xref: /linux/drivers/rtc/rtc-max31335.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * RTC driver for the MAX31335
4  *
5  * Copyright (C) 2023 Analog Devices
6  *
7  * Antoniu Miclaus <antoniu.miclaus@analog.com>
8  *
9  */
10 
11 #include <linux/unaligned.h>
12 #include <linux/bcd.h>
13 #include <linux/bitfield.h>
14 #include <linux/bitops.h>
15 #include <linux/clk.h>
16 #include <linux/clk-provider.h>
17 #include <linux/hwmon.h>
18 #include <linux/i2c.h>
19 #include <linux/interrupt.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/of_device.h>
23 #include <linux/regmap.h>
24 #include <linux/rtc.h>
25 #include <linux/util_macros.h>
26 
27 /* MAX31335 Register Map */
28 #define MAX31335_STATUS1			0x00
29 #define MAX31335_INT_EN1			0x01
30 #define MAX31335_STATUS2			0x02
31 #define MAX31335_INT_EN2			0x03
32 #define MAX31335_RTC_RESET			0x04
33 #define MAX31335_RTC_CONFIG			0x05
34 #define MAX31335_RTC_CONFIG2			0x06
35 #define MAX31335_TIMESTAMP_CONFIG		0x07
36 #define MAX31335_TIMER_CONFIG			0x08
37 #define MAX31335_SECONDS_1_128			0x09
38 #define MAX31335_SECONDS			0x0A
39 #define MAX31335_MINUTES			0x0B
40 #define MAX31335_HOURS				0x0C
41 #define MAX31335_DAY				0x0D
42 #define MAX31335_DATE				0x0E
43 #define MAX31335_MONTH				0x0F
44 #define MAX31335_YEAR				0x0F
45 #define MAX31335_ALM1_SEC			0x11
46 #define MAX31335_ALM1_MIN			0x12
47 #define MAX31335_ALM1_HRS			0x13
48 #define MAX31335_ALM1_DAY_DATE			0x14
49 #define MAX31335_ALM1_MON			0x15
50 #define MAX31335_ALM1_YEAR			0x16
51 #define MAX31335_ALM2_MIN			0x17
52 #define MAX31335_ALM2_HRS			0x18
53 #define MAX31335_ALM2_DAY_DATE			0x19
54 #define MAX31335_TIMER_COUNT			0x1A
55 #define MAX31335_TIMER_INIT			0x1B
56 #define MAX31335_PWR_MGMT			0x1C
57 #define MAX31335_TRICKLE_REG			0x1D
58 #define MAX31335_AGING_OFFSET			0x1E
59 #define MAX31335_TS_CONFIG			0x30
60 #define MAX31335_TEMP_ALARM_HIGH_MSB		0x31
61 #define MAX31335_TEMP_ALARM_HIGH_LSB		0x32
62 #define MAX31335_TEMP_ALARM_LOW_MSB		0x33
63 #define MAX31335_TEMP_ALARM_LOW_LSB		0x34
64 #define MAX31335_TEMP_DATA_MSB			0x35
65 #define MAX31335_TEMP_DATA_LSB			0x36
66 #define MAX31335_TS0_SEC_1_128			0x40
67 #define MAX31335_TS0_SEC			0x41
68 #define MAX31335_TS0_MIN			0x42
69 #define MAX31335_TS0_HOUR			0x43
70 #define MAX31335_TS0_DATE			0x44
71 #define MAX31335_TS0_MONTH			0x45
72 #define MAX31335_TS0_YEAR			0x46
73 #define MAX31335_TS0_FLAGS			0x47
74 #define MAX31335_TS1_SEC_1_128			0x48
75 #define MAX31335_TS1_SEC			0x49
76 #define MAX31335_TS1_MIN			0x4A
77 #define MAX31335_TS1_HOUR			0x4B
78 #define MAX31335_TS1_DATE			0x4C
79 #define MAX31335_TS1_MONTH			0x4D
80 #define MAX31335_TS1_YEAR			0x4E
81 #define MAX31335_TS1_FLAGS			0x4F
82 #define MAX31335_TS2_SEC_1_128			0x50
