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/acpi.h>
12#include <linux/bcd.h>
13#include <linux/i2c.h>
14#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/of_device.h>
17#include <linux/rtc/ds1307.h>
18#include <linux/rtc.h>
19#include <linux/slab.h>
20#include <linux/string.h>
21#include <linux/hwmon.h>
22#include <linux/hwmon-sysfs.h>
23#include <linux/clk-provider.h>
24#include <linux/regmap.h>
25#include <linux/watchdog.h>
26
27/*
28 * We can't determine type by probing, but if we expect pre-Linux code
29 * to have set the chip up as a clock (turning on the oscillator and
30 * setting the date and time), Linux can ignore the non-clock features.
31 * That's a natural job for a factory or repair bench.
32 */
33enum ds_type {
34	ds_1307,
35	ds_1308,
36	ds_1337,
37	ds_1338,
38	ds_1339,
39	ds_1340,
40	ds_1341,
41	ds_1388,
42	ds_3231,
43	m41t0,
44	m41t00,
45	m41t11,
46	mcp794xx,
47	rx_8025,
48	rx_8130,
49	last_ds_type /* always last */
50	/* rs5c372 too?  different address... */
51};
52
53/* RTC registers don't differ much, except for the century flag */
54#define DS1307_REG_SECS		0x00	/* 00-59 */
55#	define DS1307_BIT_CH		0x80
56#	define DS1340_BIT_nEOSC		0x80
57#	define MCP794XX_BIT_ST		0x80
58#define DS1307_REG_MIN		0x01	/* 00-59 */
59#	define M41T0_BIT_OF		0x80
60#define DS1307_REG_HOUR		0x02	/* 00-23, or 1-12{am,pm} */
61#	define DS1307_BIT_12HR		0x40	/* in REG_HOUR */
62#	define DS1307_BIT_PM		0x20	/* in REG_HOUR */
63#	define DS1340_BIT_CENTURY_EN	0x80	/* in REG_HOUR */
64#	define DS1340_BIT_CENTURY	0x40	/* in REG_HOUR */
65#define DS1307_REG_WDAY		0x03	/* 01-07 */
66#	define MCP794XX_BIT_VBATEN	0x08
67#define DS1307_REG_MDAY		0x04	/* 01-31 */
68#define DS1307_REG_MONTH	0x05	/* 01-12 */
69#	define DS1337_BIT_CENTURY	0x80	/* in REG_MONTH */
70#define DS1307_REG_YEAR		0x06	/* 00-99 */
71
72/*
73 * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
74 * start at 7, and they differ a LOT. Only control and status matter for
75 * basic RTC date and time functionality; be careful using them.
76 */
77#define DS1307_REG_CONTROL	0x07		/* or ds1338 */
78#	define DS1307_BIT_OUT		0x80
79#	define DS1338_BIT_OSF		0x20
80#	define DS1307_BIT_SQWE		0x10
81#	define DS1307_BIT_RS1		0x02
82#	define DS1307_BIT_RS0		0x01
83#define DS1337_REG_CONTROL	0x0e
84#	define DS1337_BIT_nEOSC		0x80
85#	define DS1339_BIT_BBSQI		0x20
86#	define DS3231_BIT_BBSQW		0x40 /* same as BBSQI */
87#	define DS1337_BIT_RS2		0x10
88#	define DS1337_BIT_RS1		0x08
89#	define DS1337_BIT_INTCN		0x04
90#	define DS1337_BIT_A2IE		0x02
91#	define DS1337_BIT_A1IE		0x01
92#define DS1340_REG_CONTROL	0x07
93#	define DS1340_BIT_OUT		0x80
94#	define DS1340_BIT_FT		0x40
95#	define DS1340_BIT_CALIB_SIGN	0x20
96#	define DS1340_M_CALIBRATION	0x1f
97#define DS1340_REG_FLAG		0x09
98#	define DS1340_BIT_OSF		0x80
99#define DS1337_REG_STATUS	0x0f
100#	define DS1337_BIT_OSF		0x80
101#	define DS3231_BIT_EN32KHZ	0x08
102#	define DS1337_BIT_A2I		0x02
103#	define DS1337_BIT_A1I		0x01
104#define DS1339_REG_ALARM1_SECS	0x07
105
106#define DS13XX_TRICKLE_CHARGER_MAGIC	0xa0
107
108#define RX8025_REG_CTRL1	0x0e
109#	define RX8025_BIT_2412		0x20
110#define RX8025_REG_CTRL2	0x0f
111#	define RX8025_BIT_PON		0x10
112#	define RX8025_BIT_VDET		0x40
113#	define RX8025_BIT_XST		0x20
114
115#define RX8130_REG_ALARM_MIN		0x17
116#define RX8130_REG_ALARM_HOUR		0x18
117#define RX8130_REG_ALARM_WEEK_OR_DAY	0x19
118#define RX8130_REG_EXTENSION		0x1c
119#define RX8130_REG_EXTENSION_WADA	BIT(3)
120#define RX8130_REG_FLAG			0x1d
121#define RX8130_REG_FLAG_VLF		BIT(1)
122#define RX8130_REG_FLAG_AF		BIT(3)
123#define RX8130_REG_CONTROL0		0x1e
124#define RX8130_REG_CONTROL0_AIE		BIT(3)
125#define RX8130_REG_CONTROL1		0x1f
126#define RX8130_REG_CONTROL1_INIEN	BIT(4)
127#define RX8130_REG_CONTROL1_CHGEN	BIT(5)
128
129#define MCP794XX_REG_CONTROL		0x07
130#	define MCP794XX_BIT_ALM0_EN	0x10
131#	define MCP794XX_BIT_ALM1_EN	0x20
132#define MCP794XX_REG_ALARM0_BASE	0x0a
133#define MCP794XX_REG_ALARM0_CTRL	0x0d
134#define MCP794XX_REG_ALARM1_BASE	0x11
135#define MCP794XX_REG_ALARM1_CTRL	0x14
136#	define MCP794XX_BIT_ALMX_IF	BIT(3)
137#	define MCP794XX_BIT_ALMX_C0	BIT(4)
138#	define MCP794XX_BIT_ALMX_C1	BIT(5)
139#	define MCP794XX_BIT_ALMX_C2	BIT(6)
140#	define MCP794XX_BIT_ALMX_POL	BIT(7)
141#	define MCP794XX_MSK_ALMX_MATCH	(MCP794XX_BIT_ALMX_C0 | \
142					 MCP794XX_BIT_ALMX_C1 | \
143					 MCP794XX_BIT_ALMX_C2)
144
145#define M41TXX_REG_CONTROL	0x07
146#	define M41TXX_BIT_OUT		BIT(7)
147#	define M41TXX_BIT_FT		BIT(6)
148#	define M41TXX_BIT_CALIB_SIGN	BIT(5)
149#	define M41TXX_M_CALIBRATION	GENMASK(4, 0)
150
151#define DS1388_REG_WDOG_HUN_SECS	0x08
152#define DS1388_REG_WDOG_SECS		0x09
153#define DS1388_REG_FLAG			0x0b
154#	define DS1388_BIT_WF		BIT(6)
155#	define DS1388_BIT_OSF		BIT(7)
156#define DS1388_REG_CONTROL		0x0c
157#	define DS1388_BIT_RST		BIT(0)
158#	define DS1388_BIT_WDE		BIT(1)
159#	define DS1388_BIT_nEOSC		BIT(7)
160
161/* negative offset step is -2.034ppm */
162#define M41TXX_NEG_OFFSET_STEP_PPB	2034
163/* positive offset step is +4.068ppm */
164#define M41TXX_POS_OFFSET_STEP_PPB	4068
165/* Min and max values supported with 'offset' interface by M41TXX */
166#define M41TXX_MIN_OFFSET	((-31) * M41TXX_NEG_OFFSET_STEP_PPB)
167#define M41TXX_MAX_OFFSET	((31) * M41TXX_POS_OFFSET_STEP_PPB)
168
169struct ds1307 {
170	enum ds_type		type;
171	unsigned long		flags;
172#define HAS_NVRAM	0		/* bit 0 == sysfs file active */
173#define HAS_ALARM	1		/* bit 1 == irq claimed */
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
183struct 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
208static const struct chip_desc chips[last_ds_type];
209
210static 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	}
247
248	tmp = regs[DS1307_REG_SECS];
249	switch (ds1307->type) {
250	case ds_1307:
251	case m41t0:
252	case m41t00:
253	case m41t11:
254		if (tmp & DS1307_BIT_CH)
255			return -EINVAL;
256		break;
257	case ds_1308:
258	case ds_1338:
259		if (tmp & DS1307_BIT_CH)
260			return -EINVAL;
261
262		ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &tmp);
263		if (ret)
264			return ret;
265		if (tmp & DS1338_BIT_OSF)
266			return -EINVAL;
267		break;
268	case ds_1340:
269		if (tmp & DS1340_BIT_nEOSC)
270			return -EINVAL;
271
272		ret = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
273		if (ret)
274			return ret;
275		if (tmp & DS1340_BIT_OSF)
276			return -EINVAL;
277		break;
278	case ds_1388:
279		ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &tmp);
280		if (ret)
281			return ret;
282		if (tmp & DS1388_BIT_OSF)
283			return -EINVAL;
284		break;
285	case mcp794xx:
286		if (!(tmp & MCP794XX_BIT_ST))
287			return -EINVAL;
288
289		break;
290	default:
291		break;
292	}
293
294	t->tm_sec = bcd2bin(regs[DS1307_REG_SECS] & 0x7f);
295	t->tm_min = bcd2bin(regs[DS1307_REG_MIN] & 0x7f);
296	tmp = regs[DS1307_REG_HOUR] & 0x3f;
297	t->tm_hour = bcd2bin(tmp);
298	/* rx8130 is bit position, not BCD */
299	if (ds1307->type == rx_8130)
300		t->tm_wday = fls(regs[DS1307_REG_WDAY] & 0x7f);
301	else
302		t->tm_wday = bcd2bin(regs[DS1307_REG_WDAY] & 0x07) - 1;
303	t->tm_mday = bcd2bin(regs[DS1307_REG_MDAY] & 0x3f);
304	tmp = regs[DS1307_REG_MONTH] & 0x1f;
305	t->tm_mon = bcd2bin(tmp) - 1;
306	t->tm_year = bcd2bin(regs[DS1307_REG_YEAR]) + 100;
307
308	if (regs[chip->century_reg] & chip->century_bit &&
309	    IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
310		t->tm_year += 100;
311
312	dev_dbg(dev, "%s secs=%d, mins=%d, "
