xref: /linux/drivers/rtc/rtc-ds1307.c (revision d257f9bf06129613de539ea71ecea60848b662cd)
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_1388,
43 	ds_3231,
44 	m41t0,
45 	m41t00,
46 	mcp794xx,
47 	rx_8025,
48 	rx_8130,
49 	last_ds_type /* always last */
50 	/* rs5c372 too?  different address... */
51 };
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 
117 struct ds1307 {
118 	u8			offset; /* register's offset */
119 	u8			regs[11];
120 	u16			nvram_offset;
121 	struct nvmem_config	nvmem_cfg;
122 	enum ds_type		type;
123 	unsigned long		flags;
124 #define HAS_NVRAM	0		/* bit 0 == sysfs file active */
125 #define HAS_ALARM	1		/* bit 1 == irq claimed */
126 	struct device		*dev;
127 	struct regmap		*regmap;
128 	const char		*name;
129 	int			irq;
130 	struct rtc_device	*rtc;
131 #ifdef CONFIG_COMMON_CLK
132 	struct clk_hw		clks[2];
133 #endif
134 };
135 
136 struct chip_desc {
137 	unsigned		alarm:1;
138 	u16			nvram_offset;
139 	u16			nvram_size;
140 	u8			century_reg;
141 	u8			century_enable_bit;
142 	u8			century_bit;
143 	u16			trickle_charger_reg;
144 	u8			trickle_charger_setup;
145 	u8			(*do_trickle_setup)(struct ds1307 *, uint32_t,
146 						    bool);
147 };
148 
149 static u8 do_trickle_setup_ds1339(struct ds1307 *, uint32_t ohms, bool diode);
150 
151 static struct chip_desc chips[last_ds_type] = {
152 	[ds_1307] = {
153 		.nvram_offset	= 8,
154 		.nvram_size	= 56,
155 	},
156 	[ds_1308] = {
157 		.nvram_offset	= 8,
158 		.nvram_size	= 56,
159 	},
160 	[ds_1337] = {
161 		.alarm		= 1,
162 		.century_reg	= DS1307_REG_MONTH,
163 		.century_bit	= DS1337_BIT_CENTURY,
164 	},
165 	[ds_1338] = {
166 		.nvram_offset	= 8,
167 		.nvram_size	= 56,
168 	},
169 	[ds_1339] = {
170 		.alarm		= 1,
171 		.century_reg	= DS1307_REG_MONTH,
172 		.century_bit	= DS1337_BIT_CENTURY,
173 		.trickle_charger_reg = 0x10,
174 		.do_trickle_setup = &do_trickle_setup_ds1339,
175 	},
176 	[ds_1340] = {
177 		.century_reg	= DS1307_REG_HOUR,
178 		.century_enable_bit = DS1340_BIT_CENTURY_EN,
179 		.century_bit	= DS1340_BIT_CENTURY,
180 		.trickle_charger_reg = 0x08,
181 	},
182 	[ds_1388] = {
183 		.trickle_charger_reg = 0x0a,
184 	},
185 	[ds_3231] = {
186 		.alarm		= 1,
187 		.century_reg	= DS1307_REG_MONTH,
188 		.century_bit	= DS1337_BIT_CENTURY,
189 	},
190 	[rx_8130] = {
191 		.alarm		= 1,
192 		/* this is battery backed SRAM */
193 		.nvram_offset	= 0x20,
194 		.nvram_size	= 4,	/* 32bit (4 word x 8 bit) */
195 	},
196 	[mcp794xx] = {
197 		.alarm		= 1,
198 		/* this is battery backed SRAM */
199 		.nvram_offset	= 0x20,
200 		.nvram_size	= 0x40,
201 	},
202 };
203 
204 static const struct i2c_device_id ds1307_id[] = {
205 	{ "ds1307", ds_1307 },
206 	{ "ds1308", ds_1308 },
207 	{ "ds1337", ds_1337 },
208 	{ "ds1338", ds_1338 },
209 	{ "ds1339", ds_1339 },
210 	{ "ds1388", ds_1388 },
211 	{ "ds1340", ds_1340 },
212 	{ "ds3231", ds_3231 },
213 	{ "m41t0", m41t0 },
214 	{ "m41t00", m41t00 },
215 	{ "mcp7940x", mcp794xx },
216 	{ "mcp7941x", mcp794xx },
217 	{ "pt7c4338", ds_1307 },
218 	{ "rx8025", rx_8025 },
219 	{ "isl12057", ds_1337 },
220 	{ "rx8130", rx_8130 },
221 	{ }
222 };
223 MODULE_DEVICE_TABLE(i2c, ds1307_id);
224 
225 #ifdef CONFIG_OF
226 static const struct of_device_id ds1307_of_match[] = {
227 	{
228 		.compatible = "dallas,ds1307",
229 		.data = (void *)ds_1307
230 	},
231 	{
232 		.compatible = "dallas,ds1308",
233 		.data = (void *)ds_1308
234 	},
235 	{
236 		.compatible = "dallas,ds1337",
237 		.data = (void *)ds_1337
238 	},
239 	{
240 		.compatible = "dallas,ds1338",
241 		.data = (void *)ds_1338
242 	},
243 	{
244 		.compatible = "dallas,ds1339",
245 		.data = (void *)ds_1339
246 	},
247 	{
248 		.compatible = "dallas,ds1388",
249 		.data = (void *)ds_1388
250 	},
251 	{
252 		.compatible = "dallas,ds1340",
253 		.data = (void *)ds_1340
254 	},
255 	{
256 		.compatible = "maxim,ds3231",
257 		.data = (void *)ds_3231
258 	},
259 	{
260 		.compatible = "st,m41t0",
261 		.data = (void *)m41t00
262 	},
263 	{
264 		.compatible = "st,m41t00",
265 		.data = (void *)m41t00
266 	},
267 	{
268 		.compatible = "microchip,mcp7940x",
269 		.data = (void *)mcp794xx
270 	},
271 	{
272 		.compatible = "microchip,mcp7941x",
273 		.data = (void *)mcp794xx
274 	},
275 	{
276 		.compatible = "pericom,pt7c4338",
277 		.data = (void *)ds_1307
278 	},
279 	{
280 		.compatible = "epson,rx8025",
281 		.data = (void *)rx_8025
282 	},
283 	{
284 		.compatible = "isil,isl12057",
285 		.data = (void *)ds_1337
286 	},
287 	{ }
288 };
289 MODULE_DEVICE_TABLE(of, ds1307_of_match);
290 #endif
291 
292 #ifdef CONFIG_ACPI
293 static const struct acpi_device_id ds1307_acpi_ids[] = {
294 	{ .id = "DS1307", .driver_data = ds_1307 },
295 	{ .id = "DS1308", .driver_data = ds_1308 },
296 	{ .id = "DS1337", .driver_data = ds_1337 },
297 	{ .id = "DS1338", .driver_data = ds_1338 },
298 	{ .id = "DS1339", .driver_data = ds_1339 },
299 	{ .id = "DS1388", .driver_data = ds_1388 },
300 	{ .id = "DS1340", .driver_data = ds_1340 },
301 	{ .id = "DS3231", .driver_data = ds_3231 },
302 	{ .id = "M41T0", .driver_data = m41t0 },
303 	{ .id = "M41T00", .driver_data = m41t00 },
304 	{ .id = "MCP7940X", .driver_data = mcp794xx },
305 	{ .id = "MCP7941X", .driver_data = mcp794xx },
306 	{ .id = "PT7C4338", .driver_data = ds_1307 },
307 	{ .id = "RX8025", .driver_data = rx_8025 },
308 	{ .id = "ISL12057", .driver_data = ds_1337 },
309 	{ }
310 };
311 MODULE_DEVICE_TABLE(acpi, ds1307_acpi_ids);
312 #endif
313 
314 /*
315  * The ds1337 and ds1339 both have two alarms, but we only use the first
316  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
317  * signal; ds1339 chips have only one alarm signal.
