xref: /openbmc/linux/drivers/rtc/rtc-ds1307.c (revision b78412b8)
1 /*
2  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
3  *
4  *  Copyright (C) 2005 James Chapman (ds1337 core)
5  *  Copyright (C) 2006 David Brownell
6  *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
7  *  Copyright (C) 2012 Bertrand Achard (nvram access fixes)
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/acpi.h>
15 #include <linux/bcd.h>
16 #include <linux/i2c.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/of_device.h>
20 #include <linux/rtc/ds1307.h>
21 #include <linux/rtc.h>
22 #include <linux/slab.h>
23 #include <linux/string.h>
24 #include <linux/hwmon.h>
25 #include <linux/hwmon-sysfs.h>
26 #include <linux/clk-provider.h>
27 #include <linux/regmap.h>
28 
29 /*
30  * We can't determine type by probing, but if we expect pre-Linux code
31  * to have set the chip up as a clock (turning on the oscillator and
32  * setting the date and time), Linux can ignore the non-clock features.
33  * That's a natural job for a factory or repair bench.
34  */
35 enum ds_type {
36 	ds_1307,
37 	ds_1308,
38 	ds_1337,
39 	ds_1338,
40 	ds_1339,
41 	ds_1340,
42 	ds_1341,
43 	ds_1388,
44 	ds_3231,
45 	m41t0,
46 	m41t00,
47 	mcp794xx,
48 	rx_8025,
49 	rx_8130,
50 	last_ds_type /* always last */
51 	/* rs5c372 too?  different address... */
52 };
53 
54 /* RTC registers don't differ much, except for the century flag */
55 #define DS1307_REG_SECS		0x00	/* 00-59 */
56 #	define DS1307_BIT_CH		0x80
57 #	define DS1340_BIT_nEOSC		0x80
58 #	define MCP794XX_BIT_ST		0x80
59 #define DS1307_REG_MIN		0x01	/* 00-59 */
60 #	define M41T0_BIT_OF		0x80
61 #define DS1307_REG_HOUR		0x02	/* 00-23, or 1-12{am,pm} */
62 #	define DS1307_BIT_12HR		0x40	/* in REG_HOUR */
63 #	define DS1307_BIT_PM		0x20	/* in REG_HOUR */
64 #	define DS1340_BIT_CENTURY_EN	0x80	/* in REG_HOUR */
65 #	define DS1340_BIT_CENTURY	0x40	/* in REG_HOUR */
66 #define DS1307_REG_WDAY		0x03	/* 01-07 */
67 #	define MCP794XX_BIT_VBATEN	0x08
68 #define DS1307_REG_MDAY		0x04	/* 01-31 */
69 #define DS1307_REG_MONTH	0x05	/* 01-12 */
70 #	define DS1337_BIT_CENTURY	0x80	/* in REG_MONTH */
71 #define DS1307_REG_YEAR		0x06	/* 00-99 */
72 
73 /*
74  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
75  * start at 7, and they differ a LOT. Only control and status matter for
76  * basic RTC date and time functionality; be careful using them.
77  */
78 #define DS1307_REG_CONTROL	0x07		/* or ds1338 */
79 #	define DS1307_BIT_OUT		0x80
80 #	define DS1338_BIT_OSF		0x20
81 #	define DS1307_BIT_SQWE		0x10
82 #	define DS1307_BIT_RS1		0x02
83 #	define DS1307_BIT_RS0		0x01
84 #define DS1337_REG_CONTROL	0x0e
85 #	define DS1337_BIT_nEOSC		0x80
86 #	define DS1339_BIT_BBSQI		0x20
87 #	define DS3231_BIT_BBSQW		0x40 /* same as BBSQI */
88 #	define DS1337_BIT_RS2		0x10
89 #	define DS1337_BIT_RS1		0x08
90 #	define DS1337_BIT_INTCN		0x04
91 #	define DS1337_BIT_A2IE		0x02
92 #	define DS1337_BIT_A1IE		0x01
93 #define DS1340_REG_CONTROL	0x07
94 #	define DS1340_BIT_OUT		0x80
95 #	define DS1340_BIT_FT		0x40
96 #	define DS1340_BIT_CALIB_SIGN	0x20
97 #	define DS1340_M_CALIBRATION	0x1f
98 #define DS1340_REG_FLAG		0x09
99 #	define DS1340_BIT_OSF		0x80
100 #define DS1337_REG_STATUS	0x0f
101 #	define DS1337_BIT_OSF		0x80
102 #	define DS3231_BIT_EN32KHZ	0x08
103 #	define DS1337_BIT_A2I		0x02
104 #	define DS1337_BIT_A1I		0x01
105 #define DS1339_REG_ALARM1_SECS	0x07
106 
107 #define DS13XX_TRICKLE_CHARGER_MAGIC	0xa0
108 
109 #define RX8025_REG_CTRL1	0x0e
110 #	define RX8025_BIT_2412		0x20
111 #define RX8025_REG_CTRL2	0x0f
112 #	define RX8025_BIT_PON		0x10
113 #	define RX8025_BIT_VDET		0x40
114 #	define RX8025_BIT_XST		0x20
115 
116 struct ds1307 {
117 	struct nvmem_config	nvmem_cfg;
118 	enum ds_type		type;
119 	unsigned long		flags;
120 #define HAS_NVRAM	0		/* bit 0 == sysfs file active */
121 #define HAS_ALARM	1		/* bit 1 == irq claimed */
122 	struct device		*dev;
123 	struct regmap		*regmap;
124 	const char		*name;
125 	struct rtc_device	*rtc;
126 #ifdef CONFIG_COMMON_CLK
127 	struct clk_hw		clks[2];
128 #endif
129 };
130 
131 struct chip_desc {
132 	unsigned		alarm:1;
133 	u16			nvram_offset;
134 	u16			nvram_size;
135 	u8			offset; /* register's offset */
136 	u8			century_reg;
137 	u8			century_enable_bit;
138 	u8			century_bit;
139 	u8			bbsqi_bit;
140 	irq_handler_t		irq_handler;
141 	const struct rtc_class_ops *rtc_ops;
142 	u16			trickle_charger_reg;
143 	u8			(*do_trickle_setup)(struct ds1307 *, u32,
144 						    bool);
145 };
146 
147 static int ds1307_get_time(struct device *dev, struct rtc_time *t);
148 static int ds1307_set_time(struct device *dev, struct rtc_time *t);
149 static u8 do_trickle_setup_ds1339(struct ds1307 *, u32 ohms, bool diode);
150 static irqreturn_t rx8130_irq(int irq, void *dev_id);
151 static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t);
152 static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t);
153 static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled);
154 static irqreturn_t mcp794xx_irq(int irq, void *dev_id);
155 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t);
156 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t);
157 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled);
158 
159 static const struct rtc_class_ops rx8130_rtc_ops = {
160 	.read_time      = ds1307_get_time,
161 	.set_time       = ds1307_set_time,