83 #define MAX31335_TS2_SEC			0x51
84 #define MAX31335_TS2_MIN			0x52
85 #define MAX31335_TS2_HOUR			0x53
86 #define MAX31335_TS2_DATE			0x54
87 #define MAX31335_TS2_MONTH			0x55
88 #define MAX31335_TS2_YEAR			0x56
89 #define MAX31335_TS2_FLAGS			0x57
90 #define MAX31335_TS3_SEC_1_128			0x58
91 #define MAX31335_TS3_SEC			0x59
92 #define MAX31335_TS3_MIN			0x5A
93 #define MAX31335_TS3_HOUR			0x5B
94 #define MAX31335_TS3_DATE			0x5C
95 #define MAX31335_TS3_MONTH			0x5D
96 #define MAX31335_TS3_YEAR			0x5E
97 #define MAX31335_TS3_FLAGS			0x5F
98 
99 /* MAX31335_STATUS1 Bit Definitions */
100 #define MAX31335_STATUS1_PSDECT			BIT(7)
101 #define MAX31335_STATUS1_OSF			BIT(6)
102 #define MAX31335_STATUS1_PFAIL			BIT(5)
103 #define MAX31335_STATUS1_VBATLOW		BIT(4)
104 #define MAX31335_STATUS1_DIF			BIT(3)
105 #define MAX31335_STATUS1_TIF			BIT(2)
106 #define MAX31335_STATUS1_A2F			BIT(1)
107 #define MAX31335_STATUS1_A1F			BIT(0)
108 
109 /* MAX31335_INT_EN1 Bit Definitions */
110 #define MAX31335_INT_EN1_DOSF			BIT(6)
111 #define MAX31335_INT_EN1_PFAILE			BIT(5)
112 #define MAX31335_INT_EN1_VBATLOWE		BIT(4)
113 #define MAX31335_INT_EN1_DIE			BIT(3)
114 #define MAX31335_INT_EN1_TIE			BIT(2)
115 #define MAX31335_INT_EN1_A2IE			BIT(1)
116 #define MAX31335_INT_EN1_A1IE			BIT(0)
117 
118 /* MAX31335_STATUS2 Bit Definitions */
119 #define MAX31335_STATUS2_TEMP_RDY		BIT(2)
120 #define MAX31335_STATUS2_OTF			BIT(1)
121 #define MAX31335_STATUS2_UTF			BIT(0)
122 
123 /* MAX31335_INT_EN2 Bit Definitions */
124 #define MAX31335_INT_EN2_TEMP_RDY_EN		BIT(2)
125 #define MAX31335_INT_EN2_OTIE			BIT(1)
126 #define MAX31335_INT_EN2_UTIE			BIT(0)
127 
128 /* MAX31335_RTC_RESET Bit Definitions */
129 #define MAX31335_RTC_RESET_SWRST		BIT(0)
130 
131 /* MAX31335_RTC_CONFIG1 Bit Definitions */
132 #define MAX31335_RTC_CONFIG1_EN_IO		BIT(6)
133 #define MAX31335_RTC_CONFIG1_A1AC		GENMASK(5, 4)
134 #define MAX31335_RTC_CONFIG1_DIP		BIT(3)
135 #define MAX31335_RTC_CONFIG1_I2C_TIMEOUT	BIT(1)
136 #define MAX31335_RTC_CONFIG1_EN_OSC		BIT(0)
137 
138 /* MAX31335_RTC_CONFIG2 Bit Definitions */
139 #define MAX31335_RTC_CONFIG2_ENCLKO		BIT(2)
140 #define MAX31335_RTC_CONFIG2_CLKO_HZ		GENMASK(1, 0)
141 
142 /* MAX31335_TIMESTAMP_CONFIG Bit Definitions */
143 #define MAX31335_TIMESTAMP_CONFIG_TSVLOW	BIT(5)
144 #define MAX31335_TIMESTAMP_CONFIG_TSPWM		BIT(4)
145 #define MAX31335_TIMESTAMP_CONFIG_TSDIN		BIT(3)
146 #define MAX31335_TIMESTAMP_CONFIG_TSOW		BIT(2)
147 #define MAX31335_TIMESTAMP_CONFIG_TSR		BIT(1)
148 #define MAX31335_TIMESTAMP_CONFIG_TSE		BIT(0)
149 
150 /* MAX31335_TIMER_CONFIG Bit Definitions */
151 #define MAX31335_TIMER_CONFIG_TE		BIT(4)
152 #define MAX31335_TIMER_CONFIG_TPAUSE		BIT(3)