313		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
314		"read", t->tm_sec, t->tm_min,
315		t->tm_hour, t->tm_mday,
316		t->tm_mon, t->tm_year, t->tm_wday);
317
318	return 0;
319}
320
321static int ds1307_set_time(struct device *dev, struct rtc_time *t)
322{
323	struct ds1307	*ds1307 = dev_get_drvdata(dev);
324	const struct chip_desc *chip = &chips[ds1307->type];
325	int		result;
326	int		tmp;
327	u8		regs[7];
328
329	dev_dbg(dev, "%s secs=%d, mins=%d, "
330		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
331		"write", t->tm_sec, t->tm_min,
332		t->tm_hour, t->tm_mday,
333		t->tm_mon, t->tm_year, t->tm_wday);
334
335	if (t->tm_year < 100)
336		return -EINVAL;
337
338#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
339	if (t->tm_year > (chip->century_bit ? 299 : 199))
340		return -EINVAL;
341#else
342	if (t->tm_year > 199)
343		return -EINVAL;
344#endif
345
346	regs[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
347	regs[DS1307_REG_MIN] = bin2bcd(t->tm_min);
348	regs[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
349	/* rx8130 is bit position, not BCD */
350	if (ds1307->type == rx_8130)
351		regs[DS1307_REG_WDAY] = 1 << t->tm_wday;
352	else
353		regs[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
354	regs[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
355	regs[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
356
357	/* assume 20YY not 19YY */
358	tmp = t->tm_year - 100;
359	regs[DS1307_REG_YEAR] = bin2bcd(tmp);
360
361	if (chip->century_enable_bit)
362		regs[chip->century_reg] |= chip->century_enable_bit;
363	if (t->tm_year > 199 && chip->century_bit)
364		regs[chip->century_reg] |= chip->century_bit;
365
366	switch (ds1307->type) {
367	case ds_1308:
368	case ds_1338:
369		regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
370				   DS1338_BIT_OSF, 0);
371		break;
372	case ds_1340:
373		regmap_update_bits(ds1307->regmap, DS1340_REG_FLAG,
374				   DS1340_BIT_OSF, 0);
375		break;
376	case ds_1388:
377		regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
378				   DS1388_BIT_OSF, 0);
379		break;
380	case mcp794xx:
381		/*
382		 * these bits were cleared when preparing the date/time
383		 * values and need to be set again before writing the
384		 * regsfer out to the device.
385		 */
386		regs[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
387		regs[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
388		break;
389	default:
390		break;
391	}
392
393	dev_dbg(dev, "%s: %7ph\n", "write", regs);
394
395	result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
396				   sizeof(regs));
397	if (result) {
398		dev_err(dev, "%s error %d\n", "write", result);
399		return result;
400	}
401
402	if (ds1307->type == rx_8130) {
403		/* clear Voltage Loss Flag as data is available now */
404		result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
405				      ~(u8)RX8130_REG_FLAG_VLF);
406		if (result) {
407			dev_err(dev, "%s error %d\n", "write", result);
408			return result;
409		}
410	}
411
412	return 0;
413}
414
415static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
416{
417	struct ds1307		*ds1307 = dev_get_drvdata(dev);
418	int			ret;
419	u8			regs[9];
420
421	if (!test_bit(HAS_ALARM, &ds1307->flags))
422		return -EINVAL;
423
424	/* read all ALARM1, ALARM2, and status registers at once */
425	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
426			       regs, sizeof(regs));
427	if (ret) {
428		dev_err(dev, "%s error %d\n", "alarm read", ret);
429		return ret;
430	}
431
432	dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
433		&regs[0], &regs[4], &regs[7]);
434
435	/*
436	 * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
437	 * and that all four fields are checked matches
438	 */
439	t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
440	t->time.tm_min = bcd2bin(regs[1] & 0x7f);
441	t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
442	t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
443
444	/* ... and status */
445	t->enabled = !!(regs[7] & DS1337_BIT_A1IE);
446	t->pending = !!(regs[8] & DS1337_BIT_A1I);
447
448	dev_dbg(dev, "%s secs=%d, mins=%d, "
449		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
450		"alarm read", t->time.tm_sec, t->time.tm_min,
451		t->time.tm_hour, t->time.tm_mday,
452		t->enabled, t->pending);
453
454	return 0;
455}
456
457static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
458{
459	struct ds1307		*ds1307 = dev_get_drvdata(dev);
460	unsigned char		regs[9];
461	u8			control, status;
462	int			ret;
463
464	if (!test_bit(HAS_ALARM, &ds1307->flags))
465		return -EINVAL;
466
467	dev_dbg(dev, "%s secs=%d, mins=%d, "
468		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
469		"alarm set", t->time.tm_sec, t->time.tm_min,
470		t->time.tm_hour, t->time.tm_mday,
471		t->enabled, t->pending);
472
473	/* read current status of both alarms and the chip */
474	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
475			       sizeof(regs));
476	if (ret) {
477		dev_err(dev, "%s error %d\n", "alarm write", ret);
478		return ret;
479	}
480	control = regs[7];
481	status = regs[8];
482
483	dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
484		&regs[0], &regs[4], control, status);
485
486	/* set ALARM1, using 24 hour and day-of-month modes */
487	regs[0] = bin2bcd(t->time.tm_sec);
488	regs[1] = bin2bcd(t->time.tm_min);
489	regs[2] = bin2bcd(t->time.tm_hour);
490	regs[3] = bin2bcd(t->time.tm_mday);
491
492	/* set ALARM2 to non-garbage */
493	regs[4] = 0;
494	regs[5] = 0;
495	regs[6] = 0;
496
497	/* disable alarms */
498	regs[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
499	regs[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
500
501	ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
502				sizeof(regs));
503	if (ret) {
504		dev_err(dev, "can't set alarm time\n");
505		return ret;
506	}
507
508	/* optionally enable ALARM1 */
509	if (t->enabled) {
510		dev_dbg(dev, "alarm IRQ armed\n");
511		regs[7] |= DS1337_BIT_A1IE;	/* only ALARM1 is used */
512		regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[7]);
513	}
514
515	return 0;
516}
517
518static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
519{
520	struct ds1307		*ds1307 = dev_get_drvdata(dev);
521
522	if (!test_bit(HAS_ALARM, &ds1307->flags))
523		return -ENOTTY;
524
525	return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
526				  DS1337_BIT_A1IE,
527				  enabled ? DS1337_BIT_A1IE : 0);
528}
529
530static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
531{
532	u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
533		DS1307_TRICKLE_CHARGER_NO_DIODE;
534
535	setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
536
537	switch (ohms) {
538	case 250:
539		setup |= DS1307_TRICKLE_CHARGER_250_OHM;
540		break;
541	case 2000:
542		setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
543		break;
544	case 4000:
545		setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
546		break;
547	default:
548		dev_warn(ds1307->dev,
549			 "Unsupported ohm value %u in dt\n", ohms);
550		return 0;
551	}
552	return setup;
553}
554
555static u8 do_trickle_setup_rx8130(struct ds1307 *ds1307, u32 ohms, bool diode)
556{
557	/* make sure that the backup battery is enabled */
558	u8 setup = RX8130_REG_CONTROL1_INIEN;
559	if (diode)
560		setup |= RX8130_REG_CONTROL1_CHGEN;
561
562	return setup;
563}
564
565static irqreturn_t rx8130_irq(int irq, void *dev_id)
566{
567	struct ds1307           *ds1307 = dev_id;
568	struct mutex            *lock = &ds1307->rtc->ops_lock;