162 	.read_alarm     = rx8130_read_alarm,
163 	.set_alarm      = rx8130_set_alarm,
164 	.alarm_irq_enable = rx8130_alarm_irq_enable,
165 };
166 
167 static const struct rtc_class_ops mcp794xx_rtc_ops = {
168 	.read_time      = ds1307_get_time,
169 	.set_time       = ds1307_set_time,
170 	.read_alarm     = mcp794xx_read_alarm,
171 	.set_alarm      = mcp794xx_set_alarm,
172 	.alarm_irq_enable = mcp794xx_alarm_irq_enable,
173 };
174 
175 static const struct chip_desc chips[last_ds_type] = {
176 	[ds_1307] = {
177 		.nvram_offset	= 8,
178 		.nvram_size	= 56,
179 	},
180 	[ds_1308] = {
181 		.nvram_offset	= 8,
182 		.nvram_size	= 56,
183 	},
184 	[ds_1337] = {
185 		.alarm		= 1,
186 		.century_reg	= DS1307_REG_MONTH,
187 		.century_bit	= DS1337_BIT_CENTURY,
188 	},
189 	[ds_1338] = {
190 		.nvram_offset	= 8,
191 		.nvram_size	= 56,
192 	},
193 	[ds_1339] = {
194 		.alarm		= 1,
195 		.century_reg	= DS1307_REG_MONTH,
196 		.century_bit	= DS1337_BIT_CENTURY,
197 		.bbsqi_bit	= DS1339_BIT_BBSQI,
198 		.trickle_charger_reg = 0x10,
199 		.do_trickle_setup = &do_trickle_setup_ds1339,
200 	},
201 	[ds_1340] = {
202 		.century_reg	= DS1307_REG_HOUR,
203 		.century_enable_bit = DS1340_BIT_CENTURY_EN,
204 		.century_bit	= DS1340_BIT_CENTURY,
205 		.trickle_charger_reg = 0x08,
206 	},
207 	[ds_1341] = {
208 		.century_reg	= DS1307_REG_MONTH,
209 		.century_bit	= DS1337_BIT_CENTURY,
210 	},
211 	[ds_1388] = {
212 		.offset		= 1,
213 		.trickle_charger_reg = 0x0a,
214 	},
215 	[ds_3231] = {
216 		.alarm		= 1,
217 		.century_reg	= DS1307_REG_MONTH,
218 		.century_bit	= DS1337_BIT_CENTURY,
219 		.bbsqi_bit	= DS3231_BIT_BBSQW,
220 	},
221 	[rx_8130] = {
222 		.alarm		= 1,
223 		/* this is battery backed SRAM */
224 		.nvram_offset	= 0x20,
225 		.nvram_size	= 4,	/* 32bit (4 word x 8 bit) */
226 		.offset		= 0x10,
227 		.irq_handler = rx8130_irq,
228 		.rtc_ops = &rx8130_rtc_ops,
229 	},
230 	[mcp794xx] = {
231 		.alarm		= 1,
232 		/* this is battery backed SRAM */
233 		.nvram_offset	= 0x20,
234 		.nvram_size	= 0x40,
235 		.irq_handler = mcp794xx_irq,
236 		.rtc_ops = &mcp794xx_rtc_ops,
237 	},
238 };
239 
240 static const struct i2c_device_id ds1307_id[] = {
241 	{ "ds1307", ds_1307 },
242 	{ "ds1308", ds_1308 },
243 	{ "ds1337", ds_1337 },
244 	{ "ds1338", ds_1338 },
245 	{ "ds1339", ds_1339 },
246 	{ "ds1388", ds_1388 },
247 	{ "ds1340", ds_1340 },
248 	{ "ds1341", ds_1341 },
249 	{ "ds3231", ds_3231 },
250 	{ "m41t0", m41t0 },
251 	{ "m41t00", m41t00 },
252 	{ "mcp7940x", mcp794xx },
253 	{ "mcp7941x", mcp794xx },
254 	{ "pt7c4338", ds_1307 },
255 	{ "rx8025", rx_8025 },
256 	{ "isl12057", ds_1337 },
257 	{ "rx8130", rx_8130 },
258 	{ }
259 };
260 MODULE_DEVICE_TABLE(i2c, ds1307_id);
261 
262 #ifdef CONFIG_OF
263 static const struct of_device_id ds1307_of_match[] = {
264 	{
265 		.compatible = "dallas,ds1307",
266 		.data = (void *)ds_1307
267 	},
268 	{
269 		.compatible = "dallas,ds1308",
270 		.data = (void *)ds_1308
271 	},
272 	{
273 		.compatible = "dallas,ds1337",
274 		.data = (void *)ds_1337
275 	},
276 	{
277 		.compatible = "dallas,ds1338",
278 		.data = (void *)ds_1338
279 	},
280 	{
281 		.compatible = "dallas,ds1339",
282 		.data = (void *)ds_1339
283 	},
284 	{
285 		.compatible = "dallas,ds1388",
286 		.data = (void *)ds_1388
287 	},
288 	{
289 		.compatible = "dallas,ds1340",
290 		.data = (void *)ds_1340
291 	},
292 	{
293 		.compatible = "dallas,ds1341",
294 		.data = (void *)ds_1341
295 	},
296 	{
297 		.compatible = "maxim,ds3231",
298 		.data = (void *)ds_3231
299 	},
300 	{
301 		.compatible = "st,m41t0",
302 		.data = (void *)m41t00
303 	},
304 	{
305 		.compatible = "st,m41t00",
306 		.data = (void *)m41t00
307 	},
308 	{
309 		.compatible = "microchip,mcp7940x",
310 		.data = (void *)mcp794xx
311 	},
312 	{
313 		.compatible = "microchip,mcp7941x",
314 		.data = (void *)mcp794xx
315 	},
316 	{
317 		.compatible = "pericom,pt7c4338",
318 		.data = (void *)ds_1307
319 	},
320 	{
321 		.compatible = "epson,rx8025",
322 		.data = (void *)rx_8025
323 	},
324 	{
325 		.compatible = "isil,isl12057",
326 		.data = (void *)ds_1337
327 	},
328 	{ }
329 };
330 MODULE_DEVICE_TABLE(of, ds1307_of_match);
331 #endif
332 
333 #ifdef CONFIG_ACPI
334 static const struct acpi_device_id ds1307_acpi_ids[] = {
335 	{ .id = "DS1307", .driver_data = ds_1307 },
336 	{ .id = "DS1308", .driver_data = ds_1308 },
337 	{ .id = "DS1337", .driver_data = ds_1337 },
338 	{ .id = "DS1338", .driver_data = ds_1338 },
339 	{ .id = "DS1339", .driver_data = ds_1339 },
340 	{ .id = "DS1388", .driver_data = ds_1388 },
341 	{ .id = "DS1340", .driver_data = ds_1340 },
342 	{ .id = "DS1341", .driver_data = ds_1341 },
343 	{ .id = "DS3231", .driver_data = ds_3231 },
344 	{ .id = "M41T0", .driver_data = m41t0 },
345 	{ .id = "M41T00", .driver_data = m41t00 },
346 	{ .id = "MCP7940X", .driver_data = mcp794xx },
347 	{ .id = "MCP7941X", .driver_data = mcp794xx },
348 	{ .id = "PT7C4338", .driver_data = ds_1307 },
349 	{ .id = "RX8025", .driver_data = rx_8025 },
350 	{ .id = "ISL12057", .driver_data = ds_1337 },
351 	{ }
352 };
353 MODULE_DEVICE_TABLE(acpi, ds1307_acpi_ids);
354 #endif
355 
356 /*
357  * The ds1337 and ds1339 both have two alarms, but we only use the first
358  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
359  * signal; ds1339 chips have only one alarm signal.
