 #define ABB5ZES3_REG_CTRL2_WTAF BIT(7) /* Watchdog timer A int. status */
45
46 #define ABB5ZES3_REG_CTRL3 0x02 /* Control 3 register */
47 #define ABB5ZES3_REG_CTRL3_PM2 BIT(7) /* Power Management bit 2 */
48 #define ABB5ZES3_REG_CTRL3_PM1 BIT(6) /* Power Management bit 1 */
49 #define ABB5ZES3_REG_CTRL3_PM0 BIT(5) /* Power Management bit 0 */
50 #define ABB5ZES3_REG_CTRL3_BSF BIT(3) /* Battery switchover int. status */
51 #define ABB5ZES3_REG_CTRL3_BLF BIT(2) /* Battery low int. status */
52 #define ABB5ZES3_REG_CTRL3_BSIE BIT(1) /* Battery switchover int. enable */
53 #define ABB5ZES3_REG_CTRL3_BLIE BIT(0) /* Battery low int. enable */
54
55 #define ABB5ZES3_CTRL_SEC_LEN 3
56
57 /* RTC section */
58 #define ABB5ZES3_REG_RTC_SC 0x03 /* RTC Seconds register */
59 #define ABB5ZES3_REG_RTC_SC_OSC BIT(7) /* Clock integrity status */
60 #define ABB5ZES3_REG_RTC_MN 0x04 /* RTC Minutes register */
61 #define ABB5ZES3_REG_RTC_HR 0x05 /* RTC Hours register */
62 #define ABB5ZES3_REG_RTC_HR_PM BIT(5) /* RTC Hours PM bit */
63 #define ABB5ZES3_REG_RTC_DT 0x06 /* RTC Date register */
64 #define ABB5ZES3_REG_RTC_DW 0x07 /* RTC Day of the week register */
65 #define ABB5ZES3_REG_RTC_MO 0x08 /* RTC Month register */
66 #define ABB5ZES3_REG_RTC_YR 0x09 /* RTC Year register */
67
68 #define ABB5ZES3_RTC_SEC_LEN 7
69
70 /* Alarm section (enable bits are all active low) */
71 #define ABB5ZES3_REG_ALRM_MN 0x0A /* Alarm - minute register */
72 #define ABB5ZES3_REG_ALRM_MN_AE BIT(7) /* Minute enable */
73 #define ABB5ZES3_REG_ALRM_HR 0x0B /* Alarm - hours register */
74 #define ABB5ZES3_REG_ALRM_HR_AE BIT(7) /* Hour enable */
75 #define ABB5ZES3_REG_ALRM_DT 0x0C /* Alarm - date register */
76 #define ABB5ZES3_REG_ALRM_DT_AE BIT(7) /* Date (day of the month) enable */
77 #define ABB5ZES3_REG_ALRM_DW 0x0D /* Alarm - day of the week reg. */
78 #define ABB5ZES3_REG_ALRM_DW_AE BIT(7) /* Day of the week enable */
79
80 #define ABB5ZES3_ALRM_SEC_LEN 4
81
82 /* Frequency offset section */
83 #define ABB5ZES3_REG_FREQ_OF 0x0E /* Frequency offset register */
84 #define ABB5ZES3_REG_FREQ_OF_MODE 0x0E /* Offset mode: 2 hours / minute */
85
86 /* CLOCKOUT section */
87 #define ABB5ZES3_REG_TIM_CLK 0x0F /* Timer & Clockout register */
88 #define ABB5ZES3_REG_TIM_CLK_TAM BIT(7) /* Permanent/pulsed timer A/int. 2 */
89 #define ABB5ZES3_REG_TIM_CLK_TBM BIT(6) /* Permanent/pulsed timer B */
90 #define ABB5ZES3_REG_TIM_CLK_COF2 BIT(5) /* Clkout Freq bit 2 */
91 #define ABB5ZES3_REG_TIM_CLK_COF1 BIT(4) /* Clkout Freq bit 1 */
92 #define ABB5ZES3_REG_TIM_CLK_COF0 BIT(3) /* Clkout Freq bit 0 */
93 #define ABB5ZES3_REG_TIM_CLK_TAC1 BIT(2) /* Timer A: - 01 : countdown */
94 #define ABB5ZES3_REG_TIM_CLK_TAC0 BIT(1) /* - 10 : timer */
95 #define ABB5ZES3_REG_TIM_CLK_TBC BIT(0) /* Timer B enable */
96
97 /* Timer A Section */
98 #define ABB5ZES3_REG_TIMA_CLK 0x10 /* Timer A clock register */
99 #define ABB5ZES3_REG_TIMA_CLK_TAQ2 BIT(2) /* Freq bit 2 */
100 #define ABB5ZES3_REG_TIMA_CLK_TAQ1 BIT(1) /* Freq bit 1 */
101 #define ABB5ZES3_REG_TIMA_CLK_TAQ0 BIT(0) /* Freq bit 0 */
102 #define ABB5ZES3_REG_TIMA 0x11 /* Timer A register */
103
104 #define ABB5ZES3_TIMA_SEC_LEN 2
105
106 /* Timer B Section */
107 #define ABB5ZES3_REG_TIMB_CLK 0x12 /* Timer B clock register */
108 #define ABB5ZES3_REG_TIMB_CLK_TBW2 BIT(6)
109 #define ABB5ZES3_REG_TIMB_CLK_TBW1 BIT(5)
110 #define ABB5ZES3_REG_TIMB_CLK_TBW0 BIT(4)
111 #define ABB5ZES3_REG_TIMB_CLK_TAQ2 BIT(2)
112 #define ABB5ZES3_REG_TIMB_CLK_TAQ1 BIT(1)
113 #define ABB5ZES3_REG_TIMB_CLK_TAQ0 BIT(0)
114 #define ABB5ZES3_REG_TIMB 0x13 /* Timer B register */
115 #define ABB5ZES3_TIMB_SEC_LEN 2
116
117 #define ABB5ZES3_MEM_MAP_LEN 0x14
118
119 struct abb5zes3_rtc_data {
120 struct rtc_device *rtc;
121 struct regmap *regmap;
122
123 int irq;
124
125 bool battery_low;
126 bool timer_alarm; /* current alarm is via timer A */
127 };
128
129 /*
130 * Try and match register bits w/ fixed null values to see whether we
131 * are dealing with an ABB5ZES3.