569	u8 ctl[3];
570	int ret;
571
572	mutex_lock(lock);
573
574	/* Read control registers. */
575	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
576			       sizeof(ctl));
577	if (ret < 0)
578		goto out;
579	if (!(ctl[1] & RX8130_REG_FLAG_AF))
580		goto out;
581	ctl[1] &= ~RX8130_REG_FLAG_AF;
582	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
583
584	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
585				sizeof(ctl));
586	if (ret < 0)
587		goto out;
588
589	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
590
591out:
592	mutex_unlock(lock);
593
594	return IRQ_HANDLED;
595}
596
597static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
598{
599	struct ds1307 *ds1307 = dev_get_drvdata(dev);
600	u8 ald[3], ctl[3];
601	int ret;
602
603	if (!test_bit(HAS_ALARM, &ds1307->flags))
604		return -EINVAL;
605
606	/* Read alarm registers. */
607	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
608			       sizeof(ald));
609	if (ret < 0)
610		return ret;
611
612	/* Read control registers. */
613	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
614			       sizeof(ctl));
615	if (ret < 0)
616		return ret;
617
618	t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
619	t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
620
621	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
622	t->time.tm_sec = -1;
623	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
624	t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
625	t->time.tm_wday = -1;
626	t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
627	t->time.tm_mon = -1;
628	t->time.tm_year = -1;
629	t->time.tm_yday = -1;
630	t->time.tm_isdst = -1;
631
632	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
633		__func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
634		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
635
636	return 0;
637}
638
639static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
640{
641	struct ds1307 *ds1307 = dev_get_drvdata(dev);
642	u8 ald[3], ctl[3];
643	int ret;
644
645	if (!test_bit(HAS_ALARM, &ds1307->flags))
646		return -EINVAL;
647
648	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
649		"enabled=%d pending=%d\n", __func__,
650		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
651		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
652		t->enabled, t->pending);
653
654	/* Read control registers. */
655	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
656			       sizeof(ctl));
657	if (ret < 0)
658		return ret;
659
660	ctl[0] &= RX8130_REG_EXTENSION_WADA;
661	ctl[1] &= ~RX8130_REG_FLAG_AF;
662	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
663
664	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
665				sizeof(ctl));
666	if (ret < 0)
667		return ret;
668
669	/* Hardware alarm precision is 1 minute! */
670	ald[0] = bin2bcd(t->time.tm_min);
671	ald[1] = bin2bcd(t->time.tm_hour);
672	ald[2] = bin2bcd(t->time.tm_mday);
673
674	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
675				sizeof(ald));
676	if (ret < 0)
677		return ret;
678
679	if (!t->enabled)
680		return 0;
681
682	ctl[2] |= RX8130_REG_CONTROL0_AIE;
683
684	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, ctl[2]);
685}
686
687static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
688{
689	struct ds1307 *ds1307 = dev_get_drvdata(dev);
690	int ret, reg;
691
692	if (!test_bit(HAS_ALARM, &ds1307->flags))
693		return -EINVAL;
694
695	ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
696	if (ret < 0)
697		return ret;
698
699	if (enabled)
700		reg |= RX8130_REG_CONTROL0_AIE;
701	else
702		reg &= ~RX8130_REG_CONTROL0_AIE;
703
704	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
705}
706
707static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
708{
709	struct ds1307           *ds1307 = dev_id;
710	struct mutex            *lock = &ds1307->rtc->ops_lock;
711	int reg, ret;
712
713	mutex_lock(lock);
714
715	/* Check and clear alarm 0 interrupt flag. */
716	ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
717	if (ret)
718		goto out;
719	if (!(reg & MCP794XX_BIT_ALMX_IF))
720		goto out;
721	reg &= ~MCP794XX_BIT_ALMX_IF;
722	ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
723	if (ret)
724		goto out;
725
726	/* Disable alarm 0. */
727	ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
728				 MCP794XX_BIT_ALM0_EN, 0);
729	if (ret)
730		goto out;
731
732	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
733
734out:
735	mutex_unlock(lock);
736
737	return IRQ_HANDLED;
738}
739
740static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
741{
742	struct ds1307 *ds1307 = dev_get_drvdata(dev);
743	u8 regs[10];
744	int ret;
745
746	if (!test_bit(HAS_ALARM, &ds1307->flags))
747		return -EINVAL;
748
749	/* Read control and alarm 0 registers. */
750	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
751			       sizeof(regs));
752	if (ret)
753		return ret;
754
755	t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
756
757	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
758	t->time.tm_sec = bcd2bin(regs[3] & 0x7f);
759	t->time.tm_min = bcd2bin(regs[4] & 0x7f);
760	t->time.tm_hour = bcd2bin(regs[5] & 0x3f);
761	t->time.tm_wday = bcd2bin(regs[6] & 0x7) - 1;
762	t->time.tm_mday = bcd2bin(regs[7] & 0x3f);
763	t->time.tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
764	t->time.tm_year = -1;
765	t->time.tm_yday = -1;
766	t->time.tm_isdst = -1;
767
768	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
769		"enabled=%d polarity=%d irq=%d match=%lu\n", __func__,
770		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
771		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
772		!!(regs[6] & MCP794XX_BIT_ALMX_POL),
773		!!(regs[6] & MCP794XX_BIT_ALMX_IF),
774		(regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
775
776	return 0;
777}
778
779/*
780 * We may have a random RTC weekday, therefore calculate alarm weekday based
781 * on current weekday we read from the RTC timekeeping regs
782 */
783static int mcp794xx_alm_weekday(struct device *dev, struct rtc_time *tm_alarm)
784{
785	struct rtc_time tm_now;
786	int days_now, days_alarm, ret;
787
788	ret = ds1307_get_time(dev, &tm_now);
789	if (ret)
790		return ret;
791
792	days_now = div_s64(rtc_tm_to_time64(&tm_now), 24 * 60 * 60);
793	days_alarm = div_s64(rtc_tm_to_time64(tm_alarm), 24 * 60 * 60);
794
795	return (tm_now.tm_wday + days_alarm - days_now) % 7 + 1;
796}
797
798static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
799{
800	struct ds1307 *ds1307 = dev_get_drvdata(dev);
801	unsigned char regs[10];
802	int wday, ret;
803
804	if (!test_bit(HAS_ALARM, &ds1307->flags))
805		return -EINVAL;
806
807	wday = mcp794xx_alm_weekday(dev, &t->time);
808	if (wday < 0)
809		return wday;
810
811	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
812		"enabled=%d pending=%d\n", __func__,
813		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
814		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
815		t->enabled, t->pending);
816
817	/* Read control and alarm 0 registers. */
818	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
819			       sizeof(regs));
820	if (ret)
821		return ret;
822
823	/* Set alarm 0, using 24-hour and day-of-month modes. */
824	regs[3] = bin2bcd(t->time.tm_sec);
825	regs[4] = bin2bcd(t->time.tm_min);
826	regs[5] = bin2bcd(t->time.tm_hour);
827	regs[6] = wday;
828	regs[7] = bin2bcd(t->time.tm_mday);
829	regs[8] = bin2bcd(t->time.tm_mon + 1);
830
831	/* Clear the alarm 0 interrupt flag. */
832	regs[6] &= ~MCP794XX_BIT_ALMX_IF;