360  */
361 static irqreturn_t ds1307_irq(int irq, void *dev_id)
362 {
363 	struct ds1307		*ds1307 = dev_id;
364 	struct mutex		*lock = &ds1307->rtc->ops_lock;
365 	int			stat, ret;
366 
367 	mutex_lock(lock);
368 	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
369 	if (ret)
370 		goto out;
371 
372 	if (stat & DS1337_BIT_A1I) {
373 		stat &= ~DS1337_BIT_A1I;
374 		regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
375 
376 		ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
377 					 DS1337_BIT_A1IE, 0);
378 		if (ret)
379 			goto out;
380 
381 		rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
382 	}
383 
384 out:
385 	mutex_unlock(lock);
386 
387 	return IRQ_HANDLED;
388 }
389 
390 /*----------------------------------------------------------------------*/
391 
392 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
393 {
394 	struct ds1307	*ds1307 = dev_get_drvdata(dev);
395 	int		tmp, ret;
396 	const struct chip_desc *chip = &chips[ds1307->type];
397 	u8 regs[7];
398 
399 	/* read the RTC date and time registers all at once */
400 	ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
401 			       sizeof(regs));
402 	if (ret) {
403 		dev_err(dev, "%s error %d\n", "read", ret);
404 		return ret;
405 	}
406 
407 	dev_dbg(dev, "%s: %7ph\n", "read", regs);
408 
409 	/* if oscillator fail bit is set, no data can be trusted */
410 	if (ds1307->type == m41t0 &&
411 	    regs[DS1307_REG_MIN] & M41T0_BIT_OF) {
412 		dev_warn_once(dev, "oscillator failed, set time!\n");
413 		return -EINVAL;
414 	}
415 
416 	t->tm_sec = bcd2bin(regs[DS1307_REG_SECS] & 0x7f);
417 	t->tm_min = bcd2bin(regs[DS1307_REG_MIN] & 0x7f);
418 	tmp = regs[DS1307_REG_HOUR] & 0x3f;
419 	t->tm_hour = bcd2bin(tmp);
420 	t->tm_wday = bcd2bin(regs[DS1307_REG_WDAY] & 0x07) - 1;
421 	t->tm_mday = bcd2bin(regs[DS1307_REG_MDAY] & 0x3f);
422 	tmp = regs[DS1307_REG_MONTH] & 0x1f;
423 	t->tm_mon = bcd2bin(tmp) - 1;
424 	t->tm_year = bcd2bin(regs[DS1307_REG_YEAR]) + 100;
425 
426 	if (regs[chip->century_reg] & chip->century_bit &&
427 	    IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
428 		t->tm_year += 100;
429 
430 	dev_dbg(dev, "%s secs=%d, mins=%d, "
431 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
432 		"read", t->tm_sec, t->tm_min,
433 		t->tm_hour, t->tm_mday,
434 		t->tm_mon, t->tm_year, t->tm_wday);
435 
436 	/* initial clock setting can be undefined */
437 	return rtc_valid_tm(t);
438 }
439 
440 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
441 {
442 	struct ds1307	*ds1307 = dev_get_drvdata(dev);
443 	const struct chip_desc *chip = &chips[ds1307->type];
444 	int		result;
445 	int		tmp;
446 	u8		regs[7];
447 
448 	dev_dbg(dev, "%s secs=%d, mins=%d, "
449 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
450 		"write", t->tm_sec, t->tm_min,
451 		t->tm_hour, t->tm_mday,
452 		t->tm_mon, t->tm_year, t->tm_wday);
453 
454 	if (t->tm_year < 100)
455 		return -EINVAL;
456 
457 #ifdef CONFIG_RTC_DRV_DS1307_CENTURY
458 	if (t->tm_year > (chip->century_bit ? 299 : 199))
459 		return -EINVAL;
460 #else
461 	if (t->tm_year > 199)
462 		return -EINVAL;
463 #endif
464 
465 	regs[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
466 	regs[DS1307_REG_MIN] = bin2bcd(t->tm_min);
467 	regs[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
468 	regs[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
469 	regs[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
470 	regs[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
471 
472 	/* assume 20YY not 19YY */
473 	tmp = t->tm_year - 100;
474 	regs[DS1307_REG_YEAR] = bin2bcd(tmp);
475 
476 	if (chip->century_enable_bit)
477 		regs[chip->century_reg] |= chip->century_enable_bit;
478 	if (t->tm_year > 199 && chip->century_bit)
479 		regs[chip->century_reg] |= chip->century_bit;
480 
481 	if (ds1307->type == mcp794xx) {
482 		/*
483 		 * these bits were cleared when preparing the date/time
484 		 * values and need to be set again before writing the
485 		 * regsfer out to the device.
486 		 */
487 		regs[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
488 		regs[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
489 	}
490 
491 	dev_dbg(dev, "%s: %7ph\n", "write", regs);
492 
493 	result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
494 				   sizeof(regs));
495 	if (result) {
496 		dev_err(dev, "%s error %d\n", "write", result);
497 		return result;
498 	}
499 	return 0;
500 }
501 
502 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
503 {
504 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
505 	int			ret;
506 	u8			regs[9];
507 
508 	if (!test_bit(HAS_ALARM, &ds1307->flags))
509 		return -EINVAL;
510 
511 	/* read all ALARM1, ALARM2, and status registers at once */
512 	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
513 			       regs, sizeof(regs));
514 	if (ret) {
515 		dev_err(dev, "%s error %d\n", "alarm read", ret);
516 		return ret;
517 	}
518 
519 	dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
520 		&regs[0], &regs[4], &regs[7]);
521 
522 	/*
523 	 * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
524 	 * and that all four fields are checked matches
525 	 */
526 	t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
527 	t->time.tm_min = bcd2bin(regs[1] & 0x7f);
528 	t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
529 	t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
530 
531 	/* ... and status */
532 	t->enabled = !!(regs[7] & DS1337_BIT_A1IE);
533 	t->pending = !!(regs[8] & DS1337_BIT_A1I);
534 
535 	dev_dbg(dev, "%s secs=%d, mins=%d, "
536 		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
537 		"alarm read", t->time.tm_sec, t->time.tm_min,
538 		t->time.tm_hour, t->time.tm_mday,
539 		t->enabled, t->pending);
540 
541 	return 0;
542 }
543 
544 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
545 {
546 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
547 	unsigned char		regs[9];
548 	u8			control, status;
549 	int			ret;
550 
551 	if (!test_bit(HAS_ALARM, &ds1307->flags))
552 		return -EINVAL;
553 
554 	dev_dbg(dev, "%s secs=%d, mins=%d, "
555 		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
556 		"alarm set", t->time.tm_sec, t->time.tm_min,
557 		t->time.tm_hour, t->time.tm_mday,
558 		t->enabled, t->pending);
559 
560 	/* read current status of both alarms and the chip */
561 	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
562 			       sizeof(regs));
563 	if (ret) {
564 		dev_err(dev, "%s error %d\n", "alarm write", ret);
565 		return ret;
566 	}
567 	control = regs[7];
568 	status = regs[8];
569 
570 	dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
571 		&regs[0], &regs[4], control, status);
572 
573 	/* set ALARM1, using 24 hour and day-of-month modes */
574 	regs[0] = bin2bcd(t->time.tm_sec);
575 	regs[1] = bin2bcd(t->time.tm_min);
576 	regs[2] = bin2bcd(t->time.tm_hour);
577 	regs[3] = bin2bcd(t->time.tm_mday);
578 
579 	/* set ALARM2 to non-garbage */
580 	regs[4] = 0;
581 	regs[5] = 0;
582 	regs[6] = 0;
583 
584 	/* disable alarms */
585 	regs[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
586 	regs[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
587 
588 	ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
589 				sizeof(regs));
590 	if (ret) {
591 		dev_err(dev, "can't set alarm time\n");
592 		return ret;
593 	}
594 
595 	/* optionally enable ALARM1 */
596 	if (t->enabled) {
597 		dev_dbg(dev, "alarm IRQ armed\n");
598 		regs[7] |= DS1337_BIT_A1IE;	/* only ALARM1 is used */
599 		regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[7]);
600 	}
601 
602 	return 0;
603 }
604 
605 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
606 {
607 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
608 
609 	if (!test_bit(HAS_ALARM, &ds1307->flags))
610 		return -ENOTTY;
611 
612 	return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
613 				  DS1337_BIT_A1IE,
614 				  enabled ? DS1337_BIT_A1IE : 0);
615 }
616 
617 static const struct rtc_class_ops ds13xx_rtc_ops = {
618 	.read_time	= ds1307_get_time,
619 	.set_time	= ds1307_set_time,
620 	.read_alarm	= ds1337_read_alarm,
621 	.set_alarm	= ds1337_set_alarm,
622 	.alarm_irq_enable = ds1307_alarm_irq_enable,
623 };
624 
625 /*----------------------------------------------------------------------*/
626 
627 /*
628  * Alarm support for rx8130 devices.
