1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
   4 *
   5 *  Copyright (C) 2005 James Chapman (ds1337 core)
   6 *  Copyright (C) 2006 David Brownell
   7 *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
   8 *  Copyright (C) 2012 Bertrand Achard (nvram access fixes)
   9 */
  10
  11#include <linux/bcd.h>
  12#include <linux/i2c.h>
  13#include <linux/init.h>
  14#include <linux/kstrtox.h>
  15#include <linux/mod_devicetable.h>
  16#include <linux/module.h>
  17#include <linux/property.h>
  18#include <linux/rtc/ds1307.h>
  19#include <linux/rtc.h>
  20#include <linux/slab.h>
  21#include <linux/string.h>
  22#include <linux/hwmon.h>
  23#include <linux/hwmon-sysfs.h>
  24#include <linux/clk-provider.h>
  25#include <linux/regmap.h>
  26#include <linux/watchdog.h>
  27
  28/*
  29 * We can't determine type by probing, but if we expect pre-Linux code
  30 * to have set the chip up as a clock (turning on the oscillator and
  31 * setting the date and time), Linux can ignore the non-clock features.
  32 * That's a natural job for a factory or repair bench.
  33 */
  34enum ds_type {
  35	unknown_ds_type, /* always first and 0 */
  36	ds_1307,
  37	ds_1308,
  38	ds_1337,
  39	ds_1338,
  40	ds_1339,
  41	ds_1340,
  42	ds_1341,
  43	ds_1388,
  44	ds_3231,
  45	m41t0,
  46	m41t00,
  47	m41t11,
  48	mcp794xx,
  49	rx_8025,
  50	rx_8130,
  51	last_ds_type /* always last */
  52	/* rs5c372 too?  different address... */
  53};
  54
  55/* RTC registers don't differ much, except for the century flag */
  56#define DS1307_REG_SECS		0x00	/* 00-59 */
  57#	define DS1307_BIT_CH		0x80
  58#	define DS1340_BIT_nEOSC		0x80
  59#	define MCP794XX_BIT_ST		0x80
  60#define DS1307_REG_MIN		0x01	/* 00-59 */
  61#	define M41T0_BIT_OF		0x80
  62#define DS1307_REG_HOUR		0x02	/* 00-23, or 1-12{am,pm} */
  63#	define DS1307_BIT_12HR		0x40	/* in REG_HOUR */
  64#	define DS1307_BIT_PM		0x20	/* in REG_HOUR */
  65#	define DS1340_BIT_CENTURY_EN	0x80	/* in REG_HOUR */
  66#	define DS1340_BIT_CENTURY	0x40	/* in REG_HOUR */
  67#define DS1307_REG_WDAY		0x03	/* 01-07 */
  68#	define MCP794XX_BIT_OSCRUN	BIT(5)
  69#	define MCP794XX_BIT_VBATEN	0x08
  70#define DS1307_REG_MDAY		0x04	/* 01-31 */
  71#define DS1307_REG_MONTH	0x05	/* 01-12 */
  72#	define DS1337_BIT_CENTURY	0x80	/* in REG_MONTH */
  73#define DS1307_REG_YEAR		0x06	/* 00-99 */
  74
  75/*
  76 * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
  77 * start at 7, and they differ a LOT. Only control and status matter for
  78 * basic RTC date and time functionality; be careful using them.
  79 */
  80#define DS1307_REG_CONTROL	0x07		/* or ds1338 */
  81#	define DS1307_BIT_OUT		0x80
  82#	define DS1338_BIT_OSF		0x20
  83#	define DS1307_BIT_SQWE		0x10
  84#	define DS1307_BIT_RS1		0x02
  85#	define DS1307_BIT_RS0		0x01
  86#define DS1337_REG_CONTROL	0x0e
  87#	define DS1337_BIT_nEOSC		0x80
  88#	define DS1339_BIT_BBSQI		0x20
  89#	define DS3231_BIT_BBSQW		0x40 /* same as BBSQI */
  90#	define DS1337_BIT_RS2		0x10
  91#	define DS1337_BIT_RS1		0x08
  92#	define DS1337_BIT_INTCN		0x04
  93#	define DS1337_BIT_A2IE		0x02
  94#	define DS1337_BIT_A1IE		0x01
  95#define DS1340_REG_CONTROL	0x07
  96#	define DS1340_BIT_OUT		0x80
  97#	define DS1340_BIT_FT		0x40
  98#	define DS1340_BIT_CALIB_SIGN	0x20
  99#	define DS1340_M_CALIBRATION	0x1f
 100#define DS1340_REG_FLAG		0x09
 101#	define DS1340_BIT_OSF		0x80
 102#define DS1337_REG_STATUS	0x0f
 103#	define DS1337_BIT_OSF		0x80
 104#	define DS3231_BIT_EN32KHZ	0x08
 105#	define DS1337_BIT_A2I		0x02
 106#	define DS1337_BIT_A1I		0x01
 107#define DS1339_REG_ALARM1_SECS	0x07
 108
 109#define DS13XX_TRICKLE_CHARGER_MAGIC	0xa0
 110
 111#define RX8025_REG_CTRL1	0x0e
 112#	define RX8025_BIT_2412		0x20
 113#define RX8025_REG_CTRL2	0x0f
 114#	define RX8025_BIT_PON		0x10
 115#	define RX8025_BIT_VDET		0x40
 116#	define RX8025_BIT_XST		0x20
 117
 118#define RX8130_REG_ALARM_MIN		0x17
 119#define RX8130_REG_ALARM_HOUR		0x18
 120#define RX8130_REG_ALARM_WEEK_OR_DAY	0x19
 121#define RX8130_REG_EXTENSION		0x1c
 122#define RX8130_REG_EXTENSION_WADA	BIT(3)
 123#define RX8130_REG_FLAG			0x1d
 124#define RX8130_REG_FLAG_VLF		BIT(1)
 125#define RX8130_REG_FLAG_AF		BIT(3)
 126#define RX8130_REG_CONTROL0		0x1e
 127#define RX8130_REG_CONTROL0_AIE		BIT(3)
 128#define RX8130_REG_CONTROL1		0x1f
 129#define RX8130_REG_CONTROL1_INIEN	BIT(4)
 130#define RX8130_REG_CONTROL1_CHGEN	BIT(5)
 131
 132#define MCP794XX_REG_CONTROL		0x07
 133#	define MCP794XX_BIT_ALM0_EN	0x10
 134#	define MCP794XX_BIT_ALM1_EN	0x20
 135#define MCP794XX_REG_ALARM0_BASE	0x0a
 136#define MCP794XX_REG_ALARM0_CTRL	0x0d
 137#define MCP794XX_REG_ALARM1_BASE	0x11
 138#define MCP794XX_REG_ALARM1_CTRL	0x14
 139#	define MCP794XX_BIT_ALMX_IF	BIT(3)
 140#	define MCP794XX_BIT_ALMX_C0	BIT(4)
 141#	define MCP794XX_BIT_ALMX_C1	BIT(5)
 142#	define MCP794XX_BIT_ALMX_C2	BIT(6)
 143#	define MCP794XX_BIT_ALMX_POL	BIT(7)
 144#	define MCP794XX_MSK_ALMX_MATCH	(MCP794XX_BIT_ALMX_C0 | \
 145					 MCP794XX_BIT_ALMX_C1 | \
 146					 MCP794XX_BIT_ALMX_C2)
 147
 148#define M41TXX_REG_CONTROL	0x07
 149#	define M41TXX_BIT_OUT		BIT(7)
 150#	define M41TXX_BIT_FT		BIT(6)
 151#	define M41TXX_BIT_CALIB_SIGN	BIT(5)
 152#	define M41TXX_M_CALIBRATION	GENMASK(4, 0)
 153
 154#define DS1388_REG_WDOG_HUN_SECS	0x08
 155#define DS1388_REG_WDOG_SECS		0x09
 156#define DS1388_REG_FLAG			0x0b
 157#	define DS1388_BIT_WF		BIT(6)
 158#	define DS1388_BIT_OSF		BIT(7)
 159#define DS1388_REG_CONTROL		0x0c
 160#	define DS1388_BIT_RST		BIT(0)
 161#	define DS1388_BIT_WDE		BIT(1)
 162#	define DS1388_BIT_nEOSC		BIT(7)
 163
 164/* negative offset step is -2.034ppm */
 165#define M41TXX_NEG_OFFSET_STEP_PPB	2034
 166/* positive offset step is +4.068ppm */
 167#define M41TXX_POS_OFFSET_STEP_PPB	4068
 168/* Min and max values supported with 'offset' interface by M41TXX */
 169#define M41TXX_MIN_OFFSET	((-31) * M41TXX_NEG_OFFSET_STEP_PPB)
 170#define M41TXX_MAX_OFFSET	((31) * M41TXX_POS_OFFSET_STEP_PPB)
 171
 172struct ds1307 {
 173	enum ds_type		type;
 174	struct device		*dev;
 175	struct regmap		*regmap;
 176	const char		*name;
 177	struct rtc_device	*rtc;
 178#ifdef CONFIG_COMMON_CLK
 179	struct clk_hw		clks[2];
 180#endif
 181};
 182
 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	} else if (ds1307->type == mcp794xx &&
 247	    !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_OSCRUN)) {
 248		dev_warn_once(dev, "oscillator failed, set time!\n");
 249		return -EINVAL;
 250	}
 251
 252	tmp = regs[DS1307_REG_SECS];
 253	switch (ds1307->type) {
 254	case ds_1307:
 255	case m41t0:
 256	case m41t00:
 257	case m41t11:
 258		if (tmp & DS1307_BIT_CH)
 259			return -EINVAL;
 260		break;
 261	case ds_1308:
 262	case ds_1338:
 263		if (tmp & DS1307_BIT_CH)
 264			return -EINVAL;
 265
 266		ret = regmap_read(ds1307->regmap, DS1307_REG_CONTROL, &tmp);
 267		if (ret)
 268			return ret;
 269		if (tmp & DS1338_BIT_OSF)
 270			return -EINVAL;
 271		break;
 272	case ds_1340:
 273		if (tmp & DS1340_BIT_nEOSC)
 274			return -EINVAL;
 275
 276		ret = regmap_read(ds1307->regmap, DS1340_REG_FLAG, &tmp);
 277		if (ret)
 278			return ret;
 279		if (tmp & DS1340_BIT_OSF)
 280			return -EINVAL;
 281		break;
 282	case ds_1388:
 283		ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &tmp);