153 #define MAX31335_TIMER_CONFIG_TRPT		BIT(2)
154 #define MAX31335_TIMER_CONFIG_TFS		GENMASK(1, 0)
155 
156 /* MAX31335_HOURS Bit Definitions */
157 #define MAX31335_HOURS_F_24_12			BIT(6)
158 #define MAX31335_HOURS_HR_20_AM_PM		BIT(5)
159 
160 /* MAX31335_MONTH Bit Definitions */
161 #define MAX31335_MONTH_CENTURY			BIT(7)
162 
163 /* MAX31335_PWR_MGMT Bit Definitions */
164 #define MAX31335_PWR_MGMT_PFVT			BIT(0)
165 
166 /* MAX31335_TRICKLE_REG Bit Definitions */
167 #define MAX31335_TRICKLE_REG_TRICKLE		GENMASK(3, 1)
168 #define MAX31335_TRICKLE_REG_EN_TRICKLE		BIT(0)
169 
170 /* MAX31335_TS_CONFIG Bit Definitions */
171 #define MAX31335_TS_CONFIG_AUTO			BIT(4)
172 #define MAX31335_TS_CONFIG_CONVERT_T		BIT(3)
173 #define MAX31335_TS_CONFIG_TSINT		GENMASK(2, 0)
174 
175 /* MAX31335_TS_FLAGS Bit Definitions */
176 #define MAX31335_TS_FLAGS_VLOWF			BIT(3)
177 #define MAX31335_TS_FLAGS_VBATF			BIT(2)
178 #define MAX31335_TS_FLAGS_VCCF			BIT(1)
179 #define MAX31335_TS_FLAGS_DINF			BIT(0)
180 
181 /* MAX31335 Miscellaneous Definitions */
182 #define MAX31335_TRICKLE_SCHOTTKY_DIODE		1
183 #define MAX31335_TRICKLE_STANDARD_DIODE		4
184 #define MAX31335_RAM_SIZE			32
185 #define MAX31335_TIME_SIZE			0x07
186 
187 #define clk_hw_to_max31335(_hw) container_of(_hw, struct max31335_data, clkout)
188 
189 struct max31335_data {
190 	struct regmap *regmap;
191 	struct rtc_device *rtc;
192 	struct clk_hw clkout;
193 };
194 
195 static const int max31335_clkout_freq[] = { 1, 64, 1024, 32768 };
196 
197 static const u16 max31335_trickle_resistors[] = {3000, 6000, 11000};
198 
199 static bool max31335_volatile_reg(struct device *dev, unsigned int reg)
200 {
201 	/* time keeping registers */
202 	if (reg >= MAX31335_SECONDS &&
203 	    reg < MAX31335_SECONDS + MAX31335_TIME_SIZE)
204 		return true;
205 
206 	/* interrupt status register */
207 	if (reg == MAX31335_STATUS1)
208 		return true;
209 
210 	/* temperature registers */
211 	if (reg == MAX31335_TEMP_DATA_MSB || reg == MAX31335_TEMP_DATA_LSB)
212 		return true;
213 
214 	return false;
215 }
216 
217 static const struct regmap_config regmap_config = {
218 	.reg_bits = 8,
219 	.val_bits = 8,
220 	.max_register = 0x5F,
221 	.volatile_reg = max31335_volatile_reg,
222 };
223 
224 static int max31335_read_time(struct device *dev, struct rtc_time *tm)
225 {
226 	struct max31335_data *max31335 = dev_get_drvdata(dev);
227 	u8 date[7];
228 	int ret;
229 
230 	ret = regmap_bulk_read(max31335->regmap, MAX31335_SECONDS, date,
231 			       sizeof(date));
232 	if (ret)
233 		return ret;
234 
235 	tm->tm_sec  = bcd2bin(date[0] & 0x7f);
236 	tm->tm_min  = bcd2bin(date[1] & 0x7f);
237 	tm->tm_hour = bcd2bin(date[2] & 0x3f);
238 	tm->tm_wday = bcd2bin(date[3] & 0x7) - 1;