629  */
630 
631 #define RX8130_REG_ALARM_MIN		0x07
632 #define RX8130_REG_ALARM_HOUR		0x08
633 #define RX8130_REG_ALARM_WEEK_OR_DAY	0x09
634 #define RX8130_REG_EXTENSION		0x0c
635 #define RX8130_REG_EXTENSION_WADA	BIT(3)
636 #define RX8130_REG_FLAG			0x0d
637 #define RX8130_REG_FLAG_AF		BIT(3)
638 #define RX8130_REG_CONTROL0		0x0e
639 #define RX8130_REG_CONTROL0_AIE		BIT(3)
640 
641 static irqreturn_t rx8130_irq(int irq, void *dev_id)
642 {
643 	struct ds1307           *ds1307 = dev_id;
644 	struct mutex            *lock = &ds1307->rtc->ops_lock;
645 	u8 ctl[3];
646 	int ret;
647 
648 	mutex_lock(lock);
649 
650 	/* Read control registers. */
651 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
652 			       sizeof(ctl));
653 	if (ret < 0)
654 		goto out;
655 	if (!(ctl[1] & RX8130_REG_FLAG_AF))
656 		goto out;
657 	ctl[1] &= ~RX8130_REG_FLAG_AF;
658 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
659 
660 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
661 				sizeof(ctl));
662 	if (ret < 0)
663 		goto out;
664 
665 	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
666 
667 out:
668 	mutex_unlock(lock);
669 
670 	return IRQ_HANDLED;
671 }
672 
673 static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
674 {
675 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
676 	u8 ald[3], ctl[3];
677 	int ret;
678 
679 	if (!test_bit(HAS_ALARM, &ds1307->flags))
680 		return -EINVAL;
681 
682 	/* Read alarm registers. */
683 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
684 			       sizeof(ald));
685 	if (ret < 0)
686 		return ret;
687 
688 	/* Read control registers. */
689 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
690 			       sizeof(ctl));
691 	if (ret < 0)
692 		return ret;
693 
694 	t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
695 	t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
696 
697 	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
698 	t->time.tm_sec = -1;
699 	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
700 	t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
701 	t->time.tm_wday = -1;
702 	t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
703 	t->time.tm_mon = -1;
704 	t->time.tm_year = -1;
705 	t->time.tm_yday = -1;
706 	t->time.tm_isdst = -1;
707 
708 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
709 		__func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
710 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
711 
712 	return 0;
713 }
714 
715 static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
716 {
717 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
718 	u8 ald[3], ctl[3];
719 	int ret;
720 
721 	if (!test_bit(HAS_ALARM, &ds1307->flags))
722 		return -EINVAL;
723 
724 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
725 		"enabled=%d pending=%d\n", __func__,
726 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
727 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
728 		t->enabled, t->pending);
729 
730 	/* Read control registers. */
731 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
732 			       sizeof(ctl));
733 	if (ret < 0)
734 		return ret;
735 
736 	ctl[0] &= ~RX8130_REG_EXTENSION_WADA;
737 	ctl[1] |= RX8130_REG_FLAG_AF;
738 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
739 
740 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
741 				sizeof(ctl));
742 	if (ret < 0)
743 		return ret;
744 
745 	/* Hardware alarm precision is 1 minute! */
746 	ald[0] = bin2bcd(t->time.tm_min);
747 	ald[1] = bin2bcd(t->time.tm_hour);
748 	ald[2] = bin2bcd(t->time.tm_mday);
749 
750 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
751 				sizeof(ald));
752 	if (ret < 0)
753 		return ret;
754 
755 	if (!t->enabled)
756 		return 0;
757 
758 	ctl[2] |= RX8130_REG_CONTROL0_AIE;
759 
760 	return regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
761 				 sizeof(ctl));
762 }
763 
764 static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
765 {
766 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
767 	int ret, reg;
768 
769 	if (!test_bit(HAS_ALARM, &ds1307->flags))
770 		return -EINVAL;
771 
772 	ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
773 	if (ret < 0)
774 		return ret;
775 
776 	if (enabled)
777 		reg |= RX8130_REG_CONTROL0_AIE;
778 	else
779 		reg &= ~RX8130_REG_CONTROL0_AIE;
780 
781 	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
782 }
783 
784 /*----------------------------------------------------------------------*/
785 
786 /*
787  * Alarm support for mcp794xx devices.
788  */
789 
790 #define MCP794XX_REG_WEEKDAY		0x3
791 #define MCP794XX_REG_WEEKDAY_WDAY_MASK	0x7
792 #define MCP794XX_REG_CONTROL		0x07
793 #	define MCP794XX_BIT_ALM0_EN	0x10
794 #	define MCP794XX_BIT_ALM1_EN	0x20
795 #define MCP794XX_REG_ALARM0_BASE	0x0a
796 #define MCP794XX_REG_ALARM0_CTRL	0x0d
797 #define MCP794XX_REG_ALARM1_BASE	0x11
798 #define MCP794XX_REG_ALARM1_CTRL	0x14
799 #	define MCP794XX_BIT_ALMX_IF	BIT(3)
800 #	define MCP794XX_BIT_ALMX_C0	BIT(4)
801 #	define MCP794XX_BIT_ALMX_C1	BIT(5)
802 #	define MCP794XX_BIT_ALMX_C2	BIT(6)
803 #	define MCP794XX_BIT_ALMX_POL	BIT(7)
804 #	define MCP794XX_MSK_ALMX_MATCH	(MCP794XX_BIT_ALMX_C0 | \
805 					 MCP794XX_BIT_ALMX_C1 | \
806 					 MCP794XX_BIT_ALMX_C2)
807 
808 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
809 {
810 	struct ds1307           *ds1307 = dev_id;
811 	struct mutex            *lock = &ds1307->rtc->ops_lock;
812 	int reg, ret;
813 
814 	mutex_lock(lock);
815 
816 	/* Check and clear alarm 0 interrupt flag. */
817 	ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
818 	if (ret)
819 		goto out;
820 	if (!(reg & MCP794XX_BIT_ALMX_IF))
821 		goto out;
822 	reg &= ~MCP794XX_BIT_ALMX_IF;
823 	ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
824 	if (ret)
825 		goto out;
826 
827 	/* Disable alarm 0. */
828 	ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
829 				 MCP794XX_BIT_ALM0_EN, 0);
830 	if (ret)
831 		goto out;
832 
833 	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
834 
835 out:
836 	mutex_unlock(lock);
837 
