xref: /linux/drivers/rtc/rtc-ds1307.c (revision 3c8f28578a0d68bc7fb91d881b832d55f734270c)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
4  *
5  *  Copyright (C) 2005 James Chapman (ds1337 core)
6  *  Copyright (C) 2006 David Brownell
7  *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
8  *  Copyright (C) 2012 Bertrand Achard (nvram access fixes)
9  */
10 
11 #include <linux/bcd.h>
12 #include <linux/i2c.h>
13 #include <linux/init.h>
14 #include <linux/kstrtox.h>
15 #include <linux/mod_devicetable.h>
16 #include <linux/module.h>
17 #include <linux/property.h>
18 #include <linux/rtc/ds1307.h>
19 #include <linux/rtc.h>
20 #include <linux/slab.h>
21 #include <linux/string.h>
22 #include <linux/hwmon.h>
23 #include <linux/hwmon-sysfs.h>
24 #include <linux/clk-provider.h>
25 #include <linux/regmap.h>
26 #include <linux/watchdog.h>
27 
28 /*
29  * We can't determine type by probing, but if we expect pre-Linux code
30  * to have set the chip up as a clock (turning on the oscillator and
31  * setting the date and time), Linux can ignore the non-clock features.
32  * That's a natural job for a factory or repair bench.
33  */
34 enum ds_type {
35 	unknown_ds_type, /* always first and 0 */
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 	m41t11,
48 	mcp794xx,
49 	rx_8025,
50 	rx_8130,
51 	last_ds_type /* always last */
52 	/* rs5c372 too?  different address... */
53 };
54 
55 /* RTC registers don't differ much, except for the century flag */
56 #define DS1307_REG_SECS		0x00	/* 00-59 */
57 #	define DS1307_BIT_CH		0x80
58 #	define DS1340_BIT_nEOSC		0x80
59 #	define MCP794XX_BIT_ST		0x80
60 #define DS1307_REG_MIN		0x01	/* 00-59 */
61 #	define M41T0_BIT_OF		0x80
62 #define DS1307_REG_HOUR		0x02	/* 00-23, or 1-12{am,pm} */
63 #	define DS1307_BIT_12HR		0x40	/* in REG_HOUR */
64 #	define DS1307_BIT_PM		0x20	/* in REG_HOUR */
65 #	define DS1340_BIT_CENTURY_EN	0x80	/* in REG_HOUR */
66 #	define DS1340_BIT_CENTURY	0x40	/* in REG_HOUR */
67 #define DS1307_REG_WDAY		0x03	/* 01-07 */
68 #	define MCP794XX_BIT_OSCRUN	BIT(5)
69 #	define MCP794XX_BIT_VBATEN	0x08
70 #define DS1307_REG_MDAY		0x04	/* 01-31 */
71 #define DS1307_REG_MONTH	0x05	/* 01-12 */
72 #	define DS1337_BIT_CENTURY	0x80	/* in REG_MONTH */
73 #define DS1307_REG_YEAR		0x06	/* 00-99 */
74 
75 /*
76  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
77  * start at 7, and they differ a LOT. Only control and status matter for
78  * basic RTC date and time functionality; be careful using them.
79  */
80 #define DS1307_REG_CONTROL	0x07		/* or ds1338 */
81 #	define DS1307_BIT_OUT		0x80
82 #	define DS1338_BIT_OSF		0x20
83 #	define DS1307_BIT_SQWE		0x10
84 #	define DS1307_BIT_RS1		0x02
85 #	define DS1307_BIT_RS0		0x01
86 #define DS1337_REG_CONTROL	0x0e
87 #	define DS1337_BIT_nEOSC		0x80
88 #	define DS1339_BIT_BBSQI		0x20
89 #	define DS3231_BIT_BBSQW		0x40 /* same as BBSQI */
90 #	define DS1337_BIT_RS2		0x10
91 #	define DS1337_BIT_RS1		0x08
92 #	define DS1337_BIT_INTCN		0x04
93 #	define DS1337_BIT_A2IE		0x02
94 #	define DS1337_BIT_A1IE		0x01
95 #define DS1340_REG_CONTROL	0x07
96 #	define DS1340_BIT_OUT		0x80
97 #	define DS1340_BIT_FT		0x40
98 #	define DS1340_BIT_CALIB_SIGN	0x20
99 #	define DS1340_M_CALIBRATION	0x1f
100 #define DS1340_REG_FLAG		0x09
101 #	define DS1340_BIT_OSF		0x80
102 #define DS1337_REG_STATUS	0x0f
103 #	define DS1337_BIT_OSF		0x80
104 #	define DS3231_BIT_EN32KHZ	0x08
105 #	define DS1337_BIT_A2I		0x02
106 #	define DS1337_BIT_A1I		0x01
107 #define DS1339_REG_ALARM1_SECS	0x07
108 
109 #define DS13XX_TRICKLE_CHARGER_MAGIC	0xa0
110 
111 #define RX8025_REG_CTRL1	0x0e
112 #	define RX8025_BIT_2412		0x20
113 #define RX8025_REG_CTRL2	0x0f
114 #	define RX8025_BIT_PON		0x10
115 #	define RX8025_BIT_VDET		0x40
116 #	define RX8025_BIT_XST		0x20
117 
118 #define RX8130_REG_ALARM_MIN		0x17
119 #define RX8130_REG_ALARM_HOUR		0x18
120 #define RX8130_REG_ALARM_WEEK_OR_DAY	0x19
121 #define RX8130_REG_EXTENSION		0x1c
122 #define RX8130_REG_EXTENSION_WADA	BIT(3)
123 #define RX8130_REG_FLAG			0x1d
124 #define RX8130_REG_FLAG_VLF		BIT(1)
125 #define RX8130_REG_FLAG_AF		BIT(3)
126 #define RX8130_REG_CONTROL0		0x1e
127 #define RX8130_REG_CONTROL0_AIE		BIT(3)
128 #define RX8130_REG_CONTROL1		0x1f
129 #define RX8130_REG_CONTROL1_INIEN	BIT(4)
130 #define RX8130_REG_CONTROL1_CHGEN	BIT(5)
131 
132 #define MCP794XX_REG_CONTROL		0x07
133 #	define MCP794XX_BIT_ALM0_EN	0x10
134 #	define MCP794XX_BIT_ALM1_EN	0x20
135 #define MCP794XX_REG_ALARM0_BASE	0x0a
136 #define MCP794XX_REG_ALARM0_CTRL	0x0d
137 #define MCP794XX_REG_ALARM1_BASE	0x11
138 #define MCP794XX_REG_ALARM1_CTRL	0x14
139 #	define MCP794XX_BIT_ALMX_IF	BIT(3)
140 #	define MCP794XX_BIT_ALMX_C0	BIT(4)
141 #	define MCP794XX_BIT_ALMX_C1	BIT(5)
142 #	define MCP794XX_BIT_ALMX_C2	BIT(6)
143 #	define MCP794XX_BIT_ALMX_POL	BIT(7)
144 #	define MCP794XX_MSK_ALMX_MATCH	(MCP794XX_BIT_ALMX_C0 | \
145 					 MCP794XX_BIT_ALMX_C1 | \
146 					 MCP794XX_BIT_ALMX_C2)
147 
148 #define M41TXX_REG_CONTROL	0x07
149 #	define M41TXX_BIT_OUT		BIT(7)
150 #	define M41TXX_BIT_FT		BIT(6)
151 #	define M41TXX_BIT_CALIB_SIGN	BIT(5)
152 #	define M41TXX_M_CALIBRATION	GENMASK(4, 0)
153 
154 #define DS1388_REG_WDOG_HUN_SECS	0x08
155 #define DS1388_REG_WDOG_SECS		0x09
156 #define DS1388_REG_FLAG			0x0b
157 #	define DS1388_BIT_WF		BIT(6)
158 #	define DS1388_BIT_OSF		BIT(7)
159 #define DS1388_REG_CONTROL		0x0c
160 #	define DS1388_BIT_RST		BIT(0)
161 #	define DS1388_BIT_WDE		BIT(1)
162 #	define DS1388_BIT_nEOSC		BIT(7)
163 
164 /* negative offset step is -2.034ppm */
165 #define M41TXX_NEG_OFFSET_STEP_PPB	2034
166 /* positive offset step is +4.068ppm */
167 #define M41TXX_POS_OFFSET_STEP_PPB	4068
168 /* Min and max values supported with 'offset' interface by M41TXX */
169 #define M41TXX_MIN_OFFSET	((-31) * M41TXX_NEG_OFFSET_STEP_PPB)
170 #define M41TXX_MAX_OFFSET	((31) * M41TXX_POS_OFFSET_STEP_PPB)
171 
172 struct ds1307 {
173 	enum ds_type		type;
174 	struct device		*dev;
175 	struct regmap		*regmap;
176 	const char		*name;
177 	struct rtc_device	*rtc;
178 #ifdef CONFIG_COMMON_CLK
179 	struct clk_hw		clks[2];
180 #endif
181 };
182 
183 struct chip_desc {
184 	unsigned		alarm:1;
185 	u16			nvram_offset;
186 	u16			nvram_size;
187 	u8			offset; /* register's offset */
188 	u8			century_reg;
189 	u8			century_enable_bit;
190 	u8			century_bit;
191 	u8			bbsqi_bit;
192 	irq_handler_t		irq_handler;
193 	const struct rtc_class_ops *rtc_ops;
194 	u16			trickle_charger_reg;
195 	u8			(*do_trickle_setup)(struct ds1307 *, u32,
196 						    bool);
197 	/* Does the RTC require trickle-resistor-ohms to select the value of
198 	 * the resistor between Vcc and Vbackup?