239 	tm->tm_mday = bcd2bin(date[4] & 0x3f);
240 	tm->tm_mon  = bcd2bin(date[5] & 0x1f) - 1;
241 	tm->tm_year = bcd2bin(date[6]) + 100;
242 
243 	if (FIELD_GET(MAX31335_MONTH_CENTURY, date[5]))
244 		tm->tm_year += 100;
245 
246 	return 0;
247 }
248 
249 static int max31335_set_time(struct device *dev, struct rtc_time *tm)
250 {
251 	struct max31335_data *max31335 = dev_get_drvdata(dev);
252 	u8 date[7];
253 
254 	date[0] = bin2bcd(tm->tm_sec);
255 	date[1] = bin2bcd(tm->tm_min);
256 	date[2] = bin2bcd(tm->tm_hour);
257 	date[3] = bin2bcd(tm->tm_wday + 1);
258 	date[4] = bin2bcd(tm->tm_mday);
259 	date[5] = bin2bcd(tm->tm_mon + 1);
260 	date[6] = bin2bcd(tm->tm_year % 100);
261 
262 	if (tm->tm_year >= 200)
263 		date[5] |= FIELD_PREP(MAX31335_MONTH_CENTURY, 1);
264 
265 	return regmap_bulk_write(max31335->regmap, MAX31335_SECONDS, date,
266 				 sizeof(date));
267 }
268 
269 static int max31335_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
270 {
271 	struct max31335_data *max31335 = dev_get_drvdata(dev);
272 	int ret, ctrl, status;
273 	struct rtc_time time;
274 	u8 regs[6];
275 
276 	ret = regmap_bulk_read(max31335->regmap, MAX31335_ALM1_SEC, regs,
277 			       sizeof(regs));
278 	if (ret)
279 		return ret;
280 
281 	alrm->time.tm_sec  = bcd2bin(regs[0] & 0x7f);
282 	alrm->time.tm_min  = bcd2bin(regs[1] & 0x7f);
283 	alrm->time.tm_hour = bcd2bin(regs[2] & 0x3f);
284 	alrm->time.tm_mday = bcd2bin(regs[3] & 0x3f);
285 	alrm->time.tm_mon  = bcd2bin(regs[4] & 0x1f) - 1;
286 	alrm->time.tm_year = bcd2bin(regs[5]) + 100;
287 
288 	ret = max31335_read_time(dev, &time);
289 	if (ret)
290 		return ret;
291 
292 	if (time.tm_year >= 200)
293 		alrm->time.tm_year += 100;
294 
295 	ret = regmap_read(max31335->regmap, MAX31335_INT_EN1, &ctrl);
296 	if (ret)
297 		return ret;
298 
299 	ret = regmap_read(max31335->regmap, MAX31335_STATUS1, &status);
300 	if (ret)
301 		return ret;
302 
303 	alrm->enabled = FIELD_GET(MAX31335_INT_EN1_A1IE, ctrl);
304 	alrm->pending = FIELD_GET(MAX31335_STATUS1_A1F, status);
305 
306 	return 0;
307 }
308 
309 static int max31335_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
310 {
311 	struct max31335_data *max31335 = dev_get_drvdata(dev);
312 	unsigned int reg;
313 	u8 regs[6];
314 	int ret;
315 
316 	regs[0] = bin2bcd(alrm->time.tm_sec);
317 	regs[1] = bin2bcd(alrm->time.tm_min);
318 	regs[2] = bin2bcd(alrm->time.tm_hour);
319 	regs[3] = bin2bcd(alrm->time.tm_mday);
320 	regs[4] = bin2bcd(alrm->time.tm_mon + 1);
321 	regs[5] = bin2bcd(alrm->time.tm_year % 100);
322 
323 	ret = regmap_bulk_write(max31335->regmap, MAX31335_ALM1_SEC,
324 				regs, sizeof(regs));
325 	if (ret)
326 		return ret;
327 
328 	reg = FIELD_PREP(MAX31335_INT_EN1_A1IE, alrm->enabled);