318  */
319 static irqreturn_t ds1307_irq(int irq, void *dev_id)
320 {
321 	struct ds1307		*ds1307 = dev_id;
322 	struct mutex		*lock = &ds1307->rtc->ops_lock;
323 	int			stat, ret;
324 
325 	mutex_lock(lock);
326 	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
327 	if (ret)
328 		goto out;
329 
330 	if (stat & DS1337_BIT_A1I) {
331 		stat &= ~DS1337_BIT_A1I;
332 		regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
333 
334 		ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
335 					 DS1337_BIT_A1IE, 0);
336 		if (ret)
337 			goto out;
338 
339 		rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
340 	}
341 
342 out:
343 	mutex_unlock(lock);
344 
345 	return IRQ_HANDLED;
346 }
347 
348 /*----------------------------------------------------------------------*/
349 
350 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
351 {
352 	struct ds1307	*ds1307 = dev_get_drvdata(dev);
353 	int		tmp, ret;
354 	const struct chip_desc *chip = &chips[ds1307->type];
355 
356 	/* read the RTC date and time registers all at once */
357 	ret = regmap_bulk_read(ds1307->regmap, ds1307->offset, ds1307->regs, 7);
358 	if (ret) {
359 		dev_err(dev, "%s error %d\n", "read", ret);
360 		return ret;
361 	}
362 
363 	dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
364 
365 	/* if oscillator fail bit is set, no data can be trusted */
366 	if (ds1307->type == m41t0 &&
367 	    ds1307->regs[DS1307_REG_MIN] & M41T0_BIT_OF) {
368 		dev_warn_once(dev, "oscillator failed, set time!\n");
369 		return -EINVAL;
370 	}
371 
372 	t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
373 	t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
374 	tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
375 	t->tm_hour = bcd2bin(tmp);
376 	t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
377 	t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
378 	tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
379 	t->tm_mon = bcd2bin(tmp) - 1;
380 	t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
381 
382 	if (ds1307->regs[chip->century_reg] & chip->century_bit &&
383 	    IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
384 		t->tm_year += 100;
385 
386 	dev_dbg(dev, "%s secs=%d, mins=%d, "
387 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
388 		"read", t->tm_sec, t->tm_min,
389 		t->tm_hour, t->tm_mday,
390 		t->tm_mon, t->tm_year, t->tm_wday);
391 
392 	/* initial clock setting can be undefined */
393 	return rtc_valid_tm(t);
394 }
395 
396 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
397 {
398 	struct ds1307	*ds1307 = dev_get_drvdata(dev);
399 	const struct chip_desc *chip = &chips[ds1307->type];
400 	int		result;
401 	int		tmp;
402 	u8		*buf = ds1307->regs;
403 
404 	dev_dbg(dev, "%s secs=%d, mins=%d, "
405 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
406 		"write", t->tm_sec, t->tm_min,
407 		t->tm_hour, t->tm_mday,
408 		t->tm_mon, t->tm_year, t->tm_wday);
409 
410 	if (t->tm_year < 100)
411 		return -EINVAL;
412 
413 #ifdef CONFIG_RTC_DRV_DS1307_CENTURY
414 	if (t->tm_year > (chip->century_bit ? 299 : 199))
415 		return -EINVAL;
416 #else
417 	if (t->tm_year > 199)
418 		return -EINVAL;
419 #endif
420 
421 	buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
422 	buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
423 	buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
424 	buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
425 	buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
426 	buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
427 
428 	/* assume 20YY not 19YY */
429 	tmp = t->tm_year - 100;
430 	buf[DS1307_REG_YEAR] = bin2bcd(tmp);
431 
432 	if (chip->century_enable_bit)
433 		buf[chip->century_reg] |= chip->century_enable_bit;
434 	if (t->tm_year > 199 && chip->century_bit)
435 		buf[chip->century_reg] |= chip->century_bit;
436 
437 	if (ds1307->type == mcp794xx) {
438 		/*
439 		 * these bits were cleared when preparing the date/time
440 		 * values and need to be set again before writing the
441 		 * buffer out to the device.