132 */
133 static int abb5zes3_i2c_validate_chip(struct regmap *regmap)
134 {
135 u8 regs[ABB5ZES3_MEM_MAP_LEN];
136 static const u8 mask[ABB5ZES3_MEM_MAP_LEN] = { 0x00, 0x00, 0x10, 0x00,
137 0x80, 0xc0, 0xc0, 0xf8,
138 0xe0, 0x00, 0x00, 0x40,
139 0x40, 0x78, 0x00, 0x00,
140 0xf8, 0x00, 0x88, 0x00 };
141 int ret, i;
142
143 ret = regmap_bulk_read(regmap, 0, regs, ABB5ZES3_MEM_MAP_LEN);
144 if (ret)
145 return ret;
146
147 for (i = 0; i < ABB5ZES3_MEM_MAP_LEN; ++i) {
148 if (regs[i] & mask[i]) /* check if bits are cleared */
149 return -ENODEV;
150 }
151
152 return 0;
153 }
154
155 /* Clear alarm status bit. */
156 static int _abb5zes3_rtc_clear_alarm(struct device *dev)
157 {
158 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
159 int ret;
160
161 ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_CTRL2,
162 ABB5ZES3_REG_CTRL2_AF, 0);
163 if (ret)
164 dev_err(dev, "%s: clearing alarm failed (%d)\n", __func__, ret);
165
166 return ret;
167 }
168
169 /* Enable or disable alarm (i.e. alarm interrupt generation) */
170 static int _abb5zes3_rtc_update_alarm(struct device *dev, bool enable)
171 {
172 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
173 int ret;
174
175 ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_CTRL1,
176 ABB5ZES3_REG_CTRL1_AIE,
177 enable ? ABB5ZES3_REG_CTRL1_AIE : 0);
178 if (ret)
179 dev_err(dev, "%s: writing alarm INT failed (%d)\n",
180 __func__, ret);
181
182 return ret;
183 }
184
185 /* Enable or disable timer (watchdog timer A interrupt generation) */
186 static int _abb5zes3_rtc_update_timer(struct device *dev, bool enable)
187 {
188 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
189 int ret;
190
191 ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_CTRL2,
192 ABB5ZES3_REG_CTRL2_WTAIE,
193 enable ? ABB5ZES3_REG_CTRL2_WTAIE : 0);
194 if (ret)
195 dev_err(dev, "%s: writing timer INT failed (%d)\n",
196 __func__, ret);
197
198 return ret;
199 }
200
201 /*
202 * Note: we only read, so regmap inner lock protection is sufficient, i.e.
203 * we do not need driver's main lock protection.
204 */
205 static int _abb5zes3_rtc_read_time(struct device *dev, struct rtc_time *tm)
206 {
207 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
208 u8 regs[ABB5ZES3_REG_RTC_SC + ABB5ZES3_RTC_SEC_LEN];
209 int ret = 0;
210
211 /*
212 * As we need to read CTRL1 register anyway to access 24/12h
213 * mode bit, we do a single bulk read of both control and RTC
214 * sections (they are consecutive). This also ease indexing
215 * of register values after bulk read.