329 	ret = regmap_update_bits(max31335->regmap, MAX31335_INT_EN1,
330 				 MAX31335_INT_EN1_A1IE, reg);
331 	if (ret)
332 		return ret;
333 
334 	ret = regmap_update_bits(max31335->regmap, MAX31335_STATUS1,
335 				 MAX31335_STATUS1_A1F, 0);
336 
337 	return 0;
338 }
339 
340 static int max31335_alarm_irq_enable(struct device *dev, unsigned int enabled)
341 {
342 	struct max31335_data *max31335 = dev_get_drvdata(dev);
343 
344 	return regmap_update_bits(max31335->regmap, MAX31335_INT_EN1,
345 				  MAX31335_INT_EN1_A1IE, enabled);
346 }
347 
348 static irqreturn_t max31335_handle_irq(int irq, void *dev_id)
349 {
350 	struct max31335_data *max31335 = dev_id;
351 	bool status;
352 	int ret;
353 
354 	ret = regmap_update_bits_check(max31335->regmap, MAX31335_STATUS1,
355 				       MAX31335_STATUS1_A1F, 0, &status);
356 	if (ret)
357 		return IRQ_HANDLED;
358 
359 	if (status)
360 		rtc_update_irq(max31335->rtc, 1, RTC_AF | RTC_IRQF);
361 
362 	return IRQ_HANDLED;
363 }
364 
365 static const struct rtc_class_ops max31335_rtc_ops = {
366 	.read_time = max31335_read_time,
367 	.set_time = max31335_set_time,
368 	.read_alarm = max31335_read_alarm,
369 	.set_alarm = max31335_set_alarm,
370 	.alarm_irq_enable = max31335_alarm_irq_enable,
371 };
372 
373 static int max31335_trickle_charger_setup(struct device *dev,
374 					  struct max31335_data *max31335)
375 {
376 	u32 ohms, chargeable;
377 	int i, trickle_cfg;
378 	const char *diode;
379 
380 	if (device_property_read_u32(dev, "aux-voltage-chargeable",
381 				     &chargeable))
382 		return 0;
383 
384 	if (device_property_read_u32(dev, "trickle-resistor-ohms", &ohms))
385 		return 0;
386 
387 	if (device_property_read_string(dev, "adi,tc-diode", &diode))
388 		return 0;
389 
390 	if (!strcmp(diode, "schottky"))
391 		trickle_cfg = MAX31335_TRICKLE_SCHOTTKY_DIODE;
392 	else if (!strcmp(diode, "standard+schottky"))
393 		trickle_cfg = MAX31335_TRICKLE_STANDARD_DIODE;
394 	else
395 		return dev_err_probe(dev, -EINVAL,
396 				     "Invalid tc-diode value: %s\n", diode);
397 
398 	for (i = 0; i < ARRAY_SIZE(max31335_trickle_resistors); i++)
399 		if (ohms == max31335_trickle_resistors[i])
400 			break;
401 
402 	if (i >= ARRAY_SIZE(max31335_trickle_resistors))
403 		return 0;
404 
405 	i = i + trickle_cfg;
406 
407 	return regmap_write(max31335->regmap, MAX31335_TRICKLE_REG,
408 			    FIELD_PREP(MAX31335_TRICKLE_REG_TRICKLE, i) |
409 			    FIELD_PREP(MAX31335_TRICKLE_REG_EN_TRICKLE,
410 				       chargeable));
411 }
412 
413 static unsigned long max31335_clkout_recalc_rate(struct clk_hw *hw,
414 						 unsigned long parent_rate)
415 {
416 	struct max31335_data *max31335 = clk_hw_to_max31335(hw);
417 	unsigned int freq_mask;
418 	unsigned int reg;
419 	int ret;
