[deliverable/linux.git] / drivers / rtc / rtc-ds1307.c

/*
 * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
 *
 *  Copyright (C) 2005 James Chapman (ds1337 core)
 *  Copyright (C) 2006 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/rtc.h>
#include <linux/bcd.h>


/* We can't determine type by probing, but if we expect pre-Linux code
 * to have set the chip up as a clock (turning on the oscillator and
 * setting the date and time), Linux can ignore the non-clock features.
 * That's a natural job for a factory or repair bench.
 *
 * This is currently a simple no-alarms driver.  If your board has the
 * alarm irq wired up on a ds1337 or ds1339, and you want to use that,
 * then look at the rtc-rs5c372 driver for code to steal...
 *
 * If the I2C "force" mechanism is used, we assume the chip is a ds1337.
 * (Much better would be board-specific tables of I2C devices, along with
 * the platform_data drivers would use to sort such issues out.)
 */
enum ds_type {
	unknown = 0,
	ds_1307,
	ds_1337,
	ds_1338,
	ds_1339,
	ds_1340,
	m41t00,
	// rs5c372 too?  different address...
};

static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };

I2C_CLIENT_INSMOD;


/* RTC registers don't differ much, except for the century flag */
#define DS1307_REG_SECS		0x00	/* 00-59 */
#	define DS1307_BIT_CH		0x80
#	define DS1340_BIT_nEOSC		0x80
#define DS1307_REG_MIN		0x01	/* 00-59 */
#define DS1307_REG_HOUR		0x02	/* 00-23, or 1-12{am,pm} */
#	define DS1340_BIT_CENTURY_EN	0x80	/* in REG_HOUR */
#	define DS1340_BIT_CENTURY	0x40	/* in REG_HOUR */
#define DS1307_REG_WDAY		0x03	/* 01-07 */
#define DS1307_REG_MDAY		0x04	/* 01-31 */
#define DS1307_REG_MONTH	0x05	/* 01-12 */
#	define DS1337_BIT_CENTURY	0x80	/* in REG_MONTH */
#define DS1307_REG_YEAR		0x06	/* 00-99 */

/* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
 * start at 7, and they differ a LOT. Only control and status matter for
 * basic RTC date and time functionality; be careful using them.
 */
#define DS1307_REG_CONTROL	0x07		/* or ds1338 */
#	define DS1307_BIT_OUT		0x80
#	define DS1338_BIT_OSF		0x20
#	define DS1307_BIT_SQWE		0x10
#	define DS1307_BIT_RS1		0x02
#	define DS1307_BIT_RS0		0x01
#define DS1337_REG_CONTROL	0x0e
#	define DS1337_BIT_nEOSC		0x80
#	define DS1337_BIT_RS2		0x10
#	define DS1337_BIT_RS1		0x08
#	define DS1337_BIT_INTCN		0x04
#	define DS1337_BIT_A2IE		0x02
#	define DS1337_BIT_A1IE		0x01
#define DS1340_REG_CONTROL	0x07
#	define DS1340_BIT_OUT		0x80
#	define DS1340_BIT_FT		0x40
#	define DS1340_BIT_CALIB_SIGN	0x20
#	define DS1340_M_CALIBRATION	0x1f
#define DS1340_REG_FLAG		0x09
#	define DS1340_BIT_OSF		0x80
#define DS1337_REG_STATUS	0x0f
#	define DS1337_BIT_OSF		0x80
#	define DS1337_BIT_A2I		0x02
#	define DS1337_BIT_A1I		0x01
#define DS1339_REG_TRICKLE	0x10


struct ds1307 {
	u8			reg_addr;
	u8			regs[8];
	enum ds_type		type;
	struct i2c_msg		msg[2];
	struct i2c_client	*client;
	struct i2c_client	dev;
	struct rtc_device	*rtc;
};

struct chip_desc {
	char			name[9];
	unsigned		nvram56:1;
	unsigned		alarm:1;
	enum ds_type		type;
};