199 	 */
200 	bool			requires_trickle_resistor;
201 	/* Some RTC's batteries and supercaps were charged by default, others
202 	 * allow charging but were not configured previously to do so.
203 	 * Remember this behavior to stay backwards compatible.
204 	 */
205 	bool			charge_default;
206 };
207 
208 static const struct chip_desc chips[last_ds_type];
209 
210 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
211 {
212 	struct ds1307	*ds1307 = dev_get_drvdata(dev);
213 	int		tmp, ret;
214 	const struct chip_desc *chip = &chips[ds1307->type];
215 	u8 regs[7];
216 
217 	if (ds1307->type == rx_8130) {
218 		unsigned int regflag;
219 		ret = regmap_read(ds1307->regmap, RX8130_REG_FLAG, &regflag);
220 		if (ret) {
221 			dev_err(dev, "%s error %d\n", "read", ret);
222 			return ret;
223 		}
224 
225 		if (regflag & RX8130_REG_FLAG_VLF) {
226 			dev_warn_once(dev, "oscillator failed, set time!\n");
227 			return -EINVAL;
228 		}
229 	}
230 
231 	/* read the RTC date and time registers all at once */
232 	ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
233 			       sizeof(regs));
234 	if (ret) {
235 		dev_err(dev, "%s error %d\n", "read", ret);
236 		return ret;
237 	}
238 
239 	dev_dbg(dev, "%s: %7ph\n", "read", regs);
240 
241 	/* if oscillator fail bit is set, no data can be trusted */
242 	if (ds1307->type == m41t0 &&
243 	    regs[DS1307_REG_MIN] & M41T0_BIT_OF) {
244 		dev_warn_once(dev, "oscillator failed, set time!\n");
245 		return -EINVAL;
246 	} else if (ds1307->type == mcp794xx &&
247 	    !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_OSCRUN)) {
248 		dev_warn_once(dev, "oscillator failed, set time!\n");
249 		return -EINVAL;
250 	}
251 
252 	tmp = regs[DS1307_REG_SECS];
253 	switch (ds1307->type) {
254 	case ds_1307:
255 	case m41t0:
256 	case m41t00:
257 	case m41t11:
258 		if (tmp & DS1307_BIT_CH)
259 			return -EINVAL;
260 		break;
261 	case ds_1308:
262 	case ds_1338:
263 		if (tmp & DS1307_BIT_CH)
264 			return -EINVAL;
265 
266 		ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &tmp);
267 		if (ret)
268 			return ret;
269 		if (tmp & DS1338_BIT_OSF)
270 			return -EINVAL;
271 		break;
272 	case ds_1337:
273 	case ds_1339:
274 	case ds_1341:
275 	case ds_3231:
276 		ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &tmp);
277 		if (ret)
278 			return ret;
279 		if (tmp & DS1337_BIT_OSF)
280 			return -EINVAL;
281 		break;
282 	case ds_1340:
283 		if (tmp & DS1340_BIT_nEOSC)
284 			return -EINVAL;
285 
286 		ret = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
287 		if (ret)
288 			return ret;
289 		if (tmp & DS1340_BIT_OSF)
290 			return -EINVAL;
291 		break;
292 	case ds_1388:
293 		ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &tmp);
294 		if (ret)
295 			return ret;
296 		if (tmp & DS1388_BIT_OSF)
297 			return -EINVAL;
298 		break;
299 	case mcp794xx:
300 		if (!(tmp & MCP794XX_BIT_ST))
301 			return -EINVAL;
302 
303 		break;
304 	default:
305 		break;
306 	}
307 
308 	t->tm_sec = bcd2bin(regs[DS1307_REG_SECS] & 0x7f);
309 	t->tm_min = bcd2bin(regs[DS1307_REG_MIN] & 0x7f);
310 	tmp = regs[DS1307_REG_HOUR] & 0x3f;
311 	t->tm_hour = bcd2bin(tmp);
312 	/* rx8130 is bit position, not BCD */
313 	if (ds1307->type == rx_8130)
314 		t->tm_wday = fls(regs[DS1307_REG_WDAY] & 0x7f) - 1;
315 	else
316 		t->tm_wday = bcd2bin(regs[DS1307_REG_WDAY] & 0x07) - 1;
317 	t->tm_mday = bcd2bin(regs[DS1307_REG_MDAY] & 0x3f);
318 	tmp = regs[DS1307_REG_MONTH] & 0x1f;
319 	t->tm_mon = bcd2bin(tmp) - 1;
320 	t->tm_year = bcd2bin(regs[DS1307_REG_YEAR]) + 100;
321 
322 	if (regs[chip->century_reg] & chip->century_bit &&
323 	    IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
324 		t->tm_year += 100;
325 
326 	dev_dbg(dev, "%s secs=%d, mins=%d, "
327 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
328 		"read", t->tm_sec, t->tm_min,
329 		t->tm_hour, t->tm_mday,
330 		t->tm_mon, t->tm_year, t->tm_wday);
331 
332 	return 0;
333 }
334 
335 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
336 {
337 	struct ds1307	*ds1307 = dev_get_drvdata(dev);
338 	const struct chip_desc *chip = &chips[ds1307->type];
339 	int		result;
340 	int		tmp;
341 	u8		regs[7];
342 
343 	dev_dbg(dev, "%s secs=%d, mins=%d, "
344 		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
345 		"write", t->tm_sec, t->tm_min,
346 		t->tm_hour, t->tm_mday,
347 		t->tm_mon, t->tm_year, t->tm_wday);
348 
349 	if (t->tm_year < 100)
350 		return -EINVAL;
351 
352 #ifdef CONFIG_RTC_DRV_DS1307_CENTURY
353 	if (t->tm_year > (chip->century_bit ? 299 : 199))
354 		return -EINVAL;
355 #else
356 	if (t->tm_year > 199)
357 		return -EINVAL;
358 #endif
359 
360 	regs[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
361 	regs[DS1307_REG_MIN] = bin2bcd(t->tm_min);
362 	regs[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
363 	/* rx8130 is bit position, not BCD */
364 	if (ds1307->type == rx_8130)
365 		regs[DS1307_REG_WDAY] = 1 << t->tm_wday;
366 	else
367 		regs[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
368 	regs[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
369 	regs[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
370 
371 	/* assume 20YY not 19YY */
372 	tmp = t->tm_year % 100;
373 	regs[DS1307_REG_YEAR] = bin2bcd(tmp);
374 
375 	if (chip->century_enable_bit)
376 		regs[chip->century_reg] |= chip->century_enable_bit;
377 	if (t->tm_year > 199 && chip->century_bit)
378 		regs[chip->century_reg] |= chip->century_bit;
379 
380 	switch (ds1307->type) {
381 	case ds_1308:
382 	case ds_1338:
383 		regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
384 				   DS1338_BIT_OSF, 0);
385 		break;
386 	case ds_1337:
387 	case ds_1339:
388 	case ds_1341:
389 	case ds_3231:
390 		regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
391 				   DS1337_BIT_OSF, 0);
392 		break;
393 	case ds_1340:
394 		regmap_update_bits(ds1307->regmap, DS1340_REG_FLAG,
395 				   DS1340_BIT_OSF, 0);
396 		break;
397 	case ds_1388:
398 		regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
399 				   DS1388_BIT_OSF, 0);
400 		break;
401 	case mcp794xx:
402 		/*
403 		 * these bits were cleared when preparing the date/time
404 		 * values and need to be set again before writing the
405 		 * regsfer out to the device.