420 
421 	ret = regmap_read(max31335->regmap, MAX31335_RTC_CONFIG2, &reg);
422 	if (ret)
423 		return 0;
424 
425 	freq_mask = __roundup_pow_of_two(ARRAY_SIZE(max31335_clkout_freq)) - 1;
426 
427 	return max31335_clkout_freq[reg & freq_mask];
428 }
429 
430 static long max31335_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
431 				       unsigned long *prate)
432 {
433 	int index;
434 
435 	index = find_closest(rate, max31335_clkout_freq,
436 			     ARRAY_SIZE(max31335_clkout_freq));
437 
438 	return max31335_clkout_freq[index];
439 }
440 
441 static int max31335_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
442 				    unsigned long parent_rate)
443 {
444 	struct max31335_data *max31335 = clk_hw_to_max31335(hw);
445 	unsigned int freq_mask;
446 	int index;
447 
448 	index = find_closest(rate, max31335_clkout_freq,
449 			     ARRAY_SIZE(max31335_clkout_freq));
450 	freq_mask = __roundup_pow_of_two(ARRAY_SIZE(max31335_clkout_freq)) - 1;
451 
452 	return regmap_update_bits(max31335->regmap, MAX31335_RTC_CONFIG2,
453 				  freq_mask, index);
454 }
455 
456 static int max31335_clkout_enable(struct clk_hw *hw)
457 {
458 	struct max31335_data *max31335 = clk_hw_to_max31335(hw);
459 
460 	return regmap_set_bits(max31335->regmap, MAX31335_RTC_CONFIG2,
461 			       MAX31335_RTC_CONFIG2_ENCLKO);
462 }
463 
464 static void max31335_clkout_disable(struct clk_hw *hw)
465 {
466 	struct max31335_data *max31335 = clk_hw_to_max31335(hw);
467 
468 	regmap_clear_bits(max31335->regmap, MAX31335_RTC_CONFIG2,
469 			  MAX31335_RTC_CONFIG2_ENCLKO);
470 }
471 
472 static int max31335_clkout_is_enabled(struct clk_hw *hw)
473 {
474 	struct max31335_data *max31335 = clk_hw_to_max31335(hw);
475 	unsigned int reg;
476 	int ret;
477 
478 	ret = regmap_read(max31335->regmap, MAX31335_RTC_CONFIG2, &reg);
479 	if (ret)
480 		return ret;
481 
482 	return !!(reg & MAX31335_RTC_CONFIG2_ENCLKO);
483 }
484 
485 static const struct clk_ops max31335_clkout_ops = {
486 	.recalc_rate = max31335_clkout_recalc_rate,
487 	.round_rate = max31335_clkout_round_rate,
488 	.set_rate = max31335_clkout_set_rate,
489 	.enable = max31335_clkout_enable,
490 	.disable = max31335_clkout_disable,
491 	.is_enabled = max31335_clkout_is_enabled,
492 };
493 
494 static struct clk_init_data max31335_clk_init = {
495 	.name = "max31335-clkout",
496 	.ops = &max31335_clkout_ops,
497 };
498 
499 static int max31335_nvmem_reg_read(void *priv, unsigned int offset,
500 				   void *val, size_t bytes)
501 {
502 	struct max31335_data *max31335 = priv;
503 	unsigned int reg = MAX31335_TS0_SEC_1_128 + offset;
504 
505 	return regmap_bulk_read(max31335->regmap, reg, val, bytes);
506 }
507 
508 static int max31335_nvmem_reg_write(void *priv, unsigned int offset,