833	/* Set alarm match: second, minute, hour, day, date, month. */
834	regs[6] |= MCP794XX_MSK_ALMX_MATCH;
835	/* Disable interrupt. We will not enable until completely programmed */
836	regs[0] &= ~MCP794XX_BIT_ALM0_EN;
837
838	ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
839				sizeof(regs));
840	if (ret)
841		return ret;
842
843	if (!t->enabled)
844		return 0;
845	regs[0] |= MCP794XX_BIT_ALM0_EN;
846	return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
847}
848
849static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
850{
851	struct ds1307 *ds1307 = dev_get_drvdata(dev);
852
853	if (!test_bit(HAS_ALARM, &ds1307->flags))
854		return -EINVAL;
855
856	return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
857				  MCP794XX_BIT_ALM0_EN,
858				  enabled ? MCP794XX_BIT_ALM0_EN : 0);
859}
860
861static int m41txx_rtc_read_offset(struct device *dev, long *offset)
862{
863	struct ds1307 *ds1307 = dev_get_drvdata(dev);
864	unsigned int ctrl_reg;
865	u8 val;
866
867	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
868
869	val = ctrl_reg & M41TXX_M_CALIBRATION;
870
871	/* check if positive */
872	if (ctrl_reg & M41TXX_BIT_CALIB_SIGN)
873		*offset = (val * M41TXX_POS_OFFSET_STEP_PPB);
874	else
875		*offset = -(val * M41TXX_NEG_OFFSET_STEP_PPB);
876
877	return 0;
878}
879
880static int m41txx_rtc_set_offset(struct device *dev, long offset)
881{
882	struct ds1307 *ds1307 = dev_get_drvdata(dev);
883	unsigned int ctrl_reg;
884
885	if ((offset < M41TXX_MIN_OFFSET) || (offset > M41TXX_MAX_OFFSET))
886		return -ERANGE;
887
888	if (offset >= 0) {
889		ctrl_reg = DIV_ROUND_CLOSEST(offset,
890					     M41TXX_POS_OFFSET_STEP_PPB);
891		ctrl_reg |= M41TXX_BIT_CALIB_SIGN;
892	} else {
893		ctrl_reg = DIV_ROUND_CLOSEST(abs(offset),
894					     M41TXX_NEG_OFFSET_STEP_PPB);
895	}
896
897	return regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL,
898				  M41TXX_M_CALIBRATION | M41TXX_BIT_CALIB_SIGN,
899				  ctrl_reg);
900}
901
902#ifdef CONFIG_WATCHDOG_CORE
903static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
904{
905	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
906	u8 regs[2];
907	int ret;
908
909	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
910				 DS1388_BIT_WF, 0);
911	if (ret)
912		return ret;
913
914	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
915				 DS1388_BIT_WDE | DS1388_BIT_RST, 0);
916	if (ret)
917		return ret;
918
919	/*
920	 * watchdog timeouts are measured in seconds. So ignore hundredths of
921	 * seconds field.
922	 */
923	regs[0] = 0;
924	regs[1] = bin2bcd(wdt_dev->timeout);
925
926	ret = regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
927				sizeof(regs));
928	if (ret)
929		return ret;
930
931	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
932				  DS1388_BIT_WDE | DS1388_BIT_RST,
933				  DS1388_BIT_WDE | DS1388_BIT_RST);
934}
935
936static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
937{
938	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
939
940	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
941				  DS1388_BIT_WDE | DS1388_BIT_RST, 0);
942}
943
944static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
945{
946	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
947	u8 regs[2];
948
949	return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
950				sizeof(regs));
951}
952
953static int ds1388_wdt_set_timeout(struct watchdog_device *wdt_dev,
954				  unsigned int val)
955{
956	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
957	u8 regs[2];
958
959	wdt_dev->timeout = val;
960	regs[0] = 0;
961	regs[1] = bin2bcd(wdt_dev->timeout);
962
963	return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
964				 sizeof(regs));
965}
966#endif
967
968static const struct rtc_class_ops rx8130_rtc_ops = {
969	.read_time      = ds1307_get_time,
970	.set_time       = ds1307_set_time,
971	.read_alarm     = rx8130_read_alarm,
972	.set_alarm      = rx8130_set_alarm,
973	.alarm_irq_enable = rx8130_alarm_irq_enable,
974};
975
976static const struct rtc_class_ops mcp794xx_rtc_ops = {
977	.read_time      = ds1307_get_time,
978	.set_time       = ds1307_set_time,
979	.read_alarm     = mcp794xx_read_alarm,
980	.set_alarm      = mcp794xx_set_alarm,
981	.alarm_irq_enable = mcp794xx_alarm_irq_enable,
982};
983
984static const struct rtc_class_ops m41txx_rtc_ops = {
985	.read_time      = ds1307_get_time,
986	.set_time       = ds1307_set_time,
987	.read_alarm	= ds1337_read_alarm,
988	.set_alarm	= ds1337_set_alarm,
989	.alarm_irq_enable = ds1307_alarm_irq_enable,
990	.read_offset	= m41txx_rtc_read_offset,
991	.set_offset	= m41txx_rtc_set_offset,
992};
993
994static const struct chip_desc chips[last_ds_type] = {
995	[ds_1307] = {
996		.nvram_offset	= 8,
997		.nvram_size	= 56,
998	},
999	[ds_1308] = {
1000		.nvram_offset	= 8,
1001		.nvram_size	= 56,
1002	},
1003	[ds_1337] = {
1004		.alarm		= 1,
1005		.century_reg	= DS1307_REG_MONTH,
1006		.century_bit	= DS1337_BIT_CENTURY,
1007	},
1008	[ds_1338] = {
1009		.nvram_offset	= 8,
1010		.nvram_size	= 56,
1011	},
1012	[ds_1339] = {
1013		.alarm		= 1,
1014		.century_reg	= DS1307_REG_MONTH,
1015		.century_bit	= DS1337_BIT_CENTURY,
1016		.bbsqi_bit	= DS1339_BIT_BBSQI,
1017		.trickle_charger_reg = 0x10,
1018		.do_trickle_setup = &do_trickle_setup_ds1339,
1019		.requires_trickle_resistor = true,
1020		.charge_default = true,
1021	},
1022	[ds_1340] = {
1023		.century_reg	= DS1307_REG_HOUR,
1024		.century_enable_bit = DS1340_BIT_CENTURY_EN,
1025		.century_bit	= DS1340_BIT_CENTURY,
1026		.do_trickle_setup = &do_trickle_setup_ds1339,
1027		.trickle_charger_reg = 0x08,
1028		.requires_trickle_resistor = true,
1029		.charge_default = true,
1030	},
1031	[ds_1341] = {
1032		.century_reg	= DS1307_REG_MONTH,
1033		.century_bit	= DS1337_BIT_CENTURY,
1034	},
1035	[ds_1388] = {
1036		.offset		= 1,
1037		.trickle_charger_reg = 0x0a,
1038	},
1039	[ds_3231] = {
1040		.alarm		= 1,
1041		.century_reg	= DS1307_REG_MONTH,
1042		.century_bit	= DS1337_BIT_CENTURY,
1043		.bbsqi_bit	= DS3231_BIT_BBSQW,
1044	},
1045	[rx_8130] = {
1046		.alarm		= 1,
1047		/* this is battery backed SRAM */
1048		.nvram_offset	= 0x20,
1049		.nvram_size	= 4,	/* 32bit (4 word x 8 bit) */
1050		.offset		= 0x10,
1051		.irq_handler = rx8130_irq,
1052		.rtc_ops = &rx8130_rtc_ops,
1053		.trickle_charger_reg = RX8130_REG_CONTROL1,
1054		.do_trickle_setup = &do_trickle_setup_rx8130,
1055	},
1056	[m41t0] = {
1057		.rtc_ops	= &m41txx_rtc_ops,
1058	},
1059	[m41t00] = {
1060		.rtc_ops	= &m41txx_rtc_ops,
1061	},
1062	[m41t11] = {
1063		/* this is battery backed SRAM */
1064		.nvram_offset	= 8,
1065		.nvram_size	= 56,
1066		.rtc_ops	= &m41txx_rtc_ops,
1067	},
1068	[mcp794xx] = {
1069		.alarm		= 1,
1070		/* this is battery backed SRAM */
1071		.nvram_offset	= 0x20,
1072		.nvram_size	= 0x40,
1073		.irq_handler = mcp794xx_irq,
1074		.rtc_ops = &mcp794xx_rtc_ops,
1075	},
1076};
1077
1078static const struct i2c_device_id ds1307_id[] = {
1079	{ "ds1307", ds_1307 },
1080	{ "ds1308", ds_1308 },
1081	{ "ds1337", ds_1337 },
1082	{ "ds1338", ds_1338 },
1083	{ "ds1339", ds_1339 },
1084	{ "ds1388", ds_1388 },
1085	{ "ds1340", ds_1340 },
1086	{ "ds1341", ds_1341 },
1087	{ "ds3231", ds_3231 },
1088	{ "m41t0", m41t0 },
1089	{ "m41t00", m41t00 },
1090	{ "m41t11", m41t11 },
1091	{ "mcp7940x", mcp794xx },
1092	{ "mcp7941x", mcp794xx },
1093	{ "pt7c4338", ds_1307 },
1094	{ "rx8025", rx_8025 },
1095	{ "isl12057", ds_1337 },
1096	{ "rx8130", rx_8130 },
1097	{ }
1098};
1099MODULE_DEVICE_TABLE(i2c, ds1307_id);