216 */
217 ret = regmap_bulk_read(data->regmap, ABB5ZES3_REG_CTRL1, regs,
218 sizeof(regs));
219 if (ret) {
220 dev_err(dev, "%s: reading RTC time failed (%d)\n",
221 __func__, ret);
222 return ret;
223 }
224
225 /* If clock integrity is not guaranteed, do not return a time value */
226 if (regs[ABB5ZES3_REG_RTC_SC] & ABB5ZES3_REG_RTC_SC_OSC)
227 return -ENODATA;
228
229 tm->tm_sec = bcd2bin(regs[ABB5ZES3_REG_RTC_SC] & 0x7F);
230 tm->tm_min = bcd2bin(regs[ABB5ZES3_REG_RTC_MN]);
231
232 if (regs[ABB5ZES3_REG_CTRL1] & ABB5ZES3_REG_CTRL1_PM) { /* 12hr mode */
233 tm->tm_hour = bcd2bin(regs[ABB5ZES3_REG_RTC_HR] & 0x1f);
234 if (regs[ABB5ZES3_REG_RTC_HR] & ABB5ZES3_REG_RTC_HR_PM) /* PM */
235 tm->tm_hour += 12;
236 } else { /* 24hr mode */
237 tm->tm_hour = bcd2bin(regs[ABB5ZES3_REG_RTC_HR]);
238 }
239
240 tm->tm_mday = bcd2bin(regs[ABB5ZES3_REG_RTC_DT]);
241 tm->tm_wday = bcd2bin(regs[ABB5ZES3_REG_RTC_DW]);
242 tm->tm_mon = bcd2bin(regs[ABB5ZES3_REG_RTC_MO]) - 1; /* starts at 1 */
243 tm->tm_year = bcd2bin(regs[ABB5ZES3_REG_RTC_YR]) + 100;
244
245 return ret;
246 }
247
248 static int abb5zes3_rtc_set_time(struct device *dev, struct rtc_time *tm)
249 {
250 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
251 u8 regs[ABB5ZES3_REG_RTC_SC + ABB5ZES3_RTC_SEC_LEN];
252 int ret;
253
254 regs[ABB5ZES3_REG_RTC_SC] = bin2bcd(tm->tm_sec); /* MSB=0 clears OSC */
255 regs[ABB5ZES3_REG_RTC_MN] = bin2bcd(tm->tm_min);
256 regs[ABB5ZES3_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */
257 regs[ABB5ZES3_REG_RTC_DT] = bin2bcd(tm->tm_mday);
258 regs[ABB5ZES3_REG_RTC_DW] = bin2bcd(tm->tm_wday);
259 regs[ABB5ZES3_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1);
260 regs[ABB5ZES3_REG_RTC_YR] = bin2bcd(tm->tm_year - 100);
261
262 ret = regmap_bulk_write(data->regmap, ABB5ZES3_REG_RTC_SC,
263 regs + ABB5ZES3_REG_RTC_SC,
264 ABB5ZES3_RTC_SEC_LEN);
265
266 return ret;
267 }
268
269 /*
270 * Set provided TAQ and Timer A registers (TIMA_CLK and TIMA) based on
271 * given number of seconds.
272 */
273 static inline void sec_to_timer_a(u8 secs, u8 *taq, u8 *timer_a)
274 {
275 *taq = ABB5ZES3_REG_TIMA_CLK_TAQ1; /* 1Hz */
276 *timer_a = secs;
277 }
278
279 /*
280 * Return current number of seconds in Timer A. As we only use
281 * timer A with a 1Hz freq, this is what we expect to have.
282 */
283 static inline int sec_from_timer_a(u8 *secs, u8 taq, u8 timer_a)
284 {
285 if (taq != ABB5ZES3_REG_TIMA_CLK_TAQ1) /* 1Hz */
286 return -EINVAL;
287
288 *secs = timer_a;
289
290 return 0;
291 }
292
293 /*
294 * Read alarm currently configured via a watchdog timer using timer A. This
295 * is done by reading current RTC time and adding remaining timer time.
296 */
297 static int _abb5zes3_rtc_read_timer(struct device *dev,
298 struct rtc_wkalrm *alarm)
299 {
300 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
301 struct rtc_time rtc_tm, *alarm_tm = &alarm->time;
302 u8 regs[ABB5ZES3_TIMA_SEC_LEN + 1];
303 unsigned long rtc_secs;
304 unsigned int reg;
305 u8 timer_secs;
306 int ret;
307
308 /*
309 * Instead of doing two separate calls, because they are consecutive,
310 * we grab both clockout register and Timer A section. The latter is
311 * used to decide if timer A is enabled (as a watchdog timer).