509 				    void *val, size_t bytes)
510 {
511 	struct max31335_data *max31335 = priv;
512 	unsigned int reg = MAX31335_TS0_SEC_1_128 + offset;
513 
514 	return regmap_bulk_write(max31335->regmap, reg, val, bytes);
515 }
516 
517 static struct nvmem_config max31335_nvmem_cfg = {
518 	.reg_read = max31335_nvmem_reg_read,
519 	.reg_write = max31335_nvmem_reg_write,
520 	.word_size = 8,
521 	.size = MAX31335_RAM_SIZE,
522 };
523 
524 #if IS_REACHABLE(HWMON)
525 static int max31335_read_temp(struct device *dev, enum hwmon_sensor_types type,
526 			      u32 attr, int channel, long *val)
527 {
528 	struct max31335_data *max31335 = dev_get_drvdata(dev);
529 	u8 reg[2];
530 	s16 temp;
531 	int ret;
532 
533 	if (type != hwmon_temp || attr != hwmon_temp_input)
534 		return -EOPNOTSUPP;
535 
536 	ret = regmap_bulk_read(max31335->regmap, MAX31335_TEMP_DATA_MSB,
537 			       reg, 2);
538 	if (ret)
539 		return ret;
540 
541 	temp = get_unaligned_be16(reg);
542 
543 	*val = (temp / 64) * 250;
544 
545 	return 0;
546 }
547 
548 static umode_t max31335_is_visible(const void *data,
549 				   enum hwmon_sensor_types type,
550 				   u32 attr, int channel)
551 {
552 	if (type == hwmon_temp && attr == hwmon_temp_input)
553 		return 0444;
554 
555 	return 0;
556 }
557 
558 static const struct hwmon_channel_info *max31335_info[] = {
559 	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
560 	NULL
561 };
562 
563 static const struct hwmon_ops max31335_hwmon_ops = {
564 	.is_visible = max31335_is_visible,
565 	.read = max31335_read_temp,
566 };
567 
568 static const struct hwmon_chip_info max31335_chip_info = {
569 	.ops = &max31335_hwmon_ops,
570 	.info = max31335_info,
571 };
572 #endif
573 
574 static int max31335_clkout_register(struct device *dev)
575 {
576 	struct max31335_data *max31335 = dev_get_drvdata(dev);
577 	int ret;
578 
579 	if (!device_property_present(dev, "#clock-cells"))
580 		return regmap_clear_bits(max31335->regmap, MAX31335_RTC_CONFIG2,
581 					 MAX31335_RTC_CONFIG2_ENCLKO);
582 
583 	max31335->clkout.init = &max31335_clk_init;
584 
585 	ret = devm_clk_hw_register(dev, &max31335->clkout);
586 	if (ret)
587 		return dev_err_probe(dev, ret, "cannot register clock\n");
588 
589 	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get,
590 					  &max31335->clkout);
591 	if (ret)
592 		return dev_err_probe(dev, ret, "cannot add hw provider\n");
593 
594 	max31335->clkout.clk = devm_clk_get_enabled(dev, NULL);
595 	if (IS_ERR(max31335->clkout.clk))
596 		return dev_err_probe(dev, PTR_ERR(max31335->clkout.clk),
597 				     "cannot enable clkout\n");
598 
599 	return 0;
600 }
601 
602 static int max31335_probe(struct i2c_client *client)
603 {
604 	struct max31335_data *max31335;