406 		 */
407 		regs[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
408 		regs[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
409 		break;
410 	default:
411 		break;
412 	}
413 
414 	dev_dbg(dev, "%s: %7ph\n", "write", regs);
415 
416 	result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
417 				   sizeof(regs));
418 	if (result) {
419 		dev_err(dev, "%s error %d\n", "write", result);
420 		return result;
421 	}
422 
423 	if (ds1307->type == rx_8130) {
424 		/* clear Voltage Loss Flag as data is available now */
425 		result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
426 				      ~(u8)RX8130_REG_FLAG_VLF);
427 		if (result) {
428 			dev_err(dev, "%s error %d\n", "write", result);
429 			return result;
430 		}
431 	}
432 
433 	return 0;
434 }
435 
436 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
437 {
438 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
439 	int			ret;
440 	u8			regs[9];
441 
442 	/* read all ALARM1, ALARM2, and status registers at once */
443 	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
444 			       regs, sizeof(regs));
445 	if (ret) {
446 		dev_err(dev, "%s error %d\n", "alarm read", ret);
447 		return ret;
448 	}
449 
450 	dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
451 		&regs[0], &regs[4], &regs[7]);
452 
453 	/*
454 	 * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
455 	 * and that all four fields are checked matches
456 	 */
457 	t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
458 	t->time.tm_min = bcd2bin(regs[1] & 0x7f);
459 	t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
460 	t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
461 
462 	/* ... and status */
463 	t->enabled = !!(regs[7] & DS1337_BIT_A1IE);
464 	t->pending = !!(regs[8] & DS1337_BIT_A1I);
465 
466 	dev_dbg(dev, "%s secs=%d, mins=%d, "
467 		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
468 		"alarm read", t->time.tm_sec, t->time.tm_min,
469 		t->time.tm_hour, t->time.tm_mday,
470 		t->enabled, t->pending);
471 
472 	return 0;
473 }
474 
475 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
476 {
477 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
478 	unsigned char		regs[9];
479 	u8			control, status;
480 	int			ret;
481 
482 	dev_dbg(dev, "%s secs=%d, mins=%d, "
483 		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
484 		"alarm set", t->time.tm_sec, t->time.tm_min,
485 		t->time.tm_hour, t->time.tm_mday,
486 		t->enabled, t->pending);
487 
488 	/* read current status of both alarms and the chip */
489 	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
490 			       sizeof(regs));
491 	if (ret) {
492 		dev_err(dev, "%s error %d\n", "alarm write", ret);
493 		return ret;
494 	}
495 	control = regs[7];
496 	status = regs[8];
497 
498 	dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
499 		&regs[0], &regs[4], control, status);
500 
501 	/* set ALARM1, using 24 hour and day-of-month modes */
502 	regs[0] = bin2bcd(t->time.tm_sec);
503 	regs[1] = bin2bcd(t->time.tm_min);
504 	regs[2] = bin2bcd(t->time.tm_hour);
505 	regs[3] = bin2bcd(t->time.tm_mday);
506 
507 	/* set ALARM2 to non-garbage */
508 	regs[4] = 0;
509 	regs[5] = 0;
510 	regs[6] = 0;
511 
512 	/* disable alarms */
513 	regs[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
514 	regs[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
515 
516 	ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
517 				sizeof(regs));
518 	if (ret) {
519 		dev_err(dev, "can't set alarm time\n");
520 		return ret;
521 	}
522 
523 	/* optionally enable ALARM1 */
524 	if (t->enabled) {
525 		dev_dbg(dev, "alarm IRQ armed\n");
526 		regs[7] |= DS1337_BIT_A1IE;	/* only ALARM1 is used */
527 		regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[7]);
528 	}
529 
530 	return 0;
531 }
532 
533 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
534 {
535 	struct ds1307		*ds1307 = dev_get_drvdata(dev);
536 
537 	return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
538 				  DS1337_BIT_A1IE,
539 				  enabled ? DS1337_BIT_A1IE : 0);
540 }
541 
542 static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
543 {
544 	u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
545 		DS1307_TRICKLE_CHARGER_NO_DIODE;
546 
547 	setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
548 
549 	switch (ohms) {
550 	case 250:
551 		setup |= DS1307_TRICKLE_CHARGER_250_OHM;
552 		break;
553 	case 2000:
554 		setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
555 		break;
556 	case 4000:
557 		setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
558 		break;
559 	default:
560 		dev_warn(ds1307->dev,
561 			 "Unsupported ohm value %u in dt\n", ohms);
562 		return 0;
563 	}
564 	return setup;
565 }
566 
567 static u8 do_trickle_setup_rx8130(struct ds1307 *ds1307, u32 ohms, bool diode)
568 {
569 	/* make sure that the backup battery is enabled */
570 	u8 setup = RX8130_REG_CONTROL1_INIEN;
571 	if (diode)
572 		setup |= RX8130_REG_CONTROL1_CHGEN;
573 
574 	return setup;
575 }
576 
577 static irqreturn_t rx8130_irq(int irq, void *dev_id)
578 {
579 	struct ds1307           *ds1307 = dev_id;
580 	u8 ctl[3];
581 	int ret;
582 
583 	rtc_lock(ds1307->rtc);
584 
585 	/* Read control registers. */
586 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
587 			       sizeof(ctl));
588 	if (ret < 0)
589 		goto out;
590 	if (!(ctl[1] & RX8130_REG_FLAG_AF))
591 		goto out;
592 	ctl[1] &= ~RX8130_REG_FLAG_AF;
593 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
594 
595 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
596 				sizeof(ctl));
597 	if (ret < 0)
598 		goto out;
599 
600 	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
601 
602 out:
603 	rtc_unlock(ds1307->rtc);
604 
605 	return IRQ_HANDLED;
606 }
607 
608 static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
609 {
610 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
611 	u8 ald[3], ctl[3];
612 	int ret;
613 
614 	/* Read alarm registers. */
615 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
616 			       sizeof(ald));
617 	if (ret < 0)
618 		return ret;
619 
620 	/* Read control registers. */
621 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
622 			       sizeof(ctl));
623 	if (ret < 0)
624 		return ret;
625 
626 	t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
627 	t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
628 
629 	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
630 	t->time.tm_sec = -1;
631 	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
632 	t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
633 	t->time.tm_wday = -1;
634 	t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
635 	t->time.tm_mon = -1;
636 	t->time.tm_year = -1;
637 	t->time.tm_yday = -1;
638 	t->time.tm_isdst = -1;
639 
640 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
641 		__func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
642 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
643 
644 	return 0;
645 }
646 
647 static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
648 {
649 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
650 	u8 ald[3], ctl[3];
651 	int ret;
652 
653 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
654 		"enabled=%d pending=%d\n", __func__,
655 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
656 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
657 		t->enabled, t->pending);
658 
659 	/* Read control registers. */
660 	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
661 			       sizeof(ctl));
662 	if (ret < 0)
663 		return ret;
664 
665 	ctl[0] &= RX8130_REG_EXTENSION_WADA;
666 	ctl[1] &= ~RX8130_REG_FLAG_AF;
667 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
668 
669 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
670 				sizeof(ctl));
671 	if (ret < 0)
672 		return ret;
673 
674 	/* Hardware alarm precision is 1 minute! */
675 	ald[0] = bin2bcd(t->time.tm_min);
676 	ald[1] = bin2bcd(t->time.tm_hour);
677 	ald[2] = bin2bcd(t->time.tm_mday);
678 
679 	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
680 				sizeof(ald));
681 	if (ret < 0)
682 		return ret;
683 
684 	if (!t->enabled)
685 		return 0;
686 
687 	ctl[2] |= RX8130_REG_CONTROL0_AIE;
688 
689 	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, ctl[2]);
690 }
691 
692 static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
693 {
694 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
695 	int ret, reg;
696 
697 	ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
698 	if (ret < 0)
699 		return ret;
700 
701 	if (enabled)
702 		reg |= RX8130_REG_CONTROL0_AIE;
703 	else
704 		reg &= ~RX8130_REG_CONTROL0_AIE;
705 
706 	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
707 }
708 
709 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
710 {
711 	struct ds1307           *ds1307 = dev_id;
712 	struct mutex            *lock = &ds1307->rtc->ops_lock;
713 	int reg, ret;
714 
715 	mutex_lock(lock);
716 
717 	/* Check and clear alarm 0 interrupt flag. */
718 	ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
719 	if (ret)