static const struct chip_desc chips[] = { {
	.name		= "ds1307",
	.type		= ds_1307,
	.nvram56	= 1,
}, {
	.name		= "ds1337",
	.type		= ds_1337,
	.alarm		= 1,
}, {
	.name		= "ds1338",
	.type		= ds_1338,
	.nvram56	= 1,
}, {
	.name		= "ds1339",
	.type		= ds_1339,
	.alarm		= 1,
}, {
	.name		= "ds1340",
	.type		= ds_1340,
}, {
	.name		= "m41t00",
	.type		= m41t00,
}, };

static inline const struct chip_desc *find_chip(const char *s)
{
	unsigned i;

	for (i = 0; i < ARRAY_SIZE(chips); i++)
		if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
			return &chips[i];
	return NULL;
}

static int ds1307_get_time(struct device *dev, struct rtc_time *t)
{
	struct ds1307	*ds1307 = dev_get_drvdata(dev);
	int		tmp;

	/* read the RTC date and time registers all at once */
	ds1307->msg[1].flags = I2C_M_RD;
	ds1307->msg[1].len = 7;

	tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
			ds1307->msg, 2);
	if (tmp != 2) {
		dev_err(dev, "%s error %d\n", "read", tmp);
		return -EIO;
	}

	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
			"read",
			ds1307->regs[0], ds1307->regs[1],
			ds1307->regs[2], ds1307->regs[3],
			ds1307->regs[4], ds1307->regs[5],
			ds1307->regs[6]);

	t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
	t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
	tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
	t->tm_hour = BCD2BIN(tmp);
	t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
	t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
	t->tm_mon = BCD2BIN(tmp) - 1;

	/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
	t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;

	dev_dbg(dev, "%s secs=%d, mins=%d, "
		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
		"read", t->tm_sec, t->tm_min,
		t->tm_hour, t->tm_mday,
		t->tm_mon, t->tm_year, t->tm_wday);

	/* initial clock setting can be undefined */
	return rtc_valid_tm(t);
}

static int ds1307_set_time(struct device *dev, struct rtc_time *t)
{
	struct ds1307	*ds1307 = dev_get_drvdata(dev);
	int		result;
	int		tmp;
	u8		*buf = ds1307->regs;

	dev_dbg(dev, "%s secs=%d, mins=%d, "
		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
		"write", t->tm_sec, t->tm_min,
		t->tm_hour, t->tm_mday,
		t->tm_mon, t->tm_year, t->tm_wday);

	*buf++ = 0;		/* first register addr */
	buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
	buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
	buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
	buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
	buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
	buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);

	/* assume 20YY not 19YY */
	tmp = t->tm_year - 100;
	buf[DS1307_REG_YEAR] = BIN2BCD(tmp);

	switch (ds1307->type) {
	case ds_1337:
	case ds_1339:
		buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
		break;
	case ds_1340:
		buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
				| DS1340_BIT_CENTURY;
		break;
	default:
		break;
	}

	ds1307->msg[1].flags = 0;
	ds1307->msg[1].len = 8;

	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
		"write", buf[0], buf[1], buf[2], buf[3],
		buf[4], buf[5], buf[6]);

	result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
			&ds1307->msg[1], 1);
	if (result != 1) {
		dev_err(dev, "%s error %d\n", "write", tmp);
		return -EIO;
	}
	return 0;
}

static const struct rtc_class_ops ds13xx_rtc_ops = {
	.read_time	= ds1307_get_time,
	.set_time	= ds1307_set_time,
};

static struct i2c_driver ds1307_driver;

static int __devinit
ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
{
	struct ds1307		*ds1307;
	int			err = -ENODEV;
	struct i2c_client	*client;
	int			tmp;
	const struct chip_desc	*chip;

	if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) {
		err = -ENOMEM;
		goto exit;
	}

	/* REVISIT:  pending driver model conversion, set up "client"
	 * ourselves, and use a hack to determine the RTC type (instead
	 * of reading the client->name we're given)
	 */
	client = &ds1307->dev;
	client->addr = address;
	client->adapter = adapter;
	client->driver = &ds1307_driver;

