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
 126#define MCP794XX_REG_CONTROL		0x07
 127#	define MCP794XX_BIT_ALM0_EN	0x10
 128#	define MCP794XX_BIT_ALM1_EN	0x20
 129#define MCP794XX_REG_ALARM0_BASE	0x0a
 130#define MCP794XX_REG_ALARM0_CTRL	0x0d
 131#define MCP794XX_REG_ALARM1_BASE	0x11
 132#define MCP794XX_REG_ALARM1_CTRL	0x14
 133#	define MCP794XX_BIT_ALMX_IF	BIT(3)
 134#	define MCP794XX_BIT_ALMX_C0	BIT(4)
 135#	define MCP794XX_BIT_ALMX_C1	BIT(5)
 136#	define MCP794XX_BIT_ALMX_C2	BIT(6)
 137#	define MCP794XX_BIT_ALMX_POL	BIT(7)
 138#	define MCP794XX_MSK_ALMX_MATCH	(MCP794XX_BIT_ALMX_C0 | \
 139					 MCP794XX_BIT_ALMX_C1 | \
 140					 MCP794XX_BIT_ALMX_C2)
 141
 142#define M41TXX_REG_CONTROL	0x07
 143#	define M41TXX_BIT_OUT		BIT(7)
 144#	define M41TXX_BIT_FT		BIT(6)
 145#	define M41TXX_BIT_CALIB_SIGN	BIT(5)
 146#	define M41TXX_M_CALIBRATION	GENMASK(4, 0)
 147
 148#define DS1388_REG_WDOG_HUN_SECS	0x08
 149#define DS1388_REG_WDOG_SECS		0x09
 150#define DS1388_REG_FLAG			0x0b
 151#	define DS1388_BIT_WF		BIT(6)
 152#	define DS1388_BIT_OSF		BIT(7)
 153#define DS1388_REG_CONTROL		0x0c
 154#	define DS1388_BIT_RST		BIT(0)
 155#	define DS1388_BIT_WDE		BIT(1)
 156
 157/* negative offset step is -2.034ppm */
 158#define M41TXX_NEG_OFFSET_STEP_PPB	2034
 159/* positive offset step is +4.068ppm */
 160#define M41TXX_POS_OFFSET_STEP_PPB	4068
 161/* Min and max values supported with 'offset' interface by M41TXX */
 162#define M41TXX_MIN_OFFSET	((-31) * M41TXX_NEG_OFFSET_STEP_PPB)
 163#define M41TXX_MAX_OFFSET	((31) * M41TXX_POS_OFFSET_STEP_PPB)
 164
 165struct ds1307 {
 166	enum ds_type		type;
 167	unsigned long		flags;
 168#define HAS_NVRAM	0		/* bit 0 == sysfs file active */
 169#define HAS_ALARM	1		/* bit 1 == irq claimed */
 170	struct device		*dev;
 171	struct regmap		*regmap;
 172	const char		*name;
 173	struct rtc_device	*rtc;
 174#ifdef CONFIG_COMMON_CLK
 175	struct clk_hw		clks[2];
 176#endif
 177};
 178
 179struct chip_desc {
 180	unsigned		alarm:1;
 181	u16			nvram_offset;
 182	u16			nvram_size;
 183	u8			offset; /* register's offset */
 184	u8			century_reg;
 185	u8			century_enable_bit;
 186	u8			century_bit;
 187	u8			bbsqi_bit;
 188	irq_handler_t		irq_handler;
 189	const struct rtc_class_ops *rtc_ops;
 190	u16			trickle_charger_reg;
 191	u8			(*do_trickle_setup)(struct ds1307 *, u32,
 192						    bool);
 193};
 194
 195static const struct chip_desc chips[last_ds_type];
 196
 197static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 198{
 199	struct ds1307	*ds1307 = dev_get_drvdata(dev);
 200	int		tmp, ret;
 201	const struct chip_desc *chip = &chips[ds1307->type];
 202	u8 regs[7];
 203
 204	if (ds1307->type == rx_8130) {
 205		unsigned int regflag;
 206		ret = regmap_read(ds1307->regmap, RX8130_REG_FLAG, &regflag);
 207		if (ret) {
 208			dev_err(dev, "%s error %d\n", "read", ret);
 209			return ret;
 210		}
 211
 212		if (regflag & RX8130_REG_FLAG_VLF) {
 213			dev_warn_once(dev, "oscillator failed, set time!\n");
 214			return -EINVAL;
 215		}
 216	}
 217
 218	/* read the RTC date and time registers all at once */
 219	ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
 220			       sizeof(regs));
 221	if (ret) {
 222		dev_err(dev, "%s error %d\n", "read", ret);
 223		return ret;
 224	}
 225
 226	dev_dbg(dev, "%s: %7ph\n", "read", regs);
 227
 228	/* if oscillator fail bit is set, no data can be trusted */
 229	if (ds1307->type == m41t0 &&
 230	    regs[DS1307_REG_MIN] & M41T0_BIT_OF) {
 231		dev_warn_once(dev, "oscillator failed, set time!\n");
 232		return -EINVAL;
 233	}
 234
 235	tmp = regs[DS1307_REG_SECS];
 236	switch (ds1307->type) {
 237	case ds_1307:
 238	case m41t0:
 239	case m41t00:
 240	case m41t11:
 241		if (tmp & DS1307_BIT_CH)
 242			return -EINVAL;
 243		break;
 244	case ds_1308:
 245	case ds_1338:
 246		if (tmp & DS1307_BIT_CH)
 247			return -EINVAL;
 248
 249		ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &tmp);
 250		if (ret)
 251			return ret;
 252		if (tmp & DS1338_BIT_OSF)
 253			return -EINVAL;
 254		break;
 255	case ds_1340:
 256		if (tmp & DS1340_BIT_nEOSC)
 257			return -EINVAL;
 258
 259		ret = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
 260		if (ret)
 261			return ret;
 262		if (tmp & DS1340_BIT_OSF)
 263			return -EINVAL;
 264		break;
 265	case ds_1388:
 266		ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &tmp);
 267		if (ret)
 268			return ret;
 269		if (tmp & DS1388_BIT_OSF)
 270			return -EINVAL;
 271		break;
 272	case mcp794xx:
 273		if (!(tmp & MCP794XX_BIT_ST))
 274			return -EINVAL;
 275
 276		break;
 277	default:
 278		break;
 279	}
 280
 281	t->tm_sec = bcd2bin(regs[DS1307_REG_SECS] & 0x7f);
 282	t->tm_min = bcd2bin(regs[DS1307_REG_MIN] & 0x7f);
 283	tmp = regs[DS1307_REG_HOUR] & 0x3f;
 284	t->tm_hour = bcd2bin(tmp);
 285	t->tm_wday = bcd2bin(regs[DS1307_REG_WDAY] & 0x07) - 1;
 286	t->tm_mday = bcd2bin(regs[DS1307_REG_MDAY] & 0x3f);
 287	tmp = regs[DS1307_REG_MONTH] & 0x1f;
 288	t->tm_mon = bcd2bin(tmp) - 1;
 289	t->tm_year = bcd2bin(regs[DS1307_REG_YEAR]) + 100;
 290
 291	if (regs[chip->century_reg] & chip->century_bit &&
 292	    IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
 293		t->tm_year += 100;
 294
 295	dev_dbg(dev, "%s secs=%d, mins=%d, "
 296		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 297		"read", t->tm_sec, t->tm_min,
 298		t->tm_hour, t->tm_mday,
 299		t->tm_mon, t->tm_year, t->tm_wday);
 300
 301	return 0;
 302}
 303
 304static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 305{
 306	struct ds1307	*ds1307 = dev_get_drvdata(dev);
 307	const struct chip_desc *chip = &chips[ds1307->type];
 308	int		result;
 309	int		tmp;
 310	u8		regs[7];
 311
 312	dev_dbg(dev, "%s secs=%d, mins=%d, "
 313		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 314		"write", 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	if (t->tm_year < 100)
 319		return -EINVAL;
 320
 321#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
 322	if (t->tm_year > (chip->century_bit ? 299 : 199))
 323		return -EINVAL;
 324#else
 325	if (t->tm_year > 199)
 326		return -EINVAL;
 327#endif
 328
 329	regs[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 330	regs[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 331	regs[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 332	regs[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 333	regs[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 334	regs[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 335
 336	/* assume 20YY not 19YY */
 337	tmp = t->tm_year - 100;
 338	regs[DS1307_REG_YEAR] = bin2bcd(tmp);
 339
 340	if (chip->century_enable_bit)
 341		regs[chip->century_reg] |= chip->century_enable_bit;
 342	if (t->tm_year > 199 && chip->century_bit)
 343		regs[chip->century_reg] |= chip->century_bit;
 344
 345	switch (ds1307->type) {
 346	case ds_1308:
 347	case ds_1338:
 348		regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
 349				   DS1338_BIT_OSF, 0);
 350		break;
 351	case ds_1340:
 352		regmap_update_bits(ds1307->regmap, DS1340_REG_FLAG,
 353				   DS1340_BIT_OSF, 0);
 354		break;
 355	case mcp794xx:
 356		/*
 357		 * these bits were cleared when preparing the date/time
 358		 * values and need to be set again before writing the
 359		 * regsfer out to the device.