312 */
313 ret = regmap_bulk_read(data->regmap, ABB5ZES3_REG_TIM_CLK, regs,
314 ABB5ZES3_TIMA_SEC_LEN + 1);
315 if (ret) {
316 dev_err(dev, "%s: reading Timer A section failed (%d)\n",
317 __func__, ret);
318 return ret;
319 }
320
321 /* get current time ... */
322 ret = _abb5zes3_rtc_read_time(dev, &rtc_tm);
323 if (ret)
324 return ret;
325
326 /* ... convert to seconds ... */
327 rtc_secs = rtc_tm_to_time64(&rtc_tm);
328
329 /* ... add remaining timer A time ... */
330 ret = sec_from_timer_a(&timer_secs, regs[1], regs[2]);
331 if (ret)
332 return ret;
333
334 /* ... and convert back. */
335 rtc_time64_to_tm(rtc_secs + timer_secs, alarm_tm);
336
337 ret = regmap_read(data->regmap, ABB5ZES3_REG_CTRL2, &reg);
338 if (ret) {
339 dev_err(dev, "%s: reading ctrl reg failed (%d)\n",
340 __func__, ret);
341 return ret;
342 }
343
344 alarm->enabled = !!(reg & ABB5ZES3_REG_CTRL2_WTAIE);
345
346 return 0;
347 }
348
349 /* Read alarm currently configured via a RTC alarm registers. */
350 static int _abb5zes3_rtc_read_alarm(struct device *dev,
351 struct rtc_wkalrm *alarm)
352 {
353 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
354 struct rtc_time rtc_tm, *alarm_tm = &alarm->time;
355 unsigned long rtc_secs, alarm_secs;
356 u8 regs[ABB5ZES3_ALRM_SEC_LEN];
357 unsigned int reg;
358 int ret;
359
360 ret = regmap_bulk_read(data->regmap, ABB5ZES3_REG_ALRM_MN, regs,
361 ABB5ZES3_ALRM_SEC_LEN);
362 if (ret) {
363 dev_err(dev, "%s: reading alarm section failed (%d)\n",
364 __func__, ret);
365 return ret;
366 }
367
368 alarm_tm->tm_sec = 0;
369 alarm_tm->tm_min = bcd2bin(regs[0] & 0x7f);
370 alarm_tm->tm_hour = bcd2bin(regs[1] & 0x3f);
371 alarm_tm->tm_mday = bcd2bin(regs[2] & 0x3f);
372 alarm_tm->tm_wday = -1;
373
374 /*
375 * The alarm section does not store year/month. We use the ones in rtc
376 * section as a basis and increment month and then year if needed to get
377 * alarm after current time.
378 */
379 ret = _abb5zes3_rtc_read_time(dev, &rtc_tm);
380 if (ret)
381 return ret;
382
383 alarm_tm->tm_year = rtc_tm.tm_year;
384 alarm_tm->tm_mon = rtc_tm.tm_mon;
385
386 rtc_secs = rtc_tm_to_time64(&rtc_tm);
387 alarm_secs = rtc_tm_to_time64(alarm_tm);
388
389 if (alarm_secs < rtc_secs) {
390 if (alarm_tm->tm_mon == 11) {
391 alarm_tm->tm_mon = 0;
392 alarm_tm->tm_year += 1;
393 } else {
394 alarm_tm->tm_mon += 1;
395 }
396 }
397
398 ret = regmap_read(data->regmap, ABB5ZES3_REG_CTRL1, &reg);
399 if (ret) {
400 dev_err(dev, "%s: reading ctrl reg failed (%d)\n",
401 __func__, ret);
402 return ret;
403 }
404
405 alarm->enabled = !!(reg & ABB5ZES3_REG_CTRL1_AIE);
406
407 return 0;
408 }
409
410 /*
411 * As the Alarm mechanism supported by the chip is only accurate to the
412 * minute, we use the watchdog timer mechanism provided by timer A
413 * (up to 256 seconds w/ a second accuracy) for low alarm values (below
414 * 4 minutes). Otherwise, we use the common alarm mechanism provided
415 * by the chip. In order for that to work, we keep track of currently
416 * configured timer type via 'timer_alarm' flag in our private data
417 * structure.
418 */
419 static int abb5zes3_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
420 {
421 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
422 int ret;
423
424 if (data->timer_alarm)
425 ret = _abb5zes3_rtc_read_timer(dev, alarm);
426 else
427 ret = _abb5zes3_rtc_read_alarm(dev, alarm);
428
429 return ret;
430 }
431
432 /*
433 * Set alarm using chip alarm mechanism. It is only accurate to the
434 * minute (not the second). The function expects alarm interrupt to
435 * be disabled.
436 */
437 static int _abb5zes3_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
438 {
439 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
440 struct rtc_time *alarm_tm = &alarm->time;
441 u8 regs[ABB5ZES3_ALRM_SEC_LEN];
442 struct rtc_time rtc_tm;
443 int ret, enable = 1;
444
445 if (!alarm->enabled) {
446 enable = 0;
447 } else {
448 unsigned long rtc_secs, alarm_secs;
449
450 /*
451 * Chip only support alarms up to one month in the future. Let's
452 * return an error if we get something after that limit.
453 * Comparison is done by incrementing rtc_tm month field by one
454 * and checking alarm value is still below.