720 		goto out;
721 	if (!(reg & MCP794XX_BIT_ALMX_IF))
722 		goto out;
723 	reg &= ~MCP794XX_BIT_ALMX_IF;
724 	ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
725 	if (ret)
726 		goto out;
727 
728 	/* Disable alarm 0. */
729 	ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
730 				 MCP794XX_BIT_ALM0_EN, 0);
731 	if (ret)
732 		goto out;
733 
734 	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
735 
736 out:
737 	mutex_unlock(lock);
738 
739 	return IRQ_HANDLED;
740 }
741 
742 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
743 {
744 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
745 	u8 regs[10];
746 	int ret;
747 
748 	/* Read control and alarm 0 registers. */
749 	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
750 			       sizeof(regs));
751 	if (ret)
752 		return ret;
753 
754 	t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
755 
756 	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
757 	t->time.tm_sec = bcd2bin(regs[3] & 0x7f);
758 	t->time.tm_min = bcd2bin(regs[4] & 0x7f);
759 	t->time.tm_hour = bcd2bin(regs[5] & 0x3f);
760 	t->time.tm_wday = bcd2bin(regs[6] & 0x7) - 1;
761 	t->time.tm_mday = bcd2bin(regs[7] & 0x3f);
762 	t->time.tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
763 	t->time.tm_year = -1;
764 	t->time.tm_yday = -1;
765 	t->time.tm_isdst = -1;
766 
767 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
768 		"enabled=%d polarity=%d irq=%d match=%lu\n", __func__,
769 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
770 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
771 		!!(regs[6] & MCP794XX_BIT_ALMX_POL),
772 		!!(regs[6] & MCP794XX_BIT_ALMX_IF),
773 		(regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
774 
775 	return 0;
776 }
777 
778 /*
779  * We may have a random RTC weekday, therefore calculate alarm weekday based
780  * on current weekday we read from the RTC timekeeping regs
781  */
782 static int mcp794xx_alm_weekday(struct device *dev, struct rtc_time *tm_alarm)
783 {
784 	struct rtc_time tm_now;
785 	int days_now, days_alarm, ret;
786 
787 	ret = ds1307_get_time(dev, &tm_now);
788 	if (ret)
789 		return ret;
790 
791 	days_now = div_s64(rtc_tm_to_time64(&tm_now), 24 * 60 * 60);
792 	days_alarm = div_s64(rtc_tm_to_time64(tm_alarm), 24 * 60 * 60);
793 
794 	return (tm_now.tm_wday + days_alarm - days_now) % 7 + 1;
795 }
796 
797 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
798 {
799 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
800 	unsigned char regs[10];
801 	int wday, ret;
802 
803 	wday = mcp794xx_alm_weekday(dev, &t->time);
804 	if (wday < 0)
805 		return wday;
806 
807 	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
808 		"enabled=%d pending=%d\n", __func__,
809 		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
810 		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
811 		t->enabled, t->pending);
812 
813 	/* Read control and alarm 0 registers. */
814 	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
815 			       sizeof(regs));
816 	if (ret)
817 		return ret;
818 
819 	/* Set alarm 0, using 24-hour and day-of-month modes. */
820 	regs[3] = bin2bcd(t->time.tm_sec);
821 	regs[4] = bin2bcd(t->time.tm_min);
822 	regs[5] = bin2bcd(t->time.tm_hour);
823 	regs[6] = wday;
824 	regs[7] = bin2bcd(t->time.tm_mday);
825 	regs[8] = bin2bcd(t->time.tm_mon + 1);
826 
827 	/* Clear the alarm 0 interrupt flag. */
828 	regs[6] &= ~MCP794XX_BIT_ALMX_IF;
829 	/* Set alarm match: second, minute, hour, day, date, month. */
830 	regs[6] |= MCP794XX_MSK_ALMX_MATCH;
831 	/* Disable interrupt. We will not enable until completely programmed */
832 	regs[0] &= ~MCP794XX_BIT_ALM0_EN;
833 
834 	ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
835 				sizeof(regs));
836 	if (ret)
837 		return ret;
838 
839 	if (!t->enabled)
840 		return 0;
841 	regs[0] |= MCP794XX_BIT_ALM0_EN;
842 	return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
843 }
844 
845 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
846 {
847 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
848 
849 	return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
850 				  MCP794XX_BIT_ALM0_EN,
851 				  enabled ? MCP794XX_BIT_ALM0_EN : 0);
852 }
853 
854 static int m41txx_rtc_read_offset(struct device *dev, long *offset)
855 {
856 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
857 	unsigned int ctrl_reg;
858 	u8 val;
859 
860 	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
861 
862 	val = ctrl_reg & M41TXX_M_CALIBRATION;
863 
864 	/* check if positive */
865 	if (ctrl_reg & M41TXX_BIT_CALIB_SIGN)
866 		*offset = (val * M41TXX_POS_OFFSET_STEP_PPB);
867 	else
868 		*offset = -(val * M41TXX_NEG_OFFSET_STEP_PPB);
869 
870 	return 0;
871 }
872 
873 static int m41txx_rtc_set_offset(struct device *dev, long offset)
874 {
875 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
876 	unsigned int ctrl_reg;
877 
878 	if ((offset < M41TXX_MIN_OFFSET) || (offset > M41TXX_MAX_OFFSET))
879 		return -ERANGE;
880 
881 	if (offset >= 0) {
882 		ctrl_reg = DIV_ROUND_CLOSEST(offset,
883 					     M41TXX_POS_OFFSET_STEP_PPB);
884 		ctrl_reg |= M41TXX_BIT_CALIB_SIGN;
885 	} else {
886 		ctrl_reg = DIV_ROUND_CLOSEST(abs(offset),
887 					     M41TXX_NEG_OFFSET_STEP_PPB);
888 	}
889 
890 	return regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL,
891 				  M41TXX_M_CALIBRATION | M41TXX_BIT_CALIB_SIGN,
892 				  ctrl_reg);
893 }
894 
895 #ifdef CONFIG_WATCHDOG_CORE
896 static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
897 {
898 	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
899 	u8 regs[2];
900 	int ret;
901 
902 	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
903 				 DS1388_BIT_WF, 0);
904 	if (ret)
905 		return ret;
906 
907 	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
908 				 DS1388_BIT_WDE | DS1388_BIT_RST, 0);
909 	if (ret)
910 		return ret;
911 
912 	/*
913 	 * watchdog timeouts are measured in seconds. So ignore hundredths of
914 	 * seconds field.
915 	 */
916 	regs[0] = 0;
917 	regs[1] = bin2bcd(wdt_dev->timeout);
918 
919 	ret = regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
920 				sizeof(regs));
921 	if (ret)
922 		return ret;
923 
924 	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
925 				  DS1388_BIT_WDE | DS1388_BIT_RST,
926 				  DS1388_BIT_WDE | DS1388_BIT_RST);
927 }
928 
929 static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
930 {
931 	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
932 
933 	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
934 				  DS1388_BIT_WDE | DS1388_BIT_RST, 0);
935 }
936 
937 static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
938 {
939 	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
940 	u8 regs[2];
941 
942 	return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
943 				sizeof(regs));
944 }
945 
946 static int ds1388_wdt_set_timeout(struct watchdog_device *wdt_dev,
947 				  unsigned int val)
948 {
949 	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
950 	u8 regs[2];
951 
952 	wdt_dev->timeout = val;
953 	regs[0] = 0;
954 	regs[1] = bin2bcd(wdt_dev->timeout);
955 
956 	return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
957 				 sizeof(regs));
958 }
959 #endif
960 
961 static const struct rtc_class_ops rx8130_rtc_ops = {
962 	.read_time      = ds1307_get_time,
963 	.set_time       = ds1307_set_time,
964 	.read_alarm     = rx8130_read_alarm,
965 	.set_alarm      = rx8130_set_alarm,
966 	.alarm_irq_enable = rx8130_alarm_irq_enable,
967 };
968 
969 static const struct rtc_class_ops mcp794xx_rtc_ops = {
970 	.read_time      = ds1307_get_time,
971 	.set_time       = ds1307_set_time,
972 	.read_alarm     = mcp794xx_read_alarm,
973 	.set_alarm      = mcp794xx_set_alarm,
974 	.alarm_irq_enable = mcp794xx_alarm_irq_enable,
975 };
976 
977 static const struct rtc_class_ops m41txx_rtc_ops = {
978 	.read_time      = ds1307_get_time,
979 	.set_time       = ds1307_set_time,
980 	.read_alarm	= ds1337_read_alarm,
981 	.set_alarm	= ds1337_set_alarm,
982 	.alarm_irq_enable = ds1307_alarm_irq_enable,
983 	.read_offset	= m41txx_rtc_read_offset,
984 	.set_offset	= m41txx_rtc_set_offset,
985 };
986 
987 static const struct chip_desc chips[last_ds_type] = {
988 	[ds_1307] = {
989 		.nvram_offset	= 8,
990 		.nvram_size	= 56,
991 	},
992 	[ds_1308] = {
993 		.nvram_offset	= 8,
994 		.nvram_size	= 56,
995 	},
996 	[ds_1337] = {
997 		.alarm		= 1,
998 		.century_reg	= DS1307_REG_MONTH,
999 		.century_bit	= DS1337_BIT_CENTURY,
1000 	},
1001 	[ds_1338] = {
1002 		.nvram_offset	= 8,
1003 		.nvram_size	= 56,
1004 	},
1005 	[ds_1339] = {
1006 		.alarm		= 1,
1007 		.century_reg	= DS1307_REG_MONTH,
1008 		.century_bit	= DS1337_BIT_CENTURY,
1009 		.bbsqi_bit	= DS1339_BIT_BBSQI,
1010 		.trickle_charger_reg = 0x10,
1011 		.do_trickle_setup = &do_trickle_setup_ds1339,
1012 		.requires_trickle_resistor = true,
1013 		.charge_default = true,
1014 	},
1015 	[ds_1340] = {
1016 		.century_reg	= DS1307_REG_HOUR,
1017 		.century_enable_bit = DS1340_BIT_CENTURY_EN,
1018 		.century_bit	= DS1340_BIT_CENTURY,