 360		 */
 361		regs[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
 362		regs[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
 363		break;
 364	default:
 365		break;
 366	}
 367
 368	dev_dbg(dev, "%s: %7ph\n", "write", regs);
 369
 370	result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
 371				   sizeof(regs));
 372	if (result) {
 373		dev_err(dev, "%s error %d\n", "write", result);
 374		return result;
 375	}
 376
 377	if (ds1307->type == rx_8130) {
 378		/* clear Voltage Loss Flag as data is available now */
 379		result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
 380				      ~(u8)RX8130_REG_FLAG_VLF);
 381		if (result) {
 382			dev_err(dev, "%s error %d\n", "write", result);
 383			return result;
 384		}
 385	}
 386
 387	return 0;
 388}
 389
 390static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 391{
 392	struct ds1307		*ds1307 = dev_get_drvdata(dev);
 393	int			ret;
 394	u8			regs[9];
 395
 396	if (!test_bit(HAS_ALARM, &ds1307->flags))
 397		return -EINVAL;
 398
 399	/* read all ALARM1, ALARM2, and status registers at once */
 400	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
 401			       regs, sizeof(regs));
 402	if (ret) {
 403		dev_err(dev, "%s error %d\n", "alarm read", ret);
 404		return ret;
 405	}
 406
 407	dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
 408		&regs[0], &regs[4], &regs[7]);
 409
 410	/*
 411	 * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 412	 * and that all four fields are checked matches
 413	 */
 414	t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
 415	t->time.tm_min = bcd2bin(regs[1] & 0x7f);
 416	t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
 417	t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
 418
 419	/* ... and status */
 420	t->enabled = !!(regs[7] & DS1337_BIT_A1IE);
 421	t->pending = !!(regs[8] & DS1337_BIT_A1I);
 422
 423	dev_dbg(dev, "%s secs=%d, mins=%d, "
 424		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
 425		"alarm read", t->time.tm_sec, t->time.tm_min,
 426		t->time.tm_hour, t->time.tm_mday,
 427		t->enabled, t->pending);
 428
 429	return 0;
 430}
 431
 432static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 433{
 434	struct ds1307		*ds1307 = dev_get_drvdata(dev);
 435	unsigned char		regs[9];
 436	u8			control, status;
 437	int			ret;
 438
 439	if (!test_bit(HAS_ALARM, &ds1307->flags))
 440		return -EINVAL;
 441
 442	dev_dbg(dev, "%s secs=%d, mins=%d, "
 443		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
 444		"alarm set", t->time.tm_sec, t->time.tm_min,
 445		t->time.tm_hour, t->time.tm_mday,
 446		t->enabled, t->pending);
 447
 448	/* read current status of both alarms and the chip */
 449	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 450			       sizeof(regs));
 451	if (ret) {
 452		dev_err(dev, "%s error %d\n", "alarm write", ret);
 453		return ret;
 454	}
 455	control = regs[7];
 456	status = regs[8];
 457
 458	dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
 459		&regs[0], &regs[4], control, status);
 460
 461	/* set ALARM1, using 24 hour and day-of-month modes */
 462	regs[0] = bin2bcd(t->time.tm_sec);
 463	regs[1] = bin2bcd(t->time.tm_min);
 464	regs[2] = bin2bcd(t->time.tm_hour);
 465	regs[3] = bin2bcd(t->time.tm_mday);
 466
 467	/* set ALARM2 to non-garbage */
 468	regs[4] = 0;
 469	regs[5] = 0;
 470	regs[6] = 0;
 471
 472	/* disable alarms */
 473	regs[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 474	regs[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 475
 476	ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 477				sizeof(regs));
 478	if (ret) {
 479		dev_err(dev, "can't set alarm time\n");
 480		return ret;
 481	}
 482
 483	/* optionally enable ALARM1 */
 484	if (t->enabled) {
 485		dev_dbg(dev, "alarm IRQ armed\n");
 486		regs[7] |= DS1337_BIT_A1IE;	/* only ALARM1 is used */
 487		regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[7]);
 488	}
 489
 490	return 0;
 491}
 492
 493static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 494{
 495	struct ds1307		*ds1307 = dev_get_drvdata(dev);
 496
 497	if (!test_bit(HAS_ALARM, &ds1307->flags))
 498		return -ENOTTY;
 499
 500	return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
 501				  DS1337_BIT_A1IE,
 502				  enabled ? DS1337_BIT_A1IE : 0);
 503}
 504
 505static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
 506{
 507	u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 508		DS1307_TRICKLE_CHARGER_NO_DIODE;
 509
 510	switch (ohms) {
 511	case 250:
 512		setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 513		break;
 514	case 2000:
 515		setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 516		break;
 517	case 4000:
 518		setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 519		break;
 520	default:
 521		dev_warn(ds1307->dev,
 522			 "Unsupported ohm value %u in dt\n", ohms);
 523		return 0;
 524	}
 525	return setup;
 526}
 527
 528static irqreturn_t rx8130_irq(int irq, void *dev_id)
 529{
 530	struct ds1307           *ds1307 = dev_id;
 531	struct mutex            *lock = &ds1307->rtc->ops_lock;
 532	u8 ctl[3];
 533	int ret;
 534
 535	mutex_lock(lock);
 536
 537	/* Read control registers. */
 538	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 539			       sizeof(ctl));
 540	if (ret < 0)
 541		goto out;
 542	if (!(ctl[1] & RX8130_REG_FLAG_AF))
 543		goto out;
 544	ctl[1] &= ~RX8130_REG_FLAG_AF;
 545	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 546
 547	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 548				sizeof(ctl));
 549	if (ret < 0)
 550		goto out;
 551
 552	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 553
 554out:
 555	mutex_unlock(lock);
 556
 557	return IRQ_HANDLED;
 558}
 559
 560static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 561{
 562	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 563	u8 ald[3], ctl[3];
 564	int ret;
 565
 566	if (!test_bit(HAS_ALARM, &ds1307->flags))
 567		return -EINVAL;
 568
 569	/* Read alarm registers. */
 570	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 571			       sizeof(ald));
 572	if (ret < 0)
 573		return ret;
 574
 575	/* Read control registers. */
 576	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 577			       sizeof(ctl));
 578	if (ret < 0)
 579		return ret;
 580
 581	t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
 582	t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
 583
 584	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 585	t->time.tm_sec = -1;
 586	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 587	t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
 588	t->time.tm_wday = -1;
 589	t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
 590	t->time.tm_mon = -1;
 591	t->time.tm_year = -1;
 592	t->time.tm_yday = -1;
 593	t->time.tm_isdst = -1;
 594
 595	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
 596		__func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 597		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
 598
 599	return 0;
 600}
 601
 602static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 603{
 604	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 605	u8 ald[3], ctl[3];
 606	int ret;
 607
 608	if (!test_bit(HAS_ALARM, &ds1307->flags))
 609		return -EINVAL;
 610
 611	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 612		"enabled=%d pending=%d\n", __func__,
 613		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 614		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 615		t->enabled, t->pending);
 616
 617	/* Read control registers. */
 618	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 619			       sizeof(ctl));
 620	if (ret < 0)
 621		return ret;
 622
 623	ctl[0] &= RX8130_REG_EXTENSION_WADA;
 624	ctl[1] &= ~RX8130_REG_FLAG_AF;