 284		if (ret)
 285			return ret;
 286		if (tmp & DS1388_BIT_OSF)
 287			return -EINVAL;
 288		break;
 289	case mcp794xx:
 290		if (!(tmp & MCP794XX_BIT_ST))
 291			return -EINVAL;
 292
 293		break;
 294	default:
 295		break;
 296	}
 297
 298	t->tm_sec = bcd2bin(regs[DS1307_REG_SECS] & 0x7f);
 299	t->tm_min = bcd2bin(regs[DS1307_REG_MIN] & 0x7f);
 300	tmp = regs[DS1307_REG_HOUR] & 0x3f;
 301	t->tm_hour = bcd2bin(tmp);
 302	/* rx8130 is bit position, not BCD */
 303	if (ds1307->type == rx_8130)
 304		t->tm_wday = fls(regs[DS1307_REG_WDAY] & 0x7f);
 305	else
 306		t->tm_wday = bcd2bin(regs[DS1307_REG_WDAY] & 0x07) - 1;
 307	t->tm_mday = bcd2bin(regs[DS1307_REG_MDAY] & 0x3f);
 308	tmp = regs[DS1307_REG_MONTH] & 0x1f;
 309	t->tm_mon = bcd2bin(tmp) - 1;
 310	t->tm_year = bcd2bin(regs[DS1307_REG_YEAR]) + 100;
 311
 312	if (regs[chip->century_reg] & chip->century_bit &&
 313	    IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
 314		t->tm_year += 100;
 315
 316	dev_dbg(dev, "%s secs=%d, mins=%d, "
 317		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 318		"read", t->tm_sec, t->tm_min,
 319		t->tm_hour, t->tm_mday,
 320		t->tm_mon, t->tm_year, t->tm_wday);
 321
 322	return 0;
 323}
 324
 325static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 326{
 327	struct ds1307	*ds1307 = dev_get_drvdata(dev);
 328	const struct chip_desc *chip = &chips[ds1307->type];
 329	int		result;
 330	int		tmp;
 331	u8		regs[7];
 332
 333	dev_dbg(dev, "%s secs=%d, mins=%d, "
 334		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
 335		"write", t->tm_sec, t->tm_min,
 336		t->tm_hour, t->tm_mday,
 337		t->tm_mon, t->tm_year, t->tm_wday);
 338
 339	if (t->tm_year < 100)
 340		return -EINVAL;
 341
 342#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
 343	if (t->tm_year > (chip->century_bit ? 299 : 199))
 344		return -EINVAL;
 345#else
 346	if (t->tm_year > 199)
 347		return -EINVAL;
 348#endif
 349
 350	regs[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
 351	regs[DS1307_REG_MIN] = bin2bcd(t->tm_min);
 352	regs[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
 353	/* rx8130 is bit position, not BCD */
 354	if (ds1307->type == rx_8130)
 355		regs[DS1307_REG_WDAY] = 1 << t->tm_wday;
 356	else
 357		regs[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
 358	regs[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
 359	regs[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
 360
 361	/* assume 20YY not 19YY */
 362	tmp = t->tm_year % 100;
 363	regs[DS1307_REG_YEAR] = bin2bcd(tmp);
 364
 365	if (chip->century_enable_bit)
 366		regs[chip->century_reg] |= chip->century_enable_bit;
 367	if (t->tm_year > 199 && chip->century_bit)
 368		regs[chip->century_reg] |= chip->century_bit;
 369
 370	switch (ds1307->type) {
 371	case ds_1308:
 372	case ds_1338:
 373		regmap_update_bits(ds1307->regmap, DS1307_REG_CONTROL,
 374				   DS1338_BIT_OSF, 0);
 375		break;
 376	case ds_1340:
 377		regmap_update_bits(ds1307->regmap, DS1340_REG_FLAG,
 378				   DS1340_BIT_OSF, 0);
 379		break;
 380	case ds_1388:
 381		regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
 382				   DS1388_BIT_OSF, 0);
 383		break;
 384	case mcp794xx:
 385		/*
 386		 * these bits were cleared when preparing the date/time
 387		 * values and need to be set again before writing the
 388		 * regsfer out to the device.
 389		 */
 390		regs[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
 391		regs[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
 392		break;
 393	default:
 394		break;
 395	}
 396
 397	dev_dbg(dev, "%s: %7ph\n", "write", regs);
 398
 399	result = regmap_bulk_write(ds1307->regmap, chip->offset, regs,
 400				   sizeof(regs));
 401	if (result) {
 402		dev_err(dev, "%s error %d\n", "write", result);
 403		return result;
 404	}
 405
 406	if (ds1307->type == rx_8130) {
 407		/* clear Voltage Loss Flag as data is available now */
 408		result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
 409				      ~(u8)RX8130_REG_FLAG_VLF);
 410		if (result) {
 411			dev_err(dev, "%s error %d\n", "write", result);
 412			return result;
 413		}
 414	}
 415
 416	return 0;
 417}
 418
 419static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 420{
 421	struct ds1307		*ds1307 = dev_get_drvdata(dev);
 422	int			ret;
 423	u8			regs[9];
 424
 425	/* read all ALARM1, ALARM2, and status registers at once */
 426	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS,
 427			       regs, sizeof(regs));
 428	if (ret) {
 429		dev_err(dev, "%s error %d\n", "alarm read", ret);
 430		return ret;
 431	}
 432
 433	dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
 434		&regs[0], &regs[4], &regs[7]);
 435
 436	/*
 437	 * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
 438	 * and that all four fields are checked matches
 439	 */
 440	t->time.tm_sec = bcd2bin(regs[0] & 0x7f);
 441	t->time.tm_min = bcd2bin(regs[1] & 0x7f);
 442	t->time.tm_hour = bcd2bin(regs[2] & 0x3f);
 443	t->time.tm_mday = bcd2bin(regs[3] & 0x3f);
 444
 445	/* ... and status */
 446	t->enabled = !!(regs[7] & DS1337_BIT_A1IE);
 447	t->pending = !!(regs[8] & DS1337_BIT_A1I);
 448
 449	dev_dbg(dev, "%s secs=%d, mins=%d, "
 450		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
 451		"alarm read", t->time.tm_sec, t->time.tm_min,
 452		t->time.tm_hour, t->time.tm_mday,
 453		t->enabled, t->pending);
 454
 455	return 0;
 456}
 457
 458static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 459{
 460	struct ds1307		*ds1307 = dev_get_drvdata(dev);
 461	unsigned char		regs[9];
 462	u8			control, status;
 463	int			ret;
 464
 465	dev_dbg(dev, "%s secs=%d, mins=%d, "
 466		"hours=%d, mday=%d, enabled=%d, pending=%d\n",
 467		"alarm set", t->time.tm_sec, t->time.tm_min,
 468		t->time.tm_hour, t->time.tm_mday,
 469		t->enabled, t->pending);
 470
 471	/* read current status of both alarms and the chip */
 472	ret = regmap_bulk_read(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 473			       sizeof(regs));
 474	if (ret) {
 475		dev_err(dev, "%s error %d\n", "alarm write", ret);
 476		return ret;
 477	}
 478	control = regs[7];
 479	status = regs[8];
 480
 481	dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
 482		&regs[0], &regs[4], control, status);
 483
 484	/* set ALARM1, using 24 hour and day-of-month modes */
 485	regs[0] = bin2bcd(t->time.tm_sec);
 486	regs[1] = bin2bcd(t->time.tm_min);
 487	regs[2] = bin2bcd(t->time.tm_hour);
 488	regs[3] = bin2bcd(t->time.tm_mday);
 489
 490	/* set ALARM2 to non-garbage */
 491	regs[4] = 0;
 492	regs[5] = 0;
 493	regs[6] = 0;
 494
 495	/* disable alarms */
 496	regs[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
 497	regs[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
 498
 499	ret = regmap_bulk_write(ds1307->regmap, DS1339_REG_ALARM1_SECS, regs,
 500				sizeof(regs));
 501	if (ret) {
 502		dev_err(dev, "can't set alarm time\n");
 503		return ret;
 504	}
 505
 506	/* optionally enable ALARM1 */
 507	if (t->enabled) {
 508		dev_dbg(dev, "alarm IRQ armed\n");
 509		regs[7] |= DS1337_BIT_A1IE;	/* only ALARM1 is used */
 510		regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[7]);
 511	}
 512
 513	return 0;
 514}
 515
 516static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
 517{