455 */
456 ret = _abb5zes3_rtc_read_time(dev, &rtc_tm);
457 if (ret)
458 return ret;
459
460 if (rtc_tm.tm_mon == 11) { /* handle year wrapping */
461 rtc_tm.tm_mon = 0;
462 rtc_tm.tm_year += 1;
463 } else {
464 rtc_tm.tm_mon += 1;
465 }
466
467 rtc_secs = rtc_tm_to_time64(&rtc_tm);
468 alarm_secs = rtc_tm_to_time64(alarm_tm);
469
470 if (alarm_secs > rtc_secs) {
471 dev_err(dev, "%s: alarm maximum is one month in the future (%d)\n",
472 __func__, ret);
473 return -EINVAL;
474 }
475 }
476
477 /*
478 * Program all alarm registers but DW one. For each register, setting
479 * MSB to 0 enables associated alarm.
480 */
481 regs[0] = bin2bcd(alarm_tm->tm_min) & 0x7f;
482 regs[1] = bin2bcd(alarm_tm->tm_hour) & 0x3f;
483 regs[2] = bin2bcd(alarm_tm->tm_mday) & 0x3f;
484 regs[3] = ABB5ZES3_REG_ALRM_DW_AE; /* do not match day of the week */
485
486 ret = regmap_bulk_write(data->regmap, ABB5ZES3_REG_ALRM_MN, regs,
487 ABB5ZES3_ALRM_SEC_LEN);
488 if (ret < 0) {
489 dev_err(dev, "%s: writing ALARM section failed (%d)\n",
490 __func__, ret);
491 return ret;
492 }
493
494 /* Record currently configured alarm is not a timer */
495 data->timer_alarm = 0;
496
497 /* Enable or disable alarm interrupt generation */
498 return _abb5zes3_rtc_update_alarm(dev, enable);
499 }
500
501 /*
502 * Set alarm using timer watchdog (via timer A) mechanism. The function expects
503 * timer A interrupt to be disabled.
504 */
505 static int _abb5zes3_rtc_set_timer(struct device *dev, struct rtc_wkalrm *alarm,
506 u8 secs)
507 {
508 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
509 u8 regs[ABB5ZES3_TIMA_SEC_LEN];
510 u8 mask = ABB5ZES3_REG_TIM_CLK_TAC0 | ABB5ZES3_REG_TIM_CLK_TAC1;
511 int ret = 0;
512
513 /* Program given number of seconds to Timer A registers */
514 sec_to_timer_a(secs, &regs[0], &regs[1]);
515 ret = regmap_bulk_write(data->regmap, ABB5ZES3_REG_TIMA_CLK, regs,
516 ABB5ZES3_TIMA_SEC_LEN);
517 if (ret < 0) {
518 dev_err(dev, "%s: writing timer section failed\n", __func__);
519 return ret;
520 }
521
522 /* Configure Timer A as a watchdog timer */
523 ret = regmap_update_bits(data->regmap, ABB5ZES3_REG_TIM_CLK,
524 mask, ABB5ZES3_REG_TIM_CLK_TAC1);
525 if (ret)
526 dev_err(dev, "%s: failed to update timer\n", __func__);
527
528 /* Record currently configured alarm is a timer */
529 data->timer_alarm = 1;
530
531 /* Enable or disable timer interrupt generation */
532 return _abb5zes3_rtc_update_timer(dev, alarm->enabled);
533 }
534
535 /*
536 * The chip has an alarm which is only accurate to the minute. In order to
537 * handle alarms below that limit, we use the watchdog timer function of
538 * timer A. More precisely, the timer method is used for alarms below 240
539 * seconds.
540 */
541 static int abb5zes3_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
542 {
543 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
544 struct rtc_time *alarm_tm = &alarm->time;
545 unsigned long rtc_secs, alarm_secs;
546 struct rtc_time rtc_tm;
547 int ret;
548
549 ret = _abb5zes3_rtc_read_time(dev, &rtc_tm);
550 if (ret)
551 return ret;
552
553 rtc_secs = rtc_tm_to_time64(&rtc_tm);
554 alarm_secs = rtc_tm_to_time64(alarm_tm);
555
556 /* Let's first disable both the alarm and the timer interrupts */
557 ret = _abb5zes3_rtc_update_alarm(dev, false);
558 if (ret < 0) {
559 dev_err(dev, "%s: unable to disable alarm (%d)\n", __func__,
560 ret);
561 return ret;
562 }
563 ret = _abb5zes3_rtc_update_timer(dev, false);
564 if (ret < 0) {
565 dev_err(dev, "%s: unable to disable timer (%d)\n", __func__,
566 ret);
567 return ret;
568 }
569
570 data->timer_alarm = 0;
571
572 /*
573 * Let's now configure the alarm; if we are expected to ring in
574 * more than 240s, then we setup an alarm. Otherwise, a timer.