442 		 */
443 		buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
444 		buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
445 	}
446 
447 	dev_dbg(dev, "%s: %7ph\n", "write", buf);
448 
449 	result = regmap_bulk_write(ds1307->regmap, ds1307->offset, buf, 7);
450 	if (result) {
451 		dev_err(dev, "%s error %d\n", "write", result);
452 		return result;
453 	}
454 	return 0;
455 }
456 
457 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
458 {
459 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
460 	int			ret;
461 
462 	if (!test_bit(HAS_ALARM, &ds1307->flags))
463 		return -EINVAL;
464 
465 	/* read all ALARM1, ALARM2, and status registers at once */
466 	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
467 			       ds1307->regs, 9);
468 	if (ret) {
469 		dev_err(dev, "%s error %d\n", "alarm read", ret);
470 		return ret;
471 	}
472 
473 	dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
474 		&ds1307->regs[0], &ds1307->regs[4], &ds1307->regs[7]);
475 
476 	/*
477 	 * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
478 	 * and that all four fields are checked matches
479 	 */
480 	t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
481 	t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
482 	t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
483 	t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
484 
485 	/* ... and status */
486 	t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
487 	t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
488 
489 	dev_dbg(dev, "%s secs=%d, mins=%d, "
490 		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
491 		"alarm read", t->time.tm_sec, t->time.tm_min,
492 		t->time.tm_hour, t->time.tm_mday,
493 		t->enabled, t->pending);
494 
495 	return 0;
496 }
497 
498 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
499 {
500 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
501 	unsigned char		*buf = ds1307->regs;
502 	u8			control, status;
503 	int			ret;
504 
505 	if (!test_bit(HAS_ALARM, &ds1307->flags))
506 		return -EINVAL;
507 
508 	dev_dbg(dev, "%s secs=%d, mins=%d, "
509 		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
510 		"alarm set", t->time.tm_sec, t->time.tm_min,
511 		t->time.tm_hour, t->time.tm_mday,
512 		t->enabled, t->pending);
513 
514 	/* read current status of both alarms and the chip */
515 	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, buf, 9);
516 	if (ret) {
517 		dev_err(dev, "%s error %d\n", "alarm write", ret);
518 		return ret;
519 	}
520 	control = ds1307->regs[7];
521 	status = ds1307->regs[8];
522 
523 	dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
524 		&ds1307->regs[0], &ds1307->regs[4], control, status);
525 
526 	/* set ALARM1, using 24 hour and day-of-month modes */
527 	buf[0] = bin2bcd(t->time.tm_sec);
528 	buf[1] = bin2bcd(t->time.tm_min);
529 	buf[2] = bin2bcd(t->time.tm_hour);
530 	buf[3] = bin2bcd(t->time.tm_mday);
531 
532 	/* set ALARM2 to non-garbage */
533 	buf[4] = 0;
534 	buf[5] = 0;
535 	buf[6] = 0;
536 
537 	/* disable alarms */
538 	buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
539 	buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
540 
541 	ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, buf, 9);
542 	if (ret) {
543 		dev_err(dev, "can't set alarm time\n");
544 		return ret;
545 	}
546 
547 	/* optionally enable ALARM1 */
548 	if (t->enabled) {
549 		dev_dbg(dev, "alarm IRQ armed\n");
550 		buf[7] |= DS1337_BIT_A1IE;	/* only ALARM1 is used */
551 		regmap_write(ds1307->regmap, DS1337_REG_CONTROL, buf[7]);
552 	}
553 
554 	return 0;
555 }
556 
557 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
558 {
559 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
560 
561 	if (!test_bit(HAS_ALARM, &ds1307->flags))
562 		return -ENOTTY;
563 
564 	return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
565 				  DS1337_BIT_A1IE,
566 				  enabled ? DS1337_BIT_A1IE : 0);
567 }
568 
569 static const struct rtc_class_ops ds13xx_rtc_ops = {
570 	.read_time	= ds1307_get_time,
571 	.set_time	= ds1307_set_time,
572 	.read_alarm	= ds1337_read_alarm,
573 	.set_alarm	= ds1337_set_alarm,
574 	.alarm_irq_enable = ds1307_alarm_irq_enable,
575 };
576 
577 /*----------------------------------------------------------------------*/
578 
579 /*
580  * Alarm support for rx8130 devices.
581  */
582 
583 #define RX8130_REG_ALARM_MIN		0x07
584 #define RX8130_REG_ALARM_HOUR		0x08
585 #define RX8130_REG_ALARM_WEEK_OR_DAY	0x09
586 #define RX8130_REG_EXTENSION		0x0c
587 #define RX8130_REG_EXTENSION_WADA	(1 << 3)
588 #define RX8130_REG_FLAG			0x0d
589 #define RX8130_REG_FLAG_AF		(1 << 3)
590 #define RX8130_REG_CONTROL0		0x0e
591 #define RX8130_REG_CONTROL0_AIE		(1 << 3)
592 
593 static irqreturn_t rx8130_irq(int irq, void *dev_id)
594 {
595 	struct ds1307           *ds1307 = dev_id;
596 	struct mutex            *lock = &ds1307->rtc->ops_lock;
597 	u8 ctl[3];
598 	int ret;
599 
600 	mutex_lock(lock);
601 
602 	/* Read control registers. */
603 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl, 3);
604 	if (ret < 0)
605 		goto out;
606 	if (!(ctl[1] & RX8130_REG_FLAG_AF))
607 		goto out;
608 	ctl[1] &= ~RX8130_REG_FLAG_AF;
609 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
610 
611 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl, 3);
612 	if (ret < 0)
613 		goto out;
614 
615 	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
616 
617 out:
618 	mutex_unlock(lock);
619 
620 	return IRQ_HANDLED;
621 }
622 
623 static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
624 {
625 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
626 	u8 ald[3], ctl[3];
627 	int ret;
628 
629 	if (!test_bit(HAS_ALARM, &ds1307->flags))
630 		return -EINVAL;
631 
632 	/* Read alarm registers. */
633 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald, 3);
634 	if (ret < 0)
635 		return ret;
636 
637 	/* Read control registers. */
638 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl, 3);
639 	if (ret < 0)
640 		return ret;
641 
642 	t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
643 	t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
644 
645 	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
646 	t->time.tm_sec = -1;
647 	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
648 	t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
649 	t->time.tm_wday = -1;
650 	t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
651 	t->time.tm_mon = -1;
652 	t->time.tm_year = -1;
653 	t->time.tm_yday = -1;
654 	t->time.tm_isdst = -1;
655 
656 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
657 		__func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
658 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
659 
660 	return 0;
661 }
662 
663 static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
664 {
665 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
666 	u8 ald[3], ctl[3];
667 	int ret;
668 
669 	if (!test_bit(HAS_ALARM, &ds1307->flags))
670 		return -EINVAL;
671 
672 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
673 		"enabled=%d pending=%d\n", __func__,
674 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
675 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
676 		t->enabled, t->pending);
677 
678 	/* Read control registers. */
679 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl, 3);
680 	if (ret < 0)
681 		return ret;
682 
683 	ctl[0] &= ~RX8130_REG_EXTENSION_WADA;
684 	ctl[1] |= RX8130_REG_FLAG_AF;
685 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
686 
687 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl, 3);
688 	if (ret < 0)
689 		return ret;
690 
691 	/* Hardware alarm precision is 1 minute! */
692 	ald[0] = bin2bcd(t->time.tm_min);
693 	ald[1] = bin2bcd(t->time.tm_hour);
694 	ald[2] = bin2bcd(t->time.tm_mday);
695 
696 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald, 3);
697 	if (ret < 0)
698 		return ret;
699 
700 	if (!t->enabled)
701 		return 0;
702 
703 	ctl[2] |= RX8130_REG_CONTROL0_AIE;
704 
705 	return regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl, 3);
706 }
707 
708 static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
709 {
710 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
711 	int ret, reg;
712 
713 	if (!test_bit(HAS_ALARM, &ds1307->flags))
714 		return -EINVAL;
715 
716 	ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
717 	if (ret < 0)
718 		return ret;
719 
720 	if (enabled)
721 		reg |= RX8130_REG_CONTROL0_AIE;
722 	else
723 		reg &= ~RX8130_REG_CONTROL0_AIE;
724 
725 	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
726 }
727 
728 static const struct rtc_class_ops rx8130_rtc_ops = {
729 	.read_time	= ds1307_get_time,
730 	.set_time	= ds1307_set_time,
731 	.read_alarm	= rx8130_read_alarm,
732 	.set_alarm	= rx8130_set_alarm,
733 	.alarm_irq_enable = rx8130_alarm_irq_enable,
734 };
735 
736 /*----------------------------------------------------------------------*/
737 
738 /*
739  * Alarm support for mcp794xx devices.