	/* HACK: "force" implies "needs ds1337-style-oscillator setup", and
	 * that's the only kind of chip setup we'll know about.  Until the
	 * driver model conversion, here's where to add any board-specific
	 * code to say what kind of chip is present...
	 */
	if (kind >= 0)
		chip = find_chip("ds1337");
	else
		chip = find_chip("ds1307");
	strlcpy(client->name, chip->name, I2C_NAME_SIZE);

	ds1307->client = client;
	i2c_set_clientdata(client, ds1307);

	ds1307->msg[0].addr = client->addr;
	ds1307->msg[0].flags = 0;
	ds1307->msg[0].len = 1;
	ds1307->msg[0].buf = &ds1307->reg_addr;

	ds1307->msg[1].addr = client->addr;
	ds1307->msg[1].flags = I2C_M_RD;
	ds1307->msg[1].len = sizeof(ds1307->regs);
	ds1307->msg[1].buf = ds1307->regs;

	ds1307->type = chip->type;

	switch (ds1307->type) {
	case ds_1337:
	case ds_1339:
		ds1307->reg_addr = DS1337_REG_CONTROL;
		ds1307->msg[1].len = 2;

		/* get registers that the "rtc" read below won't read... */
		tmp = i2c_transfer(adapter, ds1307->msg, 2);
		if (tmp != 2) {
			pr_debug("read error %d\n", tmp);
			err = -EIO;
			goto exit_free;
		}

		ds1307->reg_addr = 0;
		ds1307->msg[1].len = sizeof(ds1307->regs);

		/* oscillator off?  turn it on, so clock can tick. */
		if (ds1307->regs[0] & DS1337_BIT_nEOSC)
			i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
				ds1307->regs[0] & ~DS1337_BIT_nEOSC);

		/* oscillator fault?  clear flag, and warn */
		if (ds1307->regs[1] & DS1337_BIT_OSF) {
			i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
				ds1307->regs[1] & ~DS1337_BIT_OSF);
			dev_warn(&client->dev, "SET TIME!\n");
		}
		break;
	default:
		break;
	}

read_rtc:
	/* read RTC registers */

	tmp = i2c_transfer(adapter, ds1307->msg, 2);
	if (tmp != 2) {
		pr_debug("read error %d\n", tmp);
		err = -EIO;
		goto exit_free;
	}

	/* minimal sanity checking; some chips (like DS1340) don't
	 * specify the extra bits as must-be-zero, but there are
	 * still a few values that are clearly out-of-range.
	 */
	tmp = ds1307->regs[DS1307_REG_SECS];
	switch (ds1307->type) {
	case ds_1340:
		/* FIXME read register with DS1340_BIT_OSF, use that to
		 * trigger the "set time" warning (*after* restarting the
		 * oscillator!) instead of this weaker ds1307/m41t00 test.
		 */
	case ds_1307:
	case m41t00:
		/* clock halted?  turn it on, so clock can tick. */
		if (tmp & DS1307_BIT_CH) {
			i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
			dev_warn(&client->dev, "SET TIME!\n");
			goto read_rtc;
		}
		break;
	case ds_1338:
		/* clock halted?  turn it on, so clock can tick. */
		if (tmp & DS1307_BIT_CH)
			i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);

		/* oscillator fault?  clear flag, and warn */
		if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
			i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
					ds1307->regs[DS1337_REG_CONTROL]
					& ~DS1338_BIT_OSF);
			dev_warn(&client->dev, "SET TIME!\n");
			goto read_rtc;
		}
		break;
	default:
		break;
	}

	tmp = ds1307->regs[DS1307_REG_SECS];
	tmp = BCD2BIN(tmp & 0x7f);
	if (tmp > 60)
		goto exit_free;
	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
	if (tmp > 60)
		goto exit_free;

	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	if (tmp == 0 || tmp > 31)
		goto exit_free;

	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
	if (tmp == 0 || tmp > 12)
		goto exit_free;

	/* force into in 24 hour mode (most chips) or
	 * disable century bit (ds1340)
	 *
	 * REVISIT forcing 24 hour mode can prevent multi-master
	 * configs from sharing this RTC ... don't do this.
	 * The clock needs to be reset after changing it, too...
	 */
	tmp = ds1307->regs[DS1307_REG_HOUR];
	if (tmp & (1 << 6)) {
		if (tmp & (1 << 5))
			tmp = BCD2BIN(tmp & 0x1f) + 12;
		else
			tmp = BCD2BIN(tmp);
		i2c_smbus_write_byte_data(client,
				DS1307_REG_HOUR,
				BIN2BCD(tmp));
	}