 625	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 626
 627	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 628				sizeof(ctl));
 629	if (ret < 0)
 630		return ret;
 631
 632	/* Hardware alarm precision is 1 minute! */
 633	ald[0] = bin2bcd(t->time.tm_min);
 634	ald[1] = bin2bcd(t->time.tm_hour);
 635	ald[2] = bin2bcd(t->time.tm_mday);
 636
 637	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 638				sizeof(ald));
 639	if (ret < 0)
 640		return ret;
 641
 642	if (!t->enabled)
 643		return 0;
 644
 645	ctl[2] |= RX8130_REG_CONTROL0_AIE;
 646
 647	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, ctl[2]);
 648}
 649
 650static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
 651{
 652	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 653	int ret, reg;
 654
 655	if (!test_bit(HAS_ALARM, &ds1307->flags))
 656		return -EINVAL;
 657
 658	ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
 659	if (ret < 0)
 660		return ret;
 661
 662	if (enabled)
 663		reg |= RX8130_REG_CONTROL0_AIE;
 664	else
 665		reg &= ~RX8130_REG_CONTROL0_AIE;
 666
 667	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
 668}
 669
 670static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
 671{
 672	struct ds1307           *ds1307 = dev_id;
 673	struct mutex            *lock = &ds1307->rtc->ops_lock;
 674	int reg, ret;
 675
 676	mutex_lock(lock);
 677
 678	/* Check and clear alarm 0 interrupt flag. */
 679	ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
 680	if (ret)
 681		goto out;
 682	if (!(reg & MCP794XX_BIT_ALMX_IF))
 683		goto out;
 684	reg &= ~MCP794XX_BIT_ALMX_IF;
 685	ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
 686	if (ret)
 687		goto out;
 688
 689	/* Disable alarm 0. */
 690	ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 691				 MCP794XX_BIT_ALM0_EN, 0);
 692	if (ret)
 693		goto out;
 694
 695	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 696
 697out:
 698	mutex_unlock(lock);
 699
 700	return IRQ_HANDLED;
 701}
 702
 703static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 704{
 705	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 706	u8 regs[10];
 707	int ret;
 708
 709	if (!test_bit(HAS_ALARM, &ds1307->flags))
 710		return -EINVAL;
 711
 712	/* Read control and alarm 0 registers. */
 713	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 714			       sizeof(regs));
 715	if (ret)
 716		return ret;
 717
 718	t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
 719
 720	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 721	t->time.tm_sec = bcd2bin(regs[3] & 0x7f);
 722	t->time.tm_min = bcd2bin(regs[4] & 0x7f);
 723	t->time.tm_hour = bcd2bin(regs[5] & 0x3f);
 724	t->time.tm_wday = bcd2bin(regs[6] & 0x7) - 1;
 725	t->time.tm_mday = bcd2bin(regs[7] & 0x3f);
 726	t->time.tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
 727	t->time.tm_year = -1;
 728	t->time.tm_yday = -1;
 729	t->time.tm_isdst = -1;
 730
 731	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 732		"enabled=%d polarity=%d irq=%d match=%lu\n", __func__,
 733		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 734		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 735		!!(regs[6] & MCP794XX_BIT_ALMX_POL),
 736		!!(regs[6] & MCP794XX_BIT_ALMX_IF),
 737		(regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
 738
 739	return 0;
 740}
 741
 742/*
 743 * We may have a random RTC weekday, therefore calculate alarm weekday based
 744 * on current weekday we read from the RTC timekeeping regs
 745 */
 746static int mcp794xx_alm_weekday(struct device *dev, struct rtc_time *tm_alarm)
 747{
 748	struct rtc_time tm_now;
 749	int days_now, days_alarm, ret;
 750
 751	ret = ds1307_get_time(dev, &tm_now);
 752	if (ret)
 753		return ret;
 754
 755	days_now = div_s64(rtc_tm_to_time64(&tm_now), 24 * 60 * 60);
 756	days_alarm = div_s64(rtc_tm_to_time64(tm_alarm), 24 * 60 * 60);
 757
 758	return (tm_now.tm_wday + days_alarm - days_now) % 7 + 1;
 759}
 760
 761static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 762{
 763	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 764	unsigned char regs[10];
 765	int wday, ret;
 766
 767	if (!test_bit(HAS_ALARM, &ds1307->flags))
 768		return -EINVAL;
 769
 770	wday = mcp794xx_alm_weekday(dev, &t->time);
 771	if (wday < 0)
 772		return wday;
 773
 774	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 775		"enabled=%d pending=%d\n", __func__,
 776		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 777		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 778		t->enabled, t->pending);
 779
 780	/* Read control and alarm 0 registers. */
 781	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 782			       sizeof(regs));
 783	if (ret)
 784		return ret;
 785
 786	/* Set alarm 0, using 24-hour and day-of-month modes. */
 787	regs[3] = bin2bcd(t->time.tm_sec);
 788	regs[4] = bin2bcd(t->time.tm_min);
 789	regs[5] = bin2bcd(t->time.tm_hour);
 790	regs[6] = wday;
 791	regs[7] = bin2bcd(t->time.tm_mday);
 792	regs[8] = bin2bcd(t->time.tm_mon + 1);
 793
 794	/* Clear the alarm 0 interrupt flag. */
 795	regs[6] &= ~MCP794XX_BIT_ALMX_IF;
 796	/* Set alarm match: second, minute, hour, day, date, month. */
 797	regs[6] |= MCP794XX_MSK_ALMX_MATCH;
 798	/* Disable interrupt. We will not enable until completely programmed */
 799	regs[0] &= ~MCP794XX_BIT_ALM0_EN;
 800
 801	ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 802				sizeof(regs));
 803	if (ret)
 804		return ret;
 805
 806	if (!t->enabled)
 807		return 0;
 808	regs[0] |= MCP794XX_BIT_ALM0_EN;
 809	return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
 810}
 811
 812static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 813{
 814	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 815
 816	if (!test_bit(HAS_ALARM, &ds1307->flags))
 817		return -EINVAL;
 818
 819	return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 820				  MCP794XX_BIT_ALM0_EN,
 821				  enabled ? MCP794XX_BIT_ALM0_EN : 0);
 822}
 823
 824static int m41txx_rtc_read_offset(struct device *dev, long *offset)
 825{
 826	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 827	unsigned int ctrl_reg;
 828	u8 val;
 829
 830	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
 831
 832	val = ctrl_reg & M41TXX_M_CALIBRATION;
 833
 834	/* check if positive */
 835	if (ctrl_reg & M41TXX_BIT_CALIB_SIGN)
 836		*offset = (val * M41TXX_POS_OFFSET_STEP_PPB);
 837	else
 838		*offset = -(val * M41TXX_NEG_OFFSET_STEP_PPB);
 839
 840	return 0;
 841}
 842
 843static int m41txx_rtc_set_offset(struct device *dev, long offset)
 844{
 845	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 846	unsigned int ctrl_reg;
 847
 848	if ((offset < M41TXX_MIN_OFFSET) || (offset > M41TXX_MAX_OFFSET))
 849		return -ERANGE;
 850
 851	if (offset >= 0) {
 852		ctrl_reg = DIV_ROUND_CLOSEST(offset,
 853					     M41TXX_POS_OFFSET_STEP_PPB);
 854		ctrl_reg |= M41TXX_BIT_CALIB_SIGN;
 855	} else {
 856		ctrl_reg = DIV_ROUND_CLOSEST(abs(offset),
 857					     M41TXX_NEG_OFFSET_STEP_PPB);
 858	}
 859
 860	return regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL,
 861				  M41TXX_M_CALIBRATION | M41TXX_BIT_CALIB_SIGN,
 862				  ctrl_reg);
 863}
 864
 865#ifdef CONFIG_WATCHDOG_CORE
 866static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
 867{
 868	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 869	u8 regs[2];
 870	int ret;
 871
 872	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
 873				 DS1388_BIT_WF, 0);
 874	if (ret)
 875		return ret;
 876
 877	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 878				 DS1388_BIT_WDE | DS1388_BIT_RST, 0);
 879	if (ret)
 880		return ret;
 881
 882	/*
 883	 * watchdog timeouts are measured in seconds. So ignore hundredths of
 884	 * seconds field.