 518	struct ds1307		*ds1307 = dev_get_drvdata(dev);
 519
 520	return regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
 521				  DS1337_BIT_A1IE,
 522				  enabled ? DS1337_BIT_A1IE : 0);
 523}
 524
 525static u8 do_trickle_setup_ds1339(struct ds1307 *ds1307, u32 ohms, bool diode)
 526{
 527	u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
 528		DS1307_TRICKLE_CHARGER_NO_DIODE;
 529
 530	setup |= DS13XX_TRICKLE_CHARGER_MAGIC;
 531
 532	switch (ohms) {
 533	case 250:
 534		setup |= DS1307_TRICKLE_CHARGER_250_OHM;
 535		break;
 536	case 2000:
 537		setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
 538		break;
 539	case 4000:
 540		setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
 541		break;
 542	default:
 543		dev_warn(ds1307->dev,
 544			 "Unsupported ohm value %u in dt\n", ohms);
 545		return 0;
 546	}
 547	return setup;
 548}
 549
 550static u8 do_trickle_setup_rx8130(struct ds1307 *ds1307, u32 ohms, bool diode)
 551{
 552	/* make sure that the backup battery is enabled */
 553	u8 setup = RX8130_REG_CONTROL1_INIEN;
 554	if (diode)
 555		setup |= RX8130_REG_CONTROL1_CHGEN;
 556
 557	return setup;
 558}
 559
 560static irqreturn_t rx8130_irq(int irq, void *dev_id)
 561{
 562	struct ds1307           *ds1307 = dev_id;
 563	u8 ctl[3];
 564	int ret;
 565
 566	rtc_lock(ds1307->rtc);
 567
 568	/* Read control registers. */
 569	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 570			       sizeof(ctl));
 571	if (ret < 0)
 572		goto out;
 573	if (!(ctl[1] & RX8130_REG_FLAG_AF))
 574		goto out;
 575	ctl[1] &= ~RX8130_REG_FLAG_AF;
 576	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 577
 578	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 579				sizeof(ctl));
 580	if (ret < 0)
 581		goto out;
 582
 583	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 584
 585out:
 586	rtc_unlock(ds1307->rtc);
 587
 588	return IRQ_HANDLED;
 589}
 590
 591static int rx8130_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 592{
 593	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 594	u8 ald[3], ctl[3];
 595	int ret;
 596
 597	/* Read alarm registers. */
 598	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 599			       sizeof(ald));
 600	if (ret < 0)
 601		return ret;
 602
 603	/* Read control registers. */
 604	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 605			       sizeof(ctl));
 606	if (ret < 0)
 607		return ret;
 608
 609	t->enabled = !!(ctl[2] & RX8130_REG_CONTROL0_AIE);
 610	t->pending = !!(ctl[1] & RX8130_REG_FLAG_AF);
 611
 612	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 613	t->time.tm_sec = -1;
 614	t->time.tm_min = bcd2bin(ald[0] & 0x7f);
 615	t->time.tm_hour = bcd2bin(ald[1] & 0x7f);
 616	t->time.tm_wday = -1;
 617	t->time.tm_mday = bcd2bin(ald[2] & 0x7f);
 618	t->time.tm_mon = -1;
 619	t->time.tm_year = -1;
 620	t->time.tm_yday = -1;
 621	t->time.tm_isdst = -1;
 622
 623	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d enabled=%d\n",
 624		__func__, t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 625		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled);
 626
 627	return 0;
 628}
 629
 630static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 631{
 632	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 633	u8 ald[3], ctl[3];
 634	int ret;
 635
 636	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 637		"enabled=%d pending=%d\n", __func__,
 638		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 639		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 640		t->enabled, t->pending);
 641
 642	/* Read control registers. */
 643	ret = regmap_bulk_read(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 644			       sizeof(ctl));
 645	if (ret < 0)
 646		return ret;
 647
 648	ctl[0] &= RX8130_REG_EXTENSION_WADA;
 649	ctl[1] &= ~RX8130_REG_FLAG_AF;
 650	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 651
 652	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_EXTENSION, ctl,
 653				sizeof(ctl));
 654	if (ret < 0)
 655		return ret;
 656
 657	/* Hardware alarm precision is 1 minute! */
 658	ald[0] = bin2bcd(t->time.tm_min);
 659	ald[1] = bin2bcd(t->time.tm_hour);
 660	ald[2] = bin2bcd(t->time.tm_mday);
 661
 662	ret = regmap_bulk_write(ds1307->regmap, RX8130_REG_ALARM_MIN, ald,
 663				sizeof(ald));
 664	if (ret < 0)
 665		return ret;
 666
 667	if (!t->enabled)
 668		return 0;
 669
 670	ctl[2] |= RX8130_REG_CONTROL0_AIE;
 671
 672	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, ctl[2]);
 673}
 674
 675static int rx8130_alarm_irq_enable(struct device *dev, unsigned int enabled)
 676{
 677	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 678	int ret, reg;
 679
 680	ret = regmap_read(ds1307->regmap, RX8130_REG_CONTROL0, &reg);
 681	if (ret < 0)
 682		return ret;
 683
 684	if (enabled)
 685		reg |= RX8130_REG_CONTROL0_AIE;
 686	else
 687		reg &= ~RX8130_REG_CONTROL0_AIE;
 688
 689	return regmap_write(ds1307->regmap, RX8130_REG_CONTROL0, reg);
 690}
 691
 692static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
 693{
 694	struct ds1307           *ds1307 = dev_id;
 695	struct mutex            *lock = &ds1307->rtc->ops_lock;
 696	int reg, ret;
 697
 698	mutex_lock(lock);
 699
 700	/* Check and clear alarm 0 interrupt flag. */
 701	ret = regmap_read(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, &reg);
 702	if (ret)
 703		goto out;
 704	if (!(reg & MCP794XX_BIT_ALMX_IF))
 705		goto out;
 706	reg &= ~MCP794XX_BIT_ALMX_IF;
 707	ret = regmap_write(ds1307->regmap, MCP794XX_REG_ALARM0_CTRL, reg);
 708	if (ret)
 709		goto out;
 710
 711	/* Disable alarm 0. */
 712	ret = regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 713				 MCP794XX_BIT_ALM0_EN, 0);
 714	if (ret)
 715		goto out;
 716
 717	rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
 718
 719out:
 720	mutex_unlock(lock);
 721
 722	return IRQ_HANDLED;
 723}
 724
 725static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 726{
 727	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 728	u8 regs[10];
 729	int ret;
 730
 731	/* Read control and alarm 0 registers. */
 732	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 733			       sizeof(regs));
 734	if (ret)
 735		return ret;
 736
 737	t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
 738
 739	/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
 740	t->time.tm_sec = bcd2bin(regs[3] & 0x7f);
 741	t->time.tm_min = bcd2bin(regs[4] & 0x7f);
 742	t->time.tm_hour = bcd2bin(regs[5] & 0x3f);
 743	t->time.tm_wday = bcd2bin(regs[6] & 0x7) - 1;
 744	t->time.tm_mday = bcd2bin(regs[7] & 0x3f);
 745	t->time.tm_mon = bcd2bin(regs[8] & 0x1f) - 1;
 746	t->time.tm_year = -1;
 747	t->time.tm_yday = -1;
 748	t->time.tm_isdst = -1;
 749
 750	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 751		"enabled=%d polarity=%d irq=%d match=%lu\n", __func__,
 752		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 753		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
 754		!!(regs[6] & MCP794XX_BIT_ALMX_POL),
 755		!!(regs[6] & MCP794XX_BIT_ALMX_IF),
 756		(regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
 757
 758	return 0;
 759}
 760
 761/*
 762 * We may have a random RTC weekday, therefore calculate alarm weekday based
 763 * on current weekday we read from the RTC timekeeping regs