838 	return IRQ_HANDLED;
839 }
840 
841 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
842 {
843 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
844 	u8 regs[10];
845 	int ret;
846 
847 	if (!test_bit(HAS_ALARM, &ds1307->flags))
848 		return -EINVAL;
849 
850 	/* Read control and alarm 0 registers. */
851 	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
852 			       sizeof(regs));
853 	if (ret)
854 		return ret;
855 
856 	t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
857 
858 	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
859 	t->time.tm_sec = bcd2bin(regs[3] & 0x7f);
860 	t->time.tm_min = bcd2bin(regs[4] & 0x7f);
861 	t->time.tm_hour = bcd2bin(regs[5] & 0x3f);
862 	t->time.tm_wday = bcd2bin(regs[6] & 0x7) - 1;
863 	t->time.tm_mday = bcd2bin(regs[7] & 0x3f);
864 	t->time.tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
865 	t->time.tm_year = -1;
866 	t->time.tm_yday = -1;
867 	t->time.tm_isdst = -1;
868 
869 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
870 		"enabled=%d polarity=%d irq=%d match=%lu\n", __func__,
871 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
872 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
873 		!!(regs[6] & MCP794XX_BIT_ALMX_POL),
874 		!!(regs[6] & MCP794XX_BIT_ALMX_IF),
875 		(regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
876 
877 	return 0;
878 }
879 
880 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
881 {
882 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
883 	unsigned char regs[10];
884 	int ret;
885 
886 	if (!test_bit(HAS_ALARM, &ds1307->flags))
887 		return -EINVAL;
888 
889 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
890 		"enabled=%d pending=%d\n", __func__,
891 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
892 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
893 		t->enabled, t->pending);
894 
895 	/* Read control and alarm 0 registers. */
896 	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
897 			       sizeof(regs));
898 	if (ret)
899 		return ret;
900 
901 	/* Set alarm 0, using 24-hour and day-of-month modes. */
902 	regs[3] = bin2bcd(t->time.tm_sec);
903 	regs[4] = bin2bcd(t->time.tm_min);
904 	regs[5] = bin2bcd(t->time.tm_hour);
905 	regs[6] = bin2bcd(t->time.tm_wday + 1);
906 	regs[7] = bin2bcd(t->time.tm_mday);
907 	regs[8] = bin2bcd(t->time.tm_mon + 1);
908 
909 	/* Clear the alarm 0 interrupt flag. */
910 	regs[6] &= ~MCP794XX_BIT_ALMX_IF;
911 	/* Set alarm match: second, minute, hour, day, date, month. */
912 	regs[6] |= MCP794XX_MSK_ALMX_MATCH;
913 	/* Disable interrupt. We will not enable until completely programmed */
914 	regs[0] &= ~MCP794XX_BIT_ALM0_EN;
915 
916 	ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
917 				sizeof(regs));
918 	if (ret)
919 		return ret;
920 
921 	if (!t->enabled)
922 		return 0;
923 	regs[0] |= MCP794XX_BIT_ALM0_EN;
924 	return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
925 }
926 
927 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
928 {
929 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
930 
931 	if (!test_bit(HAS_ALARM, &ds1307->flags))
932 		return -EINVAL;
933 
934 	return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
935 				  MCP794XX_BIT_ALM0_EN,
936 				  enabled ? MCP794XX_BIT_ALM0_EN : 0);
937 }
938 
939 /*----------------------------------------------------------------------*/
940 
941 static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
942 			     size_t bytes)
943 {
944 	struct ds1307 *ds1307 = priv;
945 	const struct chip_desc *chip = &chips[ds1307->type];
946 
947 	return regmap_bulk_read(ds1307->regmap, chip->nvram_offset + offset,
948 				val, bytes);
949 }
950 
951 static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
952 			      size_t bytes)
953 {
954 	struct ds1307 *ds1307 = priv;
955 	const struct chip_desc *chip = &chips[ds1307->type];
956 
957 	return regmap_bulk_write(ds1307->regmap, chip->nvram_offset + offset,
958 				 val, bytes);
959 }
960 
961 /*----------------------------------------------------------------------*/
962 
963 static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307,
964 				  u32 ohms, bool diode)
965 {
966 	u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
967 		DS1307_TRICKLE_CHARGER_NO_DIODE;
968 
969 	switch (ohms) {
970 	case 250:
971 		setup |= DS1307_TRICKLE_CHARGER_250_OHM;
972 		break;
973 	case 2000:
974 		setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
975 		break;
976 	case 4000:
977 		setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
978 		break;
979 	default:
980 		dev_warn(ds1307->dev,
981 			 "Unsupported ohm value %u in dt\n", ohms);
982 		return 0;
983 	}
984 	return setup;
985 }
986 
987 static u8 ds1307_trickle_init(struct ds1307 *ds1307,
988 			      const struct chip_desc *chip)
989 {
990 	u32 ohms;
991 	bool diode = true;
992 
993 	if (!chip->do_trickle_setup)
994 		return 0;
995 
996 	if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
997 				     &ohms))
998 		return 0;
999 
1000 	if (device_property_read_bool(ds1307->dev, "trickle-diode-disable"))
1001 		diode = false;
1002 
1003 	return chip->do_trickle_setup(ds1307, ohms, diode);
1004 }
1005 
1006 /*----------------------------------------------------------------------*/
1007 
1008 #ifdef CONFIG_RTC_DRV_DS1307_HWMON
1009 
1010 /*
1011  * Temperature sensor support for ds3231 devices.
1012  */
1013 
1014 #define DS3231_REG_TEMPERATURE	0x11
1015 
1016 /*
1017  * A user-initiated temperature conversion is not started by this function,
1018  * so the temperature is updated once every 64 seconds.
1019  */
1020 static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
1021 {
1022 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
1023 	u8 temp_buf[2];
1024 	s16 temp;
1025 	int ret;
1026 
1027 	ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
1028 			       temp_buf, sizeof(temp_buf));
1029 	if (ret)
1030 		return ret;
1031 	/*
1032 	 * Temperature is represented as a 10-bit code with a resolution of
1033 	 * 0.25 degree celsius and encoded in two's complement format.