575 */
576 if ((alarm_secs > rtc_secs) && ((alarm_secs - rtc_secs) <= 240))
577 ret = _abb5zes3_rtc_set_timer(dev, alarm,
578 alarm_secs - rtc_secs);
579 else
580 ret = _abb5zes3_rtc_set_alarm(dev, alarm);
581
582 if (ret)
583 dev_err(dev, "%s: unable to configure alarm (%d)\n", __func__,
584 ret);
585
586 return ret;
587 }
588
589 /* Enable or disable battery low irq generation */
590 static inline int _abb5zes3_rtc_battery_low_irq_enable(struct regmap *regmap,
591 bool enable)
592 {
593 return regmap_update_bits(regmap, ABB5ZES3_REG_CTRL3,
594 ABB5ZES3_REG_CTRL3_BLIE,
595 enable ? ABB5ZES3_REG_CTRL3_BLIE : 0);
596 }
597
598 /*
599 * Check current RTC status and enable/disable what needs to be. Return 0 if
600 * everything went ok and a negative value upon error.
601 */
602 static int abb5zes3_rtc_check_setup(struct device *dev)
603 {
604 struct abb5zes3_rtc_data *data = dev_get_drvdata(dev);
605 struct regmap *regmap = data->regmap;
606 unsigned int reg;
607 int ret;
608 u8 mask;
609
610 /*
611 * By default, the devices generates a 32.768KHz signal on IRQ#1 pin. It
612 * is disabled here to prevent polluting the interrupt line and
613 * uselessly triggering the IRQ handler we install for alarm and battery
614 * low events. Note: this is done before clearing int. status below
615 * in this function.
616 * We also disable all timers and set timer interrupt to permanent (not
617 * pulsed).
618 */
619 mask = (ABB5ZES3_REG_TIM_CLK_TBC | ABB5ZES3_REG_TIM_CLK_TAC0 |
620 ABB5ZES3_REG_TIM_CLK_TAC1 | ABB5ZES3_REG_TIM_CLK_COF0 |
621 ABB5ZES3_REG_TIM_CLK_COF1 | ABB5ZES3_REG_TIM_CLK_COF2 |
622 ABB5ZES3_REG_TIM_CLK_TBM | ABB5ZES3_REG_TIM_CLK_TAM);
623 ret = regmap_update_bits(regmap, ABB5ZES3_REG_TIM_CLK, mask,
624 ABB5ZES3_REG_TIM_CLK_COF0 |
625 ABB5ZES3_REG_TIM_CLK_COF1 |
626 ABB5ZES3_REG_TIM_CLK_COF2);
627 if (ret < 0) {
628 dev_err(dev, "%s: unable to initialize clkout register (%d)\n",
629 __func__, ret);
630 return ret;
631 }
632
633 /*
634 * Each component of the alarm (MN, HR, DT, DW) can be enabled/disabled
635 * individually by clearing/setting MSB of each associated register. So,
636 * we set all alarm enable bits to disable current alarm setting.
637 */
638 mask = (ABB5ZES3_REG_ALRM_MN_AE | ABB5ZES3_REG_ALRM_HR_AE |
639 ABB5ZES3_REG_ALRM_DT_AE | ABB5ZES3_REG_ALRM_DW_AE);
640 ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL2, mask, mask);
641 if (ret < 0) {
642 dev_err(dev, "%s: unable to disable alarm setting (%d)\n",
643 __func__, ret);
644 return ret;
645 }
646
647 /* Set Control 1 register (RTC enabled, 24hr mode, all int. disabled) */
648 mask = (ABB5ZES3_REG_CTRL1_CIE | ABB5ZES3_REG_CTRL1_AIE |
649 ABB5ZES3_REG_CTRL1_SIE | ABB5ZES3_REG_CTRL1_PM |
650 ABB5ZES3_REG_CTRL1_CAP | ABB5ZES3_REG_CTRL1_STOP);
651 ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL1, mask, 0);
652 if (ret < 0) {
653 dev_err(dev, "%s: unable to initialize CTRL1 register (%d)\n",
654 __func__, ret);
655 return ret;
656 }
657
658 /*
659 * Set Control 2 register (timer int. disabled, alarm status cleared).
660 * WTAF is read-only and cleared automatically by reading the register.
661 */
662 mask = (ABB5ZES3_REG_CTRL2_CTBIE | ABB5ZES3_REG_CTRL2_CTAIE |
663 ABB5ZES3_REG_CTRL2_WTAIE | ABB5ZES3_REG_CTRL2_AF |
664 ABB5ZES3_REG_CTRL2_SF | ABB5ZES3_REG_CTRL2_CTBF |
665 ABB5ZES3_REG_CTRL2_CTAF);
666 ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL2, mask, 0);
667 if (ret < 0) {
668 dev_err(dev, "%s: unable to initialize CTRL2 register (%d)\n",
669 __func__, ret);
670 return ret;
671 }
672
673 /*
674 * Enable battery low detection function and battery switchover function
675 * (standard mode). Disable associated interrupts. Clear battery
676 * switchover flag but not battery low flag. The latter is checked
677 * later below.