 764 */
 765static int mcp794xx_alm_weekday(struct device *dev, struct rtc_time *tm_alarm)
 766{
 767	struct rtc_time tm_now;
 768	int days_now, days_alarm, ret;
 769
 770	ret = ds1307_get_time(dev, &tm_now);
 771	if (ret)
 772		return ret;
 773
 774	days_now = div_s64(rtc_tm_to_time64(&tm_now), 24 * 60 * 60);
 775	days_alarm = div_s64(rtc_tm_to_time64(tm_alarm), 24 * 60 * 60);
 776
 777	return (tm_now.tm_wday + days_alarm - days_now) % 7 + 1;
 778}
 779
 780static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 781{
 782	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 783	unsigned char regs[10];
 784	int wday, ret;
 785
 786	wday = mcp794xx_alm_weekday(dev, &t->time);
 787	if (wday < 0)
 788		return wday;
 789
 790	dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
 791		"enabled=%d pending=%d\n", __func__,
 792		t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
 793		t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
 794		t->enabled, t->pending);
 795
 796	/* Read control and alarm 0 registers. */
 797	ret = regmap_bulk_read(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 798			       sizeof(regs));
 799	if (ret)
 800		return ret;
 801
 802	/* Set alarm 0, using 24-hour and day-of-month modes. */
 803	regs[3] = bin2bcd(t->time.tm_sec);
 804	regs[4] = bin2bcd(t->time.tm_min);
 805	regs[5] = bin2bcd(t->time.tm_hour);
 806	regs[6] = wday;
 807	regs[7] = bin2bcd(t->time.tm_mday);
 808	regs[8] = bin2bcd(t->time.tm_mon + 1);
 809
 810	/* Clear the alarm 0 interrupt flag. */
 811	regs[6] &= ~MCP794XX_BIT_ALMX_IF;
 812	/* Set alarm match: second, minute, hour, day, date, month. */
 813	regs[6] |= MCP794XX_MSK_ALMX_MATCH;
 814	/* Disable interrupt. We will not enable until completely programmed */
 815	regs[0] &= ~MCP794XX_BIT_ALM0_EN;
 816
 817	ret = regmap_bulk_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs,
 818				sizeof(regs));
 819	if (ret)
 820		return ret;
 821
 822	if (!t->enabled)
 823		return 0;
 824	regs[0] |= MCP794XX_BIT_ALM0_EN;
 825	return regmap_write(ds1307->regmap, MCP794XX_REG_CONTROL, regs[0]);
 826}
 827
 828static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 829{
 830	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 831
 832	return regmap_update_bits(ds1307->regmap, MCP794XX_REG_CONTROL,
 833				  MCP794XX_BIT_ALM0_EN,
 834				  enabled ? MCP794XX_BIT_ALM0_EN : 0);
 835}
 836
 837static int m41txx_rtc_read_offset(struct device *dev, long *offset)
 838{
 839	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 840	unsigned int ctrl_reg;
 841	u8 val;
 842
 843	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
 844
 845	val = ctrl_reg & M41TXX_M_CALIBRATION;
 846
 847	/* check if positive */
 848	if (ctrl_reg & M41TXX_BIT_CALIB_SIGN)
 849		*offset = (val * M41TXX_POS_OFFSET_STEP_PPB);
 850	else
 851		*offset = -(val * M41TXX_NEG_OFFSET_STEP_PPB);
 852
 853	return 0;
 854}
 855
 856static int m41txx_rtc_set_offset(struct device *dev, long offset)
 857{
 858	struct ds1307 *ds1307 = dev_get_drvdata(dev);
 859	unsigned int ctrl_reg;
 860
 861	if ((offset < M41TXX_MIN_OFFSET) || (offset > M41TXX_MAX_OFFSET))
 862		return -ERANGE;
 863
 864	if (offset >= 0) {
 865		ctrl_reg = DIV_ROUND_CLOSEST(offset,
 866					     M41TXX_POS_OFFSET_STEP_PPB);
 867		ctrl_reg |= M41TXX_BIT_CALIB_SIGN;
 868	} else {
 869		ctrl_reg = DIV_ROUND_CLOSEST(abs(offset),
 870					     M41TXX_NEG_OFFSET_STEP_PPB);
 871	}
 872
 873	return regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL,
 874				  M41TXX_M_CALIBRATION | M41TXX_BIT_CALIB_SIGN,
 875				  ctrl_reg);
 876}
 877
 878#ifdef CONFIG_WATCHDOG_CORE
 879static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
 880{
 881	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 882	u8 regs[2];
 883	int ret;
 884
 885	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
 886				 DS1388_BIT_WF, 0);
 887	if (ret)
 888		return ret;
 889
 890	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 891				 DS1388_BIT_WDE | DS1388_BIT_RST, 0);
 892	if (ret)
 893		return ret;
 894
 895	/*
 896	 * watchdog timeouts are measured in seconds. So ignore hundredths of
 897	 * seconds field.
 898	 */
 899	regs[0] = 0;
 900	regs[1] = bin2bcd(wdt_dev->timeout);
 901
 902	ret = regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 903				sizeof(regs));
 904	if (ret)
 905		return ret;
 906
 907	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 908				  DS1388_BIT_WDE | DS1388_BIT_RST,
 909				  DS1388_BIT_WDE | DS1388_BIT_RST);
 910}
 911
 912static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
 913{
 914	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 915
 916	return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
 917				  DS1388_BIT_WDE | DS1388_BIT_RST, 0);
 918}
 919
 920static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
 921{
 922	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 923	u8 regs[2];
 924
 925	return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 926				sizeof(regs));
 927}
 928
 929static int ds1388_wdt_set_timeout(struct watchdog_device *wdt_dev,
 930				  unsigned int val)
 931{
 932	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
 933	u8 regs[2];
 934
 935	wdt_dev->timeout = val;
 936	regs[0] = 0;
 937	regs[1] = bin2bcd(wdt_dev->timeout);
 938
 939	return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
 940				 sizeof(regs));
 941}
 942#endif
 943
 944static const struct rtc_class_ops rx8130_rtc_ops = {
 945	.read_time      = ds1307_get_time,
 946	.set_time       = ds1307_set_time,
 947	.read_alarm     = rx8130_read_alarm,
 948	.set_alarm      = rx8130_set_alarm,
 949	.alarm_irq_enable = rx8130_alarm_irq_enable,
 950};
 951
 952static const struct rtc_class_ops mcp794xx_rtc_ops = {
 953	.read_time      = ds1307_get_time,
 954	.set_time       = ds1307_set_time,
 955	.read_alarm     = mcp794xx_read_alarm,
 956	.set_alarm      = mcp794xx_set_alarm,
 957	.alarm_irq_enable = mcp794xx_alarm_irq_enable,
 958};
 959
 960static const struct rtc_class_ops m41txx_rtc_ops = {
 961	.read_time      = ds1307_get_time,
 962	.set_time       = ds1307_set_time,
 963	.read_alarm	= ds1337_read_alarm,
 964	.set_alarm	= ds1337_set_alarm,
 965	.alarm_irq_enable = ds1307_alarm_irq_enable,
 966	.read_offset	= m41txx_rtc_read_offset,
 967	.set_offset	= m41txx_rtc_set_offset,
 968};
 969
 970static const struct chip_desc chips[last_ds_type] = {
 971	[ds_1307] = {
 972		.nvram_offset	= 8,
 973		.nvram_size	= 56,
 974	},
 975	[ds_1308] = {
 976		.nvram_offset	= 8,
 977		.nvram_size	= 56,
 978	},
 979	[ds_1337] = {
 980		.alarm		= 1,
 981		.century_reg	= DS1307_REG_MONTH,
 982		.century_bit	= DS1337_BIT_CENTURY,
 983	},
 984	[ds_1338] = {
 985		.nvram_offset	= 8,
 986		.nvram_size	= 56,
 987	},
 988	[ds_1339] = {
 989		.alarm		= 1,
 990		.century_reg	= DS1307_REG_MONTH,
 991		.century_bit	= DS1337_BIT_CENTURY,
 992		.bbsqi_bit	= DS1339_BIT_BBSQI,
 993		.trickle_charger_reg = 0x10,
 994		.do_trickle_setup = &do_trickle_setup_ds1339,
 995		.requires_trickle_resistor = true,
 996		.charge_default = true,
 997	},
 998	[ds_1340] = {
 999		.century_reg	= DS1307_REG_HOUR,
1000		.century_enable_bit = DS1340_BIT_CENTURY_EN,
1001		.century_bit	= DS1340_BIT_CENTURY,