 885	 */
 886	regs[0] = 0;
 887	regs[1] = bin2bcd(wdt_dev->timeout);
 888
 889	ret = regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 890				sizeof(regs));
 891	if (ret)
 892		return ret;
 893
 894	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 895				  DS1388_BIT_WDE | DS1388_BIT_RST,
 896				  DS1388_BIT_WDE | DS1388_BIT_RST);
 897}
 898
 899static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
 900{
 901	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 902
 903	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 904				  DS1388_BIT_WDE | DS1388_BIT_RST, 0);
 905}
 906
 907static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
 908{
 909	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 910	u8 regs[2];
 911
 912	return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 913				sizeof(regs));
 914}
 915
 916static int ds1388_wdt_set_timeout(struct watchdog_device *wdt_dev,
 917				  unsigned int val)
 918{
 919	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 920	u8 regs[2];
 921
 922	wdt_dev->timeout = val;
 923	regs[0] = 0;
 924	regs[1] = bin2bcd(wdt_dev->timeout);
 925
 926	return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 927				 sizeof(regs));
 928}
 929#endif
 930
 931static const struct rtc_class_ops rx8130_rtc_ops = {
 932	.read_time      = ds1307_get_time,
 933	.set_time       = ds1307_set_time,
 934	.read_alarm     = rx8130_read_alarm,
 935	.set_alarm      = rx8130_set_alarm,
 936	.alarm_irq_enable = rx8130_alarm_irq_enable,
 937};
 938
 939static const struct rtc_class_ops mcp794xx_rtc_ops = {
 940	.read_time      = ds1307_get_time,
 941	.set_time       = ds1307_set_time,
 942	.read_alarm     = mcp794xx_read_alarm,
 943	.set_alarm      = mcp794xx_set_alarm,
 944	.alarm_irq_enable = mcp794xx_alarm_irq_enable,
 945};
 946
 947static const struct rtc_class_ops m41txx_rtc_ops = {
 948	.read_time      = ds1307_get_time,
 949	.set_time       = ds1307_set_time,
 950	.read_alarm	= ds1337_read_alarm,
 951	.set_alarm	= ds1337_set_alarm,
 952	.alarm_irq_enable = ds1307_alarm_irq_enable,
 953	.read_offset	= m41txx_rtc_read_offset,
 954	.set_offset	= m41txx_rtc_set_offset,
 955};
 956
 957static const struct chip_desc chips[last_ds_type] = {
 958	[ds_1307] = {
 959		.nvram_offset	= 8,
 960		.nvram_size	= 56,
 961	},
 962	[ds_1308] = {
 963		.nvram_offset	= 8,
 964		.nvram_size	= 56,
 965	},
 966	[ds_1337] = {
 967		.alarm		= 1,
 968		.century_reg	= DS1307_REG_MONTH,
 969		.century_bit	= DS1337_BIT_CENTURY,
 970	},
 971	[ds_1338] = {
 972		.nvram_offset	= 8,
 973		.nvram_size	= 56,
 974	},
 975	[ds_1339] = {
 976		.alarm		= 1,
 977		.century_reg	= DS1307_REG_MONTH,
 978		.century_bit	= DS1337_BIT_CENTURY,
 979		.bbsqi_bit	= DS1339_BIT_BBSQI,
 980		.trickle_charger_reg = 0x10,
 981		.do_trickle_setup = &do_trickle_setup_ds1339,
 982	},
 983	[ds_1340] = {
 984		.century_reg	= DS1307_REG_HOUR,
 985		.century_enable_bit = DS1340_BIT_CENTURY_EN,
 986		.century_bit	= DS1340_BIT_CENTURY,
 987		.do_trickle_setup = &do_trickle_setup_ds1339,
 988		.trickle_charger_reg = 0x08,
 989	},
 990	[ds_1341] = {
 991		.century_reg	= DS1307_REG_MONTH,
 992		.century_bit	= DS1337_BIT_CENTURY,
 993	},
 994	[ds_1388] = {
 995		.offset		= 1,
 996		.trickle_charger_reg = 0x0a,
 997	},
 998	[ds_3231] = {
 999		.alarm		= 1,
1000		.century_reg	= DS1307_REG_MONTH,
1001		.century_bit	= DS1337_BIT_CENTURY,
1002		.bbsqi_bit	= DS3231_BIT_BBSQW,
1003	},
1004	[rx_8130] = {
1005		.alarm		= 1,
1006		/* this is battery backed SRAM */
1007		.nvram_offset	= 0x20,
1008		.nvram_size	= 4,	/* 32bit (4 word x 8 bit) */
1009		.offset		= 0x10,
1010		.irq_handler = rx8130_irq,
1011		.rtc_ops = &rx8130_rtc_ops,
1012	},
1013	[m41t0] = {
1014		.rtc_ops	= &m41txx_rtc_ops,
1015	},
1016	[m41t00] = {
1017		.rtc_ops	= &m41txx_rtc_ops,
1018	},
1019	[m41t11] = {
1020		/* this is battery backed SRAM */
1021		.nvram_offset	= 8,
1022		.nvram_size	= 56,
1023		.rtc_ops	= &m41txx_rtc_ops,
1024	},
1025	[mcp794xx] = {
1026		.alarm		= 1,
1027		/* this is battery backed SRAM */
1028		.nvram_offset	= 0x20,
1029		.nvram_size	= 0x40,
1030		.irq_handler = mcp794xx_irq,
1031		.rtc_ops = &mcp794xx_rtc_ops,
1032	},
1033};
1034
1035static const struct i2c_device_id ds1307_id[] = {
1036	{ "ds1307", ds_1307 },
1037	{ "ds1308", ds_1308 },
1038	{ "ds1337", ds_1337 },
1039	{ "ds1338", ds_1338 },
1040	{ "ds1339", ds_1339 },
1041	{ "ds1388", ds_1388 },
1042	{ "ds1340", ds_1340 },
1043	{ "ds1341", ds_1341 },
1044	{ "ds3231", ds_3231 },
1045	{ "m41t0", m41t0 },
1046	{ "m41t00", m41t00 },
1047	{ "m41t11", m41t11 },
1048	{ "mcp7940x", mcp794xx },
1049	{ "mcp7941x", mcp794xx },
1050	{ "pt7c4338", ds_1307 },
1051	{ "rx8025", rx_8025 },
1052	{ "isl12057", ds_1337 },
1053	{ "rx8130", rx_8130 },
1054	{ }
1055};
1056MODULE_DEVICE_TABLE(i2c, ds1307_id);
1057
1058#ifdef CONFIG_OF
1059static const struct of_device_id ds1307_of_match[] = {
1060	{
1061		.compatible = "dallas,ds1307",
1062		.data = (void *)ds_1307
1063	},
1064	{
1065		.compatible = "dallas,ds1308",
1066		.data = (void *)ds_1308
1067	},
1068	{
1069		.compatible = "dallas,ds1337",
1070		.data = (void *)ds_1337
1071	},
1072	{
1073		.compatible = "dallas,ds1338",
1074		.data = (void *)ds_1338
1075	},
1076	{
1077		.compatible = "dallas,ds1339",
1078		.data = (void *)ds_1339
1079	},
1080	{
1081		.compatible = "dallas,ds1388",
1082		.data = (void *)ds_1388
1083	},
1084	{
1085		.compatible = "dallas,ds1340",
1086		.data = (void *)ds_1340
1087	},
1088	{
1089		.compatible = "dallas,ds1341",
1090		.data = (void *)ds_1341
1091	},
1092	{
1093		.compatible = "maxim,ds3231",
1094		.data = (void *)ds_3231
1095	},
1096	{
1097		.compatible = "st,m41t0",
1098		.data = (void *)m41t0
1099	},
1100	{
1101		.compatible = "st,m41t00",
1102		.data = (void *)m41t00
1103	},
1104	{
1105		.compatible = "st,m41t11",
1106		.data = (void *)m41t11
1107	},
1108	{