1034 	 */
1035 	temp = (temp_buf[0] << 8) | temp_buf[1];
1036 	temp >>= 6;
1037 	*mC = temp * 250;
1038 
1039 	return 0;
1040 }
1041 
1042 static ssize_t ds3231_hwmon_show_temp(struct device *dev,
1043 				      struct device_attribute *attr, char *buf)
1044 {
1045 	int ret;
1046 	s32 temp;
1047 
1048 	ret = ds3231_hwmon_read_temp(dev, &temp);
1049 	if (ret)
1050 		return ret;
1051 
1052 	return sprintf(buf, "%d\n", temp);
1053 }
1054 static SENSOR_DEVICE_ATTR(temp1_input, 0444, ds3231_hwmon_show_temp,
1055 			  NULL, 0);
1056 
1057 static struct attribute *ds3231_hwmon_attrs[] = {
1058 	&sensor_dev_attr_temp1_input.dev_attr.attr,
1059 	NULL,
1060 };
1061 ATTRIBUTE_GROUPS(ds3231_hwmon);
1062 
1063 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1064 {
1065 	struct device *dev;
1066 
1067 	if (ds1307->type != ds_3231)
1068 		return;
1069 
1070 	dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1071 						     ds1307,
1072 						     ds3231_hwmon_groups);
1073 	if (IS_ERR(dev)) {
1074 		dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1075 			 PTR_ERR(dev));
1076 	}
1077 }
1078 
1079 #else
1080 
1081 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1082 {
1083 }
1084 
1085 #endif /* CONFIG_RTC_DRV_DS1307_HWMON */
1086 
1087 /*----------------------------------------------------------------------*/
1088 
1089 /*
1090  * Square-wave output support for DS3231
1091  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1092  */
1093 #ifdef CONFIG_COMMON_CLK
1094 
1095 enum {
1096 	DS3231_CLK_SQW = 0,
1097 	DS3231_CLK_32KHZ,
1098 };
1099 
1100 #define clk_sqw_to_ds1307(clk)	\
1101 	container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1102 #define clk_32khz_to_ds1307(clk)	\
1103 	container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1104 
1105 static int ds3231_clk_sqw_rates[] = {
1106 	1,
1107 	1024,
1108 	4096,
1109 	8192,
1110 };
1111 
1112 static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1113 {
1114 	struct mutex *lock = &ds1307->rtc->ops_lock;
1115 	int ret;
1116 
1117 	mutex_lock(lock);
1118 	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1119 				 mask, value);
1120 	mutex_unlock(lock);
1121 
1122 	return ret;
1123 }
1124 
1125 static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1126 						unsigned long parent_rate)
1127 {
1128 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1129 	int control, ret;
1130 	int rate_sel = 0;
1131 
1132 	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1133 	if (ret)
1134 		return ret;
1135 	if (control & DS1337_BIT_RS1)
1136 		rate_sel += 1;
1137 	if (control & DS1337_BIT_RS2)
1138 		rate_sel += 2;
1139 
1140 	return ds3231_clk_sqw_rates[rate_sel];
1141 }
1142 
1143 static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1144 				      unsigned long *prate)
1145 {
1146 	int i;
1147 
1148 	for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1149 		if (ds3231_clk_sqw_rates[i] <= rate)
1150 			return ds3231_clk_sqw_rates[i];
1151 	}
1152 
1153 	return 0;
1154 }
1155 
1156 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1157 				   unsigned long parent_rate)
1158 {
1159 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1160 	int control = 0;
1161 	int rate_sel;
1162 
1163 	for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1164 			rate_sel++) {
1165 		if (ds3231_clk_sqw_rates[rate_sel] == rate)
1166 			break;
1167 	}
1168 
1169 	if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1170 		return -EINVAL;
1171 
1172 	if (rate_sel & 1)
1173 		control |= DS1337_BIT_RS1;
1174 	if (rate_sel & 2)
1175 		control |= DS1337_BIT_RS2;
1176 
1177 	return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1178 				control);
1179 }
1180 
1181 static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1182 {
1183 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1184 
1185 	return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1186 }
1187 
1188 static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1189 {
1190 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1191 
1192 	ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1193 }
1194 
1195 static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1196 {
1197 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1198 	int control, ret;
1199 
1200 	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1201 	if (ret)
1202 		return ret;
1203 
1204 	return !(control & DS1337_BIT_INTCN);
1205 }
1206 
1207 static const struct clk_ops ds3231_clk_sqw_ops = {
1208 	.prepare = ds3231_clk_sqw_prepare,
1209 	.unprepare = ds3231_clk_sqw_unprepare,
1210 	.is_prepared = ds3231_clk_sqw_is_prepared,
1211 	.recalc_rate = ds3231_clk_sqw_recalc_rate,
1212 	.round_rate = ds3231_clk_sqw_round_rate,
1213 	.set_rate = ds3231_clk_sqw_set_rate,
1214 };
1215 
1216 static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1217 						  unsigned long parent_rate)
1218 {
1219 	return 32768;
1220 }
1221 
1222 static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1223 {
1224 	struct mutex *lock = &ds1307->rtc->ops_lock;
1225 	int ret;
1226 
1227 	mutex_lock(lock);
1228 	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1229 				 DS3231_BIT_EN32KHZ,
1230 				 enable ? DS3231_BIT_EN32KHZ : 0);
1231 	mutex_unlock(lock);
1232 
1233 	return ret;
1234 }
1235 
1236 static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1237 {
1238 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1239 
1240 	return ds3231_clk_32khz_control(ds1307, true);
1241 }
1242 
1243 static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1244 {
1245 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1246 
1247 	ds3231_clk_32khz_control(ds1307, false);
1248 }
1249 
1250 static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1251 {
1252 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1253 	int status, ret;
1254 
1255 	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1256 	if (ret)
1257 		return ret;
1258 
1259 	return !!(status & DS3231_BIT_EN32KHZ);
1260 }
1261 
1262 static const struct clk_ops ds3231_clk_32khz_ops = {
1263 	.prepare = ds3231_clk_32khz_prepare,
1264 	.unprepare = ds3231_clk_32khz_unprepare,
1265 	.is_prepared = ds3231_clk_32khz_is_prepared,
1266 	.recalc_rate = ds3231_clk_32khz_recalc_rate,
1267 };
1268 
1269 static struct clk_init_data ds3231_clks_init[] = {
1270 	[DS3231_CLK_SQW] = {
1271 		.name = "ds3231_clk_sqw",
1272 		.ops = &ds3231_clk_sqw_ops,
1273 	},
1274 	[DS3231_CLK_32KHZ] = {
1275 		.name = "ds3231_clk_32khz",
1276 		.ops = &ds3231_clk_32khz_ops,
1277 	},
1278 };
1279 
1280 static int ds3231_clks_register(struct ds1307 *ds1307)
1281 {
1282 	struct device_node *node = ds1307->dev->of_node;
1283 	struct clk_onecell_data	*onecell;
1284 	int i;
1285 
1286 	onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1287 	if (!onecell)
1288 		return -ENOMEM;
1289 
1290 	onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1291 	onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1292 				     sizeof(onecell->clks[0]), GFP_KERNEL);
1293 	if (!onecell->clks)
1294 		return -ENOMEM;
1295 
1296 	for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1297 		struct clk_init_data init = ds3231_clks_init[i];
1298 
1299 		/*
1300 		 * Interrupt signal due to alarm conditions and square-wave
1301 		 * output share same pin, so don't initialize both.