	/* Tell the I2C layer a new client has arrived */
	if ((err = i2c_attach_client(client)))
		goto exit_free;

	ds1307->rtc = rtc_device_register(client->name, &client->dev,
				&ds13xx_rtc_ops, THIS_MODULE);
	if (IS_ERR(ds1307->rtc)) {
		err = PTR_ERR(ds1307->rtc);
		dev_err(&client->dev,
			"unable to register the class device\n");
		goto exit_detach;
	}

	return 0;

exit_detach:
	i2c_detach_client(client);
exit_free:
	kfree(ds1307);
exit:
	return err;
}

static int __devinit
ds1307_attach_adapter(struct i2c_adapter *adapter)
{
	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
		return 0;
	return i2c_probe(adapter, &addr_data, ds1307_detect);
}

static int __devexit ds1307_detach_client(struct i2c_client *client)
{
	int		err;
	struct ds1307	*ds1307 = i2c_get_clientdata(client);

	rtc_device_unregister(ds1307->rtc);
	if ((err = i2c_detach_client(client)))
		return err;
	kfree(ds1307);
	return 0;
}

static struct i2c_driver ds1307_driver = {
	.driver = {
		.name	= "ds1307",
		.owner	= THIS_MODULE,
	},
	.attach_adapter	= ds1307_attach_adapter,
	.detach_client	= __devexit_p(ds1307_detach_client),
};

static int __init ds1307_init(void)
{
	return i2c_add_driver(&ds1307_driver);
}
module_init(ds1307_init);

static void __exit ds1307_exit(void)
{
	i2c_del_driver(&ds1307_driver);
}
module_exit(ds1307_exit);

MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
MODULE_LICENSE("GPL");
Commit	Line	Data
1abb0dc9 DB	1	/*
	2	* rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
	3	*
	4	* Copyright (C) 2005 James Chapman (ds1337 core)
	5	* Copyright (C) 2006 David Brownell
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/init.h>
	14	#include <linux/slab.h>
	15	#include <linux/i2c.h>
	16	#include <linux/string.h>
	17	#include <linux/rtc.h>
	18	#include <linux/bcd.h>
	19
	20
	21
	22	/* We can't determine type by probing, but if we expect pre-Linux code
	23	* to have set the chip up as a clock (turning on the oscillator and
	24	* setting the date and time), Linux can ignore the non-clock features.
	25	* That's a natural job for a factory or repair bench.
	26	*
045e0e85 DB	27	* This is currently a simple no-alarms driver. If your board has the
	28	* alarm irq wired up on a ds1337 or ds1339, and you want to use that,
	29	* then look at the rtc-rs5c372 driver for code to steal...
	30	*
1abb0dc9 DB	31	* If the I2C "force" mechanism is used, we assume the chip is a ds1337.
	32	* (Much better would be board-specific tables of I2C devices, along with
	33	* the platform_data drivers would use to sort such issues out.)
	34	*/
	35	enum ds_type {
	36	unknown = 0,
045e0e85 DB	37	ds_1307,
	38	ds_1337,
	39	ds_1338,
	40	ds_1339,
	41	ds_1340,
	42	m41t00,
1abb0dc9 DB	43	// rs5c372 too? different address...
	44	};
	45
	46	static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
	47
	48	I2C_CLIENT_INSMOD;
	49
	50
	51
	52	/* RTC registers don't differ much, except for the century flag */
	53	#define DS1307_REG_SECS 0x00 /* 00-59 */
	54	# define DS1307_BIT_CH 0x80
be5f59f4	55	# define DS1340_BIT_nEOSC 0x80
1abb0dc9 DB	56	#define DS1307_REG_MIN 0x01 /* 00-59 */
	57	#define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
	58	# define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */
	59	# define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */
	60	#define DS1307_REG_WDAY 0x03 /* 01-07 */
	61	#define DS1307_REG_MDAY 0x04 /* 01-31 */
	62	#define DS1307_REG_MONTH 0x05 /* 01-12 */
	63	# define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */
	64	#define DS1307_REG_YEAR 0x06 /* 00-99 */
	65
	66	/* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
045e0e85 DB	67	* start at 7, and they differ a LOT. Only control and status matter for
045e0e85 DB	68	* basic RTC date and time functionality; be careful using them.
1abb0dc9	69	*/
045e0e85	70	#define DS1307_REG_CONTROL 0x07 /* or ds1338 */
1abb0dc9	71	# define DS1307_BIT_OUT 0x80
be5f59f4	72	# define DS1338_BIT_OSF 0x20
1abb0dc9 DB	73	# define DS1307_BIT_SQWE 0x10
	74	# define DS1307_BIT_RS1 0x02
	75	# define DS1307_BIT_RS0 0x01
	76	#define DS1337_REG_CONTROL 0x0e
	77	# define DS1337_BIT_nEOSC 0x80
	78	# define DS1337_BIT_RS2 0x10
	79	# define DS1337_BIT_RS1 0x08
	80	# define DS1337_BIT_INTCN 0x04
	81	# define DS1337_BIT_A2IE 0x02
	82	# define DS1337_BIT_A1IE 0x01
045e0e85 DB	83	#define DS1340_REG_CONTROL 0x07
	84	# define DS1340_BIT_OUT 0x80
	85	# define DS1340_BIT_FT 0x40
	86	# define DS1340_BIT_CALIB_SIGN 0x20
	87	# define DS1340_M_CALIBRATION 0x1f
be5f59f4 RG	88	#define DS1340_REG_FLAG 0x09
be5f59f4 RG	89	# define DS1340_BIT_OSF 0x80
1abb0dc9 DB	90	#define DS1337_REG_STATUS 0x0f
	91	# define DS1337_BIT_OSF 0x80
	92	# define DS1337_BIT_A2I 0x02
	93	# define DS1337_BIT_A1I 0x01
	94	#define DS1339_REG_TRICKLE 0x10
	95
	96
	97
	98	struct ds1307 {
	99	u8 reg_addr;
	100	u8 regs[8];
	101	enum ds_type type;
	102	struct i2c_msg msg[2];
045e0e85 DB	103	struct i2c_client *client;
045e0e85 DB	104	struct i2c_client dev;
1abb0dc9 DB	105	struct rtc_device *rtc;
	106	};
	107
045e0e85 DB	108	struct chip_desc {
	109	char name[9];
	110	unsigned nvram56:1;
	111	unsigned alarm:1;
	112	enum ds_type type;