1002		.do_trickle_setup = &do_trickle_setup_ds1339,
1003		.trickle_charger_reg = 0x08,
1004		.requires_trickle_resistor = true,
1005		.charge_default = true,
1006	},
1007	[ds_1341] = {
1008		.century_reg	= DS1307_REG_MONTH,
1009		.century_bit	= DS1337_BIT_CENTURY,
1010	},
1011	[ds_1388] = {
1012		.offset		= 1,
1013		.trickle_charger_reg = 0x0a,
1014	},
1015	[ds_3231] = {
1016		.alarm		= 1,
1017		.century_reg	= DS1307_REG_MONTH,
1018		.century_bit	= DS1337_BIT_CENTURY,
1019		.bbsqi_bit	= DS3231_BIT_BBSQW,
1020	},
1021	[rx_8130] = {
1022		.alarm		= 1,
1023		/* this is battery backed SRAM */
1024		.nvram_offset	= 0x20,
1025		.nvram_size	= 4,	/* 32bit (4 word x 8 bit) */
1026		.offset		= 0x10,
1027		.irq_handler = rx8130_irq,
1028		.rtc_ops = &rx8130_rtc_ops,
1029		.trickle_charger_reg = RX8130_REG_CONTROL1,
1030		.do_trickle_setup = &do_trickle_setup_rx8130,
1031	},
1032	[m41t0] = {
1033		.rtc_ops	= &m41txx_rtc_ops,
1034	},
1035	[m41t00] = {
1036		.rtc_ops	= &m41txx_rtc_ops,
1037	},
1038	[m41t11] = {
1039		/* this is battery backed SRAM */
1040		.nvram_offset	= 8,
1041		.nvram_size	= 56,
1042		.rtc_ops	= &m41txx_rtc_ops,
1043	},
1044	[mcp794xx] = {
1045		.alarm		= 1,
1046		/* this is battery backed SRAM */
1047		.nvram_offset	= 0x20,
1048		.nvram_size	= 0x40,
1049		.irq_handler = mcp794xx_irq,
1050		.rtc_ops = &mcp794xx_rtc_ops,
1051	},
1052};
1053
1054static const struct i2c_device_id ds1307_id[] = {
1055	{ "ds1307", ds_1307 },
1056	{ "ds1308", ds_1308 },
1057	{ "ds1337", ds_1337 },
1058	{ "ds1338", ds_1338 },
1059	{ "ds1339", ds_1339 },
1060	{ "ds1388", ds_1388 },
1061	{ "ds1340", ds_1340 },
1062	{ "ds1341", ds_1341 },
1063	{ "ds3231", ds_3231 },
1064	{ "m41t0", m41t0 },
1065	{ "m41t00", m41t00 },
1066	{ "m41t11", m41t11 },
1067	{ "mcp7940x", mcp794xx },
1068	{ "mcp7941x", mcp794xx },
1069	{ "pt7c4338", ds_1307 },
1070	{ "rx8025", rx_8025 },
1071	{ "isl12057", ds_1337 },
1072	{ "rx8130", rx_8130 },
1073	{ }
1074};
1075MODULE_DEVICE_TABLE(i2c, ds1307_id);
1076
1077static const struct of_device_id ds1307_of_match[] = {
1078	{
1079		.compatible = "dallas,ds1307",
1080		.data = (void *)ds_1307
1081	},
1082	{
1083		.compatible = "dallas,ds1308",
1084		.data = (void *)ds_1308
1085	},
1086	{
1087		.compatible = "dallas,ds1337",
1088		.data = (void *)ds_1337
1089	},
1090	{
1091		.compatible = "dallas,ds1338",
1092		.data = (void *)ds_1338
1093	},
1094	{
1095		.compatible = "dallas,ds1339",
1096		.data = (void *)ds_1339
1097	},
1098	{
1099		.compatible = "dallas,ds1388",
1100		.data = (void *)ds_1388
1101	},
1102	{
1103		.compatible = "dallas,ds1340",
1104		.data = (void *)ds_1340
1105	},
1106	{
1107		.compatible = "dallas,ds1341",
1108		.data = (void *)ds_1341
1109	},
1110	{
1111		.compatible = "maxim,ds3231",
1112		.data = (void *)ds_3231
1113	},
1114	{
1115		.compatible = "st,m41t0",
1116		.data = (void *)m41t0
1117	},
1118	{
1119		.compatible = "st,m41t00",
1120		.data = (void *)m41t00
1121	},
1122	{
1123		.compatible = "st,m41t11",
1124		.data = (void *)m41t11
1125	},
1126	{
1127		.compatible = "microchip,mcp7940x",
1128		.data = (void *)mcp794xx
1129	},
1130	{
1131		.compatible = "microchip,mcp7941x",
1132		.data = (void *)mcp794xx
1133	},
1134	{
1135		.compatible = "pericom,pt7c4338",
1136		.data = (void *)ds_1307
1137	},
1138	{
1139		.compatible = "epson,rx8025",
1140		.data = (void *)rx_8025
1141	},
1142	{
1143		.compatible = "isil,isl12057",
1144		.data = (void *)ds_1337
1145	},
1146	{
1147		.compatible = "epson,rx8130",
1148		.data = (void *)rx_8130
1149	},
1150	{ }
1151};
1152MODULE_DEVICE_TABLE(of, ds1307_of_match);
1153
1154/*
1155 * The ds1337 and ds1339 both have two alarms, but we only use the first
1156 * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
1157 * signal; ds1339 chips have only one alarm signal.
1158 */
1159static irqreturn_t ds1307_irq(int irq, void *dev_id)
1160{
1161	struct ds1307		*ds1307 = dev_id;
1162	struct mutex		*lock = &ds1307->rtc->ops_lock;
1163	int			stat, ret;
1164
1165	mutex_lock(lock);
1166	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &stat);
1167	if (ret)
1168		goto out;
1169
1170	if (stat & DS1337_BIT_A1I) {
1171		stat &= ~DS1337_BIT_A1I;
1172		regmap_write(ds1307->regmap, DS1337_REG_STATUS, stat);
1173
1174		ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1175					 DS1337_BIT_A1IE, 0);
1176		if (ret)
1177			goto out;
1178
1179		rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
1180	}
1181
1182out:
1183	mutex_unlock(lock);
1184
1185	return IRQ_HANDLED;
1186}
1187
1188/*----------------------------------------------------------------------*/
1189
1190static const struct rtc_class_ops ds13xx_rtc_ops = {
1191	.read_time	= ds1307_get_time,
1192	.set_time	= ds1307_set_time,
1193	.read_alarm	= ds1337_read_alarm,
1194	.set_alarm	= ds1337_set_alarm,
1195	.alarm_irq_enable = ds1307_alarm_irq_enable,
1196};
1197
1198static ssize_t frequency_test_store(struct device *dev,
1199				    struct device_attribute *attr,
1200				    const char *buf, size_t count)
1201{
1202	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1203	bool freq_test_en;
1204	int ret;
1205
1206	ret = kstrtobool(buf, &freq_test_en);
1207	if (ret) {
1208		dev_err(dev, "Failed to store RTC Frequency Test attribute\n");
1209		return ret;
1210	}
1211
1212	regmap_update_bits(ds1307->regmap, M41TXX_REG_CONTROL, M41TXX_BIT_FT,
1213			   freq_test_en ? M41TXX_BIT_FT : 0);
1214
1215	return count;
1216}
1217
1218static ssize_t frequency_test_show(struct device *dev,
1219				   struct device_attribute *attr,
1220				   char *buf)
1221{
1222	struct ds1307 *ds1307 = dev_get_drvdata(dev->parent);
1223	unsigned int ctrl_reg;
1224
1225	regmap_read(ds1307->regmap, M41TXX_REG_CONTROL, &ctrl_reg);
1226
1227	return sysfs_emit(buf, (ctrl_reg & M41TXX_BIT_FT) ? "on\n" : "off\n");
 
1228}
1229
1230static DEVICE_ATTR_RW(frequency_test);
1231
1232static struct attribute *rtc_freq_test_attrs[] = {
1233	&dev_attr_frequency_test.attr,
1234	NULL,
1235};
1236
1237static const struct attribute_group rtc_freq_test_attr_group = {
1238	.attrs		= rtc_freq_test_attrs,
1239};
1240
1241static int ds1307_add_frequency_test(struct ds1307 *ds1307)
1242{
1243	int err;
1244
1245	switch (ds1307->type) {
1246	case m41t0:
1247	case m41t00:
1248	case m41t11:
1249		err = rtc_add_group(ds1307->rtc, &rtc_freq_test_attr_group);
1250		if (err)
1251			return err;
1252		break;
1253	default:
1254		break;
1255	}
1256
1257	return 0;
1258}
1259
1260/*----------------------------------------------------------------------*/
1261
1262static int ds1307_nvram_read(void *priv, unsigned int offset, void *val,
1263			     size_t bytes)
1264{
1265	struct ds1307 *ds1307 = priv;
1266	const struct chip_desc *chip = &chips[ds1307->type];
1267
1268	return regmap_bulk_read(ds1307->regmap, chip->nvram_offset + offset,
1269				val, bytes);
1270}
1271
1272static int ds1307_nvram_write(void *priv, unsigned int offset, void *val,
1273			      size_t bytes)
1274{
1275	struct ds1307 *ds1307 = priv;
1276	const struct chip_desc *chip = &chips[ds1307->type];
1277
1278	return regmap_bulk_write(ds1307->regmap, chip->nvram_offset + offset,
1279				 val, bytes);
1280}
1281
1282/*----------------------------------------------------------------------*/
1283
1284static u8 ds1307_trickle_init(struct ds1307 *ds1307,