1302 		 */
1303 		if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
1304 			continue;
1305 
1306 		/* optional override of the clockname */
1307 		of_property_read_string_index(node, "clock-output-names", i,
1308 					      &init.name);
1309 		ds1307->clks[i].init = &init;
1310 
1311 		onecell->clks[i] = devm_clk_register(ds1307->dev,
1312 						     &ds1307->clks[i]);
1313 		if (IS_ERR(onecell->clks[i]))
1314 			return PTR_ERR(onecell->clks[i]);
1315 	}
1316 
1317 	if (!node)
1318 		return 0;
1319 
1320 	of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1321 
1322 	return 0;
1323 }
1324 
1325 static void ds1307_clks_register(struct ds1307 *ds1307)
1326 {
1327 	int ret;
1328 
1329 	if (ds1307->type != ds_3231)
1330 		return;
1331 
1332 	ret = ds3231_clks_register(ds1307);
1333 	if (ret) {
1334 		dev_warn(ds1307->dev, "unable to register clock device %d\n",
1335 			 ret);
1336 	}
1337 }
1338 
1339 #else
1340 
1341 static void ds1307_clks_register(struct ds1307 *ds1307)
1342 {
1343 }
1344 
1345 #endif /* CONFIG_COMMON_CLK */
1346 
1347 static const struct regmap_config regmap_config = {
1348 	.reg_bits = 8,
1349 	.val_bits = 8,
1350 };
1351 
1352 static int ds1307_probe(struct i2c_client *client,
1353 			const struct i2c_device_id *id)
1354 {
1355 	struct ds1307		*ds1307;
1356 	int			err = -ENODEV;
1357 	int			tmp, wday;
1358 	const struct chip_desc	*chip;
1359 	bool			want_irq;
1360 	bool			ds1307_can_wakeup_device = false;
1361 	unsigned char		regs[8];
1362 	struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1363 	struct rtc_time		tm;
1364 	unsigned long		timestamp;
1365 	u8			trickle_charger_setup = 0;
1366 
1367 	ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1368 	if (!ds1307)
1369 		return -ENOMEM;
1370 
1371 	dev_set_drvdata(&client->dev, ds1307);
1372 	ds1307->dev = &client->dev;
1373 	ds1307->name = client->name;
1374 
1375 	ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1376 	if (IS_ERR(ds1307->regmap)) {
1377 		dev_err(ds1307->dev, "regmap allocation failed\n");
1378 		return PTR_ERR(ds1307->regmap);
1379 	}
1380 
1381 	i2c_set_clientdata(client, ds1307);
1382 
1383 	if (client->dev.of_node) {
1384 		ds1307->type = (enum ds_type)
1385 			of_device_get_match_data(&client->dev);
1386 		chip = &chips[ds1307->type];
1387 	} else if (id) {
1388 		chip = &chips[id->driver_data];
1389 		ds1307->type = id->driver_data;
1390 	} else {
1391 		const struct acpi_device_id *acpi_id;
1392 
1393 		acpi_id = acpi_match_device(ACPI_PTR(ds1307_acpi_ids),
1394 					    ds1307->dev);
1395 		if (!acpi_id)
1396 			return -ENODEV;
1397 		chip = &chips[acpi_id->driver_data];
1398 		ds1307->type = acpi_id->driver_data;
1399 	}
1400 
1401 	want_irq = client->irq > 0 && chip->alarm;
1402 
1403 	if (!pdata)
1404 		trickle_charger_setup = ds1307_trickle_init(ds1307, chip);
1405 	else if (pdata->trickle_charger_setup)
1406 		trickle_charger_setup = pdata->trickle_charger_setup;
1407 
1408 	if (trickle_charger_setup && chip->trickle_charger_reg) {
1409 		trickle_charger_setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
1410 		dev_dbg(ds1307->dev,
1411 			"writing trickle charger info 0x%x to 0x%x\n",
1412 			trickle_charger_setup, chip->trickle_charger_reg);
1413 		regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1414 			     trickle_charger_setup);
1415 	}
1416 
1417 #ifdef CONFIG_OF
1418 /*
1419  * For devices with no IRQ directly connected to the SoC, the RTC chip
1420  * can be forced as a wakeup source by stating that explicitly in
1421  * the device's .dts file using the "wakeup-source" boolean property.
1422  * If the "wakeup-source" property is set, don't request an IRQ.
1423  * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1424  * if supported by the RTC.
1425  */
1426 	if (chip->alarm && of_property_read_bool(client->dev.of_node,
1427 						 "wakeup-source"))
1428 		ds1307_can_wakeup_device = true;
1429 #endif
1430 
1431 	switch (ds1307->type) {
1432 	case ds_1337:
1433 	case ds_1339:
1434 	case ds_1341:
1435 	case ds_3231:
1436 		/* get registers that the "rtc" read below won't read... */
1437 		err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1438 				       regs, 2);
1439 		if (err) {
1440 			dev_dbg(ds1307->dev, "read error %d\n", err);
1441 			goto exit;
1442 		}
1443 
1444 		/* oscillator off?  turn it on, so clock can tick. */
1445 		if (regs[0] & DS1337_BIT_nEOSC)
1446 			regs[0] &= ~DS1337_BIT_nEOSC;
1447 
1448 		/*
1449 		 * Using IRQ or defined as wakeup-source?
1450 		 * Disable the square wave and both alarms.
1451 		 * For some variants, be sure alarms can trigger when we're
1452 		 * running on Vbackup (BBSQI/BBSQW)
1453 		 */
1454 		if (want_irq || ds1307_can_wakeup_device) {
1455 			regs[0] |= DS1337_BIT_INTCN | chip->bbsqi_bit;
1456 			regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1457 		}
1458 
1459 		regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1460 			     regs[0]);
1461 
1462 		/* oscillator fault?  clear flag, and warn */
1463 		if (regs[1] & DS1337_BIT_OSF) {
1464 			regmap_write(ds1307->regmap, DS1337_REG_STATUS,
1465 				     regs[1] & ~DS1337_BIT_OSF);
1466 			dev_warn(ds1307->dev, "SET TIME!\n");
1467 		}
1468 		break;
1469 
1470 	case rx_8025:
1471 		err = regmap_bulk_read(ds1307->regmap,
1472 				       RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
1473 		if (err) {
1474 			dev_dbg(ds1307->dev, "read error %d\n", err);
1475 			goto exit;
1476 		}
1477 
1478 		/* oscillator off?  turn it on, so clock can tick. */
1479 		if (!(regs[1] & RX8025_BIT_XST)) {
1480 			regs[1] |= RX8025_BIT_XST;
1481 			regmap_write(ds1307->regmap,
1482 				     RX8025_REG_CTRL2 << 4 | 0x08,
1483 				     regs[1]);
1484 			dev_warn(ds1307->dev,
1485 				 "oscillator stop detected - SET TIME!\n");
1486 		}
1487 
1488 		if (regs[1] & RX8025_BIT_PON) {
1489 			regs[1] &= ~RX8025_BIT_PON;
1490 			regmap_write(ds1307->regmap,
1491 				     RX8025_REG_CTRL2 << 4 | 0x08,
1492 				     regs[1]);
1493 			dev_warn(ds1307->dev, "power-on detected\n");
1494 		}
1495 
1496 		if (regs[1] & RX8025_BIT_VDET) {
1497 			regs[1] &= ~RX8025_BIT_VDET;
1498 			regmap_write(ds1307->regmap,
1499 				     RX8025_REG_CTRL2 << 4 | 0x08,
1500 				     regs[1]);
1501 			dev_warn(ds1307->dev, "voltage drop detected\n");
1502 		}
1503 
1504 		/* make sure we are running in 24hour mode */
1505 		if (!(regs[0] & RX8025_BIT_2412)) {
1506 			u8 hour;
1507 
1508 			/* switch to 24 hour mode */
1509 			regmap_write(ds1307->regmap,
1510 				     RX8025_REG_CTRL1 << 4 | 0x08,
1511 				     regs[0] | RX8025_BIT_2412);
1512 
1513 			err = regmap_bulk_read(ds1307->regmap,
1514 					       RX8025_REG_CTRL1 << 4 | 0x08,
1515 					       regs, 2);
1516 			if (err) {
1517 				dev_dbg(ds1307->dev, "read error %d\n", err);
1518 				goto exit;
1519 			}
1520 
1521 			/* correct hour */
1522 			hour = bcd2bin(regs[DS1307_REG_HOUR]);
1523 			if (hour == 12)
1524 				hour = 0;
1525 			if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1526 				hour += 12;
1527 
1528 			regmap_write(ds1307->regmap,
1529 				     DS1307_REG_HOUR << 4 | 0x08, hour);
1530 		}
1531 		break;
1532 	default:
1533 		break;
1534 	}
1535 
1536 read_rtc:
1537 	/* read RTC registers */
1538 	err = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
1539 			       sizeof(regs));
1540 	if (err) {
1541 		dev_dbg(ds1307->dev, "read error %d\n", err);
1542 		goto exit;
1543 	}
1544 
1545 	/*
1546 	 * minimal sanity checking; some chips (like DS1340) don't
1547 	 * specify the extra bits as must-be-zero, but there are
1548 	 * still a few values that are clearly out-of-range.