740  */
741 
742 #define MCP794XX_REG_WEEKDAY		0x3
743 #define MCP794XX_REG_WEEKDAY_WDAY_MASK	0x7
744 #define MCP794XX_REG_CONTROL		0x07
745 #	define MCP794XX_BIT_ALM0_EN	0x10
746 #	define MCP794XX_BIT_ALM1_EN	0x20
747 #define MCP794XX_REG_ALARM0_BASE	0x0a
748 #define MCP794XX_REG_ALARM0_CTRL	0x0d
749 #define MCP794XX_REG_ALARM1_BASE	0x11
750 #define MCP794XX_REG_ALARM1_CTRL	0x14
751 #	define MCP794XX_BIT_ALMX_IF	(1 << 3)
752 #	define MCP794XX_BIT_ALMX_C0	(1 << 4)
753 #	define MCP794XX_BIT_ALMX_C1	(1 << 5)
754 #	define MCP794XX_BIT_ALMX_C2	(1 << 6)
755 #	define MCP794XX_BIT_ALMX_POL	(1 << 7)
756 #	define MCP794XX_MSK_ALMX_MATCH	(MCP794XX_BIT_ALMX_C0 | \
757 					 MCP794XX_BIT_ALMX_C1 | \
758 					 MCP794XX_BIT_ALMX_C2)
759 
760 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
761 {
762 	struct ds1307           *ds1307 = dev_id;
763 	struct mutex            *lock = &ds1307->rtc->ops_lock;
764 	int reg, ret;
765 
766 	mutex_lock(lock);
767 
768 	/* Check and clear alarm 0 interrupt flag. */
769 	ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
770 	if (ret)
771 		goto out;
772 	if (!(reg & MCP794XX_BIT_ALMX_IF))
773 		goto out;
774 	reg &= ~MCP794XX_BIT_ALMX_IF;
775 	ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
776 	if (ret)
777 		goto out;
778 
779 	/* Disable alarm 0. */
780 	ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
781 				 MCP794XX_BIT_ALM0_EN, 0);
782 	if (ret)
783 		goto out;
784 
785 	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
786 
787 out:
788 	mutex_unlock(lock);
789 
790 	return IRQ_HANDLED;
791 }
792 
793 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
794 {
795 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
796 	u8 *regs = ds1307->regs;
797 	int ret;
798 
799 	if (!test_bit(HAS_ALARM, &ds1307->flags))
800 		return -EINVAL;
801 
802 	/* Read control and alarm 0 registers. */
803 	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs, 10);
804 	if (ret)
805 		return ret;
806 
807 	t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
808 
809 	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
810 	t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
811 	t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
812 	t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
813 	t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
814 	t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
815 	t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
816 	t->time.tm_year = -1;
817 	t->time.tm_yday = -1;
818 	t->time.tm_isdst = -1;
819 
820 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
821 		"enabled=%d polarity=%d irq=%d match=%d\n", __func__,
822 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
823 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
824 		!!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
825 		!!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
826 		(ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
827 
828 	return 0;
829 }
830 
831 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
832 {
833 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
834 	unsigned char *regs = ds1307->regs;
835 	int ret;
836 
837 	if (!test_bit(HAS_ALARM, &ds1307->flags))
838 		return -EINVAL;
839 
840 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
841 		"enabled=%d pending=%d\n", __func__,
842 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
843 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
844 		t->enabled, t->pending);
845 
846 	/* Read control and alarm 0 registers. */
847 	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs, 10);
848 	if (ret)
849 		return ret;
850 
851 	/* Set alarm 0, using 24-hour and day-of-month modes. */
852 	regs[3] = bin2bcd(t->time.tm_sec);
853 	regs[4] = bin2bcd(t->time.tm_min);
854 	regs[5] = bin2bcd(t->time.tm_hour);
855 	regs[6] = bin2bcd(t->time.tm_wday + 1);
856 	regs[7] = bin2bcd(t->time.tm_mday);
857 	regs[8] = bin2bcd(t->time.tm_mon + 1);
858 
859 	/* Clear the alarm 0 interrupt flag. */
860 	regs[6] &= ~MCP794XX_BIT_ALMX_IF;
861 	/* Set alarm match: second, minute, hour, day, date, month. */
862 	regs[6] |= MCP794XX_MSK_ALMX_MATCH;
863 	/* Disable interrupt. We will not enable until completely programmed */
864 	regs[0] &= ~MCP794XX_BIT_ALM0_EN;
865 
866 	ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs, 10);
867 	if (ret)
868 		return ret;
869 
870 	if (!t->enabled)
871 		return 0;
872 	regs[0] |= MCP794XX_BIT_ALM0_EN;
873 	return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
874 }
875 
876 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
877 {
878 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
879 
880 	if (!test_bit(HAS_ALARM, &ds1307->flags))
881 		return -EINVAL;
882 
883 	return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
884 				  MCP794XX_BIT_ALM0_EN,
885 				  enabled ? MCP794XX_BIT_ALM0_EN : 0);
886 }
887 
888 static const struct rtc_class_ops mcp794xx_rtc_ops = {
889 	.read_time	= ds1307_get_time,
890 	.set_time	= ds1307_set_time,
891 	.read_alarm	= mcp794xx_read_alarm,
892 	.set_alarm	= mcp794xx_set_alarm,
893 	.alarm_irq_enable = mcp794xx_alarm_irq_enable,
894 };
895 
896 /*----------------------------------------------------------------------*/
897 
898 static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
899 			     size_t bytes)
900 {
901 	struct ds1307 *ds1307 = priv;
902 
903 	return regmap_bulk_read(ds1307->regmap, ds1307->nvram_offset + offset,
904 				val, bytes);
905 }
906 
907 static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
908 			      size_t bytes)
909 {
910 	struct ds1307 *ds1307 = priv;
911 
912 	return regmap_bulk_write(ds1307->regmap, ds1307->nvram_offset + offset,
913 				 val, bytes);
914 }
915 
916 /*----------------------------------------------------------------------*/
917 
918 static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307,
919 				  uint32_t ohms, bool diode)
920 {
921 	u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
922 		DS1307_TRICKLE_CHARGER_NO_DIODE;
923 
924 	switch (ohms) {
925 	case 250:
926 		setup |= DS1307_TRICKLE_CHARGER_250_OHM;
927 		break;
928 	case 2000:
929 		setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
930 		break;
931 	case 4000:
932 		setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
933 		break;
934 	default:
935 		dev_warn(ds1307->dev,
936 			 "Unsupported ohm value %u in dt\n", ohms);
937 		return 0;
938 	}
939 	return setup;
940 }
941 
942 static void ds1307_trickle_init(struct ds1307 *ds1307,
943 				struct chip_desc *chip)
944 {
945 	uint32_t ohms = 0;
946 	bool diode = true;
947 
948 	if (!chip->do_trickle_setup)
949 		goto out;
950 	if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
951 				     &ohms))
952 		goto out;
953 	if (device_property_read_bool(ds1307->dev, "trickle-diode-disable"))
954 		diode = false;
955 	chip->trickle_charger_setup = chip->do_trickle_setup(ds1307,
956 							     ohms, diode);
957 out:
958 	return;
959 }
960 
961 /*----------------------------------------------------------------------*/
962 
963 #ifdef CONFIG_RTC_DRV_DS1307_HWMON
964 
965 /*
966  * Temperature sensor support for ds3231 devices.