1100
1101#ifdef CONFIG_OF
1102static const struct of_device_id ds1307_of_match[] = {
1103	{
1104		.compatible = "dallas,ds1307",
1105		.data = (void *)ds_1307
1106	},
1107	{
1108		.compatible = "dallas,ds1308",
1109		.data = (void *)ds_1308
1110	},
1111	{
1112		.compatible = "dallas,ds1337",
1113		.data = (void *)ds_1337
1114	},
1115	{
1116		.compatible = "dallas,ds1338",
1117		.data = (void *)ds_1338
1118	},
1119	{
1120		.compatible = "dallas,ds1339",
1121		.data = (void *)ds_1339
1122	},
1123	{
1124		.compatible = "dallas,ds1388",
1125		.data = (void *)ds_1388
1126	},
1127	{
1128		.compatible = "dallas,ds1340",
1129		.data = (void *)ds_1340
1130	},
1131	{
1132		.compatible = "dallas,ds1341",
1133		.data = (void *)ds_1341
1134	},
1135	{
1136		.compatible = "maxim,ds3231",
1137		.data = (void *)ds_3231
1138	},
1139	{
1140		.compatible = "st,m41t0",
1141		.data = (void *)m41t0
1142	},
1143	{
1144		.compatible = "st,m41t00",
1145		.data = (void *)m41t00
1146	},
1147	{
1148		.compatible = "st,m41t11",
1149		.data = (void *)m41t11
1150	},
1151	{
1152		.compatible = "microchip,mcp7940x",
1153		.data = (void *)mcp794xx
1154	},
1155	{
1156		.compatible = "microchip,mcp7941x",
1157		.data = (void *)mcp794xx
1158	},
1159	{
1160		.compatible = "pericom,pt7c4338",
1161		.data = (void *)ds_1307
1162	},
1163	{
1164		.compatible = "epson,rx8025",
1165		.data = (void *)rx_8025
1166	},
1167	{
1168		.compatible = "isil,isl12057",
1169		.data = (void *)ds_1337
1170	},
1171	{
1172		.compatible = "epson,rx8130",
1173		.data = (void *)rx_8130
1174	},
1175	{ }
1176};
1177MODULE_DEVICE_TABLE(of, ds1307_of_match);
1178#endif
1179
1180#ifdef CONFIG_ACPI
1181static const struct acpi_device_id ds1307_acpi_ids[] = {
1182	{ .id = "DS1307", .driver_data = ds_1307 },
1183	{ .id = "DS1308", .driver_data = ds_1308 },
1184	{ .id = "DS1337", .driver_data = ds_1337 },
1185	{ .id = "DS1338", .driver_data = ds_1338 },
1186	{ .id = "DS1339", .driver_data = ds_1339 },
1187	{ .id = "DS1388", .driver_data = ds_1388 },
1188	{ .id = "DS1340", .driver_data = ds_1340 },
1189	{ .id = "DS1341", .driver_data = ds_1341 },
1190	{ .id = "DS3231", .driver_data = ds_3231 },
1191	{ .id = "M41T0", .driver_data = m41t0 },
1192	{ .id = "M41T00", .driver_data = m41t00 },
1193	{ .id = "M41T11", .driver_data = m41t11 },
1194	{ .id = "MCP7940X", .driver_data = mcp794xx },
1195	{ .id = "MCP7941X", .driver_data = mcp794xx },
1196	{ .id = "PT7C4338", .driver_data = ds_1307 },
1197	{ .id = "RX8025", .driver_data = rx_8025 },
1198	{ .id = "ISL12057", .driver_data = ds_1337 },
1199	{ .id = "RX8130", .driver_data = rx_8130 },
1200	{ }
1201};
1202MODULE_DEVICE_TABLE(acpi, ds1307_acpi_ids);
1203#endif
1204
1205/*
1206 * The ds1337 and ds1339 both have two alarms, but we only use the first
1207 * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
1208 * signal; ds1339 chips have only one alarm signal.
1209 */
1210static irqreturn_t ds1307_irq(int irq, void *dev_id)
1211{
1212	struct ds1307		*ds1307 = dev_id;
1213	struct mutex		*lock = &ds1307->rtc->ops_lock;
1214	int			stat, ret;
1215
1216	mutex_lock(lock);
1217	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
1218	if (ret)
1219		goto out;
1220
1221	if (stat & DS1337_BIT_A1I) {
1222		stat &= ~DS1337_BIT_A1I;
1223		regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
1224
1225		ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1226					 DS1337_BIT_A1IE, 0);
1227		if (ret)
1228			goto out;
1229
1230		rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
1231	}
1232
1233out:
1234	mutex_unlock(lock);
1235
1236	return IRQ_HANDLED;
1237}
1238
1239/*----------------------------------------------------------------------*/
1240
1241static const struct rtc_class_ops ds13xx_rtc_ops = {
1242	.read_time	= ds1307_get_time,
1243	.set_time	= ds1307_set_time,
1244	.read_alarm	= ds1337_read_alarm,
1245	.set_alarm	= ds1337_set_alarm,
1246	.alarm_irq_enable = ds1307_alarm_irq_enable,
1247};
1248
1249static ssize_t frequency_test_store(struct device *dev,
1250				    struct device_attribute *attr,
1251				    const char *buf, size_t count)
1252{
1253	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1254	bool freq_test_en;
1255	int ret;
1256
1257	ret = kstrtobool(buf, &freq_test_en);
1258	if (ret) {
1259		dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
1260		return ret;
1261	}
1262
1263	regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, M41TXX_BIT_FT,
1264			   freq_test_en ? M41TXX_BIT_FT : 0);
1265
1266	return count;
1267}
1268
1269static ssize_t frequency_test_show(struct device *dev,
1270				   struct device_attribute *attr,
1271				   char *buf)
1272{
1273	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1274	unsigned int ctrl_reg;
1275
1276	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
1277
1278	return scnprintf(buf, PAGE_SIZE, (ctrl_reg & M41TXX_BIT_FT) ? "on\n" :
1279			"off\n");
1280}
1281
1282static DEVICE_ATTR_RW(frequency_test);
1283
1284static struct attribute *rtc_freq_test_attrs[] = {
1285	&dev_attr_frequency_test.attr,
1286	NULL,
1287};
1288
1289static const struct attribute_group rtc_freq_test_attr_group = {
1290	.attrs		= rtc_freq_test_attrs,
1291};
1292
1293static int ds1307_add_frequency_test(struct ds1307 *ds1307)
1294{
1295	int err;
1296
1297	switch (ds1307->type) {
1298	case m41t0:
1299	case m41t00:
1300	case m41t11:
1301		err = rtc_add_group(ds1307->rtc, &rtc_freq_test_attr_group);
1302		if (err)
1303			return err;
1304		break;
1305	default:
1306		break;
1307	}
1308
1309	return 0;
1310}
1311
1312/*----------------------------------------------------------------------*/
1313
1314static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
1315			     size_t bytes)
1316{
1317	struct ds1307 *ds1307 = priv;
1318	const struct chip_desc *chip = &chips[ds1307->type];
1319
1320	return regmap_bulk_read(ds1307->regmap, chip->nvram_offset + offset,
1321				val, bytes);
1322}
1323
1324static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
1325			      size_t bytes)
1326{
1327	struct ds1307 *ds1307 = priv;
1328	const struct chip_desc *chip = &chips[ds1307->type];
1329
1330	return regmap_bulk_write(ds1307->regmap, chip->nvram_offset + offset,
1331				 val, bytes);
1332}
1333
1334/*----------------------------------------------------------------------*/
1335
1336static u8 ds1307_trickle_init(struct ds1307 *ds1307,
1337			      const struct chip_desc *chip)
1338{
1339	u32 ohms, chargeable;
1340	bool diode = chip->charge_default;
1341
1342	if (!chip->do_trickle_setup)
1343		return 0;
1344
1345	if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
1346				     &ohms) && chip->requires_trickle_resistor)
1347		return 0;
1348
1349	/* aux-voltage-chargeable takes precedence over the deprecated
1350	 * trickle-diode-disable
1351	 */
1352	if (!device_property_read_u32(ds1307->dev, "aux-voltage-chargeable",
1353				     &chargeable)) {
1354		switch (chargeable) {
1355		case 0:
1356			diode = false;
1357			break;
1358		case 1:
1359			diode = true;
1360			break;
1361		default:
1362			dev_warn(ds1307->dev,
1363				 "unsupported aux-voltage-chargeable value\n");
1364			break;
1365		}
1366	} else if (device_property_read_bool(ds1307->dev,
1367					     "trickle-diode-disable")) {
1368		diode = false;
1369	}
1370
1371	return chip->do_trickle_setup(ds1307, ohms, diode);
1372}
1373
1374/*----------------------------------------------------------------------*/
1375
1376#if IS_REACHABLE(CONFIG_HWMON)
1377
1378/*
1379 * Temperature sensor support for ds3231 devices.