1549 	 */
1550 	tmp = regs[DS1307_REG_SECS];
1551 	switch (ds1307->type) {
1552 	case ds_1307:
1553 	case m41t0:
1554 	case m41t00:
1555 		/* clock halted?  turn it on, so clock can tick. */
1556 		if (tmp & DS1307_BIT_CH) {
1557 			regmap_write(ds1307->regmap, DS1307_REG_SECS, 0);
1558 			dev_warn(ds1307->dev, "SET TIME!\n");
1559 			goto read_rtc;
1560 		}
1561 		break;
1562 	case ds_1308:
1563 	case ds_1338:
1564 		/* clock halted?  turn it on, so clock can tick. */
1565 		if (tmp & DS1307_BIT_CH)
1566 			regmap_write(ds1307->regmap, DS1307_REG_SECS, 0);
1567 
1568 		/* oscillator fault?  clear flag, and warn */
1569 		if (regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1570 			regmap_write(ds1307->regmap, DS1307_REG_CONTROL,
1571 				     regs[DS1307_REG_CONTROL] &
1572 				     ~DS1338_BIT_OSF);
1573 			dev_warn(ds1307->dev, "SET TIME!\n");
1574 			goto read_rtc;
1575 		}
1576 		break;
1577 	case ds_1340:
1578 		/* clock halted?  turn it on, so clock can tick. */
1579 		if (tmp & DS1340_BIT_nEOSC)
1580 			regmap_write(ds1307->regmap, DS1307_REG_SECS, 0);
1581 
1582 		err = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
1583 		if (err) {
1584 			dev_dbg(ds1307->dev, "read error %d\n", err);
1585 			goto exit;
1586 		}
1587 
1588 		/* oscillator fault?  clear flag, and warn */
1589 		if (tmp & DS1340_BIT_OSF) {
1590 			regmap_write(ds1307->regmap, DS1340_REG_FLAG, 0);
1591 			dev_warn(ds1307->dev, "SET TIME!\n");
1592 		}
1593 		break;
1594 	case mcp794xx:
1595 		/* make sure that the backup battery is enabled */
1596 		if (!(regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1597 			regmap_write(ds1307->regmap, DS1307_REG_WDAY,
1598 				     regs[DS1307_REG_WDAY] |
1599 				     MCP794XX_BIT_VBATEN);
1600 		}
1601 
1602 		/* clock halted?  turn it on, so clock can tick. */
1603 		if (!(tmp & MCP794XX_BIT_ST)) {
1604 			regmap_write(ds1307->regmap, DS1307_REG_SECS,
1605 				     MCP794XX_BIT_ST);
1606 			dev_warn(ds1307->dev, "SET TIME!\n");
1607 			goto read_rtc;
1608 		}
1609 
1610 		break;
1611 	default:
1612 		break;
1613 	}
1614 
1615 	tmp = regs[DS1307_REG_HOUR];
1616 	switch (ds1307->type) {
1617 	case ds_1340:
1618 	case m41t0:
1619 	case m41t00:
1620 		/*
1621 		 * NOTE: ignores century bits; fix before deploying
1622 		 * systems that will run through year 2100.
1623 		 */
1624 		break;
1625 	case rx_8025:
1626 		break;
1627 	default:
1628 		if (!(tmp & DS1307_BIT_12HR))
1629 			break;
1630 
1631 		/*
1632 		 * Be sure we're in 24 hour mode.  Multi-master systems
1633 		 * take note...
1634 		 */
1635 		tmp = bcd2bin(tmp & 0x1f);
1636 		if (tmp == 12)
1637 			tmp = 0;
1638 		if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1639 			tmp += 12;
1640 		regmap_write(ds1307->regmap, chip->offset + DS1307_REG_HOUR,
1641 			     bin2bcd(tmp));
1642 	}
1643 
1644 	/*
1645 	 * Some IPs have weekday reset value = 0x1 which might not correct
1646 	 * hence compute the wday using the current date/month/year values
1647 	 */
1648 	ds1307_get_time(ds1307->dev, &tm);
1649 	wday = tm.tm_wday;
1650 	timestamp = rtc_tm_to_time64(&tm);
1651 	rtc_time64_to_tm(timestamp, &tm);
1652 
1653 	/*
1654 	 * Check if reset wday is different from the computed wday
1655 	 * If different then set the wday which we computed using
1656 	 * timestamp
1657 	 */
1658 	if (wday != tm.tm_wday)
1659 		regmap_update_bits(ds1307->regmap, MCP794XX_REG_WEEKDAY,
1660 				   MCP794XX_REG_WEEKDAY_WDAY_MASK,
1661 				   tm.tm_wday + 1);
1662 
1663 	if (want_irq || ds1307_can_wakeup_device) {
1664 		device_set_wakeup_capable(ds1307->dev, true);
1665 		set_bit(HAS_ALARM, &ds1307->flags);
1666 	}
1667 
1668 	ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
1669 	if (IS_ERR(ds1307->rtc))
1670 		return PTR_ERR(ds1307->rtc);
1671 
1672 	if (ds1307_can_wakeup_device && !want_irq) {
1673 		dev_info(ds1307->dev,
1674 			 "'wakeup-source' is set, request for an IRQ is disabled!\n");
1675 		/* We cannot support UIE mode if we do not have an IRQ line */
1676 		ds1307->rtc->uie_unsupported = 1;
1677 	}
1678 
1679 	if (want_irq) {
1680 		err = devm_request_threaded_irq(ds1307->dev, client->irq, NULL,
1681 						chip->irq_handler ?: ds1307_irq,
1682 						IRQF_SHARED | IRQF_ONESHOT,
1683 						ds1307->name, ds1307);
1684 		if (err) {
1685 			client->irq = 0;
1686 			device_set_wakeup_capable(ds1307->dev, false);
1687 			clear_bit(HAS_ALARM, &ds1307->flags);
1688 			dev_err(ds1307->dev, "unable to request IRQ!\n");
1689 		} else {
1690 			dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
1691 		}
1692 	}
1693 
1694 	if (chip->nvram_size) {
1695 		ds1307->nvmem_cfg.name = "ds1307_nvram";
1696 		ds1307->nvmem_cfg.word_size = 1;
1697 		ds1307->nvmem_cfg.stride = 1;
1698 		ds1307->nvmem_cfg.size = chip->nvram_size;
1699 		ds1307->nvmem_cfg.reg_read = ds1307_nvram_read;
1700 		ds1307->nvmem_cfg.reg_write = ds1307_nvram_write;
1701 		ds1307->nvmem_cfg.priv = ds1307;
1702 
1703 		ds1307->rtc->nvmem_config = &ds1307->nvmem_cfg;
1704 		ds1307->rtc->nvram_old_abi = true;
1705 	}
1706 
1707 	ds1307->rtc->ops = chip->rtc_ops ?: &ds13xx_rtc_ops;
1708 	err = rtc_register_device(ds1307->rtc);
1709 	if (err)
1710 		return err;
1711 
1712 	ds1307_hwmon_register(ds1307);
1713 	ds1307_clks_register(ds1307);
1714 
1715 	return 0;
1716 
1717 exit:
1718 	return err;
1719 }
1720 
1721 static struct i2c_driver ds1307_driver = {
1722 	.driver = {
1723 		.name	= "rtc-ds1307",
1724 		.of_match_table = of_match_ptr(ds1307_of_match),
1725 		.acpi_match_table = ACPI_PTR(ds1307_acpi_ids),
1726 	},
1727 	.probe		= ds1307_probe,
1728 	.id_table	= ds1307_id,
1729 };
1730 
1731 module_i2c_driver(ds1307_driver);
1732 
1733 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1734 MODULE_LICENSE("GPL");
1735