1109		.compatible = "microchip,mcp7940x",
1110		.data = (void *)mcp794xx
1111	},
1112	{
1113		.compatible = "microchip,mcp7941x",
1114		.data = (void *)mcp794xx
1115	},
1116	{
1117		.compatible = "pericom,pt7c4338",
1118		.data = (void *)ds_1307
1119	},
1120	{
1121		.compatible = "epson,rx8025",
1122		.data = (void *)rx_8025
1123	},
1124	{
1125		.compatible = "isil,isl12057",
1126		.data = (void *)ds_1337
1127	},
1128	{
1129		.compatible = "epson,rx8130",
1130		.data = (void *)rx_8130
1131	},
1132	{ }
1133};
1134MODULE_DEVICE_TABLE(of, ds1307_of_match);
1135#endif
1136
1137#ifdef CONFIG_ACPI
1138static const struct acpi_device_id ds1307_acpi_ids[] = {
1139	{ .id = "DS1307", .driver_data = ds_1307 },
1140	{ .id = "DS1308", .driver_data = ds_1308 },
1141	{ .id = "DS1337", .driver_data = ds_1337 },
1142	{ .id = "DS1338", .driver_data = ds_1338 },
1143	{ .id = "DS1339", .driver_data = ds_1339 },
1144	{ .id = "DS1388", .driver_data = ds_1388 },
1145	{ .id = "DS1340", .driver_data = ds_1340 },
1146	{ .id = "DS1341", .driver_data = ds_1341 },
1147	{ .id = "DS3231", .driver_data = ds_3231 },
1148	{ .id = "M41T0", .driver_data = m41t0 },
1149	{ .id = "M41T00", .driver_data = m41t00 },
1150	{ .id = "M41T11", .driver_data = m41t11 },
1151	{ .id = "MCP7940X", .driver_data = mcp794xx },
1152	{ .id = "MCP7941X", .driver_data = mcp794xx },
1153	{ .id = "PT7C4338", .driver_data = ds_1307 },
1154	{ .id = "RX8025", .driver_data = rx_8025 },
1155	{ .id = "ISL12057", .driver_data = ds_1337 },
1156	{ .id = "RX8130", .driver_data = rx_8130 },
1157	{ }
1158};
1159MODULE_DEVICE_TABLE(acpi, ds1307_acpi_ids);
1160#endif
1161
1162/*
1163 * The ds1337 and ds1339 both have two alarms, but we only use the first
1164 * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
1165 * signal; ds1339 chips have only one alarm signal.
1166 */
1167static irqreturn_t ds1307_irq(int irq, void *dev_id)
1168{
1169	struct ds1307		*ds1307 = dev_id;
1170	struct mutex		*lock = &ds1307->rtc->ops_lock;
1171	int			stat, ret;
1172
1173	mutex_lock(lock);
1174	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
1175	if (ret)
1176		goto out;
1177
1178	if (stat & DS1337_BIT_A1I) {
1179		stat &= ~DS1337_BIT_A1I;
1180		regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
1181
1182		ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1183					 DS1337_BIT_A1IE, 0);
1184		if (ret)
1185			goto out;
1186
1187		rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
1188	}
1189
1190out:
1191	mutex_unlock(lock);
1192
1193	return IRQ_HANDLED;
1194}
1195
1196/*----------------------------------------------------------------------*/
1197
1198static const struct rtc_class_ops ds13xx_rtc_ops = {
1199	.read_time	= ds1307_get_time,
1200	.set_time	= ds1307_set_time,
1201	.read_alarm	= ds1337_read_alarm,
1202	.set_alarm	= ds1337_set_alarm,
1203	.alarm_irq_enable = ds1307_alarm_irq_enable,
1204};
1205
1206static ssize_t frequency_test_store(struct device *dev,
1207				    struct device_attribute *attr,
1208				    const char *buf, size_t count)
1209{
1210	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1211	bool freq_test_en;
1212	int ret;
1213
1214	ret = kstrtobool(buf, &freq_test_en);
1215	if (ret) {
1216		dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
1217		return ret;
1218	}
1219
1220	regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, M41TXX_BIT_FT,
1221			   freq_test_en ? M41TXX_BIT_FT : 0);
1222
1223	return count;
1224}
1225
1226static ssize_t frequency_test_show(struct device *dev,
1227				   struct device_attribute *attr,
1228				   char *buf)
1229{
1230	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1231	unsigned int ctrl_reg;
1232
1233	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
1234
1235	return scnprintf(buf, PAGE_SIZE, (ctrl_reg & M41TXX_BIT_FT) ? "on\n" :
1236			"off\n");
1237}
1238
1239static DEVICE_ATTR_RW(frequency_test);
1240
1241static struct attribute *rtc_freq_test_attrs[] = {
1242	&dev_attr_frequency_test.attr,
1243	NULL,
1244};
1245
1246static const struct attribute_group rtc_freq_test_attr_group = {
1247	.attrs		= rtc_freq_test_attrs,
1248};
1249
1250static int ds1307_add_frequency_test(struct ds1307 *ds1307)
1251{
1252	int err;
1253
1254	switch (ds1307->type) {
1255	case m41t0:
1256	case m41t00:
1257	case m41t11:
1258		err = rtc_add_group(ds1307->rtc, &rtc_freq_test_attr_group);
1259		if (err)
1260			return err;
1261		break;
1262	default:
1263		break;
1264	}
1265
1266	return 0;
1267}
1268
1269/*----------------------------------------------------------------------*/
1270
1271static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
1272			     size_t bytes)
1273{
1274	struct ds1307 *ds1307 = priv;
1275	const struct chip_desc *chip = &chips[ds1307->type];
1276
1277	return regmap_bulk_read(ds1307->regmap, chip->nvram_offset + offset,
1278				val, bytes);
1279}
1280
1281static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
1282			      size_t bytes)
1283{
1284	struct ds1307 *ds1307 = priv;
1285	const struct chip_desc *chip = &chips[ds1307->type];
1286
1287	return regmap_bulk_write(ds1307->regmap, chip->nvram_offset + offset,
1288				 val, bytes);
1289}
1290
1291/*----------------------------------------------------------------------*/
1292
1293static u8 ds1307_trickle_init(struct ds1307 *ds1307,
1294			      const struct chip_desc *chip)
1295{
1296	u32 ohms;
1297	bool diode = true;
1298
1299	if (!chip->do_trickle_setup)
1300		return 0;
1301
1302	if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
1303				     &ohms))
1304		return 0;
1305
1306	if (device_property_read_bool(ds1307->dev, "trickle-diode-disable"))
1307		diode = false;
1308
1309	return chip->do_trickle_setup(ds1307, ohms, diode);
1310}
1311
1312/*----------------------------------------------------------------------*/
1313
1314#if IS_REACHABLE(CONFIG_HWMON)
1315
1316/*
1317 * Temperature sensor support for ds3231 devices.