1380 */
1381
1382#define DS3231_REG_TEMPERATURE	0x11
1383
1384/*
1385 * A user-initiated temperature conversion is not started by this function,
1386 * so the temperature is updated once every 64 seconds.
1387 */
1388static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
1389{
1390	struct ds1307 *ds1307 = dev_get_drvdata(dev);
1391	u8 temp_buf[2];
1392	s16 temp;
1393	int ret;
1394
1395	ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
1396			       temp_buf, sizeof(temp_buf));
1397	if (ret)
1398		return ret;
1399	/*
1400	 * Temperature is represented as a 10-bit code with a resolution of
1401	 * 0.25 degree celsius and encoded in two's complement format.
1402	 */
1403	temp = (temp_buf[0] << 8) | temp_buf[1];
1404	temp >>= 6;
1405	*mC = temp * 250;
1406
1407	return 0;
1408}
1409
1410static ssize_t ds3231_hwmon_show_temp(struct device *dev,
1411				      struct device_attribute *attr, char *buf)
1412{
1413	int ret;
1414	s32 temp;
1415
1416	ret = ds3231_hwmon_read_temp(dev, &temp);
1417	if (ret)
1418		return ret;
1419
1420	return sprintf(buf, "%d\n", temp);
1421}
1422static SENSOR_DEVICE_ATTR(temp1_input, 0444, ds3231_hwmon_show_temp,
1423			  NULL, 0);
1424
1425static struct attribute *ds3231_hwmon_attrs[] = {
1426	&sensor_dev_attr_temp1_input.dev_attr.attr,
1427	NULL,
1428};
1429ATTRIBUTE_GROUPS(ds3231_hwmon);
1430
1431static void ds1307_hwmon_register(struct ds1307 *ds1307)
1432{
1433	struct device *dev;
1434
1435	if (ds1307->type != ds_3231)
1436		return;
1437
1438	dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1439						     ds1307,
1440						     ds3231_hwmon_groups);
1441	if (IS_ERR(dev)) {
1442		dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1443			 PTR_ERR(dev));
1444	}
1445}
1446
1447#else
1448
1449static void ds1307_hwmon_register(struct ds1307 *ds1307)
1450{
1451}
1452
1453#endif /* CONFIG_RTC_DRV_DS1307_HWMON */
1454
1455/*----------------------------------------------------------------------*/
1456
1457/*
1458 * Square-wave output support for DS3231
1459 * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1460 */
1461#ifdef CONFIG_COMMON_CLK
1462
1463enum {
1464	DS3231_CLK_SQW = 0,
1465	DS3231_CLK_32KHZ,
1466};
1467
1468#define clk_sqw_to_ds1307(clk)	\
1469	container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1470#define clk_32khz_to_ds1307(clk)	\
1471	container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1472
1473static int ds3231_clk_sqw_rates[] = {
1474	1,
1475	1024,
1476	4096,
1477	8192,
1478};
1479
1480static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1481{
1482	struct mutex *lock = &ds1307->rtc->ops_lock;
1483	int ret;
1484
1485	mutex_lock(lock);
1486	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1487				 mask, value);
1488	mutex_unlock(lock);
1489
1490	return ret;
1491}
1492
1493static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1494						unsigned long parent_rate)
1495{
1496	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1497	int control, ret;
1498	int rate_sel = 0;
1499
1500	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1501	if (ret)
1502		return ret;
1503	if (control & DS1337_BIT_RS1)
1504		rate_sel += 1;
1505	if (control & DS1337_BIT_RS2)
1506		rate_sel += 2;
1507
1508	return ds3231_clk_sqw_rates[rate_sel];
1509}
1510
1511static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1512				      unsigned long *prate)
1513{
1514	int i;
1515
1516	for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1517		if (ds3231_clk_sqw_rates[i] <= rate)
1518			return ds3231_clk_sqw_rates[i];
1519	}
1520
1521	return 0;
1522}
1523
1524static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1525				   unsigned long parent_rate)
1526{
1527	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1528	int control = 0;
1529	int rate_sel;
1530
1531	for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1532			rate_sel++) {
1533		if (ds3231_clk_sqw_rates[rate_sel] == rate)
1534			break;
1535	}
1536
1537	if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1538		return -EINVAL;
1539
1540	if (rate_sel & 1)
1541		control |= DS1337_BIT_RS1;
1542	if (rate_sel & 2)
1543		control |= DS1337_BIT_RS2;
1544
1545	return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1546				control);
1547}
1548
1549static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1550{
1551	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1552
1553	return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1554}
1555
1556static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1557{
1558	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1559
1560	ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1561}
1562
1563static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1564{
1565	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1566	int control, ret;
1567
1568	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1569	if (ret)
1570		return ret;
1571
1572	return !(control & DS1337_BIT_INTCN);
1573}
1574
1575static const struct clk_ops ds3231_clk_sqw_ops = {
1576	.prepare = ds3231_clk_sqw_prepare,
1577	.unprepare = ds3231_clk_sqw_unprepare,
1578	.is_prepared = ds3231_clk_sqw_is_prepared,
1579	.recalc_rate = ds3231_clk_sqw_recalc_rate,
1580	.round_rate = ds3231_clk_sqw_round_rate,
1581	.set_rate = ds3231_clk_sqw_set_rate,
1582};
1583
1584static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1585						  unsigned long parent_rate)
1586{
1587	return 32768;
1588}
1589
1590static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1591{
1592	struct mutex *lock = &ds1307->rtc->ops_lock;
1593	int ret;
1594
1595	mutex_lock(lock);
1596	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1597				 DS3231_BIT_EN32KHZ,
1598				 enable ? DS3231_BIT_EN32KHZ : 0);
1599	mutex_unlock(lock);
1600
1601	return ret;
1602}
1603
1604static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1605{
1606	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1607
1608	return ds3231_clk_32khz_control(ds1307, true);
1609}
1610
1611static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1612{
1613	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1614
1615	ds3231_clk_32khz_control(ds1307, false);
1616}
1617
1618static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1619{
1620	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1621	int status, ret;
1622
1623	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1624	if (ret)
1625		return ret;
1626
1627	return !!(status & DS3231_BIT_EN32KHZ);
1628}
1629
1630static const struct clk_ops ds3231_clk_32khz_ops = {
1631	.prepare = ds3231_clk_32khz_prepare,
1632	.unprepare = ds3231_clk_32khz_unprepare,
1633	.is_prepared = ds3231_clk_32khz_is_prepared,
1634	.recalc_rate = ds3231_clk_32khz_recalc_rate,
1635};
1636
1637static struct clk_init_data ds3231_clks_init[] = {
1638	[DS3231_CLK_SQW] = {
1639		.name = "ds3231_clk_sqw",
1640		.ops = &ds3231_clk_sqw_ops,
1641	},
1642	[DS3231_CLK_32KHZ] = {
1643		.name = "ds3231_clk_32khz",
1644		.ops = &ds3231_clk_32khz_ops,
1645	},
1646};
1647
1648static int ds3231_clks_register(struct ds1307 *ds1307)
1649{
1650	struct device_node *node = ds1307->dev->of_node;
1651	struct clk_onecell_data	*onecell;
1652	int i;
1653
1654	onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1655	if (!onecell)
1656		return -ENOMEM;
1657
1658	onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1659	onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1660				     sizeof(onecell->clks[0]), GFP_KERNEL);
1661	if (!onecell->clks)
1662		return -ENOMEM;
1663
1664	for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1665		struct clk_init_data init = ds3231_clks_init[i];
1666
1667		/*
1668		 * Interrupt signal due to alarm conditions and square-wave
1669		 * output share same pin, so don't initialize both.