1285			      const struct chip_desc *chip)
1286{
1287	u32 ohms, chargeable;
1288	bool diode = chip->charge_default;
1289
1290	if (!chip->do_trickle_setup)
1291		return 0;
1292
1293	if (device_property_read_u32(ds1307->dev, "trickle-resistor-ohms",
1294				     &ohms) && chip->requires_trickle_resistor)
1295		return 0;
1296
1297	/* aux-voltage-chargeable takes precedence over the deprecated
1298	 * trickle-diode-disable
1299	 */
1300	if (!device_property_read_u32(ds1307->dev, "aux-voltage-chargeable",
1301				     &chargeable)) {
1302		switch (chargeable) {
1303		case 0:
1304			diode = false;
1305			break;
1306		case 1:
1307			diode = true;
1308			break;
1309		default:
1310			dev_warn(ds1307->dev,
1311				 "unsupported aux-voltage-chargeable value\n");
1312			break;
1313		}
1314	} else if (device_property_read_bool(ds1307->dev,
1315					     "trickle-diode-disable")) {
1316		diode = false;
1317	}
1318
1319	return chip->do_trickle_setup(ds1307, ohms, diode);
1320}
1321
1322/*----------------------------------------------------------------------*/
1323
1324#if IS_REACHABLE(CONFIG_HWMON)
1325
1326/*
1327 * Temperature sensor support for ds3231 devices.
1328 */
1329
1330#define DS3231_REG_TEMPERATURE	0x11
1331
1332/*
1333 * A user-initiated temperature conversion is not started by this function,
1334 * so the temperature is updated once every 64 seconds.
1335 */
1336static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
1337{
1338	struct ds1307 *ds1307 = dev_get_drvdata(dev);
1339	u8 temp_buf[2];
1340	s16 temp;
1341	int ret;
1342
1343	ret = regmap_bulk_read(ds1307->regmap, DS3231_REG_TEMPERATURE,
1344			       temp_buf, sizeof(temp_buf));
1345	if (ret)
1346		return ret;
1347	/*
1348	 * Temperature is represented as a 10-bit code with a resolution of
1349	 * 0.25 degree celsius and encoded in two's complement format.
1350	 */
1351	temp = (temp_buf[0] << 8) | temp_buf[1];
1352	temp >>= 6;
1353	*mC = temp * 250;
1354
1355	return 0;
1356}
1357
1358static ssize_t ds3231_hwmon_show_temp(struct device *dev,
1359				      struct device_attribute *attr, char *buf)
1360{
1361	int ret;
1362	s32 temp;
1363
1364	ret = ds3231_hwmon_read_temp(dev, &temp);
1365	if (ret)
1366		return ret;
1367
1368	return sprintf(buf, "%d\n", temp);
1369}
1370static SENSOR_DEVICE_ATTR(temp1_input, 0444, ds3231_hwmon_show_temp,
1371			  NULL, 0);
1372
1373static struct attribute *ds3231_hwmon_attrs[] = {
1374	&sensor_dev_attr_temp1_input.dev_attr.attr,
1375	NULL,
1376};
1377ATTRIBUTE_GROUPS(ds3231_hwmon);
1378
1379static void ds1307_hwmon_register(struct ds1307 *ds1307)
1380{
1381	struct device *dev;
1382
1383	if (ds1307->type != ds_3231)
1384		return;
1385
1386	dev = devm_hwmon_device_register_with_groups(ds1307->dev, ds1307->name,
1387						     ds1307,
1388						     ds3231_hwmon_groups);
1389	if (IS_ERR(dev)) {
1390		dev_warn(ds1307->dev, "unable to register hwmon device %ld\n",
1391			 PTR_ERR(dev));
1392	}
1393}
1394
1395#else
1396
1397static void ds1307_hwmon_register(struct ds1307 *ds1307)
1398{
1399}
1400
1401#endif /* CONFIG_RTC_DRV_DS1307_HWMON */
1402
1403/*----------------------------------------------------------------------*/
1404
1405/*
1406 * Square-wave output support for DS3231
1407 * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1408 */
1409#ifdef CONFIG_COMMON_CLK
1410
1411enum {
1412	DS3231_CLK_SQW = 0,
1413	DS3231_CLK_32KHZ,
1414};
1415
1416#define clk_sqw_to_ds1307(clk)	\
1417	container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1418#define clk_32khz_to_ds1307(clk)	\
1419	container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1420
1421static int ds3231_clk_sqw_rates[] = {
1422	1,
1423	1024,
1424	4096,
1425	8192,
1426};
1427
1428static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1429{
1430	struct mutex *lock = &ds1307->rtc->ops_lock;
1431	int ret;
1432
1433	mutex_lock(lock);
1434	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_CONTROL,
1435				 mask, value);
1436	mutex_unlock(lock);
1437
1438	return ret;
1439}
1440
1441static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1442						unsigned long parent_rate)
1443{
1444	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1445	int control, ret;
1446	int rate_sel = 0;
1447
1448	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1449	if (ret)
1450		return ret;
1451	if (control & DS1337_BIT_RS1)
1452		rate_sel += 1;
1453	if (control & DS1337_BIT_RS2)
1454		rate_sel += 2;
1455
1456	return ds3231_clk_sqw_rates[rate_sel];
1457}
1458
1459static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1460				      unsigned long *prate)
1461{
1462	int i;
1463
1464	for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1465		if (ds3231_clk_sqw_rates[i] <= rate)
1466			return ds3231_clk_sqw_rates[i];
1467	}
1468
1469	return 0;
1470}
1471
1472static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1473				   unsigned long parent_rate)
1474{
1475	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1476	int control = 0;
1477	int rate_sel;
1478
1479	for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1480			rate_sel++) {
1481		if (ds3231_clk_sqw_rates[rate_sel] == rate)
1482			break;
1483	}
1484
1485	if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1486		return -EINVAL;
1487
1488	if (rate_sel & 1)
1489		control |= DS1337_BIT_RS1;
1490	if (rate_sel & 2)
1491		control |= DS1337_BIT_RS2;
1492
1493	return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1494				control);
1495}
1496
1497static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1498{
1499	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1500
1501	return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1502}
1503
1504static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1505{
1506	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1507
1508	ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1509}
1510
1511static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1512{
1513	struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1514	int control, ret;
1515
1516	ret = regmap_read(ds1307->regmap, DS1337_REG_CONTROL, &control);
1517	if (ret)
1518		return ret;
1519
1520	return !(control & DS1337_BIT_INTCN);
1521}
1522
1523static const struct clk_ops ds3231_clk_sqw_ops = {
1524	.prepare = ds3231_clk_sqw_prepare,
1525	.unprepare = ds3231_clk_sqw_unprepare,
1526	.is_prepared = ds3231_clk_sqw_is_prepared,
1527	.recalc_rate = ds3231_clk_sqw_recalc_rate,
1528	.round_rate = ds3231_clk_sqw_round_rate,
1529	.set_rate = ds3231_clk_sqw_set_rate,
1530};
1531
1532static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1533						  unsigned long parent_rate)
1534{
1535	return 32768;
1536}
1537
1538static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1539{
1540	struct mutex *lock = &ds1307->rtc->ops_lock;
1541	int ret;
1542
1543	mutex_lock(lock);
1544	ret = regmap_update_bits(ds1307->regmap, DS1337_REG_STATUS,
1545				 DS3231_BIT_EN32KHZ,
1546				 enable ? DS3231_BIT_EN32KHZ : 0);
1547	mutex_unlock(lock);
1548
1549	return ret;
1550}
1551
1552static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1553{
1554	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1555
1556	return ds3231_clk_32khz_control(ds1307, true);
1557}
1558