	113	};
	114
	115	static const struct chip_desc chips[] = { {
	116	.name = "ds1307",
	117	.type = ds_1307,
	118	.nvram56 = 1,
	119	}, {
	120	.name = "ds1337",
	121	.type = ds_1337,
	122	.alarm = 1,
	123	}, {
	124	.name = "ds1338",
	125	.type = ds_1338,
	126	.nvram56 = 1,
	127	}, {
	128	.name = "ds1339",
	129	.type = ds_1339,
	130	.alarm = 1,
	131	}, {
	132	.name = "ds1340",
	133	.type = ds_1340,
	134	}, {
	135	.name = "m41t00",
	136	.type = m41t00,
	137	}, };
	138
	139	static inline const struct chip_desc find_chip(const char s)
	140	{
	141	unsigned i;
	142
	143	for (i = 0; i < ARRAY_SIZE(chips); i++)
	144	if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
	145	return &chips[i];
	146	return NULL;
	147	}
1abb0dc9 DB	148
	149	static int ds1307_get_time(struct device dev, struct rtc_time t)
	150	{
	151	struct ds1307 *ds1307 = dev_get_drvdata(dev);
	152	int tmp;
	153
045e0e85	154	/* read the RTC date and time registers all at once */
1abb0dc9 DB	155	ds1307->msg[1].flags = I2C_M_RD;
	156	ds1307->msg[1].len = 7;
	157
045e0e85 DB	158	tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
045e0e85 DB	159	ds1307->msg, 2);
1abb0dc9 DB	160	if (tmp != 2) {
	161	dev_err(dev, "%s error %d\n", "read", tmp);
	162	return -EIO;
	163	}
	164
	165	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
	166	"read",
	167	ds1307->regs[0], ds1307->regs[1],
	168	ds1307->regs[2], ds1307->regs[3],
	169	ds1307->regs[4], ds1307->regs[5],
	170	ds1307->regs[6]);
	171
	172	t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
	173	t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
	174	tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
	175	t->tm_hour = BCD2BIN(tmp);
	176	t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
	177	t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	178	tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
	179	t->tm_mon = BCD2BIN(tmp) - 1;
	180
	181	/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
	182	t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;
	183
	184	dev_dbg(dev, "%s secs=%d, mins=%d, "
	185	"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
	186	"read", t->tm_sec, t->tm_min,
	187	t->tm_hour, t->tm_mday,
	188	t->tm_mon, t->tm_year, t->tm_wday);
	189
045e0e85 DB	190	/* initial clock setting can be undefined */
045e0e85 DB	191	return rtc_valid_tm(t);
1abb0dc9 DB	192	}
	193
	194	static int ds1307_set_time(struct device dev, struct rtc_time t)
	195	{
	196	struct ds1307 *ds1307 = dev_get_drvdata(dev);
	197	int result;
	198	int tmp;
	199	u8 *buf = ds1307->regs;
	200
	201	dev_dbg(dev, "%s secs=%d, mins=%d, "
	202	"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
11966adc JG	203	"write", t->tm_sec, t->tm_min,
	204	t->tm_hour, t->tm_mday,
	205	t->tm_mon, t->tm_year, t->tm_wday);
1abb0dc9 DB	206
	207	buf++ = 0; / first register addr */
	208	buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
	209	buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
	210	buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
	211	buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
	212	buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
	213	buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);
	214
	215	/* assume 20YY not 19YY */
	216	tmp = t->tm_year - 100;
	217	buf[DS1307_REG_YEAR] = BIN2BCD(tmp);
	218
be5f59f4 RG	219	switch (ds1307->type) {
	220	case ds_1337:
	221	case ds_1339:
1abb0dc9	222	buf[DS1307_REG_MONTH] \|= DS1337_BIT_CENTURY;
be5f59f4 RG	223	break;
be5f59f4 RG	224	case ds_1340:
1abb0dc9 DB	225	buf[DS1307_REG_HOUR] \|= DS1340_BIT_CENTURY_EN
1abb0dc9 DB	226	\| DS1340_BIT_CENTURY;
be5f59f4 RG	227	break;
	228	default:
	229	break;
	230	}
1abb0dc9 DB	231
	232	ds1307->msg[1].flags = 0;
	233	ds1307->msg[1].len = 8;
	234
	235	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