605 #if IS_REACHABLE(HWMON)
606 	struct device *hwmon;
607 #endif
608 	int ret;
609 
610 	max31335 = devm_kzalloc(&client->dev, sizeof(*max31335), GFP_KERNEL);
611 	if (!max31335)
612 		return -ENOMEM;
613 
614 	max31335->regmap = devm_regmap_init_i2c(client, &regmap_config);
615 	if (IS_ERR(max31335->regmap))
616 		return PTR_ERR(max31335->regmap);
617 
618 	i2c_set_clientdata(client, max31335);
619 
620 	max31335->rtc = devm_rtc_allocate_device(&client->dev);
621 	if (IS_ERR(max31335->rtc))
622 		return PTR_ERR(max31335->rtc);
623 
624 	max31335->rtc->ops = &max31335_rtc_ops;
625 	max31335->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
626 	max31335->rtc->range_max = RTC_TIMESTAMP_END_2199;
627 	max31335->rtc->alarm_offset_max = 24 * 60 * 60;
628 
629 	ret = max31335_clkout_register(&client->dev);
630 	if (ret)
631 		return ret;
632 
633 	if (client->irq > 0) {
634 		ret = devm_request_threaded_irq(&client->dev, client->irq,
635 						NULL, max31335_handle_irq,
636 						IRQF_ONESHOT,
637 						"max31335", max31335);
638 		if (ret) {
639 			dev_warn(&client->dev,
640 				 "unable to request IRQ, alarm max31335 disabled\n");
641 			client->irq = 0;
642 		}
643 	}
644 
645 	if (!client->irq)
646 		clear_bit(RTC_FEATURE_ALARM, max31335->rtc->features);
647 
648 	max31335_nvmem_cfg.priv = max31335;
649 	ret = devm_rtc_nvmem_register(max31335->rtc, &max31335_nvmem_cfg);
650 	if (ret)
651 		return dev_err_probe(&client->dev, ret,
652 				     "cannot register rtc nvmem\n");
653 
654 #if IS_REACHABLE(HWMON)
655 	hwmon = devm_hwmon_device_register_with_info(&client->dev, client->name,
656 						     max31335,
657 						     &max31335_chip_info,
658 						     NULL);
659 	if (IS_ERR(hwmon))
660 		return dev_err_probe(&client->dev, PTR_ERR(hwmon),
661 				     "cannot register hwmon device\n");
662 #endif
663 
664 	ret = max31335_trickle_charger_setup(&client->dev, max31335);
665 	if (ret)
666 		return ret;
667 
668 	return devm_rtc_register_device(max31335->rtc);
669 }
670 
671 static const struct i2c_device_id max31335_id[] = {
672 	{ "max31335" },
673 	{ }
674 };
675 
676 MODULE_DEVICE_TABLE(i2c, max31335_id);
677 
678 static const struct of_device_id max31335_of_match[] = {
679 	{ .compatible = "adi,max31335" },
680 	{ }
681 };
682 
683 MODULE_DEVICE_TABLE(of, max31335_of_match);
684 
685 static struct i2c_driver max31335_driver = {
686 	.driver = {
687 		.name = "rtc-max31335",
688 		.of_match_table = max31335_of_match,
689 	},
690 	.probe = max31335_probe,
691 	.id_table = max31335_id,
692 };
693 module_i2c_driver(max31335_driver);
694 
695 MODULE_AUTHOR("Antoniu Miclaus <antoniu.miclaus@analog.com>");
696 MODULE_DESCRIPTION("MAX31335 RTC driver");
697 MODULE_LICENSE("GPL");
698