1559static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1560{
1561	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1562
1563	ds3231_clk_32khz_control(ds1307, false);
1564}
1565
1566static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1567{
1568	struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1569	int status, ret;
1570
1571	ret = regmap_read(ds1307->regmap, DS1337_REG_STATUS, &status);
1572	if (ret)
1573		return ret;
1574
1575	return !!(status & DS3231_BIT_EN32KHZ);
1576}
1577
1578static const struct clk_ops ds3231_clk_32khz_ops = {
1579	.prepare = ds3231_clk_32khz_prepare,
1580	.unprepare = ds3231_clk_32khz_unprepare,
1581	.is_prepared = ds3231_clk_32khz_is_prepared,
1582	.recalc_rate = ds3231_clk_32khz_recalc_rate,
1583};
1584
1585static const char *ds3231_clks_names[] = {
1586	[DS3231_CLK_SQW] = "ds3231_clk_sqw",
1587	[DS3231_CLK_32KHZ] = "ds3231_clk_32khz",
1588};
1589
1590static struct clk_init_data ds3231_clks_init[] = {
1591	[DS3231_CLK_SQW] = {
1592		.ops = &ds3231_clk_sqw_ops,
1593	},
1594	[DS3231_CLK_32KHZ] = {
1595		.ops = &ds3231_clk_32khz_ops,
1596	},
1597};
1598
1599static int ds3231_clks_register(struct ds1307 *ds1307)
1600{
1601	struct device_node *node = ds1307->dev->of_node;
1602	struct clk_onecell_data	*onecell;
1603	int i;
1604
1605	onecell = devm_kzalloc(ds1307->dev, sizeof(*onecell), GFP_KERNEL);
1606	if (!onecell)
1607		return -ENOMEM;
1608
1609	onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1610	onecell->clks = devm_kcalloc(ds1307->dev, onecell->clk_num,
1611				     sizeof(onecell->clks[0]), GFP_KERNEL);
1612	if (!onecell->clks)
1613		return -ENOMEM;
1614
1615	/* optional override of the clockname */
1616	device_property_read_string_array(ds1307->dev, "clock-output-names",
1617					  ds3231_clks_names,
1618					  ARRAY_SIZE(ds3231_clks_names));
1619
1620	for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1621		struct clk_init_data init = ds3231_clks_init[i];
1622
1623		/*
1624		 * Interrupt signal due to alarm conditions and square-wave
1625		 * output share same pin, so don't initialize both.
1626		 */
1627		if (i == DS3231_CLK_SQW && test_bit(RTC_FEATURE_ALARM, ds1307->rtc->features))
1628			continue;
1629
1630		init.name = ds3231_clks_names[i];
1631		ds1307->clks[i].init = &init;
1632
1633		onecell->clks[i] = devm_clk_register(ds1307->dev,
1634						     &ds1307->clks[i]);
1635		if (IS_ERR(onecell->clks[i]))
1636			return PTR_ERR(onecell->clks[i]);
1637	}
1638
1639	if (node)
1640		of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1641
1642	return 0;
1643}
1644
1645static void ds1307_clks_register(struct ds1307 *ds1307)
1646{
1647	int ret;
1648
1649	if (ds1307->type != ds_3231)
1650		return;
1651
1652	ret = ds3231_clks_register(ds1307);
1653	if (ret) {
1654		dev_warn(ds1307->dev, "unable to register clock device %d\n",
1655			 ret);
1656	}
1657}
1658
1659#else
1660
1661static void ds1307_clks_register(struct ds1307 *ds1307)
1662{
1663}
1664
1665#endif /* CONFIG_COMMON_CLK */
1666
1667#ifdef CONFIG_WATCHDOG_CORE
1668static const struct watchdog_info ds1388_wdt_info = {
1669	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
1670	.identity = "DS1388 watchdog",
1671};
1672
1673static const struct watchdog_ops ds1388_wdt_ops = {
1674	.owner = THIS_MODULE,
1675	.start = ds1388_wdt_start,
1676	.stop = ds1388_wdt_stop,
1677	.ping = ds1388_wdt_ping,
1678	.set_timeout = ds1388_wdt_set_timeout,
1679
1680};
1681
1682static void ds1307_wdt_register(struct ds1307 *ds1307)
1683{
1684	struct watchdog_device	*wdt;
1685	int err;
1686	int val;
1687
1688	if (ds1307->type != ds_1388)
1689		return;
1690
1691	wdt = devm_kzalloc(ds1307->dev, sizeof(*wdt), GFP_KERNEL);
1692	if (!wdt)
1693		return;
1694
1695	err = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
1696	if (!err && val & DS1388_BIT_WF)
1697		wdt->bootstatus = WDIOF_CARDRESET;
1698
1699	wdt->info = &ds1388_wdt_info;
1700	wdt->ops = &ds1388_wdt_ops;
1701	wdt->timeout = 99;
1702	wdt->max_timeout = 99;
1703	wdt->min_timeout = 1;
1704
1705	watchdog_init_timeout(wdt, 0, ds1307->dev);
1706	watchdog_set_drvdata(wdt, ds1307);
1707	devm_watchdog_register_device(ds1307->dev, wdt);
1708}
1709#else
1710static void ds1307_wdt_register(struct ds1307 *ds1307)
1711{
1712}
1713#endif /* CONFIG_WATCHDOG_CORE */
1714
1715static const struct regmap_config regmap_config = {
1716	.reg_bits = 8,
1717	.val_bits = 8,
1718};
1719
1720static int ds1307_probe(struct i2c_client *client)
 
1721{
1722	const struct i2c_device_id *id = i2c_client_get_device_id(client);
1723	struct ds1307		*ds1307;
1724	const void		*match;
1725	int			err = -ENODEV;
1726	int			tmp;
1727	const struct chip_desc	*chip;
1728	bool			want_irq;
1729	bool			ds1307_can_wakeup_device = false;
1730	unsigned char		regs[8];
1731	struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1732	u8			trickle_charger_setup = 0;
1733
1734	ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1735	if (!ds1307)
1736		return -ENOMEM;
1737
1738	dev_set_drvdata(&client->dev, ds1307);
1739	ds1307->dev = &client->dev;
1740	ds1307->name = client->name;
1741
1742	ds1307->regmap = devm_regmap_init_i2c(client, &regmap_config);
1743	if (IS_ERR(ds1307->regmap)) {
1744		dev_err(ds1307->dev, "regmap allocation failed\n");
1745		return PTR_ERR(ds1307->regmap);
1746	}
1747
1748	i2c_set_clientdata(client, ds1307);
1749
1750	match = device_get_match_data(&client->dev);
1751	if (match) {
1752		ds1307->type = (uintptr_t)match;
1753		chip = &chips[ds1307->type];
1754	} else if (id) {
1755		chip = &chips[id->driver_data];
1756		ds1307->type = id->driver_data;
1757	} else {
1758		return -ENODEV;
1759	}
1760
1761	want_irq = client->irq > 0 && chip->alarm;
1762
1763	if (!pdata)
1764		trickle_charger_setup = ds1307_trickle_init(ds1307, chip);
1765	else if (pdata->trickle_charger_setup)
1766		trickle_charger_setup = pdata->trickle_charger_setup;
1767
1768	if (trickle_charger_setup && chip->trickle_charger_reg) {
1769		dev_dbg(ds1307->dev,
1770			"writing trickle charger info 0x%x to 0x%x\n",
1771			trickle_charger_setup, chip->trickle_charger_reg);
1772		regmap_write(ds1307->regmap, chip->trickle_charger_reg,
1773			     trickle_charger_setup);
1774	}
1775
1776/*
1777 * For devices with no IRQ directly connected to the SoC, the RTC chip
1778 * can be forced as a wakeup source by stating that explicitly in
1779 * the device's .dts file using the "wakeup-source" boolean property.
1780 * If the "wakeup-source" property is set, don't request an IRQ.
1781 * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1782 * if supported by the RTC.
1783 */
1784	if (chip->alarm && device_property_read_bool(&client->dev, "wakeup-source"))
1785		ds1307_can_wakeup_device = true;
1786
1787	switch (ds1307->type) {
1788	case ds_1337:
1789	case ds_1339:
1790	case ds_1341:
1791	case ds_3231:
1792		/* get registers that the "rtc" read below won't read... */
1793		err = regmap_bulk_read(ds1307->regmap, DS1337_REG_CONTROL,
1794				       regs, 2);
1795		if (err) {
1796			dev_dbg(ds1307->dev, "read error %d\n", err);
1797			goto exit;
1798		}
1799
1800		/* oscillator off?  turn it on, so clock can tick. */
1801		if (regs[0] & DS1337_BIT_nEOSC)
1802			regs[0] &= ~DS1337_BIT_nEOSC;
1803
1804		/*
1805		 * Using IRQ or defined as wakeup-source?