1318 */
1319
1320#define DS3231_REG_TEMPERATURE	0x11
1321
1322/*
1323 * A user-initiated temperature conversion is not started by this function,
1324 * so the temperature is updated once every 64 seconds.
1325 */
1326static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
1327{
1328	struct ds1307 *ds1307 = dev_get_drvdata(dev);
1329	u8 temp_buf[2];
1330	s16 temp;
1331	int ret;
1332
1333	ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
1334			       temp_buf, sizeof(temp_buf));
1335	if (ret)
1336		return ret;
1337	/*
1338	 * Temperature is represented as a 10-bit code with a resolution of
1339	 * 0.25 degree celsius and encoded in two's complement format.
1340	 */
1341	temp = (temp_buf[0] << 8) | temp_buf[1];
1342	temp >>= 6;
1343	*mC = temp * 250;
1344
1345	return 0;
1346}
1347
1348static ssize_t ds3231_hwmon_show_temp(struct device *dev,
1349				      struct device_attribute *attr, char *buf)
1350{
1351	int ret;
1352	s32 temp;
1353
1354	ret = ds3231_hwmon_read_temp(dev, &temp);
1355	if (ret)
1356		return ret;
1357
1358	return sprintf(buf, "%d\n", temp);
1359}
1360static SENSOR_DEVICE_ATTR(temp1_input, 0444, ds3231_hwmon_show_temp,
1361			  NULL, 0);
1362
1363static struct attribute *ds3231_hwmon_attrs[] = {
1364	&sensor_dev_attr_temp1_input.dev_attr.attr,
1365	NULL,
1366};
1367ATTRIBUTE_GROUPS(ds3231_hwmon);
1368
1369static void ds1307_hwmon_register(struct ds1307 *ds1307)
1370{
1371	struct device *dev;
1372
1373	if (ds1307->type != ds_3231)
1374		return;
1375
1376	dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1377						     ds1307,
1378						     ds3231_hwmon_groups);
1379	if (IS_ERR(dev)) {
1380		dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1381			 PTR_ERR(dev));
1382	}
1383}
1384
1385#else
1386
1387static void ds1307_hwmon_register(struct ds1307 *ds1307)
1388{
1389}
1390
1391#endif /* CONFIG_RTC_DRV_DS1307_HWMON */
1392
1393/*----------------------------------------------------------------------*/
1394
1395/*
1396 * Square-wave output support for DS3231
1397 * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1398 */
1399#ifdef CONFIG_COMMON_CLK
1400
1401enum {
1402	DS3231_CLK_SQW = 0,
1403	DS3231_CLK_32KHZ,
1404};
1405
1406#define clk_sqw_to_ds1307(clk)	\
1407	container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1408#define clk_32khz_to_ds1307(clk)	\
1409	container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1410
1411static int ds3231_clk_sqw_rates[] = {
1412	1,
1413	1024,
1414	4096,
1415	8192,
1416};
1417
1418static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1419{
1420	struct mutex *lock = &ds1307->rtc->ops_lock;
1421	int ret;
1422
1423	mutex_lock(lock);
1424	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1425				 mask, value);
1426	mutex_unlock(lock);
1427
1428	return ret;
1429}
1430
1431static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1432						unsigned long parent_rate)
1433{
1434	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1435	int control, ret;
1436	int rate_sel = 0;
1437
1438	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1439	if (ret)
1440		return ret;
1441	if (control & DS1337_BIT_RS1)
1442		rate_sel += 1;
1443	if (control & DS1337_BIT_RS2)
1444		rate_sel += 2;
1445
1446	return ds3231_clk_sqw_rates[rate_sel];
1447}
1448
1449static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1450				      unsigned long *prate)
1451{
1452	int i;
1453
1454	for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1455		if (ds3231_clk_sqw_rates[i] <= rate)
1456			return ds3231_clk_sqw_rates[i];
1457	}
1458
1459	return 0;
1460}
1461
1462static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1463				   unsigned long parent_rate)
1464{
1465	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1466	int control = 0;
1467	int rate_sel;
1468
1469	for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1470			rate_sel++) {
1471		if (ds3231_clk_sqw_rates[rate_sel] == rate)
1472			break;
1473	}
1474
1475	if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1476		return -EINVAL;
1477
1478	if (rate_sel & 1)
1479		control |= DS1337_BIT_RS1;
1480	if (rate_sel & 2)
1481		control |= DS1337_BIT_RS2;
1482
1483	return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1484				control);
1485}
1486
1487static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1488{
1489	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1490
1491	return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1492}
1493
1494static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1495{
1496	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1497
1498	ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1499}
1500
1501static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1502{
1503	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1504	int control, ret;
1505
1506	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1507	if (ret)
1508		return ret;
1509
1510	return !(control & DS1337_BIT_INTCN);
1511}
1512
1513static const struct clk_ops ds3231_clk_sqw_ops = {
1514	.prepare = ds3231_clk_sqw_prepare,
1515	.unprepare = ds3231_clk_sqw_unprepare,
1516	.is_prepared = ds3231_clk_sqw_is_prepared,
1517	.recalc_rate = ds3231_clk_sqw_recalc_rate,
1518	.round_rate = ds3231_clk_sqw_round_rate,
1519	.set_rate = ds3231_clk_sqw_set_rate,
1520};
1521
1522static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1523						  unsigned long parent_rate)
1524{
1525	return 32768;
1526}
1527
1528static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1529{
1530	struct mutex *lock = &ds1307->rtc->ops_lock;
1531	int ret;
1532
1533	mutex_lock(lock);
1534	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1535				 DS3231_BIT_EN32KHZ,
1536				 enable ? DS3231_BIT_EN32KHZ : 0);
1537	mutex_unlock(lock);
1538
1539	return ret;
1540}
1541
1542static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1543{
1544	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1545
1546	return ds3231_clk_32khz_control(ds1307, true);
1547}
1548
1549static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1550{
1551	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1552
1553	ds3231_clk_32khz_control(ds1307, false);
1554}
1555
1556static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1557{
1558	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1559	int status, ret;
1560
1561	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1562	if (ret)
1563		return ret;
1564
1565	return !!(status & DS3231_BIT_EN32KHZ);
1566}
1567
1568static const struct clk_ops ds3231_clk_32khz_ops = {
1569	.prepare = ds3231_clk_32khz_prepare,
1570	.unprepare = ds3231_clk_32khz_unprepare,
1571	.is_prepared = ds3231_clk_32khz_is_prepared,
1572	.recalc_rate = ds3231_clk_32khz_recalc_rate,
1573};
1574
1575static struct clk_init_data ds3231_clks_init[] = {
1576	[DS3231_CLK_SQW] = {
1577		.name = "ds3231_clk_sqw",
1578		.ops = &ds3231_clk_sqw_ops,
1579	},
1580	[DS3231_CLK_32KHZ] = {
1581		.name = "ds3231_clk_32khz",
1582		.ops = &ds3231_clk_32khz_ops,
1583	},
1584};
1585
1586static int ds3231_clks_register(struct ds1307 *ds1307)
1587{
1588	struct device_node *node = ds1307->dev->of_node;
1589	struct clk_onecell_data	*onecell;
1590	int i;
1591
1592	onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1593	if (!onecell)
1594		return -ENOMEM;
1595
1596	onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1597	onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1598				     sizeof(onecell->clks[0]), GFP_KERNEL);
1599	if (!onecell->clks)
1600		return -ENOMEM;
1601
1602	for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1603		struct clk_init_data init = ds3231_clks_init[i];
1604
1605		/*
1606		 * Interrupt signal due to alarm conditions and square-wave
1607		 * output share same pin, so don't initialize both.