967  */
968 
969 #define DS3231_REG_TEMPERATURE	0x11
970 
971 /*
972  * A user-initiated temperature conversion is not started by this function,
973  * so the temperature is updated once every 64 seconds.
974  */
975 static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
976 {
977 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
978 	u8 temp_buf[2];
979 	s16 temp;
980 	int ret;
981 
982 	ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
983 			       temp_buf, sizeof(temp_buf));
984 	if (ret)
985 		return ret;
986 	/*
987 	 * Temperature is represented as a 10-bit code with a resolution of
988 	 * 0.25 degree celsius and encoded in two's complement format.
989 	 */
990 	temp = (temp_buf[0] << 8) | temp_buf[1];
991 	temp >>= 6;
992 	*mC = temp * 250;
993 
994 	return 0;
995 }
996 
997 static ssize_t ds3231_hwmon_show_temp(struct device *dev,
998 				struct device_attribute *attr, char *buf)
999 {
1000 	int ret;
1001 	s32 temp;
1002 
1003 	ret = ds3231_hwmon_read_temp(dev, &temp);
1004 	if (ret)
1005 		return ret;
1006 
1007 	return sprintf(buf, "%d\n", temp);
1008 }
1009 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ds3231_hwmon_show_temp,
1010 			NULL, 0);
1011 
1012 static struct attribute *ds3231_hwmon_attrs[] = {
1013 	&sensor_dev_attr_temp1_input.dev_attr.attr,
1014 	NULL,
1015 };
1016 ATTRIBUTE_GROUPS(ds3231_hwmon);
1017 
1018 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1019 {
1020 	struct device *dev;
1021 
1022 	if (ds1307->type != ds_3231)
1023 		return;
1024 
1025 	dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1026 						ds1307, ds3231_hwmon_groups);
1027 	if (IS_ERR(dev)) {
1028 		dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1029 			 PTR_ERR(dev));
1030 	}
1031 }
1032 
1033 #else
1034 
1035 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1036 {
1037 }
1038 
1039 #endif /* CONFIG_RTC_DRV_DS1307_HWMON */
1040 
1041 /*----------------------------------------------------------------------*/
1042 
1043 /*
1044  * Square-wave output support for DS3231
1045  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1046  */
1047 #ifdef CONFIG_COMMON_CLK
1048 
1049 enum {
1050 	DS3231_CLK_SQW = 0,
1051 	DS3231_CLK_32KHZ,
1052 };
1053 
1054 #define clk_sqw_to_ds1307(clk)	\
1055 	container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1056 #define clk_32khz_to_ds1307(clk)	\
1057 	container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1058 
1059 static int ds3231_clk_sqw_rates[] = {
1060 	1,
1061 	1024,
1062 	4096,
1063 	8192,
1064 };
1065 
1066 static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1067 {
1068 	struct mutex *lock = &ds1307->rtc->ops_lock;
1069 	int ret;
1070 
1071 	mutex_lock(lock);
1072 	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1073 				 mask, value);
1074 	mutex_unlock(lock);
1075 
1076 	return ret;
1077 }
1078 
1079 static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1080 						unsigned long parent_rate)
1081 {
1082 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1083 	int control, ret;
1084 	int rate_sel = 0;
1085 
1086 	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1087 	if (ret)
1088 		return ret;
1089 	if (control & DS1337_BIT_RS1)
1090 		rate_sel += 1;
1091 	if (control & DS1337_BIT_RS2)
1092 		rate_sel += 2;
1093 
1094 	return ds3231_clk_sqw_rates[rate_sel];
1095 }
1096 
1097 static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1098 					unsigned long *prate)
1099 {
1100 	int i;
1101 
1102 	for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1103 		if (ds3231_clk_sqw_rates[i] <= rate)
1104 			return ds3231_clk_sqw_rates[i];
1105 	}
1106 
1107 	return 0;
1108 }
1109 
1110 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1111 					unsigned long parent_rate)
1112 {
1113 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1114 	int control = 0;
1115 	int rate_sel;
1116 
1117 	for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1118 			rate_sel++) {
1119 		if (ds3231_clk_sqw_rates[rate_sel] == rate)
1120 			break;
1121 	}
1122 
1123 	if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1124 		return -EINVAL;
1125 
1126 	if (rate_sel & 1)
1127 		control |= DS1337_BIT_RS1;
1128 	if (rate_sel & 2)
1129 		control |= DS1337_BIT_RS2;
1130 
1131 	return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1132 				control);
1133 }
1134 
1135 static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1136 {
1137 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1138 
1139 	return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1140 }
1141 
1142 static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1143 {
1144 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1145 
1146 	ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1147 }
1148 
1149 static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1150 {
1151 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1152 	int control, ret;
1153 
1154 	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1155 	if (ret)
1156 		return ret;
1157 
1158 	return !(control & DS1337_BIT_INTCN);
1159 }
1160 
1161 static const struct clk_ops ds3231_clk_sqw_ops = {
1162 	.prepare = ds3231_clk_sqw_prepare,
1163 	.unprepare = ds3231_clk_sqw_unprepare,
1164 	.is_prepared = ds3231_clk_sqw_is_prepared,
1165 	.recalc_rate = ds3231_clk_sqw_recalc_rate,
1166 	.round_rate = ds3231_clk_sqw_round_rate,
1167 	.set_rate = ds3231_clk_sqw_set_rate,
1168 };
1169 
1170 static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1171 						unsigned long parent_rate)
1172 {
1173 	return 32768;
1174 }
1175 
1176 static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1177 {
1178 	struct mutex *lock = &ds1307->rtc->ops_lock;
1179 	int ret;
1180 
1181 	mutex_lock(lock);
1182 	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1183 				 DS3231_BIT_EN32KHZ,
1184 				 enable ? DS3231_BIT_EN32KHZ : 0);
1185 	mutex_unlock(lock);
1186 
1187 	return ret;
1188 }
1189 
1190 static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1191 {