1806		 * Disable the square wave and both alarms.
1807		 * For some variants, be sure alarms can trigger when we're
1808		 * running on Vbackup (BBSQI/BBSQW)
1809		 */
1810		if (want_irq || ds1307_can_wakeup_device) {
1811			regs[0] |= DS1337_BIT_INTCN | chip->bbsqi_bit;
1812			regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1813		}
1814
1815		regmap_write(ds1307->regmap, DS1337_REG_CONTROL,
1816			     regs[0]);
1817
1818		/* oscillator fault?  clear flag, and warn */
1819		if (regs[1] & DS1337_BIT_OSF) {
1820			regmap_write(ds1307->regmap, DS1337_REG_STATUS,
1821				     regs[1] & ~DS1337_BIT_OSF);
1822			dev_warn(ds1307->dev, "SET TIME!\n");
1823		}
1824		break;
1825
1826	case rx_8025:
1827		err = regmap_bulk_read(ds1307->regmap,
1828				       RX8025_REG_CTRL1 << 4 | 0x08, regs, 2);
1829		if (err) {
1830			dev_dbg(ds1307->dev, "read error %d\n", err);
1831			goto exit;
1832		}
1833
1834		/* oscillator off?  turn it on, so clock can tick. */
1835		if (!(regs[1] & RX8025_BIT_XST)) {
1836			regs[1] |= RX8025_BIT_XST;
1837			regmap_write(ds1307->regmap,
1838				     RX8025_REG_CTRL2 << 4 | 0x08,
1839				     regs[1]);
1840			dev_warn(ds1307->dev,
1841				 "oscillator stop detected - SET TIME!\n");
1842		}
1843
1844		if (regs[1] & RX8025_BIT_PON) {
1845			regs[1] &= ~RX8025_BIT_PON;
1846			regmap_write(ds1307->regmap,
1847				     RX8025_REG_CTRL2 << 4 | 0x08,
1848				     regs[1]);
1849			dev_warn(ds1307->dev, "power-on detected\n");
1850		}
1851
1852		if (regs[1] & RX8025_BIT_VDET) {
1853			regs[1] &= ~RX8025_BIT_VDET;
1854			regmap_write(ds1307->regmap,
1855				     RX8025_REG_CTRL2 << 4 | 0x08,
1856				     regs[1]);
1857			dev_warn(ds1307->dev, "voltage drop detected\n");
1858		}
1859
1860		/* make sure we are running in 24hour mode */
1861		if (!(regs[0] & RX8025_BIT_2412)) {
1862			u8 hour;
1863
1864			/* switch to 24 hour mode */
1865			regmap_write(ds1307->regmap,
1866				     RX8025_REG_CTRL1 << 4 | 0x08,
1867				     regs[0] | RX8025_BIT_2412);
1868
1869			err = regmap_bulk_read(ds1307->regmap,
1870					       RX8025_REG_CTRL1 << 4 | 0x08,
1871					       regs, 2);
1872			if (err) {
1873				dev_dbg(ds1307->dev, "read error %d\n", err);
1874				goto exit;
1875			}
1876
1877			/* correct hour */
1878			hour = bcd2bin(regs[DS1307_REG_HOUR]);
1879			if (hour == 12)
1880				hour = 0;
1881			if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1882				hour += 12;
1883
1884			regmap_write(ds1307->regmap,
1885				     DS1307_REG_HOUR << 4 | 0x08, hour);
1886		}
1887		break;
1888	case ds_1388:
1889		err = regmap_read(ds1307->regmap, DS1388_REG_CONTROL, &tmp);
1890		if (err) {
1891			dev_dbg(ds1307->dev, "read error %d\n", err);
1892			goto exit;
1893		}
1894
1895		/* oscillator off?  turn it on, so clock can tick. */
1896		if (tmp & DS1388_BIT_nEOSC) {
1897			tmp &= ~DS1388_BIT_nEOSC;
1898			regmap_write(ds1307->regmap, DS1388_REG_CONTROL, tmp);
1899		}
1900		break;
1901	default:
1902		break;
1903	}
1904
1905	/* read RTC registers */
1906	err = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
1907			       sizeof(regs));
1908	if (err) {
1909		dev_dbg(ds1307->dev, "read error %d\n", err);
1910		goto exit;
1911	}
1912
1913	if (ds1307->type == mcp794xx &&
1914	    !(regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1915		regmap_write(ds1307->regmap, DS1307_REG_WDAY,
1916			     regs[DS1307_REG_WDAY] |
1917			     MCP794XX_BIT_VBATEN);
1918	}
1919
1920	tmp = regs[DS1307_REG_HOUR];
1921	switch (ds1307->type) {
1922	case ds_1340:
1923	case m41t0:
1924	case m41t00:
1925	case m41t11:
1926		/*
1927		 * NOTE: ignores century bits; fix before deploying
1928		 * systems that will run through year 2100.
1929		 */
1930		break;
1931	case rx_8025:
1932		break;
1933	default:
1934		if (!(tmp & DS1307_BIT_12HR))
1935			break;
1936
1937		/*
1938		 * Be sure we're in 24 hour mode.  Multi-master systems
1939		 * take note...
1940		 */
1941		tmp = bcd2bin(tmp & 0x1f);
1942		if (tmp == 12)
1943			tmp = 0;
1944		if (regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1945			tmp += 12;
1946		regmap_write(ds1307->regmap, chip->offset + DS1307_REG_HOUR,
1947			     bin2bcd(tmp));
1948	}
1949
1950	ds1307->rtc = devm_rtc_allocate_device(ds1307->dev);
1951	if (IS_ERR(ds1307->rtc))
1952		return PTR_ERR(ds1307->rtc);
1953
1954	if (want_irq || ds1307_can_wakeup_device)
1955		device_set_wakeup_capable(ds1307->dev, true);
1956	else
1957		clear_bit(RTC_FEATURE_ALARM, ds1307->rtc->features);
1958
1959	if (ds1307_can_wakeup_device && !want_irq) {
1960		dev_info(ds1307->dev,
1961			 "'wakeup-source' is set, request for an IRQ is disabled!\n");
1962		/* We cannot support UIE mode if we do not have an IRQ line */
1963		clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, ds1307->rtc->features);
1964	}
1965
1966	if (want_irq) {
1967		err = devm_request_threaded_irq(ds1307->dev, client->irq, NULL,
1968						chip->irq_handler ?: ds1307_irq,
1969						IRQF_SHARED | IRQF_ONESHOT,
1970						ds1307->name, ds1307);
1971		if (err) {
1972			client->irq = 0;
1973			device_set_wakeup_capable(ds1307->dev, false);
1974			clear_bit(RTC_FEATURE_ALARM, ds1307->rtc->features);
1975			dev_err(ds1307->dev, "unable to request IRQ!\n");
1976		} else {
1977			dev_dbg(ds1307->dev, "got IRQ %d\n", client->irq);
1978		}
1979	}
1980
1981	ds1307->rtc->ops = chip->rtc_ops ?: &ds13xx_rtc_ops;
1982	err = ds1307_add_frequency_test(ds1307);
1983	if (err)
1984		return err;
1985
1986	err = devm_rtc_register_device(ds1307->rtc);
1987	if (err)
1988		return err;
1989
1990	if (chip->nvram_size) {
1991		struct nvmem_config nvmem_cfg = {
1992			.name = "ds1307_nvram",
1993			.word_size = 1,
1994			.stride = 1,
1995			.size = chip->nvram_size,
1996			.reg_read = ds1307_nvram_read,
1997			.reg_write = ds1307_nvram_write,
1998			.priv = ds1307,
1999		};
2000
2001		devm_rtc_nvmem_register(ds1307->rtc, &nvmem_cfg);
2002	}
2003
2004	ds1307_hwmon_register(ds1307);
2005	ds1307_clks_register(ds1307);
2006	ds1307_wdt_register(ds1307);
2007
2008	return 0;
2009
2010exit:
2011	return err;
2012}
2013
2014static struct i2c_driver ds1307_driver = {
2015	.driver = {
2016		.name	= "rtc-ds1307",
2017		.of_match_table = ds1307_of_match,
2018	},
2019	.probe		= ds1307_probe,
2020	.id_table	= ds1307_id,
2021};
2022
2023module_i2c_driver(ds1307_driver);
2024
2025MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
2026MODULE_LICENSE("GPL");