678 */
679 mask = (ABB5ZES3_REG_CTRL3_PM0 | ABB5ZES3_REG_CTRL3_PM1 |
680 ABB5ZES3_REG_CTRL3_PM2 | ABB5ZES3_REG_CTRL3_BLIE |
681 ABB5ZES3_REG_CTRL3_BSIE | ABB5ZES3_REG_CTRL3_BSF);
682 ret = regmap_update_bits(regmap, ABB5ZES3_REG_CTRL3, mask, 0);
683 if (ret < 0) {
684 dev_err(dev, "%s: unable to initialize CTRL3 register (%d)\n",
685 __func__, ret);
686 return ret;
687 }
688
689 /* Check oscillator integrity flag */
690 ret = regmap_read(regmap, ABB5ZES3_REG_RTC_SC, &reg);
691 if (ret < 0) {
692 dev_err(dev, "%s: unable to read osc. integrity flag (%d)\n",
693 __func__, ret);
694 return ret;
695 }
696
697 if (reg & ABB5ZES3_REG_RTC_SC_OSC) {
698 dev_err(dev, "clock integrity not guaranteed. Osc. has stopped or has been interrupted.\n");
699 dev_err(dev, "change battery (if not already done) and then set time to reset osc. failure flag.\n");
700 }
701
702 /*
703 * Check battery low flag at startup: this allows reporting battery
704 * is low at startup when IRQ line is not connected. Note: we record
705 * current status to avoid reenabling this interrupt later in probe
706 * function if battery is low.
707 */
708 ret = regmap_read(regmap, ABB5ZES3_REG_CTRL3, &reg);
709 if (ret < 0) {
710 dev_err(dev, "%s: unable to read battery low flag (%d)\n",
711 __func__, ret);
712 return ret;
713 }
714
715 data->battery_low = reg & ABB5ZES3_REG_CTRL3_BLF;
716 if (data->battery_low) {
717 dev_err(dev, "RTC battery is low; please, consider changing it!\n");
718
719 ret = _abb5zes3_rtc_battery_low_irq_enable(regmap, false);
720 if (ret)
721 dev_err(dev, "%s: disabling battery low interrupt generation failed (%d)\n",
722 __func__, ret);
723 }
724
725 return ret;
726 }
727
728 static int abb5zes3_rtc_alarm_irq_enable(struct device *dev,
729 unsigned int enable)
730 {
731 struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev);
732 int ret = 0;
733
734 if (rtc_data->irq) {
735 if (rtc_data->timer_alarm)
736 ret = _abb5zes3_rtc_update_timer(dev, enable);
737 else
738 ret = _abb5zes3_rtc_update_alarm(dev, enable);
739 }
740
741 return ret;
742 }
743
744 static irqreturn_t _abb5zes3_rtc_interrupt(int irq, void *data)
745 {
746 struct i2c_client *client = data;
747 struct device *dev = &client->dev;
748 struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev);
749 struct rtc_device *rtc = rtc_data->rtc;
750 u8 regs[ABB5ZES3_CTRL_SEC_LEN];
751 int ret, handled = IRQ_NONE;
752
753 ret = regmap_bulk_read(rtc_data->regmap, 0, regs,
754 ABB5ZES3_CTRL_SEC_LEN);
755 if (ret) {
756 dev_err(dev, "%s: unable to read control section (%d)!\n",
757 __func__, ret);
758 return handled;
759 }
760
761 /*
762 * Check battery low detection flag and disable battery low interrupt
763 * generation if flag is set (interrupt can only be cleared when
764 * battery is replaced).
765 */
766 if (regs[ABB5ZES3_REG_CTRL3] & ABB5ZES3_REG_CTRL3_BLF) {
767 dev_err(dev, "RTC battery is low; please change it!\n");
768
769 _abb5zes3_rtc_battery_low_irq_enable(rtc_data->regmap, false);
770
771 handled = IRQ_HANDLED;
772 }
773
774 /* Check alarm flag */
775 if (regs[ABB5ZES3_REG_CTRL2] & ABB5ZES3_REG_CTRL2_AF) {
776 dev_dbg(dev, "RTC alarm!\n");
777
778 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
779
780 /* Acknowledge and disable the alarm */
781 _abb5zes3_rtc_clear_alarm(dev);
782 _abb5zes3_rtc_update_alarm(dev, 0);
783
784 handled = IRQ_HANDLED;
785 }
786
787 /* Check watchdog Timer A flag */
788 if (regs[ABB5ZES3_REG_CTRL2] & ABB5ZES3_REG_CTRL2_WTAF) {
789 dev_dbg(dev, "RTC timer!\n");
790
791 rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF);
792
793 /*
794 * Acknowledge and disable the alarm. Note: WTAF
795 * flag had been cleared when reading CTRL2
796 */
797 _abb5zes3_rtc_update_timer(dev, 0);
798
799 rtc_data->timer_alarm = 0;
800
801 handled = IRQ_HANDLED;
802 }
803
804 return handled;
805 }
806
807 static const struct rtc_class_ops rtc_ops = {
808 .read_time = _abb5zes3_rtc_read_time,