1192 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1193 
1194 	return ds3231_clk_32khz_control(ds1307, true);
1195 }
1196 
1197 static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1198 {
1199 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1200 
1201 	ds3231_clk_32khz_control(ds1307, false);
1202 }
1203 
1204 static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1205 {
1206 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1207 	int status, ret;
1208 
1209 	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1210 	if (ret)
1211 		return ret;
1212 
1213 	return !!(status & DS3231_BIT_EN32KHZ);
1214 }
1215 
1216 static const struct clk_ops ds3231_clk_32khz_ops = {
1217 	.prepare = ds3231_clk_32khz_prepare,
1218 	.unprepare = ds3231_clk_32khz_unprepare,
1219 	.is_prepared = ds3231_clk_32khz_is_prepared,
1220 	.recalc_rate = ds3231_clk_32khz_recalc_rate,
1221 };
1222 
1223 static struct clk_init_data ds3231_clks_init[] = {
1224 	[DS3231_CLK_SQW] = {
1225 		.name = "ds3231_clk_sqw",
1226 		.ops = &ds3231_clk_sqw_ops,
1227 	},
1228 	[DS3231_CLK_32KHZ] = {
1229 		.name = "ds3231_clk_32khz",
1230 		.ops = &ds3231_clk_32khz_ops,
1231 	},
1232 };
1233 
1234 static int ds3231_clks_register(struct ds1307 *ds1307)
1235 {
1236 	struct device_node *node = ds1307->dev->of_node;
1237 	struct clk_onecell_data	*onecell;
1238 	int i;
1239 
1240 	onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1241 	if (!onecell)
1242 		return -ENOMEM;
1243 
1244 	onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1245 	onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1246 				     sizeof(onecell->clks[0]), GFP_KERNEL);
1247 	if (!onecell->clks)
1248 		return -ENOMEM;
1249 
1250 	for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1251 		struct clk_init_data init = ds3231_clks_init[i];
1252 
1253 		/*
1254 		 * Interrupt signal due to alarm conditions and square-wave
1255 		 * output share same pin, so don't initialize both.
1256 		 */
1257 		if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
1258 			continue;
1259 
1260 		/* optional override of the clockname */
1261 		of_property_read_string_index(node, "clock-output-names", i,
1262 						&init.name);
1263 		ds1307->clks[i].init = &init;
1264 
1265 		onecell->clks[i] = devm_clk_register(ds1307->dev,
1266 						     &ds1307->clks[i]);
1267 		if (IS_ERR(onecell->clks[i]))
1268 			return PTR_ERR(onecell->clks[i]);
1269 	}
1270 
1271 	if (!node)
1272 		return 0;
1273 
1274 	of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1275 
1276 	return 0;
1277 }
1278 
1279 static void ds1307_clks_register(struct ds1307 *ds1307)
1280 {
1281 	int ret;
1282 
1283 	if (ds1307->type != ds_3231)
1284 		return;
1285 
1286 	ret = ds3231_clks_register(ds1307);
1287 	if (ret) {
1288 		dev_warn(ds1307->dev, "unable to register clock device %d\n",
1289 			 ret);
1290 	}
1291 }
1292 
1293 #else
1294 
1295 static void ds1307_clks_register(struct ds1307 *ds1307)
1296 {
1297 }
1298 
1299 #endif /* CONFIG_COMMON_CLK */
1300 
1301 static const struct regmap_config regmap_config = {
1302 	.reg_bits = 8,
1303 	.val_bits = 8,
1304 	.max_register = 0x12,
1305 };
1306 
1307 static int ds1307_probe(struct i2c_client *client,
1308 			const struct i2c_device_id *id)
1309 {
1310 	struct ds1307		*ds1307;
1311 	int			err = -ENODEV;
1312 	int			tmp, wday;
1313 	struct chip_desc	*chip;
1314 	bool			want_irq = false;
1315 	bool			ds1307_can_wakeup_device = false;
1316 	unsigned char		*buf;
1317 	struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1318 	struct rtc_time		tm;
1319 	unsigned long		timestamp;
1320 
1321 	irq_handler_t	irq_handler = ds1307_irq;
1322 
1323 	static const int	bbsqi_bitpos[] = {
1324 		[ds_1337] = 0,
1325 		[ds_1339] = DS1339_BIT_BBSQI,
1326 		[ds_3231] = DS3231_BIT_BBSQW,
1327 	};
1328 	const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
1329 
1330 	ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1331 	if (!ds1307)
1332 		return -ENOMEM;
1333 
1334 	dev_set_drvdata(&client->dev, ds1307);
1335 	ds1307->dev = &client->dev;
1336 	ds1307->name = client->name;
1337 	ds1307->irq = client->irq;
1338 
1339 	ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1340 	if (IS_ERR(ds1307->regmap)) {
1341 		dev_err(ds1307->dev, "regmap allocation failed\n");
1342 		return PTR_ERR(ds1307->regmap);
1343 	}
1344 
1345 	i2c_set_clientdata(client, ds1307);
1346 
1347 	if (client->dev.of_node) {
1348 		ds1307->type = (enum ds_type)
1349 			of_device_get_match_data(&client->dev);
1350 		chip = &chips[ds1307->type];
1351 	} else if (id) {
1352 		chip = &chips[id->driver_data];
1353 		ds1307->type = id->driver_data;
1354 	} else {
1355 		const struct acpi_device_id *acpi_id;
1356 
1357 		acpi_id = acpi_match_device(ACPI_PTR(ds1307_acpi_ids),
1358 					    ds1307->dev);
1359 		if (!acpi_id)
1360 			return -ENODEV;
1361 		chip = &chips[acpi_id->driver_data];
1362 		ds1307->type = acpi_id->driver_data;
1363 	}
1364 
1365 	if (!pdata)
1366 		ds1307_trickle_init(ds1307, chip);
1367 	else if (pdata->trickle_charger_setup)
1368 		chip->trickle_charger_setup = pdata->trickle_charger_setup;
1369 
1370 	if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
1371 		dev_dbg(ds1307->dev,
1372 			"writing trickle charger info 0x%x to 0x%x\n",
1373 		    DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
1374 		    chip->trickle_charger_reg);
1375 		regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1376 		    DS13XX_TRICKLE_CHARGER_MAGIC |
1377 		    chip->trickle_charger_setup);
1378 	}
1379 
1380 	buf = ds1307->regs;
1381 
1382 #ifdef CONFIG_OF
1383 /*
1384  * For devices with no IRQ directly connected to the SoC, the RTC chip
1385  * can be forced as a wakeup source by stating that explicitly in
1386  * the device's .dts file using the "wakeup-source" boolean property.
1387  * If the "wakeup-source" property is set, don't request an IRQ.
1388  * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1389  * if supported by the RTC.