1019 		.do_trickle_setup = &do_trickle_setup_ds1339,
1020 		.trickle_charger_reg = 0x08,
1021 		.requires_trickle_resistor = true,
1022 		.charge_default = true,
1023 	},
1024 	[ds_1341] = {
1025 		.century_reg	= DS1307_REG_MONTH,
1026 		.century_bit	= DS1337_BIT_CENTURY,
1027 	},
1028 	[ds_1388] = {
1029 		.offset		= 1,
1030 		.trickle_charger_reg = 0x0a,
1031 	},
1032 	[ds_3231] = {
1033 		.alarm		= 1,
1034 		.century_reg	= DS1307_REG_MONTH,
1035 		.century_bit	= DS1337_BIT_CENTURY,
1036 		.bbsqi_bit	= DS3231_BIT_BBSQW,
1037 	},
1038 	[rx_8130] = {
1039 		.alarm		= 1,
1040 		/* this is battery backed SRAM */
1041 		.nvram_offset	= 0x20,
1042 		.nvram_size	= 4,	/* 32bit (4 word x 8 bit) */
1043 		.offset		= 0x10,
1044 		.irq_handler = rx8130_irq,
1045 		.rtc_ops = &rx8130_rtc_ops,
1046 		.trickle_charger_reg = RX8130_REG_CONTROL1,
1047 		.do_trickle_setup = &do_trickle_setup_rx8130,
1048 	},
1049 	[m41t0] = {
1050 		.rtc_ops	= &m41txx_rtc_ops,
1051 	},
1052 	[m41t00] = {
1053 		.rtc_ops	= &m41txx_rtc_ops,
1054 	},
1055 	[m41t11] = {
1056 		/* this is battery backed SRAM */
1057 		.nvram_offset	= 8,
1058 		.nvram_size	= 56,
1059 		.rtc_ops	= &m41txx_rtc_ops,
1060 	},
1061 	[mcp794xx] = {
1062 		.alarm		= 1,
1063 		/* this is battery backed SRAM */
1064 		.nvram_offset	= 0x20,
1065 		.nvram_size	= 0x40,
1066 		.irq_handler = mcp794xx_irq,
1067 		.rtc_ops = &mcp794xx_rtc_ops,
1068 	},
1069 };
1070 
1071 static const struct i2c_device_id ds1307_id[] = {
1072 	{ .name = "ds1307", .driver_data = ds_1307 },
1073 	{ .name = "ds1308", .driver_data = ds_1308 },
1074 	{ .name = "ds1337", .driver_data = ds_1337 },
1075 	{ .name = "ds1338", .driver_data = ds_1338 },
1076 	{ .name = "ds1339", .driver_data = ds_1339 },
1077 	{ .name = "ds1388", .driver_data = ds_1388 },
1078 	{ .name = "ds1340", .driver_data = ds_1340 },
1079 	{ .name = "ds1341", .driver_data = ds_1341 },
1080 	{ .name = "ds3231", .driver_data = ds_3231 },
1081 	{ .name = "m41t0", .driver_data = m41t0 },
1082 	{ .name = "m41t00", .driver_data = m41t00 },
1083 	{ .name = "m41t11", .driver_data = m41t11 },
1084 	{ .name = "mcp7940x", .driver_data = mcp794xx },
1085 	{ .name = "mcp7941x", .driver_data = mcp794xx },
1086 	{ .name = "pt7c4338", .driver_data = ds_1307 },
1087 	{ .name = "rx8025", .driver_data = rx_8025 },
1088 	{ .name = "isl12057", .driver_data = ds_1337 },
1089 	{ .name = "rx8130", .driver_data = rx_8130 },
1090 	{ }
1091 };
1092 MODULE_DEVICE_TABLE(i2c, ds1307_id);
1093 
1094 static const struct of_device_id ds1307_of_match[] = {
1095 	{
1096 		.compatible = "dallas,ds1307",
1097 		.data = (void *)ds_1307
1098 	},
1099 	{
1100 		.compatible = "dallas,ds1308",
1101 		.data = (void *)ds_1308
1102 	},
1103 	{
1104 		.compatible = "dallas,ds1337",
1105 		.data = (void *)ds_1337
1106 	},
1107 	{
1108 		.compatible = "dallas,ds1338",
1109 		.data = (void *)ds_1338
1110 	},
1111 	{
1112 		.compatible = "dallas,ds1339",
1113 		.data = (void *)ds_1339
1114 	},
1115 	{
1116 		.compatible = "dallas,ds1388",
1117 		.data = (void *)ds_1388
1118 	},
1119 	{
1120 		.compatible = "dallas,ds1340",
1121 		.data = (void *)ds_1340
1122 	},
1123 	{
1124 		.compatible = "dallas,ds1341",
1125 		.data = (void *)ds_1341
1126 	},
1127 	{
1128 		.compatible = "maxim,ds3231",
1129 		.data = (void *)ds_3231
1130 	},
1131 	{
1132 		.compatible = "st,m41t0",
1133 		.data = (void *)m41t0
1134 	},
1135 	{
1136 		.compatible = "st,m41t00",
1137 		.data = (void *)m41t00
1138 	},
1139 	{
1140 		.compatible = "st,m41t11",
1141 		.data = (void *)m41t11
1142 	},
1143 	{
1144 		.compatible = "microchip,mcp7940x",
1145 		.data = (void *)mcp794xx
1146 	},
1147 	{
1148 		.compatible = "microchip,mcp7941x",
1149 		.data = (void *)mcp794xx
1150 	},
1151 	{
1152 		.compatible = "pericom,pt7c4338",
1153 		.data = (void *)ds_1307
1154 	},
1155 	{
1156 		.compatible = "epson,rx8025",
1157 		.data = (void *)rx_8025
1158 	},
1159 	{
1160 		.compatible = "isil,isl12057",
1161 		.data = (void *)ds_1337
1162 	},
1163 	{
1164 		.compatible = "epson,rx8130",
1165 		.data = (void *)rx_8130
1166 	},
1167 	{ }
1168 };
1169 MODULE_DEVICE_TABLE(of, ds1307_of_match);
1170 
1171 /*
1172  * The ds1337 and ds1339 both have two alarms, but we only use the first
1173  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
1174  * signal; ds1339 chips have only one alarm signal.
1175  */
1176 static irqreturn_t ds1307_irq(int irq, void *dev_id)
1177 {
1178 	struct ds1307		*ds1307 = dev_id;
1179 	struct mutex		*lock = &ds1307->rtc->ops_lock;
1180 	int			stat, ret;
1181 
1182 	mutex_lock(lock);
1183 	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
1184 	if (ret)
1185 		goto out;
1186 
1187 	if (stat & DS1337_BIT_A1I) {
1188 		stat &= ~DS1337_BIT_A1I;
1189 		regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
1190 
1191 		ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1192 					 DS1337_BIT_A1IE, 0);
1193 		if (ret)
1194 			goto out;
1195 
1196 		rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
1197 	}
1198 
1199 out:
1200 	mutex_unlock(lock);
1201 
1202 	return IRQ_HANDLED;
1203 }
1204 
1205 /*----------------------------------------------------------------------*/
1206 
1207 static const struct rtc_class_ops ds13xx_rtc_ops = {
1208 	.read_time	= ds1307_get_time,
1209 	.set_time	= ds1307_set_time,
1210 	.read_alarm	= ds1337_read_alarm,
1211 	.set_alarm	= ds1337_set_alarm,
1212 	.alarm_irq_enable = ds1307_alarm_irq_enable,
1213 };
1214 
1215 static ssize_t frequency_test_store(struct device *dev,
1216 				    struct device_attribute *attr,
1217 				    const char *buf, size_t count)
1218 {
1219 	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1220 	bool freq_test_en;
1221 	int ret;
1222 
1223 	ret = kstrtobool(buf, &freq_test_en);
1224 	if (ret) {
1225 		dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
1226 		return ret;
1227 	}
1228 
1229 	regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, M41TXX_BIT_FT,
1230 			   freq_test_en ? M41TXX_BIT_FT : 0);
1231 
1232 	return count;
1233 }
1234 
1235 static ssize_t frequency_test_show(struct device *dev,
1236 				   struct device_attribute *attr,
1237 				   char *buf)
1238 {
1239 	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1240 	unsigned int ctrl_reg;
1241 
1242 	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
1243 
1244 	return sysfs_emit(buf, (ctrl_reg & M41TXX_BIT_FT) ? "on\n" : "off\n");
1245 }
1246 
1247 static DEVICE_ATTR_RW(frequency_test);
1248 
1249 static struct attribute *rtc_freq_test_attrs[] = {
1250 	&dev_attr_frequency_test.attr,
1251 	NULL,
1252 };
1253 
1254 static const struct attribute_group rtc_freq_test_attr_group = {
1255 	.attrs		= rtc_freq_test_attrs,
1256 };
1257 
1258 static int ds1307_add_frequency_test(struct ds1307 *ds1307)
1259 {
1260 	int err;
1261 
1262 	switch (ds1307->type) {
1263 	case m41t0:
1264 	case m41t00:
1265 	case m41t11:
1266 		err = rtc_add_group(ds1307->rtc, &rtc_freq_test_attr_group);
1267 		if (err)
1268 			return err;
1269 		break;
1270 	default:
1271 		break;
1272 	}
1273 
1274 	return 0;
1275 }
1276 
1277 /*----------------------------------------------------------------------*/
1278 
1279 static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
1280 			     size_t bytes)
1281 {
1282 	struct ds1307 *ds1307 = priv;
1283 	const struct chip_desc *chip = &chips[ds1307->type];
1284 
1285 	return regmap_bulk_read(ds1307->regmap, chip->nvram_offset + offset,
1286 				val, bytes);
1287 }
1288 
1289 static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
1290 			      size_t bytes)
1291 {
1292 	struct ds1307 *ds1307 = priv;
1293 	const struct chip_desc *chip = &chips[ds1307->type];
1294 
1295 	return regmap_bulk_write(ds1307->regmap, chip->nvram_offset + offset,
1296 				 val, bytes);
1297 }
1298 
1299 /*----------------------------------------------------------------------*/
1300 
1301 static u8 ds1307_trickle_init(struct ds1307 *ds1307,
1302 			      const struct chip_desc *chip)
1303 {
1304 	u32 ohms, chargeable;
1305 	bool diode = chip->charge_default;
1306 
1307 	if (!chip->do_trickle_setup)
1308 		return 0;
1309 
1310 	if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
1311 				     &ohms) && chip->requires_trickle_resistor)
1312 		return 0;
1313 
1314 	/* aux-voltage-chargeable takes precedence over the deprecated
1315 	 * trickle-diode-disable
1316 	 */
1317 	if (!device_property_read_u32(ds1307->dev, "aux-voltage-chargeable",
1318 				     &chargeable)) {
1319 		switch (chargeable) {
1320 		case 0:
1321 			diode = false;
1322 			break;
1323 		case 1:
1324 			diode = true;
1325 			break;
1326 		default:
1327 			dev_warn(ds1307->dev,
1328 				 "unsupported aux-voltage-chargeable value\n");
1329 			break;
1330 		}
1331 	} else if (device_property_read_bool(ds1307->dev,
1332 					     "trickle-diode-disable")) {
1333 		diode = false;
1334 	}
1335 
1336 	return chip->do_trickle_setup(ds1307, ohms, diode);
1337 }
1338 
1339 /*----------------------------------------------------------------------*/
1340 
1341 #if IS_REACHABLE(CONFIG_HWMON)
1342 
1343 /*
1344  * Temperature sensor support for ds3231 devices.