	236	"write", buf[0], buf[1], buf[2], buf[3],
	237	buf[4], buf[5], buf[6]);
	238
045e0e85 DB	239	result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
045e0e85 DB	240	&ds1307->msg[1], 1);
1abb0dc9 DB	241	if (result != 1) {
	242	dev_err(dev, "%s error %d\n", "write", tmp);
	243	return -EIO;
	244	}
	245	return 0;
	246	}
	247
ff8371ac	248	static const struct rtc_class_ops ds13xx_rtc_ops = {
1abb0dc9 DB	249	.read_time = ds1307_get_time,
	250	.set_time = ds1307_set_time,
	251	};
	252
	253	static struct i2c_driver ds1307_driver;
	254
	255	static int __devinit
	256	ds1307_detect(struct i2c_adapter *adapter, int address, int kind)
	257	{
	258	struct ds1307 *ds1307;
	259	int err = -ENODEV;
	260	struct i2c_client *client;
	261	int tmp;
045e0e85	262	const struct chip_desc *chip;
1abb0dc9 DB	263
	264	if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) {
	265	err = -ENOMEM;
	266	goto exit;
	267	}
	268
045e0e85 DB	269	/* REVISIT: pending driver model conversion, set up "client"
	270	* ourselves, and use a hack to determine the RTC type (instead
	271	* of reading the client->name we're given)
	272	*/
	273	client = &ds1307->dev;
1abb0dc9 DB	274	client->addr = address;
	275	client->adapter = adapter;
	276	client->driver = &ds1307_driver;
1abb0dc9	277
045e0e85 DB	278	/* HACK: "force" implies "needs ds1337-style-oscillator setup", and
	279	* that's the only kind of chip setup we'll know about. Until the
	280	* driver model conversion, here's where to add any board-specific
	281	* code to say what kind of chip is present...
	282	*/
	283	if (kind >= 0)
	284	chip = find_chip("ds1337");
	285	else
	286	chip = find_chip("ds1307");
	287	strlcpy(client->name, chip->name, I2C_NAME_SIZE);
	288
	289	ds1307->client = client;
1abb0dc9 DB	290	i2c_set_clientdata(client, ds1307);
	291
	292	ds1307->msg[0].addr = client->addr;
	293	ds1307->msg[0].flags = 0;
	294	ds1307->msg[0].len = 1;
	295	ds1307->msg[0].buf = &ds1307->reg_addr;
	296
	297	ds1307->msg[1].addr = client->addr;
	298	ds1307->msg[1].flags = I2C_M_RD;
	299	ds1307->msg[1].len = sizeof(ds1307->regs);
	300	ds1307->msg[1].buf = ds1307->regs;
	301
045e0e85 DB	302	ds1307->type = chip->type;
	303
	304	switch (ds1307->type) {
	305	case ds_1337:
	306	case ds_1339:
1abb0dc9 DB	307	ds1307->reg_addr = DS1337_REG_CONTROL;
	308	ds1307->msg[1].len = 2;
	309
be5f59f4	310	/* get registers that the "rtc" read below won't read... */
045e0e85	311	tmp = i2c_transfer(adapter, ds1307->msg, 2);
1abb0dc9 DB	312	if (tmp != 2) {
	313	pr_debug("read error %d\n", tmp);
	314	err = -EIO;
	315	goto exit_free;
	316	}
	317
	318	ds1307->reg_addr = 0;
	319	ds1307->msg[1].len = sizeof(ds1307->regs);
	320
be5f59f4 RG	321	/* oscillator off? turn it on, so clock can tick. */
	322	if (ds1307->regs[0] & DS1337_BIT_nEOSC)
	323	i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
	324	ds1307->regs[0] & ~DS1337_BIT_nEOSC);
	325
	326	/* oscillator fault? clear flag, and warn */
	327	if (ds1307->regs[1] & DS1337_BIT_OSF) {
	328	i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
	329	ds1307->regs[1] & ~DS1337_BIT_OSF);
	330	dev_warn(&client->dev, "SET TIME!\n");
1abb0dc9	331	}
045e0e85 DB	332	break;
	333	default:
	334	break;
	335	}
1abb0dc9 DB	336
	337	read_rtc:
	338	/* read RTC registers */
	339
045e0e85	340	tmp = i2c_transfer(adapter, ds1307->msg, 2);
1abb0dc9 DB	341	if (tmp != 2) {
	342	pr_debug("read error %d\n", tmp);
	343	err = -EIO;
	344	goto exit_free;
	345	}
	346
	347	/* minimal sanity checking; some chips (like DS1340) don't
	348	* specify the extra bits as must-be-zero, but there are
	349	* still a few values that are clearly out-of-range.
	350	*/
	351	tmp = ds1307->regs[DS1307_REG_SECS];
045e0e85	352	switch (ds1307->type) {
be5f59f4 RG	353	case ds_1340:
	354	/* FIXME read register with DS1340_BIT_OSF, use that to