1390  */
1391 	if (of_property_read_bool(client->dev.of_node, "wakeup-source")) {
1392 		ds1307_can_wakeup_device = true;
1393 	}
1394 	/* Intersil ISL12057 DT backward compatibility */
1395 	if (of_property_read_bool(client->dev.of_node,
1396 				  "isil,irq2-can-wakeup-machine")) {
1397 		ds1307_can_wakeup_device = true;
1398 	}
1399 #endif
1400 
1401 	switch (ds1307->type) {
1402 	case ds_1337:
1403 	case ds_1339:
1404 	case ds_3231:
1405 		/* get registers that the "rtc" read below won't read... */
1406 		err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1407 				       buf, 2);
1408 		if (err) {
1409 			dev_dbg(ds1307->dev, "read error %d\n", err);
1410 			goto exit;
1411 		}
1412 
1413 		/* oscillator off?  turn it on, so clock can tick. */
1414 		if (ds1307->regs[0] & DS1337_BIT_nEOSC)
1415 			ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
1416 
1417 		/*
1418 		 * Using IRQ or defined as wakeup-source?
1419 		 * Disable the square wave and both alarms.
1420 		 * For some variants, be sure alarms can trigger when we're
1421 		 * running on Vbackup (BBSQI/BBSQW)
1422 		 */
1423 		if (chip->alarm && (ds1307->irq > 0 ||
1424 				    ds1307_can_wakeup_device)) {
1425 			ds1307->regs[0] |= DS1337_BIT_INTCN
1426 					| bbsqi_bitpos[ds1307->type];
1427 			ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1428 
1429 			want_irq = true;
1430 		}
1431 
1432 		regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1433 			     ds1307->regs[0]);
1434 
1435 		/* oscillator fault?  clear flag, and warn */
1436 		if (ds1307->regs[1] & DS1337_BIT_OSF) {
1437 			regmap_write(ds1307->regmap, DS1337_REG_STATUS,
1438 				     ds1307->regs[1] & ~DS1337_BIT_OSF);
1439 			dev_warn(ds1307->dev, "SET TIME!\n");
1440 		}
1441 		break;
1442 
1443 	case rx_8025:
1444 		err = regmap_bulk_read(ds1307->regmap,
1445 				       RX8025_REG_CTRL1 << 4 | 0x08, buf, 2);
1446 		if (err) {
1447 			dev_dbg(ds1307->dev, "read error %d\n", err);
1448 			goto exit;
1449 		}
1450 
1451 		/* oscillator off?  turn it on, so clock can tick. */
1452 		if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
1453 			ds1307->regs[1] |= RX8025_BIT_XST;
1454 			regmap_write(ds1307->regmap,
1455 				     RX8025_REG_CTRL2 << 4 | 0x08,
1456 				     ds1307->regs[1]);
1457 			dev_warn(ds1307->dev,
1458 				 "oscillator stop detected - SET TIME!\n");
1459 		}
1460 
1461 		if (ds1307->regs[1] & RX8025_BIT_PON) {
1462 			ds1307->regs[1] &= ~RX8025_BIT_PON;
1463 			regmap_write(ds1307->regmap,
1464 				     RX8025_REG_CTRL2 << 4 | 0x08,
1465 				     ds1307->regs[1]);
1466 			dev_warn(ds1307->dev, "power-on detected\n");
1467 		}
1468 
1469 		if (ds1307->regs[1] & RX8025_BIT_VDET) {
1470 			ds1307->regs[1] &= ~RX8025_BIT_VDET;
1471 			regmap_write(ds1307->regmap,
1472 				     RX8025_REG_CTRL2 << 4 | 0x08,
1473 				     ds1307->regs[1]);
1474 			dev_warn(ds1307->dev, "voltage drop detected\n");
1475 		}
1476 
1477 		/* make sure we are running in 24hour mode */
1478 		if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
1479 			u8 hour;
1480 
1481 			/* switch to 24 hour mode */
1482 			regmap_write(ds1307->regmap,
1483 				     RX8025_REG_CTRL1 << 4 | 0x08,
1484 				     ds1307->regs[0] | RX8025_BIT_2412);
1485 
1486 			err = regmap_bulk_read(ds1307->regmap,
1487 					       RX8025_REG_CTRL1 << 4 | 0x08,
1488 					       buf, 2);
1489 			if (err) {
1490 				dev_dbg(ds1307->dev, "read error %d\n", err);
1491 				goto exit;
1492 			}
1493 
1494 			/* correct hour */
1495 			hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
1496 			if (hour == 12)
1497 				hour = 0;
1498 			if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1499 				hour += 12;
1500 
1501 			regmap_write(ds1307->regmap,
1502 				     DS1307_REG_HOUR << 4 | 0x08, hour);
1503 		}
1504 		break;
1505 	case rx_8130:
1506 		ds1307->offset = 0x10; /* Seconds starts at 0x10 */
1507 		rtc_ops = &rx8130_rtc_ops;
1508 		if (chip->alarm && ds1307->irq > 0) {
1509 			irq_handler = rx8130_irq;
1510 			want_irq = true;
1511 		}
1512 		break;
1513 	case ds_1388:
1514 		ds1307->offset = 1; /* Seconds starts at 1 */
1515 		break;
1516 	case mcp794xx:
1517 		rtc_ops = &mcp794xx_rtc_ops;
1518 		if (chip->alarm && (ds1307->irq > 0 ||
1519 				    ds1307_can_wakeup_device)) {
1520 			irq_handler = mcp794xx_irq;
1521 			want_irq = true;
1522 		}
1523 		break;
1524 	default:
1525 		break;
1526 	}
1527 
1528 read_rtc:
1529 	/* read RTC registers */
1530 	err = regmap_bulk_read(ds1307->regmap, ds1307->offset, buf, 8);
1531 	if (err) {
1532 		dev_dbg(ds1307->dev, "read error %d\n", err);
1533 		goto exit;
1534 	}
1535 
1536 	/*
1537 	 * minimal sanity checking; some chips (like DS1340) don't
1538 	 * specify the extra bits as must-be-zero, but there are
1539 	 * still a few values that are clearly out-of-range.