1345  */
1346 
1347 #define DS3231_REG_TEMPERATURE	0x11
1348 
1349 /*
1350  * A user-initiated temperature conversion is not started by this function,
1351  * so the temperature is updated once every 64 seconds.
1352  */
1353 static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
1354 {
1355 	struct ds1307 *ds1307 = dev_get_drvdata(dev);
1356 	u8 temp_buf[2];
1357 	s16 temp;
1358 	int ret;
1359 
1360 	ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
1361 			       temp_buf, sizeof(temp_buf));
1362 	if (ret)
1363 		return ret;
1364 	/*
1365 	 * Temperature is represented as a 10-bit code with a resolution of
1366 	 * 0.25 degree celsius and encoded in two's complement format.
1367 	 */
1368 	temp = (temp_buf[0] << 8) | temp_buf[1];
1369 	temp >>= 6;
1370 	*mC = temp * 250;
1371 
1372 	return 0;
1373 }
1374 
1375 static ssize_t ds3231_hwmon_show_temp(struct device *dev,
1376 				      struct device_attribute *attr, char *buf)
1377 {
1378 	int ret;
1379 	s32 temp;
1380 
1381 	ret = ds3231_hwmon_read_temp(dev, &temp);
1382 	if (ret)
1383 		return ret;
1384 
1385 	return sprintf(buf, "%d\n", temp);
1386 }
1387 static SENSOR_DEVICE_ATTR(temp1_input, 0444, ds3231_hwmon_show_temp,
1388 			  NULL, 0);
1389 
1390 static struct attribute *ds3231_hwmon_attrs[] = {
1391 	&sensor_dev_attr_temp1_input.dev_attr.attr,
1392 	NULL,
1393 };
1394 ATTRIBUTE_GROUPS(ds3231_hwmon);
1395 
1396 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1397 {
1398 	struct device *dev;
1399 
1400 	if (ds1307->type != ds_3231)
1401 		return;
1402 
1403 	dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1404 						     ds1307,
1405 						     ds3231_hwmon_groups);
1406 	if (IS_ERR(dev)) {
1407 		dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1408 			 PTR_ERR(dev));
1409 	}
1410 }
1411 
1412 #else
1413 
1414 static void ds1307_hwmon_register(struct ds1307 *ds1307)
1415 {
1416 }
1417 
1418 #endif /* IS_REACHABLE(CONFIG_HWMON) */
1419 
1420 /*----------------------------------------------------------------------*/
1421 
1422 /*
1423  * Square-wave output support for DS3231
1424  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1425  */
1426 #ifdef CONFIG_COMMON_CLK
1427 
1428 enum {
1429 	DS3231_CLK_SQW = 0,
1430 	DS3231_CLK_32KHZ,
1431 };
1432 
1433 #define clk_sqw_to_ds1307(clk)	\
1434 	container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1435 #define clk_32khz_to_ds1307(clk)	\
1436 	container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1437 
1438 static int ds3231_clk_sqw_rates[] = {
1439 	1,
1440 	1024,
1441 	4096,
1442 	8192,
1443 };
1444 
1445 static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1446 {
1447 	struct mutex *lock = &ds1307->rtc->ops_lock;
1448 	int ret;
1449 
1450 	mutex_lock(lock);
1451 	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1452 				 mask, value);
1453 	mutex_unlock(lock);
1454 
1455 	return ret;
1456 }
1457 
1458 static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1459 						unsigned long parent_rate)
1460 {
1461 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1462 	int control, ret;
1463 	int rate_sel = 0;
1464 
1465 	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1466 	if (ret)
1467 		return ret;
1468 	if (control & DS1337_BIT_RS1)
1469 		rate_sel += 1;
1470 	if (control & DS1337_BIT_RS2)
1471 		rate_sel += 2;
1472 
1473 	return ds3231_clk_sqw_rates[rate_sel];
1474 }
1475 
1476 static int ds3231_clk_sqw_determine_rate(struct clk_hw *hw,
1477 					 struct clk_rate_request *req)
1478 {
1479 	int i;
1480 
1481 	for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1482 		if (ds3231_clk_sqw_rates[i] <= req->rate) {
1483 			req->rate = ds3231_clk_sqw_rates[i];
1484 
1485 			return 0;
1486 		}
1487 	}
1488 
1489 	req->rate = ds3231_clk_sqw_rates[ARRAY_SIZE(ds3231_clk_sqw_rates) - 1];
1490 
1491 	return 0;
1492 }
1493 
1494 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1495 				   unsigned long parent_rate)
1496 {
1497 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1498 	int control = 0;
1499 	int rate_sel;
1500 
1501 	for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1502 			rate_sel++) {
1503 		if (ds3231_clk_sqw_rates[rate_sel] == rate)
1504 			break;
1505 	}
1506 
1507 	if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1508 		return -EINVAL;
1509 
1510 	if (rate_sel & 1)
1511 		control |= DS1337_BIT_RS1;
1512 	if (rate_sel & 2)
1513 		control |= DS1337_BIT_RS2;
1514 
1515 	return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1516 				control);
1517 }
1518 
1519 static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1520 {
1521 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1522 
1523 	return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1524 }
1525 
1526 static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1527 {
1528 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1529 
1530 	ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1531 }
1532 
1533 static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1534 {
1535 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1536 	int control, ret;
1537 
1538 	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1539 	if (ret)
1540 		return ret;
1541 
1542 	return !(control & DS1337_BIT_INTCN);
1543 }
1544 
1545 static const struct clk_ops ds3231_clk_sqw_ops = {
1546 	.prepare = ds3231_clk_sqw_prepare,
1547 	.unprepare = ds3231_clk_sqw_unprepare,
1548 	.is_prepared = ds3231_clk_sqw_is_prepared,
1549 	.recalc_rate = ds3231_clk_sqw_recalc_rate,
1550 	.determine_rate = ds3231_clk_sqw_determine_rate,
1551 	.set_rate = ds3231_clk_sqw_set_rate,
1552 };
1553 
1554 static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1555 						  unsigned long parent_rate)
1556 {
1557 	return 32768;
1558 }
1559 
1560 static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1561 {
1562 	struct mutex *lock = &ds1307->rtc->ops_lock;
1563 	int ret;
1564 
1565 	mutex_lock(lock);
1566 	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1567 				 DS3231_BIT_EN32KHZ,
1568 				 enable ? DS3231_BIT_EN32KHZ : 0);
1569 	mutex_unlock(lock);
1570 
1571 	return ret;
1572 }
1573 
1574 static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1575 {
1576 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1577 
1578 	return ds3231_clk_32khz_control(ds1307, true);
1579 }
1580 
1581 static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1582 {
1583 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1584 
1585 	ds3231_clk_32khz_control(ds1307, false);
1586 }
1587 
1588 static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1589 {
1590 	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1591 	int status, ret;
1592 
1593 	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1594 	if (ret)
1595 		return ret;
1596 
1597 	return !!(status & DS3231_BIT_EN32KHZ);
1598 }
1599 
1600 static const struct clk_ops ds3231_clk_32khz_ops = {
1601 	.prepare = ds3231_clk_32khz_prepare,
1602 	.unprepare = ds3231_clk_32khz_unprepare,
1603 	.is_prepared = ds3231_clk_32khz_is_prepared,
1604 	.recalc_rate = ds3231_clk_32khz_recalc_rate,
1605 };
1606 
1607 static const char *ds3231_clks_names[] = {
1608 	[DS3231_CLK_SQW] = "ds3231_clk_sqw",
1609 	[DS3231_CLK_32KHZ] = "ds3231_clk_32khz",
1610 };
1611 
1612 static struct clk_init_data ds3231_clks_init[] = {
1613 	[DS3231_CLK_SQW] = {
1614 		.ops = &ds3231_clk_sqw_ops,
1615 	},
1616 	[DS3231_CLK_32KHZ] = {
1617 		.ops = &ds3231_clk_32khz_ops,
1618 	},
1619 };
1620 
1621 static int ds3231_clks_register(struct ds1307 *ds1307)
1622 {
1623 	struct device_node *node = ds1307->dev->of_node;
1624 	struct clk_onecell_data	*onecell;
1625 	int i;
1626 
1627 	onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1628 	if (!onecell)
1629 		return -ENOMEM;
1630 
1631 	onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1632 	onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1633 				     sizeof(onecell->clks[0]), GFP_KERNEL);
1634 	if (!onecell->clks)
1635 		return -ENOMEM;
1636 
1637 	/* optional override of the clockname */
1638 	device_property_read_string_array(ds1307->dev, "clock-output-names",
1639 					  ds3231_clks_names,
1640 					  ARRAY_SIZE(ds3231_clks_names));
1641 
1642 	for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1643 		struct clk_init_data init = ds3231_clks_init[i];
1644 
1645 		/*
1646 		 * Interrupt signal due to alarm conditions and square-wave
1647 		 * output share same pin, so don't initialize both.