	355	* trigger the "set time" warning (after restarting the
	356	* oscillator!) instead of this weaker ds1307/m41t00 test.
	357	*/
045e0e85	358	case ds_1307:
045e0e85	359	case m41t00:
be5f59f4	360	/* clock halted? turn it on, so clock can tick. */
045e0e85	361	if (tmp & DS1307_BIT_CH) {
be5f59f4 RG	362	i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
be5f59f4 RG	363	dev_warn(&client->dev, "SET TIME!\n");
045e0e85	364	goto read_rtc;
1abb0dc9	365	}
045e0e85	366	break;
be5f59f4 RG	367	case ds_1338:
be5f59f4 RG	368	/* clock halted? turn it on, so clock can tick. */
045e0e85	369	if (tmp & DS1307_BIT_CH)
be5f59f4 RG	370	i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
	371
	372	/* oscillator fault? clear flag, and warn */
	373	if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
	374	i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
	375	ds1307->regs[DS1337_REG_CONTROL]
	376	& ~DS1338_BIT_OSF);
	377	dev_warn(&client->dev, "SET TIME!\n");
	378	goto read_rtc;
	379	}
045e0e85 DB	380	break;
	381	default:
	382	break;
1abb0dc9	383	}
045e0e85 DB	384
045e0e85 DB	385	tmp = ds1307->regs[DS1307_REG_SECS];
1abb0dc9 DB	386	tmp = BCD2BIN(tmp & 0x7f);
	387	if (tmp > 60)
	388	goto exit_free;
	389	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
	390	if (tmp > 60)
	391	goto exit_free;
	392
	393	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	394	if (tmp == 0 \|\| tmp > 31)
	395	goto exit_free;
	396
	397	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
	398	if (tmp == 0 \|\| tmp > 12)
	399	goto exit_free;
	400
	401	/* force into in 24 hour mode (most chips) or
	402	* disable century bit (ds1340)
045e0e85 DB	403	*
	404	* REVISIT forcing 24 hour mode can prevent multi-master
	405	* configs from sharing this RTC ... don't do this.
be5f59f4	406	* The clock needs to be reset after changing it, too...
1abb0dc9 DB	407	*/
	408	tmp = ds1307->regs[DS1307_REG_HOUR];
	409	if (tmp & (1 << 6)) {
	410	if (tmp & (1 << 5))
	411	tmp = BCD2BIN(tmp & 0x1f) + 12;
	412	else
	413	tmp = BCD2BIN(tmp);
	414	i2c_smbus_write_byte_data(client,
	415	DS1307_REG_HOUR,
	416	BIN2BCD(tmp));
	417	}
	418
1abb0dc9 DB	419	/* Tell the I2C layer a new client has arrived */
	420	if ((err = i2c_attach_client(client)))
	421	goto exit_free;
	422
	423	ds1307->rtc = rtc_device_register(client->name, &client->dev,
	424	&ds13xx_rtc_ops, THIS_MODULE);
	425	if (IS_ERR(ds1307->rtc)) {
	426	err = PTR_ERR(ds1307->rtc);
	427	dev_err(&client->dev,
	428	"unable to register the class device\n");
	429	goto exit_detach;
	430	}
	431
	432	return 0;
	433
	434	exit_detach:
	435	i2c_detach_client(client);
	436	exit_free:
	437	kfree(ds1307);
	438	exit:
	439	return err;
	440	}
	441
	442	static int __devinit
	443	ds1307_attach_adapter(struct i2c_adapter *adapter)
	444	{
	445	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))
	446	return 0;
	447	return i2c_probe(adapter, &addr_data, ds1307_detect);
	448	}
	449
	450	static int __devexit ds1307_detach_client(struct i2c_client *client)
	451	{
	452	int err;
	453	struct ds1307 *ds1307 = i2c_get_clientdata(client);
	454
	455	rtc_device_unregister(ds1307->rtc);
	456	if ((err = i2c_detach_client(client)))
	457	return err;
	458	kfree(ds1307);
	459	return 0;
	460	}
	461
	462	static struct i2c_driver ds1307_driver = {
	463	.driver = {
	464	.name = "ds1307",
	465	.owner = THIS_MODULE,
	466	},
	467	.attach_adapter = ds1307_attach_adapter,
	468	.detach_client = __devexit_p(ds1307_detach_client),
	469	};
	470
	471	static int __init ds1307_init(void)
	472	{
	473	return i2c_add_driver(&ds1307_driver);
	474	}
	475	module_init(ds1307_init);
	476
	477	static void __exit ds1307_exit(void)
	478	{
	479	i2c_del_driver(&ds1307_driver);
	480	}
	481	module_exit(ds1307_exit);
	482
483	MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
484	MODULE_LICENSE("GPL");