1540 	 */
1541 	tmp = ds1307->regs[DS1307_REG_SECS];
1542 	switch (ds1307->type) {
1543 	case ds_1307:
1544 	case m41t0:
1545 	case m41t00:
1546 		/* clock halted?  turn it on, so clock can tick. */
1547 		if (tmp & DS1307_BIT_CH) {
1548 			regmap_write(ds1307->regmap, DS1307_REG_SECS, 0);
1549 			dev_warn(ds1307->dev, "SET TIME!\n");
1550 			goto read_rtc;
1551 		}
1552 		break;
1553 	case ds_1308:
1554 	case ds_1338:
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 
1559 		/* oscillator fault?  clear flag, and warn */
1560 		if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1561 			regmap_write(ds1307->regmap, DS1307_REG_CONTROL,
1562 					ds1307->regs[DS1307_REG_CONTROL] &
1563 					~DS1338_BIT_OSF);
1564 			dev_warn(ds1307->dev, "SET TIME!\n");
1565 			goto read_rtc;
1566 		}
1567 		break;
1568 	case ds_1340:
1569 		/* clock halted?  turn it on, so clock can tick. */
1570 		if (tmp & DS1340_BIT_nEOSC)
1571 			regmap_write(ds1307->regmap, DS1307_REG_SECS, 0);
1572 
1573 		err = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
1574 		if (err) {
1575 			dev_dbg(ds1307->dev, "read error %d\n", err);
1576 			goto exit;
1577 		}
1578 
1579 		/* oscillator fault?  clear flag, and warn */
1580 		if (tmp & DS1340_BIT_OSF) {
1581 			regmap_write(ds1307->regmap, DS1340_REG_FLAG, 0);
1582 			dev_warn(ds1307->dev, "SET TIME!\n");
1583 		}
1584 		break;
1585 	case mcp794xx:
1586 		/* make sure that the backup battery is enabled */
1587 		if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1588 			regmap_write(ds1307->regmap, DS1307_REG_WDAY,
1589 				     ds1307->regs[DS1307_REG_WDAY] |
1590 				     MCP794XX_BIT_VBATEN);
1591 		}
1592 
1593 		/* clock halted?  turn it on, so clock can tick. */
1594 		if (!(tmp & MCP794XX_BIT_ST)) {
1595 			regmap_write(ds1307->regmap, DS1307_REG_SECS,
1596 				     MCP794XX_BIT_ST);
1597 			dev_warn(ds1307->dev, "SET TIME!\n");
1598 			goto read_rtc;
1599 		}
1600 
1601 		break;
1602 	default:
1603 		break;
1604 	}
1605 
1606 	tmp = ds1307->regs[DS1307_REG_HOUR];
1607 	switch (ds1307->type) {
1608 	case ds_1340:
1609 	case m41t0:
1610 	case m41t00:
1611 		/*
1612 		 * NOTE: ignores century bits; fix before deploying
1613 		 * systems that will run through year 2100.
1614 		 */
1615 		break;
1616 	case rx_8025:
1617 		break;
1618 	default:
1619 		if (!(tmp & DS1307_BIT_12HR))
1620 			break;
1621 
1622 		/*
1623 		 * Be sure we're in 24 hour mode.  Multi-master systems
1624 		 * take note...
1625 		 */
1626 		tmp = bcd2bin(tmp & 0x1f);
1627 		if (tmp == 12)
1628 			tmp = 0;
1629 		if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1630 			tmp += 12;
1631 		regmap_write(ds1307->regmap, ds1307->offset + DS1307_REG_HOUR,
1632 			     bin2bcd(tmp));
1633 	}
1634 
1635 	/*
1636 	 * Some IPs have weekday reset value = 0x1 which might not correct
1637 	 * hence compute the wday using the current date/month/year values
1638 	 */
1639 	ds1307_get_time(ds1307->dev, &tm);
1640 	wday = tm.tm_wday;
1641 	timestamp = rtc_tm_to_time64(&tm);
1642 	rtc_time64_to_tm(timestamp, &tm);
1643 
1644 	/*
1645 	 * Check if reset wday is different from the computed wday
1646 	 * If different then set the wday which we computed using
1647 	 * timestamp
1648 	 */
1649 	if (wday != tm.tm_wday)
1650 		regmap_update_bits(ds1307->regmap, MCP794XX_REG_WEEKDAY,
1651 				   MCP794XX_REG_WEEKDAY_WDAY_MASK,
1652 				   tm.tm_wday + 1);
1653 
1654 	if (want_irq) {
1655 		device_set_wakeup_capable(ds1307->dev, true);
1656 		set_bit(HAS_ALARM, &ds1307->flags);
1657 	}
1658 
1659 	ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
1660 	if (IS_ERR(ds1307->rtc)) {
1661 		return PTR_ERR(ds1307->rtc);
1662 	}
1663 
1664 	if (ds1307_can_wakeup_device && ds1307->irq <= 0) {
1665 		/* Disable request for an IRQ */
1666 		want_irq = false;
1667 		dev_info(ds1307->dev,
1668 			 "'wakeup-source' is set, request for an IRQ is disabled!\n");
1669 		/* We cannot support UIE mode if we do not have an IRQ line */
1670 		ds1307->rtc->uie_unsupported = 1;
1671 	}
1672 
1673 	if (want_irq) {
1674 		err = devm_request_threaded_irq(ds1307->dev,
1675 						ds1307->irq, NULL, irq_handler,
1676 						IRQF_SHARED | IRQF_ONESHOT,
1677 						ds1307->name, ds1307);
1678 		if (err) {
1679 			client->irq = 0;
1680 			device_set_wakeup_capable(ds1307->dev, false);
1681 			clear_bit(HAS_ALARM, &ds1307->flags);
1682 			dev_err(ds1307->dev, "unable to request IRQ!\n");
1683 		} else
1684 			dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
1685 	}
1686 
1687 	if (chip->nvram_size) {
1688 		ds1307->nvmem_cfg.name = "ds1307_nvram";
1689 		ds1307->nvmem_cfg.word_size = 1;
1690 		ds1307->nvmem_cfg.stride = 1;
1691 		ds1307->nvmem_cfg.size = chip->nvram_size;
1692 		ds1307->nvmem_cfg.reg_read = ds1307_nvram_read;
1693 		ds1307->nvmem_cfg.reg_write = ds1307_nvram_write;
1694 		ds1307->nvmem_cfg.priv = ds1307;
1695 		ds1307->nvram_offset = chip->nvram_offset;
1696 
1697 		ds1307->rtc->nvmem_config = &ds1307->nvmem_cfg;
1698 		ds1307->rtc->nvram_old_abi = true;
1699 	}
1700 
1701 	ds1307->rtc->ops = rtc_ops;
1702 	err = rtc_register_device(ds1307->rtc);
1703 	if (err)
1704 		return err;
1705 
1706 	ds1307_hwmon_register(ds1307);
1707 	ds1307_clks_register(ds1307);
1708 
1709 	return 0;
1710 
1711 exit:
1712 	return err;
1713 }
1714 
1715 static struct i2c_driver ds1307_driver = {
1716 	.driver = {
1717 		.name	= "rtc-ds1307",
1718 		.of_match_table = of_match_ptr(ds1307_of_match),
1719 		.acpi_match_table = ACPI_PTR(ds1307_acpi_ids),
1720 	},
1721 	.probe		= ds1307_probe,
1722 	.id_table	= ds1307_id,
1723 };
1724 
1725 module_i2c_driver(ds1307_driver);
1726 
1727 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1728 MODULE_LICENSE("GPL");
1729