1648 		 */
1649 		if (i == DS3231_CLK_SQW && test_bit(RTC_FEATURE_ALARM, ds1307->rtc->features))
1650 			continue;
1651 
1652 		init.name = ds3231_clks_names[i];
1653 		ds1307->clks[i].init = &init;
1654 
1655 		onecell->clks[i] = devm_clk_register(ds1307->dev,
1656 						     &ds1307->clks[i]);
1657 		if (IS_ERR(onecell->clks[i]))
1658 			return PTR_ERR(onecell->clks[i]);
1659 	}
1660 
1661 	if (node)
1662 		of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1663 
1664 	return 0;
1665 }
1666 
1667 /* ds1307 RTC clock output support */
1668 static unsigned long ds1307_clk_rates[] = {
1669 	1,
1670 	4096,
1671 	8192,
1672 	32768,
1673 };
1674 
1675 static unsigned long ds1307_clk_sqw_recalc_rate(struct clk_hw *hw,
1676 						  unsigned long parent_rate)
1677 {
1678 	int ret;
1679 	unsigned int rate_id;
1680 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1681 
1682 	ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &rate_id);
1683 	if (ret)
1684 		return ret;
1685 
1686 	rate_id &= (DS1307_BIT_RS1 | DS1307_BIT_RS0);
1687 
1688 	return ds1307_clk_rates[rate_id];
1689 }
1690 
1691 static int ds1307_clk_sqw_determine_rate(struct clk_hw *hw,
1692 					 struct clk_rate_request *req)
1693 {
1694 	int i;
1695 
1696 	for (i = 0; i < ARRAY_SIZE(ds1307_clk_rates); i++) {
1697 		if (req->rate <= ds1307_clk_rates[i]) {
1698 			req->rate = ds1307_clk_rates[i];
1699 			return 0;
1700 		}
1701 	}
1702 
1703 	/* Default rate 1Hz */
1704 	req->rate = ds1307_clk_rates[0];
1705 
1706 	return 0;
1707 }
1708 
1709 static int ds1307_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1710 				   unsigned long parent_rate)
1711 {
1712 	int id, ret;
1713 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1714 
1715 	for (id = 0; id < ARRAY_SIZE(ds1307_clk_rates); id++) {
1716 		if (ds1307_clk_rates[id] == rate)
1717 			break;
1718 	}
1719 
1720 	if (id >= ARRAY_SIZE(ds1307_clk_rates))
1721 		return -EINVAL;
1722 
1723 	ret = regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
1724 				 DS1307_BIT_RS0 | DS1307_BIT_RS1, id);
1725 
1726 	return ret;
1727 }
1728 
1729 static int ds1307_clk_sqw_prepare(struct clk_hw *hw)
1730 {
1731 	int ret;
1732 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1733 
1734 	ret = regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
1735 				 DS1307_BIT_SQWE, DS1307_BIT_SQWE);
1736 
1737 	return ret;
1738 }
1739 
1740 static void ds1307_clk_sqw_unprepare(struct clk_hw *hw)
1741 {
1742 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1743 
1744 	regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
1745 			   DS1307_BIT_SQWE, ~DS1307_BIT_SQWE);
1746 }
1747 
1748 static int ds1307_clk_sqw_is_prepared(struct clk_hw *hw)
1749 {
1750 	int ret;
1751 	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1752 	unsigned int status;
1753 
1754 	ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &status);
1755 	if (ret)
1756 		return ret;
1757 
1758 	return !!(status & DS1307_BIT_SQWE);
1759 }
1760 
1761 static const struct clk_ops ds1307_clk_sqw_ops = {
1762 	.prepare = ds1307_clk_sqw_prepare,
1763 	.unprepare = ds1307_clk_sqw_unprepare,
1764 	.is_prepared = ds1307_clk_sqw_is_prepared,
1765 	.recalc_rate = ds1307_clk_sqw_recalc_rate,
1766 	.set_rate = ds1307_clk_sqw_set_rate,
1767 	.determine_rate = ds1307_clk_sqw_determine_rate,
1768 };
1769 
1770 static int rtc_ds1307_clks_register(struct ds1307 *ds1307)
1771 {
1772 	struct device_node *node = ds1307->dev->of_node;
1773 	struct clk *clk;
1774 	struct clk_init_data init = {0};
1775 
1776 	init.name = "ds1307_clk_sqw";
1777 	init.ops = &ds1307_clk_sqw_ops;
1778 
1779 	ds1307->clks[0].init = &init;
1780 
1781 	/* Register the clock with CCF */
1782 	clk = devm_clk_register(ds1307->dev, &ds1307->clks[0]);
1783 	if (IS_ERR(clk))
1784 		return PTR_ERR(clk);
1785 
1786 	if (node)
1787 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
1788 
1789 	return 0;
1790 }
1791 
1792 static void ds1307_clks_register(struct ds1307 *ds1307)
1793 {
1794 	int ret;
1795 
1796 	switch (ds1307->type) {
1797 	case ds_3231:
1798 		ret = ds3231_clks_register(ds1307);
1799 		break;
1800 
1801 	case ds_1307:
1802 		ret = rtc_ds1307_clks_register(ds1307);
1803 		break;
1804 
1805 	default:
1806 		return;
1807 	}
1808 
1809 	if (ret) {
1810 		dev_warn(ds1307->dev, "unable to register clock device %d\n",
1811 			 ret);
1812 	}
1813 
1814 }
1815 
1816 #else
1817 
1818 static void ds1307_clks_register(struct ds1307 *ds1307)
1819 {
1820 }
1821 
1822 #endif /* CONFIG_COMMON_CLK */
1823 
1824 #ifdef CONFIG_WATCHDOG_CORE
1825 static const struct watchdog_info ds1388_wdt_info = {
1826 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
1827 	.identity = "DS1388 watchdog",
1828 };
1829 
1830 static const struct watchdog_ops ds1388_wdt_ops = {
1831 	.owner = THIS_MODULE,
1832 	.start = ds1388_wdt_start,
1833 	.stop = ds1388_wdt_stop,
1834 	.ping = ds1388_wdt_ping,
1835 	.set_timeout = ds1388_wdt_set_timeout,
1836 
1837 };
1838 
1839 static void ds1307_wdt_register(struct ds1307 *ds1307)
1840 {
1841 	struct watchdog_device	*wdt;
1842 	int err;
1843 	int val;
1844 
1845 	if (ds1307->type != ds_1388)
1846 		return;
1847 
1848 	wdt = devm_kzalloc(ds1307->dev, sizeof(*wdt), GFP_KERNEL);
1849 	if (!wdt)
1850 		return;
1851 
1852 	err = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
1853 	if (!err && val & DS1388_BIT_WF)
1854 		wdt->bootstatus = WDIOF_CARDRESET;
1855 
1856 	wdt->info = &ds1388_wdt_info;
1857 	wdt->ops = &ds1388_wdt_ops;
1858 	wdt->timeout = 99;
1859 	wdt->max_timeout = 99;
1860 	wdt->min_timeout = 1;
1861 
1862 	watchdog_init_timeout(wdt, 0, ds1307->dev);
1863 	watchdog_set_drvdata(wdt, ds1307);
1864 	devm_watchdog_register_device(ds1307->dev, wdt);
1865 }
1866 #else
1867 static void ds1307_wdt_register(struct ds1307 *ds1307)
1868 {
1869 }
1870 #endif /* CONFIG_WATCHDOG_CORE */
1871 
1872 static const struct regmap_config regmap_config = {
1873 	.reg_bits = 8,
1874 	.val_bits = 8,
1875 };
1876 
1877 static int ds1307_probe(struct i2c_client *client)
1878 {
1879 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
1880 	struct ds1307		*ds1307;
1881 	const void		*match;
1882 	int			err = -ENODEV;
1883 	int			tmp;
1884 	const struct chip_desc	*chip;
1885 	bool			want_irq;
1886 	bool			ds1307_can_wakeup_device = false;
1887 	unsigned char		regs[8];
1888 	struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1889 	u8			trickle_charger_setup = 0;
1890 
1891 	ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1892 	if (!ds1307)
1893 		return -ENOMEM;
1894 
1895 	dev_set_drvdata(&client->dev, ds1307);
1896 	ds1307->dev = &client->dev;
1897 	ds1307->name = client->name;
1898 
1899 	ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1900 	if (IS_ERR(ds1307->regmap)) {
1901 		dev_err(ds1307->dev, "regmap allocation failed\n");
1902 		return PTR_ERR(ds1307->regmap);
1903 	}
1904 
1905 	i2c_set_clientdata(client, ds1307);
1906 
1907 	match = device_get_match_data(&client->dev);
1908 	if (match) {
1909 		ds1307->type = (uintptr_t)match;
1910 		chip = &chips[ds1307->type];
1911 	} else if (id) {
1912 		chip = &chips[id->driver_data];
1913 		ds1307->type = id->driver_data;
1914 	} else {
1915 		return -ENODEV;
1916 	}
1917 
1918 	want_irq = client->irq > 0 && chip->alarm;
1919 
1920 	if (!pdata)
1921 		trickle_charger_setup = ds1307_trickle_init(ds1307, chip);
1922 	else if (pdata->trickle_charger_setup)
1923 		trickle_charger_setup = pdata->trickle_charger_setup;
1924 
1925 	if (trickle_charger_setup && chip->trickle_charger_reg) {
1926 		dev_dbg(ds1307->dev,
1927 			"writing trickle charger info 0x%x to 0x%x\n",
1928 			trickle_charger_setup, chip->trickle_charger_reg);
1929 		regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1930 			     trickle_charger_setup);
1931 	}
1932 
1933 /*
1934  * For devices with no IRQ directly connected to the SoC, the RTC chip
1935  * can be forced as a wakeup source by stating that explicitly in
1936  * the device's .dts file using the "wakeup-source" boolean property.