1608		 */
1609		if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
1610			continue;
1611
1612		/* optional override of the clockname */
1613		of_property_read_string_index(node, "clock-output-names", i,
1614					      &init.name);
1615		ds1307->clks[i].init = &init;
1616
1617		onecell->clks[i] = devm_clk_register(ds1307->dev,
1618						     &ds1307->clks[i]);
1619		if (IS_ERR(onecell->clks[i]))
1620			return PTR_ERR(onecell->clks[i]);
1621	}
1622
1623	if (!node)
1624		return 0;
1625
1626	of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1627
1628	return 0;
1629}
1630
1631static void ds1307_clks_register(struct ds1307 *ds1307)
1632{
1633	int ret;
1634
1635	if (ds1307->type != ds_3231)
1636		return;
1637
1638	ret = ds3231_clks_register(ds1307);
1639	if (ret) {
1640		dev_warn(ds1307->dev, "unable to register clock device %d\n",
1641			 ret);
1642	}
1643}
1644
1645#else
1646
1647static void ds1307_clks_register(struct ds1307 *ds1307)
1648{
1649}
1650
1651#endif /* CONFIG_COMMON_CLK */
1652
1653#ifdef CONFIG_WATCHDOG_CORE
1654static const struct watchdog_info ds1388_wdt_info = {
1655	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
1656	.identity = "DS1388 watchdog",
1657};
1658
1659static const struct watchdog_ops ds1388_wdt_ops = {
1660	.owner = THIS_MODULE,
1661	.start = ds1388_wdt_start,
1662	.stop = ds1388_wdt_stop,
1663	.ping = ds1388_wdt_ping,
1664	.set_timeout = ds1388_wdt_set_timeout,
1665
1666};
1667
1668static void ds1307_wdt_register(struct ds1307 *ds1307)
1669{
1670	struct watchdog_device	*wdt;
1671	int err;
1672	int val;
1673
1674	if (ds1307->type != ds_1388)
1675		return;
1676
1677	wdt = devm_kzalloc(ds1307->dev, sizeof(*wdt), GFP_KERNEL);
1678	if (!wdt)
1679		return;
1680
1681	err = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
1682	if (!err && val & DS1388_BIT_WF)
1683		wdt->bootstatus = WDIOF_CARDRESET;
1684
1685	wdt->info = &ds1388_wdt_info;
1686	wdt->ops = &ds1388_wdt_ops;
1687	wdt->timeout = 99;
1688	wdt->max_timeout = 99;
1689	wdt->min_timeout = 1;
1690
1691	watchdog_init_timeout(wdt, 0, ds1307->dev);
1692	watchdog_set_drvdata(wdt, ds1307);
1693	devm_watchdog_register_device(ds1307->dev, wdt);
1694}
1695#else
1696static void ds1307_wdt_register(struct ds1307 *ds1307)
1697{
1698}
1699#endif /* CONFIG_WATCHDOG_CORE */
1700
1701static const struct regmap_config regmap_config = {
1702	.reg_bits = 8,
1703	.val_bits = 8,
1704};
1705
1706static int ds1307_probe(struct i2c_client *client,
1707			const struct i2c_device_id *id)
1708{
1709	struct ds1307		*ds1307;
1710	int			err = -ENODEV;
1711	int			tmp;
1712	const struct chip_desc	*chip;
1713	bool			want_irq;
1714	bool			ds1307_can_wakeup_device = false;
1715	unsigned char		regs[8];
1716	struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1717	u8			trickle_charger_setup = 0;
1718
1719	ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1720	if (!ds1307)
1721		return -ENOMEM;
1722
1723	dev_set_drvdata(&client->dev, ds1307);
1724	ds1307->dev = &client->dev;
1725	ds1307->name = client->name;
1726
1727	ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1728	if (IS_ERR(ds1307->regmap)) {
1729		dev_err(ds1307->dev, "regmap allocation failed\n");
1730		return PTR_ERR(ds1307->regmap);
1731	}
1732
1733	i2c_set_clientdata(client, ds1307);
1734
1735	if (client->dev.of_node) {
1736		ds1307->type = (enum ds_type)
1737			of_device_get_match_data(&client->dev);
1738		chip = &chips[ds1307->type];
1739	} else if (id) {
1740		chip = &chips[id->driver_data];
1741		ds1307->type = id->driver_data;
1742	} else {
1743		const struct acpi_device_id *acpi_id;
1744
1745		acpi_id = acpi_match_device(ACPI_PTR(ds1307_acpi_ids),
1746					    ds1307->dev);
1747		if (!acpi_id)
1748			return -ENODEV;
1749		chip = &chips[acpi_id->driver_data];
1750		ds1307->type = acpi_id->driver_data;
1751	}
1752
1753	want_irq = client->irq > 0 && chip->alarm;
1754
1755	if (!pdata)
1756		trickle_charger_setup = ds1307_trickle_init(ds1307, chip);
1757	else if (pdata->trickle_charger_setup)
1758		trickle_charger_setup = pdata->trickle_charger_setup;
1759
1760	if (trickle_charger_setup && chip->trickle_charger_reg) {
1761		trickle_charger_setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
1762		dev_dbg(ds1307->dev,
1763			"writing trickle charger info 0x%x to 0x%x\n",
1764			trickle_charger_setup, chip->trickle_charger_reg);
1765		regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1766			     trickle_charger_setup);
1767	}
1768
1769#ifdef CONFIG_OF
1770/*
1771 * For devices with no IRQ directly connected to the SoC, the RTC chip
1772 * can be forced as a wakeup source by stating that explicitly in
1773 * the device's .dts file using the "wakeup-source" boolean property.
1774 * If the "wakeup-source" property is set, don't request an IRQ.
1775 * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1776 * if supported by the RTC.
1777 */
1778	if (chip->alarm && of_property_read_bool(client->dev.of_node,
1779						 "wakeup-source"))
1780		ds1307_can_wakeup_device = true;
1781#endif
1782
1783	switch (ds1307->type) {
1784	case ds_1337:
1785	case ds_1339:
1786	case ds_1341:
1787	case ds_3231:
1788		/* get registers that the "rtc" read below won't read... */
1789		err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1790				       regs, 2);
1791		if (err) {
1792			dev_dbg(ds1307->dev, "read error %d\n", err);
1793			goto exit;
1794		}
1795
1796		/* oscillator off?  turn it on, so clock can tick. */
1797		if (regs[0] & DS1337_BIT_nEOSC)
1798			regs[0] &= ~DS1337_BIT_nEOSC;
1799
1800		/*
1801		 * Using IRQ or defined as wakeup-source?