1670		 */
1671		if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
1672			continue;
1673
1674		/* optional override of the clockname */
1675		of_property_read_string_index(node, "clock-output-names", i,
1676					      &init.name);
1677		ds1307->clks[i].init = &init;
1678
1679		onecell->clks[i] = devm_clk_register(ds1307->dev,
1680						     &ds1307->clks[i]);
1681		if (IS_ERR(onecell->clks[i]))
1682			return PTR_ERR(onecell->clks[i]);
1683	}
1684
1685	if (!node)
1686		return 0;
1687
1688	of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1689
1690	return 0;
1691}
1692
1693static void ds1307_clks_register(struct ds1307 *ds1307)
1694{
1695	int ret;
1696
1697	if (ds1307->type != ds_3231)
1698		return;
1699
1700	ret = ds3231_clks_register(ds1307);
1701	if (ret) {
1702		dev_warn(ds1307->dev, "unable to register clock device %d\n",
1703			 ret);
1704	}
1705}
1706
1707#else
1708
1709static void ds1307_clks_register(struct ds1307 *ds1307)
1710{
1711}
1712
1713#endif /* CONFIG_COMMON_CLK */
1714
1715#ifdef CONFIG_WATCHDOG_CORE
1716static const struct watchdog_info ds1388_wdt_info = {
1717	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
1718	.identity = "DS1388 watchdog",
1719};
1720
1721static const struct watchdog_ops ds1388_wdt_ops = {
1722	.owner = THIS_MODULE,
1723	.start = ds1388_wdt_start,
1724	.stop = ds1388_wdt_stop,
1725	.ping = ds1388_wdt_ping,
1726	.set_timeout = ds1388_wdt_set_timeout,
1727
1728};
1729
1730static void ds1307_wdt_register(struct ds1307 *ds1307)
1731{
1732	struct watchdog_device	*wdt;
1733	int err;
1734	int val;
1735
1736	if (ds1307->type != ds_1388)
1737		return;
1738
1739	wdt = devm_kzalloc(ds1307->dev, sizeof(*wdt), GFP_KERNEL);
1740	if (!wdt)
1741		return;
1742
1743	err = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
1744	if (!err && val & DS1388_BIT_WF)
1745		wdt->bootstatus = WDIOF_CARDRESET;
1746
1747	wdt->info = &ds1388_wdt_info;
1748	wdt->ops = &ds1388_wdt_ops;
1749	wdt->timeout = 99;
1750	wdt->max_timeout = 99;
1751	wdt->min_timeout = 1;
1752
1753	watchdog_init_timeout(wdt, 0, ds1307->dev);
1754	watchdog_set_drvdata(wdt, ds1307);
1755	devm_watchdog_register_device(ds1307->dev, wdt);
1756}
1757#else
1758static void ds1307_wdt_register(struct ds1307 *ds1307)
1759{
1760}
1761#endif /* CONFIG_WATCHDOG_CORE */
1762
1763static const struct regmap_config regmap_config = {
1764	.reg_bits = 8,
1765	.val_bits = 8,
1766};
1767
1768static int ds1307_probe(struct i2c_client *client,
1769			const struct i2c_device_id *id)
1770{
1771	struct ds1307		*ds1307;
1772	int			err = -ENODEV;
1773	int			tmp;
1774	const struct chip_desc	*chip;
1775	bool			want_irq;
1776	bool			ds1307_can_wakeup_device = false;
1777	unsigned char		regs[8];
1778	struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1779	u8			trickle_charger_setup = 0;
1780
1781	ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1782	if (!ds1307)
1783		return -ENOMEM;
1784
1785	dev_set_drvdata(&client->dev, ds1307);
1786	ds1307->dev = &client->dev;
1787	ds1307->name = client->name;
1788
1789	ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1790	if (IS_ERR(ds1307->regmap)) {
1791		dev_err(ds1307->dev, "regmap allocation failed\n");
1792		return PTR_ERR(ds1307->regmap);
1793	}
1794
1795	i2c_set_clientdata(client, ds1307);
1796
1797	if (client->dev.of_node) {
1798		ds1307->type = (enum ds_type)
1799			of_device_get_match_data(&client->dev);
1800		chip = &chips[ds1307->type];
1801	} else if (id) {
1802		chip = &chips[id->driver_data];
1803		ds1307->type = id->driver_data;
1804	} else {
1805		const struct acpi_device_id *acpi_id;
1806
1807		acpi_id = acpi_match_device(ACPI_PTR(ds1307_acpi_ids),
1808					    ds1307->dev);
1809		if (!acpi_id)
1810			return -ENODEV;
1811		chip = &chips[acpi_id->driver_data];
1812		ds1307->type = acpi_id->driver_data;
1813	}
1814
1815	want_irq = client->irq > 0 && chip->alarm;
1816
1817	if (!pdata)
1818		trickle_charger_setup = ds1307_trickle_init(ds1307, chip);
1819	else if (pdata->trickle_charger_setup)
1820		trickle_charger_setup = pdata->trickle_charger_setup;
1821
1822	if (trickle_charger_setup && chip->trickle_charger_reg) {
1823		dev_dbg(ds1307->dev,
1824			"writing trickle charger info 0x%x to 0x%x\n",
1825			trickle_charger_setup, chip->trickle_charger_reg);
1826		regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1827			     trickle_charger_setup);
1828	}
1829
1830#ifdef CONFIG_OF
1831/*
1832 * For devices with no IRQ directly connected to the SoC, the RTC chip
1833 * can be forced as a wakeup source by stating that explicitly in
1834 * the device's .dts file using the "wakeup-source" boolean property.
1835 * If the "wakeup-source" property is set, don't request an IRQ.
1836 * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1837 * if supported by the RTC.
1838 */
1839	if (chip->alarm && of_property_read_bool(client->dev.of_node,
1840						 "wakeup-source"))
1841		ds1307_can_wakeup_device = true;
1842#endif
1843
1844	switch (ds1307->type) {
1845	case ds_1337:
1846	case ds_1339:
1847	case ds_1341:
1848	case ds_3231:
1849		/* get registers that the "rtc" read below won't read... */
1850		err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1851				       regs, 2);
1852		if (err) {
1853			dev_dbg(ds1307->dev, "read error %d\n", err);
1854			goto exit;
1855		}
1856
1857		/* oscillator off?  turn it on, so clock can tick. */
1858		if (regs[0] & DS1337_BIT_nEOSC)
1859			regs[0] &= ~DS1337_BIT_nEOSC;
1860
1861		/*
1862		 * Using IRQ or defined as wakeup-source?