1937  * If the "wakeup-source" property is set, don't request an IRQ.
1938  * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1939  * if supported by the RTC.
1940  */
1941 	if (chip->alarm && device_property_read_bool(&client->dev, "wakeup-source"))
1942 		ds1307_can_wakeup_device = true;
1943 
1944 	switch (ds1307->type) {
1945 	case ds_1337:
1946 	case ds_1339:
1947 	case ds_1341:
1948 	case ds_3231:
1949 		/* get registers that the "rtc" read below won't read... */
1950 		err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1951 				       regs, 2);
1952 		if (err) {
1953 			dev_dbg(ds1307->dev, "read error %d\n", err);
1954 			goto exit;
1955 		}
1956 
1957 		/* oscillator off?  turn it on, so clock can tick. */
1958 		if (regs[0] & DS1337_BIT_nEOSC)
1959 			regs[0] &= ~DS1337_BIT_nEOSC;
1960 
1961 		/*
1962 		 * Using IRQ or defined as wakeup-source?
1963 		 * Disable the square wave and both alarms.
1964 		 * For some variants, be sure alarms can trigger when we're
1965 		 * running on Vbackup (BBSQI/BBSQW)
1966 		 */
1967 		if (want_irq || ds1307_can_wakeup_device)
1968 			regs[0] |= DS1337_BIT_INTCN | chip->bbsqi_bit;
1969 
1970 		regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1971 			     regs[0]);
1972 
1973 		/* oscillator fault? warn */
1974 		if (regs[1] & DS1337_BIT_OSF) {
1975 			dev_warn(ds1307->dev, "SET TIME!\n");
1976 		}
1977 		break;
1978 
1979 	case rx_8025:
1980 		err = regmap_bulk_read(ds1307->regmap,
1981 				       RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
1982 		if (err) {
1983 			dev_dbg(ds1307->dev, "read error %d\n", err);
1984 			goto exit;
1985 		}
1986 
1987 		/* oscillator off?  turn it on, so clock can tick. */
1988 		if (!(regs[1] & RX8025_BIT_XST)) {
1989 			regs[1] |= RX8025_BIT_XST;
1990 			regmap_write(ds1307->regmap,
1991 				     RX8025_REG_CTRL2 << 4 | 0x08,
1992 				     regs[1]);
1993 			dev_warn(ds1307->dev,
1994 				 "oscillator stop detected - SET TIME!\n");
1995 		}
1996 
1997 		if (regs[1] & RX8025_BIT_PON) {
1998 			regs[1] &= ~RX8025_BIT_PON;
1999 			regmap_write(ds1307->regmap,
2000 				     RX8025_REG_CTRL2 << 4 | 0x08,
2001 				     regs[1]);
2002 			dev_warn(ds1307->dev, "power-on detected\n");
2003 		}
2004 
2005 		if (regs[1] & RX8025_BIT_VDET) {
2006 			regs[1] &= ~RX8025_BIT_VDET;
2007 			regmap_write(ds1307->regmap,
2008 				     RX8025_REG_CTRL2 << 4 | 0x08,
2009 				     regs[1]);
2010 			dev_warn(ds1307->dev, "voltage drop detected\n");
2011 		}
2012 
2013 		/* make sure we are running in 24hour mode */
2014 		if (!(regs[0] & RX8025_BIT_2412)) {
2015 			u8 hour;
2016 
2017 			/* switch to 24 hour mode */
2018 			regmap_write(ds1307->regmap,
2019 				     RX8025_REG_CTRL1 << 4 | 0x08,
2020 				     regs[0] | RX8025_BIT_2412);
2021 
2022 			err = regmap_bulk_read(ds1307->regmap,
2023 					       RX8025_REG_CTRL1 << 4 | 0x08,
2024 					       regs, 2);
2025 			if (err) {
2026 				dev_dbg(ds1307->dev, "read error %d\n", err);
2027 				goto exit;
2028 			}
2029 
2030 			/* correct hour */
2031 			hour = bcd2bin(regs[DS1307_REG_HOUR]);
2032 			if (hour == 12)
2033 				hour = 0;
2034 			if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
2035 				hour += 12;
2036 
2037 			regmap_write(ds1307->regmap,
2038 				     DS1307_REG_HOUR << 4 | 0x08, hour);
2039 		}
2040 		break;
2041 	case ds_1388:
2042 		err = regmap_read(ds1307->regmap, DS1388_REG_CONTROL, &tmp);
2043 		if (err) {
2044 			dev_dbg(ds1307->dev, "read error %d\n", err);
2045 			goto exit;
2046 		}
2047 
2048 		/* oscillator off?  turn it on, so clock can tick. */
2049 		if (tmp & DS1388_BIT_nEOSC) {
2050 			tmp &= ~DS1388_BIT_nEOSC;
2051 			regmap_write(ds1307->regmap, DS1388_REG_CONTROL, tmp);
2052 		}
2053 		break;
2054 	default:
2055 		break;
2056 	}
2057 
2058 	/* read RTC registers */
2059 	err = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
2060 			       sizeof(regs));
2061 	if (err) {
2062 		dev_dbg(ds1307->dev, "read error %d\n", err);
2063 		goto exit;
2064 	}
2065 
2066 	if (ds1307->type == mcp794xx &&
2067 	    !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
2068 		regmap_write(ds1307->regmap, DS1307_REG_WDAY,
2069 			     regs[DS1307_REG_WDAY] |
2070 			     MCP794XX_BIT_VBATEN);
2071 	}
2072 
2073 	tmp = regs[DS1307_REG_HOUR];
2074 	switch (ds1307->type) {
2075 	case ds_1340:
2076 	case m41t0:
2077 	case m41t00:
2078 	case m41t11:
2079 		/*
2080 		 * NOTE: ignores century bits; fix before deploying
2081 		 * systems that will run through year 2100.
2082 		 */
2083 		break;
2084 	case rx_8025:
2085 		break;
2086 	default:
2087 		if (!(tmp & DS1307_BIT_12HR))
2088 			break;
2089 
2090 		/*
2091 		 * Be sure we're in 24 hour mode.  Multi-master systems
2092 		 * take note...
2093 		 */
2094 		tmp = bcd2bin(tmp & 0x1f);
2095 		if (tmp == 12)
2096 			tmp = 0;
2097 		if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
2098 			tmp += 12;
2099 		regmap_write(ds1307->regmap, chip->offset + DS1307_REG_HOUR,
2100 			     bin2bcd(tmp));
2101 	}
2102 
2103 	ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
2104 	if (IS_ERR(ds1307->rtc))
2105 		return PTR_ERR(ds1307->rtc);
2106 
2107 	if (want_irq || ds1307_can_wakeup_device)
2108 		device_set_wakeup_capable(ds1307->dev, true);
2109 	else
2110 		clear_bit(RTC_FEATURE_ALARM, ds1307->rtc->features);
2111 
2112 	if (ds1307_can_wakeup_device && !want_irq) {
2113 		dev_info(ds1307->dev,
2114 			 "'wakeup-source' is set, request for an IRQ is disabled!\n");
2115 		/* We cannot support UIE mode if we do not have an IRQ line */
2116 		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, ds1307->rtc->features);
2117 	}
2118 
2119 	if (want_irq) {
2120 		err = devm_request_threaded_irq(ds1307->dev, client->irq, NULL,
2121 						chip->irq_handler ?: ds1307_irq,
2122 						IRQF_SHARED | IRQF_ONESHOT,
2123 						ds1307->name, ds1307);
2124 		if (err) {
2125 			client->irq = 0;
2126 			device_set_wakeup_capable(ds1307->dev, false);
2127 			clear_bit(RTC_FEATURE_ALARM, ds1307->rtc->features);
2128 			dev_err(ds1307->dev, "unable to request IRQ!\n");
2129 		} else {
2130 			dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
2131 		}
2132 	}
2133 
2134 	ds1307->rtc->ops = chip->rtc_ops ?: &ds13xx_rtc_ops;
2135 	err = ds1307_add_frequency_test(ds1307);
2136 	if (err)
2137 		return err;
2138 
2139 	err = devm_rtc_register_device(ds1307->rtc);
2140 	if (err)
2141 		return err;
2142 
2143 	if (chip->nvram_size) {
2144 		struct nvmem_config nvmem_cfg = {
2145 			.name = "ds1307_nvram",
2146 			.word_size = 1,
2147 			.stride = 1,
2148 			.size = chip->nvram_size,
2149 			.reg_read = ds1307_nvram_read,
2150 			.reg_write = ds1307_nvram_write,
2151 			.priv = ds1307,
2152 		};
2153 
2154 		devm_rtc_nvmem_register(ds1307->rtc, &nvmem_cfg);
2155 	}
2156 
2157 	ds1307_hwmon_register(ds1307);
2158 	ds1307_clks_register(ds1307);
2159 	ds1307_wdt_register(ds1307);
2160 
2161 	return 0;
2162 
2163 exit:
2164 	return err;
2165 }
2166 
2167 static struct i2c_driver ds1307_driver = {
2168 	.driver = {
2169 		.name	= "rtc-ds1307",
2170 		.of_match_table = ds1307_of_match,
2171 	},
2172 	.probe		= ds1307_probe,
2173 	.id_table	= ds1307_id,
2174 };
2175 
2176 module_i2c_driver(ds1307_driver);
2177 
2178 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
2179 MODULE_LICENSE("GPL");
2180