809 .set_time = abb5zes3_rtc_set_time,
810 .read_alarm = abb5zes3_rtc_read_alarm,
811 .set_alarm = abb5zes3_rtc_set_alarm,
812 .alarm_irq_enable = abb5zes3_rtc_alarm_irq_enable,
813 };
814
815 static const struct regmap_config abb5zes3_rtc_regmap_config = {
816 .reg_bits = 8,
817 .val_bits = 8,
818 };
819
820 static int abb5zes3_probe(struct i2c_client *client,
821 const struct i2c_device_id *id)
822 {
823 struct abb5zes3_rtc_data *data = NULL;
824 struct device *dev = &client->dev;
825 struct regmap *regmap;
826 int ret;
827
828 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
829 I2C_FUNC_SMBUS_BYTE_DATA |
830 I2C_FUNC_SMBUS_I2C_BLOCK))
831 return -ENODEV;
832
833 regmap = devm_regmap_init_i2c(client, &abb5zes3_rtc_regmap_config);
834 if (IS_ERR(regmap)) {
835 ret = PTR_ERR(regmap);
836 dev_err(dev, "%s: regmap allocation failed: %d\n",
837 __func__, ret);
838 return ret;
839 }
840
841 ret = abb5zes3_i2c_validate_chip(regmap);
842 if (ret)
843 return ret;
844
845 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
846 if (!data)
847 return -ENOMEM;
848
849 data->regmap = regmap;
850 dev_set_drvdata(dev, data);
851
852 ret = abb5zes3_rtc_check_setup(dev);
853 if (ret)
854 return ret;
855
856 data->rtc = devm_rtc_allocate_device(dev);
857 ret = PTR_ERR_OR_ZERO(data->rtc);
858 if (ret) {
859 dev_err(dev, "%s: unable to allocate RTC device (%d)\n",
860 __func__, ret);
861 return ret;
862 }
863
864 if (client->irq > 0) {
865 ret = devm_request_threaded_irq(dev, client->irq, NULL,
866 _abb5zes3_rtc_interrupt,
867 IRQF_SHARED | IRQF_ONESHOT,
868 DRV_NAME, client);
869 if (!ret) {
870 device_init_wakeup(dev, true);
871 data->irq = client->irq;
872 dev_dbg(dev, "%s: irq %d used by RTC\n", __func__,
873 client->irq);
874 } else {
875 dev_err(dev, "%s: irq %d unavailable (%d)\n",
876 __func__, client->irq, ret);
877 goto err;
878 }
879 }
880
881 data->rtc->ops = &rtc_ops;
882 data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
883 data->rtc->range_max = RTC_TIMESTAMP_END_2099;
884
885 /* Enable battery low detection interrupt if battery not already low */
886 if (!data->battery_low && data->irq) {
887 ret = _abb5zes3_rtc_battery_low_irq_enable(regmap, true);
888 if (ret) {
889 dev_err(dev, "%s: enabling battery low interrupt generation failed (%d)\n",
890 __func__, ret);
891 goto err;
892 }
893 }
894
895 ret = devm_rtc_register_device(data->rtc);
896
897 err:
898 if (ret && data->irq)
899 device_init_wakeup(dev, false);
900 return ret;
901 }
902
903 #ifdef CONFIG_PM_SLEEP
904 static int abb5zes3_rtc_suspend(struct device *dev)
905 {
906 struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev);
907
908 if (device_may_wakeup(dev))
909 return enable_irq_wake(rtc_data->irq);
910
911 return 0;
912 }
913
914 static int abb5zes3_rtc_resume(struct device *dev)
915 {
916 struct abb5zes3_rtc_data *rtc_data = dev_get_drvdata(dev);
917
918 if (device_may_wakeup(dev))
919 return disable_irq_wake(rtc_data->irq);
920
921 return 0;
922 }
923 #endif
924
925 static SIMPLE_DEV_PM_OPS(abb5zes3_rtc_pm_ops, abb5zes3_rtc_suspend,
926 abb5zes3_rtc_resume);
927
928 #ifdef CONFIG_OF
929 static const struct of_device_id abb5zes3_dt_match[] = {
930 { .compatible = "abracon,abb5zes3" },
931 { },
932 };
933 MODULE_DEVICE_TABLE(of, abb5zes3_dt_match);
934 #endif
935
936 static const struct i2c_device_id abb5zes3_id[] = {
937 { "abb5zes3", 0 },
938 { }
939 };
940 MODULE_DEVICE_TABLE(i2c, abb5zes3_id);
941
942 static struct i2c_driver abb5zes3_driver = {
943 .driver = {
944 .name = DRV_NAME,
945 .pm = &abb5zes3_rtc_pm_ops,
946 .of_match_table = of_match_ptr(abb5zes3_dt_match),
947 },
948 .probe = abb5zes3_probe,
949 .id_table = abb5zes3_id,
950 };
951 module_i2c_driver(abb5zes3_driver);
952
953 MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>");
954 MODULE_DESCRIPTION("Abracon AB-RTCMC-32.768kHz-B5ZE-S3 RTC/Alarm driver");
955 MODULE_LICENSE("GPL");
Linux with added FPC-III support