1863		 * Disable the square wave and both alarms.
1864		 * For some variants, be sure alarms can trigger when we're
1865		 * running on Vbackup (BBSQI/BBSQW)
1866		 */
1867		if (want_irq || ds1307_can_wakeup_device) {
1868			regs[0] |= DS1337_BIT_INTCN | chip->bbsqi_bit;
1869			regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1870		}
1871
1872		regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1873			     regs[0]);
1874
1875		/* oscillator fault?  clear flag, and warn */
1876		if (regs[1] & DS1337_BIT_OSF) {
1877			regmap_write(ds1307->regmap, DS1337_REG_STATUS,
1878				     regs[1] & ~DS1337_BIT_OSF);
1879			dev_warn(ds1307->dev, "SET TIME!\n");
1880		}
1881		break;
1882
1883	case rx_8025:
1884		err = regmap_bulk_read(ds1307->regmap,
1885				       RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
1886		if (err) {
1887			dev_dbg(ds1307->dev, "read error %d\n", err);
1888			goto exit;
1889		}
1890
1891		/* oscillator off?  turn it on, so clock can tick. */
1892		if (!(regs[1] & RX8025_BIT_XST)) {
1893			regs[1] |= RX8025_BIT_XST;
1894			regmap_write(ds1307->regmap,
1895				     RX8025_REG_CTRL2 << 4 | 0x08,
1896				     regs[1]);
1897			dev_warn(ds1307->dev,
1898				 "oscillator stop detected - SET TIME!\n");
1899		}
1900
1901		if (regs[1] & RX8025_BIT_PON) {
1902			regs[1] &= ~RX8025_BIT_PON;
1903			regmap_write(ds1307->regmap,
1904				     RX8025_REG_CTRL2 << 4 | 0x08,
1905				     regs[1]);
1906			dev_warn(ds1307->dev, "power-on detected\n");
1907		}
1908
1909		if (regs[1] & RX8025_BIT_VDET) {
1910			regs[1] &= ~RX8025_BIT_VDET;
1911			regmap_write(ds1307->regmap,
1912				     RX8025_REG_CTRL2 << 4 | 0x08,
1913				     regs[1]);
1914			dev_warn(ds1307->dev, "voltage drop detected\n");
1915		}
1916
1917		/* make sure we are running in 24hour mode */
1918		if (!(regs[0] & RX8025_BIT_2412)) {
1919			u8 hour;
1920
1921			/* switch to 24 hour mode */
1922			regmap_write(ds1307->regmap,
1923				     RX8025_REG_CTRL1 << 4 | 0x08,
1924				     regs[0] | RX8025_BIT_2412);
1925
1926			err = regmap_bulk_read(ds1307->regmap,
1927					       RX8025_REG_CTRL1 << 4 | 0x08,
1928					       regs, 2);
1929			if (err) {
1930				dev_dbg(ds1307->dev, "read error %d\n", err);
1931				goto exit;
1932			}
1933
1934			/* correct hour */
1935			hour = bcd2bin(regs[DS1307_REG_HOUR]);
1936			if (hour == 12)
1937				hour = 0;
1938			if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1939				hour += 12;
1940
1941			regmap_write(ds1307->regmap,
1942				     DS1307_REG_HOUR << 4 | 0x08, hour);
1943		}
1944		break;
1945	case ds_1388:
1946		err = regmap_read(ds1307->regmap, DS1388_REG_CONTROL, &tmp);
1947		if (err) {
1948			dev_dbg(ds1307->dev, "read error %d\n", err);
1949			goto exit;
1950		}
1951
1952		/* oscillator off?  turn it on, so clock can tick. */
1953		if (tmp & DS1388_BIT_nEOSC) {
1954			tmp &= ~DS1388_BIT_nEOSC;
1955			regmap_write(ds1307->regmap, DS1388_REG_CONTROL, tmp);
1956		}
1957		break;
1958	default:
1959		break;
1960	}
1961
1962	/* read RTC registers */
1963	err = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
1964			       sizeof(regs));
1965	if (err) {
1966		dev_dbg(ds1307->dev, "read error %d\n", err);
1967		goto exit;
1968	}
1969
1970	if (ds1307->type == mcp794xx &&
1971	    !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1972		regmap_write(ds1307->regmap, DS1307_REG_WDAY,
1973			     regs[DS1307_REG_WDAY] |
1974			     MCP794XX_BIT_VBATEN);
1975	}
1976
1977	tmp = regs[DS1307_REG_HOUR];
1978	switch (ds1307->type) {
1979	case ds_1340:
1980	case m41t0:
1981	case m41t00:
1982	case m41t11:
1983		/*
1984		 * NOTE: ignores century bits; fix before deploying
1985		 * systems that will run through year 2100.
1986		 */
1987		break;
1988	case rx_8025:
1989		break;
1990	default:
1991		if (!(tmp & DS1307_BIT_12HR))
1992			break;
1993
1994		/*
1995		 * Be sure we're in 24 hour mode.  Multi-master systems
1996		 * take note...
1997		 */
1998		tmp = bcd2bin(tmp & 0x1f);
1999		if (tmp == 12)
2000			tmp = 0;
2001		if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
2002			tmp += 12;
2003		regmap_write(ds1307->regmap, chip->offset + DS1307_REG_HOUR,
2004			     bin2bcd(tmp));
2005	}
2006
2007	if (want_irq || ds1307_can_wakeup_device) {
2008		device_set_wakeup_capable(ds1307->dev, true);
2009		set_bit(HAS_ALARM, &ds1307->flags);
2010	}
2011
2012	ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
2013	if (IS_ERR(ds1307->rtc))
2014		return PTR_ERR(ds1307->rtc);
2015
2016	if (ds1307_can_wakeup_device && !want_irq) {
2017		dev_info(ds1307->dev,
2018			 "'wakeup-source' is set, request for an IRQ is disabled!\n");
2019		/* We cannot support UIE mode if we do not have an IRQ line */
2020		ds1307->rtc->uie_unsupported = 1;
2021	}
2022
2023	if (want_irq) {
2024		err = devm_request_threaded_irq(ds1307->dev, client->irq, NULL,
2025						chip->irq_handler ?: ds1307_irq,
2026						IRQF_SHARED | IRQF_ONESHOT,
2027						ds1307->name, ds1307);
2028		if (err) {
2029			client->irq = 0;
2030			device_set_wakeup_capable(ds1307->dev, false);
2031			clear_bit(HAS_ALARM, &ds1307->flags);
2032			dev_err(ds1307->dev, "unable to request IRQ!\n");
2033		} else {
2034			dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
2035		}
2036	}
2037
2038	ds1307->rtc->ops = chip->rtc_ops ?: &ds13xx_rtc_ops;
2039	err = ds1307_add_frequency_test(ds1307);
2040	if (err)
2041		return err;
2042
2043	err = rtc_register_device(ds1307->rtc);
2044	if (err)
2045		return err;
2046
2047	if (chip->nvram_size) {
2048		struct nvmem_config nvmem_cfg = {
2049			.name = "ds1307_nvram",
2050			.word_size = 1,
2051			.stride = 1,
2052			.size = chip->nvram_size,
2053			.reg_read = ds1307_nvram_read,
2054			.reg_write = ds1307_nvram_write,
2055			.priv = ds1307,
2056		};
2057
2058		ds1307->rtc->nvram_old_abi = true;
2059		rtc_nvmem_register(ds1307->rtc, &nvmem_cfg);
2060	}
2061
2062	ds1307_hwmon_register(ds1307);
2063	ds1307_clks_register(ds1307);
2064	ds1307_wdt_register(ds1307);
2065
2066	return 0;
2067
2068exit:
2069	return err;
2070}
2071
2072static struct i2c_driver ds1307_driver = {
2073	.driver = {
2074		.name	= "rtc-ds1307",
2075		.of_match_table = of_match_ptr(ds1307_of_match),
2076		.acpi_match_table = ACPI_PTR(ds1307_acpi_ids),
2077	},
2078	.probe		= ds1307_probe,
2079	.id_table	= ds1307_id,
2080};
2081
2082module_i2c_driver(ds1307_driver);
2083
2084MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
2085MODULE_LICENSE("GPL");
2086