1802		 * Disable the square wave and both alarms.
1803		 * For some variants, be sure alarms can trigger when we're
1804		 * running on Vbackup (BBSQI/BBSQW)
1805		 */
1806		if (want_irq || ds1307_can_wakeup_device) {
1807			regs[0] |= DS1337_BIT_INTCN | chip->bbsqi_bit;
1808			regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1809		}
1810
1811		regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1812			     regs[0]);
1813
1814		/* oscillator fault?  clear flag, and warn */
1815		if (regs[1] & DS1337_BIT_OSF) {
1816			regmap_write(ds1307->regmap, DS1337_REG_STATUS,
1817				     regs[1] & ~DS1337_BIT_OSF);
1818			dev_warn(ds1307->dev, "SET TIME!\n");
1819		}
1820		break;
1821
1822	case rx_8025:
1823		err = regmap_bulk_read(ds1307->regmap,
1824				       RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
1825		if (err) {
1826			dev_dbg(ds1307->dev, "read error %d\n", err);
1827			goto exit;
1828		}
1829
1830		/* oscillator off?  turn it on, so clock can tick. */
1831		if (!(regs[1] & RX8025_BIT_XST)) {
1832			regs[1] |= RX8025_BIT_XST;
1833			regmap_write(ds1307->regmap,
1834				     RX8025_REG_CTRL2 << 4 | 0x08,
1835				     regs[1]);
1836			dev_warn(ds1307->dev,
1837				 "oscillator stop detected - SET TIME!\n");
1838		}
1839
1840		if (regs[1] & RX8025_BIT_PON) {
1841			regs[1] &= ~RX8025_BIT_PON;
1842			regmap_write(ds1307->regmap,
1843				     RX8025_REG_CTRL2 << 4 | 0x08,
1844				     regs[1]);
1845			dev_warn(ds1307->dev, "power-on detected\n");
1846		}
1847
1848		if (regs[1] & RX8025_BIT_VDET) {
1849			regs[1] &= ~RX8025_BIT_VDET;
1850			regmap_write(ds1307->regmap,
1851				     RX8025_REG_CTRL2 << 4 | 0x08,
1852				     regs[1]);
1853			dev_warn(ds1307->dev, "voltage drop detected\n");
1854		}
1855
1856		/* make sure we are running in 24hour mode */
1857		if (!(regs[0] & RX8025_BIT_2412)) {
1858			u8 hour;
1859
1860			/* switch to 24 hour mode */
1861			regmap_write(ds1307->regmap,
1862				     RX8025_REG_CTRL1 << 4 | 0x08,
1863				     regs[0] | RX8025_BIT_2412);
1864
1865			err = regmap_bulk_read(ds1307->regmap,
1866					       RX8025_REG_CTRL1 << 4 | 0x08,
1867					       regs, 2);
1868			if (err) {
1869				dev_dbg(ds1307->dev, "read error %d\n", err);
1870				goto exit;
1871			}
1872
1873			/* correct hour */
1874			hour = bcd2bin(regs[DS1307_REG_HOUR]);
1875			if (hour == 12)
1876				hour = 0;
1877			if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1878				hour += 12;
1879
1880			regmap_write(ds1307->regmap,
1881				     DS1307_REG_HOUR << 4 | 0x08, hour);
1882		}
1883		break;
1884	default:
1885		break;
1886	}
1887
1888	/* read RTC registers */
1889	err = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
1890			       sizeof(regs));
1891	if (err) {
1892		dev_dbg(ds1307->dev, "read error %d\n", err);
1893		goto exit;
1894	}
1895
1896	if (ds1307->type == mcp794xx &&
1897	    !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1898		regmap_write(ds1307->regmap, DS1307_REG_WDAY,
1899			     regs[DS1307_REG_WDAY] |
1900			     MCP794XX_BIT_VBATEN);
1901	}
1902
1903	tmp = regs[DS1307_REG_HOUR];
1904	switch (ds1307->type) {
1905	case ds_1340:
1906	case m41t0:
1907	case m41t00:
1908	case m41t11:
1909		/*
1910		 * NOTE: ignores century bits; fix before deploying
1911		 * systems that will run through year 2100.
1912		 */
1913		break;
1914	case rx_8025:
1915		break;
1916	default:
1917		if (!(tmp & DS1307_BIT_12HR))
1918			break;
1919
1920		/*
1921		 * Be sure we're in 24 hour mode.  Multi-master systems
1922		 * take note...
1923		 */
1924		tmp = bcd2bin(tmp & 0x1f);
1925		if (tmp == 12)
1926			tmp = 0;
1927		if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1928			tmp += 12;
1929		regmap_write(ds1307->regmap, chip->offset + DS1307_REG_HOUR,
1930			     bin2bcd(tmp));
1931	}
1932
1933	if (want_irq || ds1307_can_wakeup_device) {
1934		device_set_wakeup_capable(ds1307->dev, true);
1935		set_bit(HAS_ALARM, &ds1307->flags);
1936	}
1937
1938	ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
1939	if (IS_ERR(ds1307->rtc))
1940		return PTR_ERR(ds1307->rtc);
1941
1942	if (ds1307_can_wakeup_device && !want_irq) {
1943		dev_info(ds1307->dev,
1944			 "'wakeup-source' is set, request for an IRQ is disabled!\n");
1945		/* We cannot support UIE mode if we do not have an IRQ line */
1946		ds1307->rtc->uie_unsupported = 1;
1947	}
1948
1949	if (want_irq) {
1950		err = devm_request_threaded_irq(ds1307->dev, client->irq, NULL,
1951						chip->irq_handler ?: ds1307_irq,
1952						IRQF_SHARED | IRQF_ONESHOT,
1953						ds1307->name, ds1307);
1954		if (err) {
1955			client->irq = 0;
1956			device_set_wakeup_capable(ds1307->dev, false);
1957			clear_bit(HAS_ALARM, &ds1307->flags);
1958			dev_err(ds1307->dev, "unable to request IRQ!\n");
1959		} else {
1960			dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
1961		}
1962	}
1963
1964	ds1307->rtc->ops = chip->rtc_ops ?: &ds13xx_rtc_ops;
1965	err = ds1307_add_frequency_test(ds1307);
1966	if (err)
1967		return err;
1968
1969	err = rtc_register_device(ds1307->rtc);
1970	if (err)
1971		return err;
1972
1973	if (chip->nvram_size) {
1974		struct nvmem_config nvmem_cfg = {
1975			.name = "ds1307_nvram",
1976			.word_size = 1,
1977			.stride = 1,
1978			.size = chip->nvram_size,
1979			.reg_read = ds1307_nvram_read,
1980			.reg_write = ds1307_nvram_write,
1981			.priv = ds1307,
1982		};
1983
1984		ds1307->rtc->nvram_old_abi = true;
1985		rtc_nvmem_register(ds1307->rtc, &nvmem_cfg);
1986	}
1987
1988	ds1307_hwmon_register(ds1307);
1989	ds1307_clks_register(ds1307);
1990	ds1307_wdt_register(ds1307);
1991
1992	return 0;
1993
1994exit:
1995	return err;
1996}
1997
1998static struct i2c_driver ds1307_driver = {
1999	.driver = {
2000		.name	= "rtc-ds1307",
2001		.of_match_table = of_match_ptr(ds1307_of_match),
2002		.acpi_match_table = ACPI_PTR(ds1307_acpi_ids),
2003	},
2004	.probe		= ds1307_probe,
2005	.id_table	= ds1307_id,
2006};
2007
2008module_i2c_driver(ds1307_driver);
2009
2010MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
2011MODULE_LICENSE("GPL");